Author's personal copy ARTICLE IN PRESS Deep-Sea Research II 56 (2009) 1775–1803 Contents lists available at ScienceDirect Deep-Sea Research II journal homepage: www.elsevier.com/locate/dsr2 Long-term benthic infaunal monitoring at a deep-ocean dredged material disposal site off Northern California James A. Blake a,, Nancy J. Maciolek a, Allan Y. Ota b, Isabelle P. Williams a a b Marine and Coastal Center, AECOM Environment, 89 Water Street, Woods Hole, MA 02543, USA United States Environmental Protection Agency, Region 9, 75 Hawthorne Street, San Francisco, CA 94105, USA a r t i c l e in fo abstract Available online 29 May 2009 One hundred and thirty-five benthic infaunal samples were collected from the San Francisco DeepOcean Disposal Site (SF-DODS) over a 10-year period from January 1996 to September 2004. Each sample was 0.1 m2, cut to a depth of 10 cm, and sieved through a 300-mm mesh. A total of 810 species of benthic invertebrates were identified; the majority of taxa (65.4%) new to science. The fauna represents a rich lower slope infaunal assemblage that rivals similarly studied locations in the western North Atlantic. No regional impact or degradation of benthic infauna due to dredged material disposal was detected. All reference stations and stations on the site boundary maintained high species richness and diversity during the monitoring period. Exceptions included an occasional sample with anomalously high numbers of one or two species that reduced the diversity and/or equitability. Within SF-DODS species richness and diversity were often reduced. Stations within the disposal site were recolonized by the same taxa that normally occurred in adjacent reference areas. Initial colonizers of fresh dredged material included spionid and paraonid polychaetes that were typical dominants at the site. At least one polychaete species, Ophelina sp. 1, sometimes colonized dredged materials containing coarse sand. One sample at Station 13, located in the middle of SF-DODS (September 2002), contained 57 species of benthic invertebrates, suggesting that colonization of fresh dredged material is rapid. It seems unlikely that larval dispersal and settlement account for this rapid recolonization; therefore it is postulated that adult organisms from adjacent areas move to the disturbed sites via boundary layer currents. The steep continental slope adjacent to SF-DODS is subject to turbidity flows and the resident fauna are likely preadapted to rapidly colonize disturbed sediments. Larval dispersal, especially by spionid polychaetes such as Prionospio delta, may also be important in colonizing newly deposited sediments. Subtle year-toyear shifts in faunal assemblages were evident at stations on the boundary of SF-DODS. At these stations species richness and diversity remained high, but numerically dominant taxa differed, possibly due to changes in sediment grain size associated with the dredged material. However, some year-to-year changes appeared to be regional in nature. Large epifaunal organisms such as the elasapoid holothurian Scotoplanes globosa appeared to be locally important in modifying surficial sediments: it moves through the sediment like a bulldozer, disturbing the surface and disrupting resident infauna as it ingests sediment. Other deposit-feeding holothurians such as Ypsilothuria bitentaculata were found throughout the study area including sediments with fresh dredged material. A long, narrow-bodied tube-like agglutinated foraminiferan of the genus Bathysiphon is commonly found in sediments containing dredged material. This foraminiferan is poorly understood, but may be opportunistic on soft dredged material. & 2009 Elsevier Ltd. All rights reserved. Keywords: Benthic infauna Biodiversity Species richness Community structure Disposal site Monitoring Eastern Pacific Deep sea 1. Introduction The understanding of biological processes and biodiversity in the deep sea is greatly hindered by the expense of collecting and processing samples from deep-water sediments and the limited availability of the expertise needed to identify the organisms in  Corresponding author. Tel.: +1 508 457 7900; fax: +1 508 457 7595. E-mail address: James.Blake@aecom.com (J.A. Blake). 0967-0645/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.dsr2.2009.05.021 such samples. The programs carried out in the early 1980s on the Atlantic Continental Slope and Rise (ACSAR) on the east coast of the United States represents the largest and most consistent effort to date (Gage and Tyler, 1991; Maciolek and Smith, 2009). As part of that program, 0.25-m2 box core samples were collected in three study areas: 190 samples from the north (250–2100 m); 233 from the mid (1400–2500 m), and 150 from the south (580–3500 m) study areas (Grassle and Maciolek, 1992; Blake and Grassle, 1994). On the United States Pacific coast, a comparable program was carried out in shelf and upper slope depths off southern California Author's personal copy ARTICLE IN PRESS 1776 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 (230 samples from 90 to 565 m) (Hyland et al., 1991; Blake, 1993), but apart from studies of seeps and vents, only limited studies have been carried out on middle and lower slope depths. Among these were baseline transects sampled in 1990 and 1991 by the US Navy (USN) and the US Environmental Protection Agency (USEPA) in a study to identify deep-water disposal sites off San Francisco (64 samples from 500 to 3000 m) (Blake et al., 1992, 1994; Hilbig and Blake, 2006). Despite only limited understanding of ocean processes, dumping of various materials including radioactive and other hazardous wastes; sewage, both raw and treated to varying degrees; and dredged material was allowed by the United States for several decades. In response to concerns about the effects of pollutants entering the oceans, legislation was enacted beginning in the early 1970s, most notably the Marine Protection, Resources and Sanctuaries Act (MPRSA) of 1972, which was amended by the Ocean Dumping Ban Act in 1988. Under this legislation, the USEPA can set the conditions and issue permits for ocean disposal of dredged material that is generated during projects conducted by the US Army Corps of Engineers (USACE). The San Francisco DeepOcean Disposal Site (SF-DODS), on the lower continental slope off the coast of California, is managed jointly by the USEPA and the USACE under regulations included in MPRSA, 33 USC Sections 1401 et. seq. and the USEPA Ocean Dumping Regulations (40 CFR 228.5 and 228.6(a)). As part of the management of SF-DODS, annual surveys are made to monitor benthic conditions, including the status of the infaunal community. Benthic monitoring includes the collection of (1) sediment profile images (SPI) to map the depth of dredged material and the extent of the dredged material footprint; and (2) the collection of sediment by means of a Sandia box core for analysis of sediment chemistry, total organic carbon, sediment grain-size, and benthic biology. Dredged material disposal began in 1995 and the first monitoring survey was conducted in January 1996. With the exception of the second survey, which was in December 1996, and the most recent survey in July 2008, the annual surveys have usually been in September or October of each year. This paper synthesizes the results of 10 years of benthic monitoring (1996–2004), with emphasis on infaunal stations sampled every year; minimal information developed from SPI images is included. Benthic community structure, diversity, and species richness patterns at 2160–3142 m off the California coast are described based on results from 135 0.25-m2 box core samples. This paper represents the first effort to describe the impacts of a large anthropogenic disturbance on a deep-sea benthic habitat. 1.1. Site selection and historical use The SF-DODS is located within Study Area 5, an area of historical ocean disposal (Fig. 1) that was identified as the preferred alternative for an ocean disposal site (USEPA 1993) because it met the general and site-specific criteria listed in the Ocean Dumping Regulations. Study Area 5 and the surrounding region had been used as a chemical and conventional munitions disposal area (CMDA) and as a depository for low-level radioactive waste. From 1951 to 1954, sealed containers of low-level radioactive wastes from defense-related, commercial, and laboratory activities were dumped in the general area, particularly the SE corner. From approximately 1958 to the late 1960s, the USN disposed chemical and conventional munitions in the northern portion of the study area. In August 1990 and July 1991, environmental studies were conducted at the CDMA by the USN as part of the MPRSA Section 103 ocean dredged material disposal site (ODMDS) designation process specifically for a US Navy dredging project (SAIC, 1991; Blake et al., 1992). Baseline investigations included studies of benthic infauna, sediment characteristics, and chemical constituents using samples taken with a box core and SPI. Megafaunal organisms were observed from photographs taken with towed camera sleds and from specimens collected with trawls (Hecker, 1992). Biological communities were rich and diverse and chemical constituents were not elevated but were within the range of ambient deep-sea sediments (Blake et al., 1992, 1994). The baseline studies were also used by the USEPA as part of their evaluation of Study Area 5, which eventually became the SF-DODS. Dispersion models used to predict the deposition patterns of dredged materials were also used to define the final size and location of the site (Courtney et al., 1994). The designated site is located in the SW corner of the CMDA, and the Navy ODMDS is located within the SF-DODS (Fig. 1). The USN applied for and received a Section 103 ocean disposal permit and disposed approximately 1.2 million yd s3 of dredged material at the ODMDS between May and December 1993. Dredged material disposal at the SF-DODS began in the fall of 1995 following permanent site designation in the Federal Register and implementation of the Site Management and Monitoring Plan (SMMP) (USEPA 1994, 1998). Dredged material volumes disposed at SF-DODS from 1996 to 2004 ranged from a low of 178,000 yds3 in 1995 to a high of 3,370,765 yds3 in 1997; the following year 1998 was the second highest disposal year with 2,120,140 yds3 of dredged material (Table 1). Fig. 1. Historical ocean disposal sites used by the US Navy relative to location of SF-DODS. Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table 1 Volume of dredged material disposed at SF-DODS, 1996–2004. Year Volume (cubic yards) 1996 (Jan) 1996 (Dec) 1997 1998 1999 2000 2001 2002 2003 2004 178,000 746,000 3,370,765 2,120,149 309,189 402,390 766,037 721,890 1,198,732 316,247 2. Methods 1777 damage to the delicate organisms that live in the top 2–3 cm. The lower compacted portion was then gently washed through a 300mm-mesh sieve and preserved. For samples where the sediment was heavy and there was no flocculent layer, all of the sediment was sieved. Samples were transferred to 80% ethanol as soon as possible after the survey. Five replicate SPI images were collected at each station using a Benthos Model 3731 sediment profile system initially equipped with an Olympus 35-mm camera; later a Nikon digital camera was used with a similar system. Film was developed immediately after collection and later digitized; digital images were downloaded after sampling. During each survey, preliminary estimates of dredged material thickness were determined and site maps established. This on-site assessment of dredged material distribution and thickness was used to locate additional SPI stations during the survey. 2.1. Station location and rationale 2.3. Laboratory methods The initial benthic sampling design was focused on potential site-specific and nearfield impacts of dredged material. Therefore, the stations were mostly within and adjacent to the disposal site boundaries, with relatively few reference stations. This array provided information on the accumulation of dredged material near the borders of the disposal site as well as nearfield chemical signatures. However, in 1999, the emphasis shifted to evaluating impacts outside the site boundary where thin layers and finer grained dredged material had been detected. Stations within the site were mostly abandoned, although stations on the boundary of the site were retained, and additional reference stations were established at greater distances from the site to identify the limit of any dredged material deposits and determine any potential impacts at those farfield locations. During this transition, several stations that had been sampled sequentially early in the program (3, 7, 9, 11, 13, 14, 18, and 23) were dropped in favor of stations at greater distances from the site. Further, with the accumulation of dredged material within the site, it became increasingly more difficult to collect sediment from within-site locations. To replace these stations, others in more strategic locations were added (6, 20, 27, and 57) and sampled annually; some stations were sampled in single years and then dropped (e.g., 26, 33, 50). The final design was established in 2002: Station 23 was reestablished and new farfield reference Stations 64, 92, 114, and 116 were added. Station 108 was added in 2003. Station 17 is the only station to be sampled during all ten surveys. A total of 135 benthic biology samples were collected during the 10 years of sampling. Stations that were sampled are shown in Fig. 2. The details of each station, including coordinates, depth, and years sampled are given in Appendix A. 2.2. Field sampling and processing methods Single sediment samples were collected at each station with a 0.25-m2 Sandia box core fitted with a ‘‘vegematic’’ insert that divided the sample into 25 subcores (10 cm  10 cm  50 cm), each with a surface area of 0.01 m2. Ten individual subcores were designated for infaunal biology and others were used for sediment grain-size and sediment chemistry analysis. The surface of each sample was examined for evidence of disturbance, sediment color, and any interesting or unusual biological or physical features. The top 10 cm of individual subcores were removed by slicing the sediment with a stainless-steel cutting blade at the bottom of a specially designed core cutter. In most cases, the upper flocculent portion was rinsed directly into a prelabeled 32-oz plastic jar and preserved in 10% buffered formalin. This procedure avoided excess After sorting, all specimens were identified to the lowest possible taxonomic category, usually species. Organisms such as planktic fauna and colonial epifauna were not included in the raw data. Infaunal taxa such as juveniles and indeterminate specimens that could not be identified to the species level, as well as epifauna, shell-borers and parasites were not included in community parameters except total density. The aplacophoran group Chaetodermamorpha was identified to species only in 2004; therefore the counts for this taxon were combined in calculations of community parameters. Taxonomists identifying the organisms are acknowledged by name at the end of this paper. Using image analyzing software, a minimum of three SPI images per station were analyzed for dredged material distribution and depth, sediment grain size (major mode and range), optical prism penetration depth, surface boundary roughness, mud clasts, depth of the apparent Redox Potential Discontinuity (aRPD), and the infaunal successional stage. Additional parameters included presence/absence of oxic voids, numbers of tubes, relative density of infauna, presence/absence of bedforms, and inferred source of these bedforms (physical vs. biogenic). These data provide considerable insight on the near-surface geology and degree of bioturbation. For this paper, only limited SPI data are presented in order to support the biological results. 2.4. Data analysis The PRIMER package of statistical routines was used to calculate several diversity indices, including Shannon’s H0 (base 2), Pielou’s evenness (J0 ), and Fisher’s alpha (Clarke and Gorley, 2001). The rarefaction (ESn) method (Sanders, 1968) as modified by Hurlbert (1971) was used to generate curves for each replicate sample, with the number of points set at 25, from 2 to the maximal number of specimens in the sample. Similarity patterns among stations were analyzed using COMPAH, a software package distributed by Dr. E.D. Gallagher, University of Massachusetts, Boston, http://alpha.es.umb.edu/ faculty/edg/files/edgwebp.htm. The similarity measure used was chord-normalized expected species shared (CNESS). Normalized expected species shared (NESS) was originally developed for analysis of deep-sea benthic communities (Grassle and Smith, 1976); CNESS is a version developed by Gallagher (Trueblood et al., 1994; Snelgrove et al., 2001). CNESS is more sensitive to rare species in the community and more versatile than other similarity measures such as Bray–Curtis, which is influenced by dominant species. CNESS is calculated from the expected species shared (ESS) between two random draws of m individuals from two Author's personal copy ARTICLE IN PRESS 1778 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Fig. 2. Stations (squares) sampled for benthic infauna at SF-DODS (January 1996–2004). samples, and has a maximum value of O2 (1.41). Results of these analyses were inspected for patterns among stations and between years. Principal components analysis of hypergeometric probabilities (PCA-H) was also applied to the benthic data. This method produces a metric scaling of the samples in multidimensional space, as well as two types of plots based on Gabriel (1971). A Gabriel Euclidean distance biplot can be overlaid on the metric scaling plot to provide a two-dimensional projection of those species that are the major sources of the CNESS variation. The species that contribute to this variation are determined using matrix methods adapted from Greenacre’s correspondence analysis (Greenacre, 1984), where the length and direction of species vectors are proportional to the CNESS variation attributable to that species. The multidimensional nature of these analyses typically results in axes 1 and 2 accounting for the greatest variation in the results. Therefore, only these two axes are presented graphically. Gallagher and Grassle (1997) discussed the relationship between rarefaction curves and the expected log-series curve for single samples. Gallagher later developed a method termed ‘‘nondimensional diversity’’ (NDD) in which the curve generated for Fisher’s alpha is compared with the one generated by the Hurlbert rarefaction method. Gallagher suggested that a NDD value of 0.75 or more (in either direction) serves as a benchmark to indicate severe departure from an undisturbed community (E.D. Gallagher, personal communication). The null hypothesis that there was no departure of NDD in the vicinity of disposal site boundaries was tested in this study. 3. Results 3.1. Sedimentary parameters and dredged material thickness from SPI Sedimentary parameters relevant to interpreting the biological results include sediment grain size and total organic carbon taken from the box cores and dredged material thickness and depth of the apparent redox potential discontinuity (RPD) estimated from the sediment profile images. In some years, SPI images were not collected when sediment was taken from box cores and vice versa. The most consistent sedimentary data was collected at Stations 6, 10, 17, and 19. Station 17, on the eastern boundary of the site, showed a decline in the silt+clay or mud fraction from January 1996 through 1998–1999 (Fig. 3). The increase in the sand fraction was very evident during that period as a distinct grit that affected sample Author's personal copy ARTICLE IN PRESS 1779 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 processing by clogging the core cutters and sieves. Stations located about 1 mi E of the site also showed an increase in sand during that same period. Station 10, 1 mi W of the site, did not exhibit the same decline in silt+clay. Total organic carbon (TOC) was highest in samples with high silt+clay content, e.g., Stations 6, 10, and 17 (Fig. 3). Dredged material thickness has been mapped from SPI data since 1996 (Figs. 3 and 4). Early in the program there was a distinct drift of particles resulting in trace amounts of accumulation up to 7 mi NW of the site; this trend followed early model predictions (Courtney et al., 1994). By 1999, probably as a result of the large-scale disposals in 1997 and 1998, significant accumulations 45 cm, the depth that would trigger additional monitoring, were observed outside the site boundaries and some accumulation was also observed to the S and SE of the site. Although long-term accumulation of dredged material had been observed outside the site boundaries, infaunal successional data recorded from SPI images suggested that benthic infauna were present at nearly all locations. Station 16, which had 414 cm dredged material accumulation in October 2000 (Fig. 4), did not have any evidence of large, deep-burrowing organisms; in October 2001, however these same sediments were well colonized by burrowers and oxic voids were clearly evident. These results suggest that infaunal recolonization of sediment receiving dredged material in these continental slope sediments is rapid. 3.2. Benthic community structure (1996–2004) 3.2.1. Species composition A total of 810 invertebrate species in 11 phyla were identified from the 135 box core samples taken from December 1996 through September 2004 (Table 2; Appendix B). The Polychaeta accounted for nearly half of the species (45.9%) and included 372 species in 45 families. The most speciose family was the Paraonidae with 38 species representing five genera; onehalf of the paraonid species (19) were members of the genus Aricidea. Other polychaete families having numerous species included the Dorvilleidae (30 species), Spionidae (26 species), Ampharetidae (25 species), Cirratulidae (25 species), Maldanidae (19 species), Phyllodocidae (17 species), Sphaerodoridae (17 species), Capitellidae (16 species), Terebellidae (15 species), Lumbrineridae (14 species), and Hesionidae (14 species). The Crustacea (271 species) was the second largest component of the infauna, accounting for 33.5% of the recorded invertebrate 2.5 80 70 2 60 50 1.5 40 1 30 20 0.5 10 0 0 Dec96 1997 1998 1999 2000 2001 2002 90 2.5 80 70 2 60 1.5 50 40 1 30 20 0.5 10 0 0 2003 Jan96 Dec96 1997 1998 2001 2002 DM thickness (mm) RPD Average (mm) DM thickness (mm) RPD Average (cm) Silt + Clay % TOC % Silt + Clay % TOC % 3 90 2.5 80 70 2 50 1.5 40 1 30 20 0.5 10 0 0 1997 1998 1999 2000 2001 2002 2003 % TOC 60 Dec96 2003 SF-DODS Station 19 100 % silt + clay; DM thickness and Mean RPD Depth (mm) SF-DODS Station 17 % silt + clay; DM thickness and Mean RPD Depth (mm) 2000 Year Year Jan96 1999 4.5 100 90 4 80 3.5 70 3 60 2.5 50 2 40 1.5 30 20 1 10 0.5 0 0 Jan96 Dec96 1997 1998 1999 2000 2001 2002 2003 Year Year DM thickness (mm) RPD Average (mm) DM thickness (mm) RPD Average (mm) Silt + Clay % TOC % Silt + Clay % TOC % Fig. 3. Sedimentary data acquired from box core sediment and sediment profile images for selected stations at SF-DODS: Stations 6, 10, 17, and 19. % TOC Jan96 3 100 % TOC 90 % silt + clay; DM thickness and Mean RPD Depth (mm) SF-DODS Station 10 3 % TOC % silt + clay; DM thickness and Mean RPD Depth (mm) SF-DODS Station 6 100 Author's personal copy ARTICLE IN PRESS 1780 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Fig. 4. Map of dredged material accumulation at SF-DODS in October 2000. Bold numbers indicate thickness in centimeters (from Tetra Tech, 2001). species. The amphipods were the dominant group with a total of 89 species in 19 families. The dominant amphipod families were the Oedicerotidae with 18 species and the Phoxocephalidae with 13 species. The isopods were represented by 80 species in 13 families, of which the Desmosomatidae was the most speciose with 31 species. The tanaidaceans included 60 species belonging to families typical of the deep-sea: Typhlotanaidae (17 species), Pseudotanaidae (8 species), and Anarthruridae (33 species in at least 14 genera and others likely unnamed). The cumaceans with 40 species belonging to five families and the Mysidacea with two species comprised the remainder of the Crustacea. The Mollusca (92 species) accounted for 11.4% of the species recorded. Bivalves (41 species in 14 families) accounted for 44.6% of the molluscs. The most prevalent bivalve family was the common continental slope family, Thyasiridae, with 13 species. The remaining molluscs were the aplacophorans (32 species), gastropods (16 species), and scaphopods (3 species). The echinoderms (30 species) and nemerteans (12 species) each accounted for less than 4% of the total species recorded. The largest echinoderm group was the Holothuroidea with 16 species in six families. The remaining smaller taxa (Cnidaria, Oligochaeta, Pogonophora, Priapulida, Pycnogonida, Hemichordata, Sipuncula, and Echiura) accounted for an additional 33 species. Of the 810 species identified, a total of 520 (64.2%), could not be assigned to any known species and most are believed to be new to science. This total does not include taxa identified as close to (nr. or cf.) already described species, but many of these will probably also prove to be undescribed. About 59% of the polychaetes remain undescribed, including numerous new species in the Ampharetidae, Cirratulidae, Dorvilleidae, Paraonidae, Phyllodocidae, Spionidae, and Trichobranchidae. Of the 271 crustacean taxa, the majority (223 species or 82%) could not be assigned to known species; 90% of the tanaidaceans are undescribed. The bivalve molluscs are much better known and 65% of the taxa could be named; the aplacophorans (32 species) are all new to science. Many of the echinoderms were unidentifiable juveniles and most of the nemerteans were faded and fragmented, making identification to the species level difficult. Nevertheless, deep-water nemerteans are poorly known and the taxa encountered are all likely new to science. 3.2.2. Numerically dominant infaunal species Of the 70,923 individuals and 810 species recorded, only 28 taxa (3.46%) had 500 or more specimens (Table 3).The most abundant taxon was the combined Chaetodermamorpha, the dominant group of aplacophoran mollusks found in the collections. This taxon was identified to species only in the 2004 samples, when 14 species were identified. The remaining 27 taxa included 19 polychaetes, five bivalves, two tanaidaceans, and one Author's personal copy ARTICLE IN PRESS 1781 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table 2 Taxonomic summary of the benthic infauna collected from 135 benthic samples from ten SF-DODS surveys (1996–2004). Phylum Class Total number of speciesa Number unnamed species Percent of entire Fauna by species Cnidaria Nemertea Priapulida Annelida Annelida Annelida Sipuncula Echiura Mollusca Mollusca Mollusca Mollusca Crustacea Crustacea Crustacea Crustacea Crustacea Pycnogonida Echinodermata Echinodermata Echinodermata Echinodermata Hemichordata Anthozoa 6 12 1 372 1 7 4 6 32 41 16 3 89 40 80 2 60 3 1 1 16 12 5 810 2 12 1 220 1 5 3 6 32 14 6 1 62 39 66 2 54 1 0 0 9 3 4 520 0.74 1.48 0.12 45.93 0.12 0.86 0.49 0.74 3.95 5.06 1.98 0.37 10.99 4.94 9.88 0.25 7.41 0.37 0.12 0.12 1.98 1.48 0.62 100.0 Polychaeta Oligochaeta Pogonophorab Aplacophorac Bivalvia Gastropoda Scaphopoda Amphipoda Cumacea Isopoda Mysdidacea Tanaidacea Asteroidea Echinoidea Holothuroidea Ophiuroidea Enteropneusta Total a Named species include those that have been identified as close to or that conform to (nr. or cf.) previously described species. It is likely that many of these taxa will also prove to be unnamed species. b Pogonophora recently have been shown to be polychaetes and placed in the Family Siboglinidae. c Chaetodermamorpha were identified to species only for the 2004 samples. Table 3 Taxa with 500 or more specimens in 135 benthic box cores from the SF-DODS study area (1996–2004). Taxon Total Chaetodermamorpha spp. Levinsenia flava Strelzov, 1973 Aricidea simplex-type 1 Prionospio delta Hartman, 1965 Cossura rostrata Fauchald, 1972 Aricidea sp. 4 Chaetozone brunnea Blake, 2006 Chaetozone allanotai Blake, 2006 Nemertea sp. A (Carinomella) Cossura modica Fauchald & Hancock, 1981 Aricidea sp. 3 Pettiboneia brevipalpa Hilbig & Ruff, 1990 Sphaerosyllis sp. 1 Levinsenia sp. 3 Axinopsida sp. 1 Spiophanes kroyeri Grube, 1860 Chaetozone spinosa (Moore, 1905) Aricidea simplex-type 2 Mendicula ferruginosa (Forbes, 1844) Prionospio fauchaldi Maciolek, 1985 Aricidea sp. 5 Leptaxinus cf. minutus Ophelina abranchiata Støp-Bowitz, 1948 Araphura sp. 2 Ophelina sp. 1 Anarthrurinae sp. 2 Thyasiridae sp. 1 Adontorhina lynnae Coan, Scott & Bernard, 2000 4970 4705 3735 3416 2941 1892 1644 1601 1454 1228 1056 1034 1019 820 807 799 772 752 731 727 678 600 598 580 569 567 549 519 nemertean. The five most abundant polychaetes were Levinsenia flava, Aricidea simplex type 1, Prionospio delta, Cossura rostrata, and Aricidea sp. 4. These polychaetes were typically among the numerically dominant species at individual stations and often characterized certain depth intervals. P. delta appeared to be an early colonizer of sediments in areas of heavy dredged material accumulation. In contrast, the high numbers of Sphaerosyllis sp. 1 were due to 952 specimens in a single sample (Station 19, 2003); this species was otherwise uncommon. Another species with an irregular occurrence was Ophelina sp. 1. This species, with 569 specimens, occurred in 34 of 135 samples, but 432 specimens occurred in only six samples (December 1996: Station 3 [51], Station 12 [93], Station 13 [31], Station 18 [49]; 1997: Station 9 [72]; 1999: Station 17 [136]). The remaining 125 specimens were scattered over 28 samples. Interestingly, this species has been collected only twice since 1999: Station 13 (18 specimens) and Station 50 (1 specimen), both in 2002. The densest populations of Ophelina sp. 1 were at stations either within or on the boundary of SF-DODS. It is possible that this species is opportunistic in sediments that receive dredged material; if so, it appears to be the only species thus identified. 3.2.3. Infaunal density, species richness, diversity, and evenness The number of benthic organisms at any one station ranged from a low of 15 individuals 0.1 m2 recorded at Station 13 in the middle of the disposal site in 1998 to a high of 1280 individuals 0.1 m2 recorded at Station 19 on SW boundary of the site in 2003 (Appendix C). When averaged over the entire 135 samples, total infaunal density was approximately 500 individuals 0.1 m2. Apart from Stations 50 and 52, located at slightly shallower 2100–2200 m depths where densities were generally higher (1180 and 1068 individuals 0.1 m2, respectively), the majority of stations down to 3150 m did not exhibit any depth-related trend in density. For example, Station 64, at 3130–3140 m the deepest station in the project, had densities of 537, 788, and 691 individuals 0.1 m2, in 2002–2004, respectively. Densities at stations within the disposal site such as Station 13 were always reduced when sampled, obviously due to the deeper layers of dredged material from the disposal operations (Appendix C). The number of species at any one station ranged from a low of 10 at Station 13 in the middle of the disposal site in 1998 to a high Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 of 176 at Station 114 in 2004, with an average of 92.4 species 0.1 m2 (Appendix C). Three other samples had 150 or more species: Station 16 (162 species in 2004), Station 50 (154 species in 2002), and Station 52 (150 species in 2003). Species diversity, whether measured by ES(100), Fisher’s logseries alpha, or Shannon’s H0 (log2), was generally high at all stations except for sites immediately within the disposal area in 1997 and 1998, when large amounts of dredged material were present (Appendix C). Shannon’s H0 was nearly always 5.00 and higher as is typical for species-rich continental slope habitats; values below 4.00 were found at stations such as 13 in the middle of the disposal site. The low value of 2.03 at Station 19 in 2003 was due to anomalously high densities of Sphaerosyllis sp. 1, a onetime occurrence. Evenness (Pielou’s J0 ) was high throughout the study; only rarely dropping below 0.75 (Appendix C). The lowest J0 was 0.34 at Station 19 in 2003. This anomalous value was the result of the unusual occurrence of 952 individuals of a single polychaete, Sphaerosyllis sp. 1, which has not been recorded in such high numbers before or since. The second lowest value, 0.49, was recorded at Station 13 in 1997 when only 100 specimens were found in the sample; of these, 69 were the spionid polychaete P. delta. Evenness values of 0.90 or higher were recorded for four samples, including a sample at Station 13 in 1998 where nine species were distributed among 15 specimens. The average J0 value for all 135 samples was 0.81 (70.69). 0.5 4 2003 5 2002 PCA-H Axis 2 (17%) 1782 1999 1996 1 0 2004 1995 2001 2000 1997 3 2 1998 Metric Scaling of Station 17 Samples, CNESS m =30 -0.5 0 PCA-H Axis 1 (24%) 0.5 0.5 Chaetozone sp. 1 3.3. Impact of dredged material disposal An analysis of whether dredged material disposal had any effect on benthic community structure over the entire 10-year sampling program is difficult because sampling stations shifted with changing priorities during the course of the program. The data were therefore organized into two sets with 1999 included in both; a few stations at which only one or two samples were taken were excluded and emphasis placed on stations sampled in multiple years. Data sets were (1) January 1996–1999, which included 50 samples from Stations 7–14, 16–18, 23, and 53; and (2) 1999–2004, which included 79 samples from Stations 6, 10, 16, 17, 19, 20, 23, 24, 27, 57, 92, 114, and 116. The 1996–1999 databases encompasses samples taken during and after the major disposal events in 1997 and 1998; any obvious impacts of dredged material disposal would be apparent in those data. 3.3.1. January 1996–1999 Benthic community parameters. During 1997 and 1998, density, species richness, and diversity declined at some, but not all, Levinsenia sp. 3 Chaetozone spinosa PCA-H Axis 2 (17%) 3.2.4. Station 17 Station 17 was the only station sampled in each of the 10 years. Similarity and cluster analysis indicated five faunal assemblages that appeared to be associated with changes in grain size (Fig. 5A–B). An initial assemblage, sampled in January and December 1996, characterized by the spionid polychaete P. delta shifted to one dominated by paraonid polychaetes in the genera Aricidea and Levinsenia (1997–1998). The 1999 sample was the most dissimilar, reflecting the high density of Ophelina sp. 1, a species that appeared to be associated with the coarse sediments present that year. In 2000 and 2001, the fauna shifted again to one characterized by other species of Aricidea and two bivalves; then in 2002 and 2003 again shifted to cirratulid polychaetes of the genus Chaetozone and another species of Levinsenia. In 2004, the fauna returned to the 2000–2001 assemblage; the sample from 2004 showed high similarity to and clustered with those from 2000 and 2001. Ophelina sp. 1 Adontorhina lynnae Sigambra setosa Leptaxinus cf. minutus Prionospio delta 0 Aricidea simplex type 1 Cossura modica Aricidea sp. 5 Levinsenia flava Aricidea sp. 4 Gabriel Euclidean Distance Biplot (2%): CNESS m =30 0 PCA-H Axis 1 (24%) Fig. 5. PCA-H results for Station 17 (January 1996–September 2004). (A) Metric scaling of all samples, CNESS distances based on m ¼ 30. Station groups are numbered; (B) Gabriel Euclidean distance biplot showing the 14 species that accounted for 2% or more of the variation in 5A. stations within and on the boundaries of the disposal site compared with original values recorded in 1996 (Appendix C). For example, at Station 7 on the NW boundary of the site, these parameters declined in 1997–1998 but recovered in 1999 (Fig. 6A–B). In contrast, Station 23 on the southern boundary did not exhibit the same trends although evenness (J0 ) declined in 1998 (Fig. 6C–D). These patterns reflect the relative distribution of dredged material in those years, when the greatest accumulations were to the NW of the site center. Stations located on the southern boundaries received only minimal amounts of dredged material. Rarefaction curves for each sample (Fig. 7A) indicated a wide range of diversities, reflecting the low diversity at stations that had received large volumes of dredged material and higher Author's personal copy ARTICLE IN PRESS 1783 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Station 7 500 400 300 200 100 60 0.92 50 0.9 0.88 40 0.86 30 0.84 20 0.82 10 0.8 0 0 12/1996 1997 # of Species 1998 0.78 1/1996 1999 # of Individuals 12/1996 Fisher's Station 23 1998 ESn(100) 1999 J' Station 23 600 0.85 0.84 0.83 0.82 0.81 0.80 0.79 0.78 0.77 0.76 0.75 0.74 60 Fisher's alpha & Rarefaction Abundance & Species Richness per sample 1997 500 400 300 200 100 0 55 50 45 40 35 30 25 20 15 10 1/1996 12/1996 1997 # of Individuals 1998 1999 # of Species 1/1996 12/1996 1997 Fisher's alpha 1998 ES(100) Evenness (J') 1/1996 Evenness (J') 600 Fisher's alpha& Rarefaction Abundance & Species Richness per sample Station 7 700 1999 J' Fig. 6. Species richness, density, and diversity trends at Stations 7 (A–B) and 23 (C–D) at SF-DODS (1996–1999). diversity at stations that were not thus affected. Samples from Station 13 (1997 and 1998) and Station 53 (1997) in the middle of SF-DODS had some of the lowest diversities. Three stations with the high diversities, 16-1997, 16-1998, and 17-1998, were positioned close to the site, but to the S and SE, and did not receive large amounts of dredged material. Non-dimensional diversity. The depth of each non-dimensional diversity curve in Fig. 7B indicates the degree to which a sample departs from the projected log-series and defines the degree of disturbance in the sample. Three samples (11-1999, 12-Dec 1996, and 14-Jan 1996) were close to the 0.75 threshold value and 131997, which approached 0.6, fell well below, indicating a severely disturbed community. These samples had high numbers of the spionid polychaete P. delta relative to the total number of organisms in the samples (30.3%, 21.9%, 37.8%, and 69%, respectively), and Station 12 (December 1996) had significant numbers of Ophelina sp. 1 (23.7%). Spionid polychaetes are often considered opportunistic species in shallow-water disturbed sediments; however, in this study area, P. delta is an indicator species of the lower slope habitat adjacent to SF-DODS and may also be an early colonizer of sediments that receive dredged material. Community assemblage patterns. Cluster analysis based on CNESS similarity indicated five major groups of samples at the 0.9 level. The two most dissimilar samples were from Station 13, which was heavily impacted by the large disposal projects in 1997–1998 (Fig. 8). Both 13-97 (cluster 1) and 13-98 (cluster 2) had reduced densities of 100 and 15 specimens, respectively; as noted earlier, sample 13-97 was dominated by P. delta. The largest group of samples (cluster 3) comprised stations at depths of 2850–3000 m, while six samples from 2700 to 2800 m formed cluster 4. A single sample, Station 7-Jan96 (cluster 5), had only 75 specimens distributed over 29 species, none of which were abundant. Faunal assemblage patterns generally followed depth zonation even when stations were within or adjacent to the disposal site. Metric scaling of the CNESS similarity values indicated that 34% of the variation was accounted for by axes 1 and 2 (Fig. 9A). The outlier clusters 1 and 2 clearly separated from the remaining groups along axis 1; the remaining single-station cluster 5 was positioned closer to the large cluster 3 on these two axes than it appeared in the dendrogram (Fig. 8). Cluster 3 was an amorphous cloud of points lying in three of the four quadrants and represented stations that were either within the disposal site or on the border; only Stations 10, 11, and 16 were outside the site boundaries. The six stations in cluster 4 separated primarily along axis 2; these stations were characterized by the bivalve Mendicula ferruginosa and the polychaetes A. simplex types 1 and 2 as shown in the Gabriel Euclidean distance biplot (Fig. 9B). Deeper stations (42800 m) were characterized by P. delta and L. flava; these species occurred, often in high densities, at stations that were being recolonized following dredged material disposal as well as at stations that were not heavily impacted. High densities of Ophelina sp.1 influenced several stations (12-Dec96, 13-Dec96, 14 Dec96, 18 Dec96, and 53-97) located in the lower right quadrant of Fig. 9B. Station 17-99, positioned closer to the center point of the diagram, also had high numbers of Ophelina sp. 1. This species was occasionally present in samples in relatively high densities, usually in coarse sediments. Depth-related trends were Author's personal copy ARTICLE IN PRESS 1784 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 140 Sanders-Hurlbert Rarefaction Diversity Curves 120 E(Sn) 100 80 60 40 20 0 0 100 200 300 400 500 600 700 Rarefied sample size Non-dimensional diversity 1.3 1.2 1.1 1 0.9 0.8 12-dec96 14-jan96 0.7 11-99 13-97 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 Non-dimensional abundance Fig. 7. Rarefaction curves (A) and non-dimensional diversity plots and (B) for SF-DODS stations sampled January 1996 through 1999. somewhat obscured by dredged material impacts at certain stations such as 13-97 and 13-98, where densities were low following periods of heavy disposal. 3.3.2. 1999–2004 Benthic community parameters. Species richness, Shannon’s (H0 ) diversity, and Fisher’s log-series alpha generally were consistent or trended higher over this 6-year period at most stations (Fig. 10A–C). Stations 57 and 114, the most species rich of the stations, showed a marked increase in species richness and diversity after 2002. Station 10 showed a gradual increase in numbers of species after 1999. At Station 19 on the SW boundary, these parameters all declined sharply in 2003 due to an anomalous population increase of a single species, Sphaerosyllis sp. 1, which resulted in higher densities, but fewer species and lower diversities at that station; some recovery was evident in 2004 when this species disappeared from the station and diversity values returned to near the levels of 2002. Station 17 on the SE boundary of the site showed an increase in species richness between 2001 and 2002, and remained at that level through 2004. Other stations were more or less steady in numbers of species beginning in 1999. Rarefaction curves for all 79 samples collected from 1999 to 2004 (Fig. 11) reflect the low diversity at Station 19 in 2003 and the high diversity of Stations 57 and 114 in 2004. Other individual samples with high diversities included 24-00, 114-03, and 57-01; samples with low diversity, 11-99, 12-99, and 13-02, were all within the disposal site. Community assemblage patterns. Similarity and cluster analysis of the 1999–2004 data indicated four major groups at the 0.9 level (Fig. 12). Cluster 1 included only a single outlier sample, 19-03, previously noted to have an anomalous high density of a single species. Clusters 2–4 represent three assemblages associated with a depth gradient: cluster 2 samples were from 2300 to 2550 m; cluster 3 stations were from 2500 to 2850 m; and cluster 4 stations were from 2800 to 3250 m. Within these three major clusters are groups comprised of samples taken at the same station in different years; for these stations, the within-station similarity is greater than similarity to other samples taken in each specific year. For example, all samples from Station 114 formed a subgroup in cluster 2; in cluster 3, most of the samples from Stations 6, 24, and 57 clustered together in station groups; and in cluster 4, all samples from Station 64 clustered together. Cluster 4, however, also included a subgroup with 7 of the 15 stations sampled in 2004. Metric scaling of the CNESS similarity for these 79 samples indicated that 30% of the variation was accounted for by axes 1 and 2 (Fig. 13A). With the exception of the outlier Station 19-03 (cluster 1), the samples appear to be distributed along axis 1 according to depth. These results demonstrate that regardless of whether a station lies on or within the SF-DODS boundary, the faunal assemblages were comprised of taxa that would normally occur there according to the existing depth gradient. As in the cluster dendrogram (Fig. 12), most of the samples taken from the same station occur together within one of the three main clusters. One exception was sample 16-00 which scaled with the shallower cluster 2 samples along axis 2 rather than in cluster 3 with the other Station 16 samples. Station 16 in 2000 had unusually high numbers of the polychaetes L. flava, P. fauchaldi, and Scalibregma californicum, as well as the tanaidaceans Paragathotanais sp. 1 and Leptognathiodes sp. 1. Together with unusually low densities of chaetoderm molluscs, these taxa probably accounted for the 2000 sample scaling with the shallower stations rather than with the other Station 16 samples taken in 2002–2004. Actual depths of those samples for the 4 years were similar, so this result was not an artifact of taking a shallower sample. The Gabriel Euclidean biplot shows the 14 taxa that contributed at least 2% of the CNESS variation on axes 1 and 2 (Fig. 13B). Aricidea simplex type 1 and two bivalves, Thyasiridae sp. 3 and M. ferruginosa, are most likely the taxa that best characterized the shallower cluster 2, while two other paraonids, A. simplex type 2 and A. sp. 4, defined cluster 3. The nine taxa to the right of the plot are species that influenced the deeper samples (cluster 4). Of these, the spionid polychaete P. delta and the cirratulid polychaetes Chaetozone sp. 1 and C. sp. 4 were the most important. 4. Discussion This study represents the first description of benthic communities on the lower continental slope off San Francisco, California, as well as the first long-term assessment of the impact of largescale disposal events on benthic infaunal communities in the deep sea. Reviews of the subject by Pequegnat (1983) and Thiel (2003) Author's personal copy ARTICLE IN PRESS 1785 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 CNESS levels (m= 10) 0.39 0.52 0.68 StationYear 7-196 7-1296 16-1296 16-97 17-97 17-98 16-98 7-97 8-196 8-98 8-97 53-1296 18-97 18-98 10-96 23-99 10-97 23-97 10-99 23-98 11-1296 11-97 12-196 12-97 11-99 23-196 14-196 14-97 14-98 17-1296 14-1296 53-97 17-196 18-99 7-98 7-99 8-1296 9-1296 23-1296 12-98 12-99 9-196 11-96 9-97 17-99 12-1296 18-1296 13-1296 13-97 13-98 0.84 1.00 1.16 5 4 3 2 1 Fig. 8. Dendrogram showing similarity among samples collected from January 1996 to October 1999, based on CNESS with m ¼ 10. did not provide any actual examples and therefore were speculative about potential impacts of dredged material disposal. Pequegnat (1983), however, suspected that impacts would be minimal; this conjecture is confirmed by the results of the present study. Boundary and reference stations at SF-DODS were not affected by small or moderate amounts of dredged material. Heavy depositions of dredged material at stations in the center of the site, resulted in decreased species densities, richness, and diversity; recolonization, however, appears to occur rapidly. Author's personal copy ARTICLE IN PRESS 1786 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 0.5 3 23-99 23-97 PCA-H Axis 2 (12%) 9-Dec96 10-96 23-Dec96 8-Dec96 10-99 23-98 10-97 7-99 7-98 0 11-Dec96 8-97 9-Jan96 53-1296 11-97 12-Jan96 18-98 8-98 12-97 8-Jan96 9-97 11-99 11-96 18-97 18-99 17-Dec96 14-98 14-97 7-97 23-Jan96 17-97 17-98 4 17-99 17-Jan96 16-97 18-Dec96 7-Jan96 16-Dec96 53-97 12-Dec96 160 140 120 100 80 60 13-Dec96 5 40 1999 2 1 7-Dec96 -0.5 12-99 14-Jan96 14-Dec96 12-98 Number of Species per Sample 180 -0.5 0 2000 2001 2002 2003 2004 13-97 13-98 16-98 0.5 Sta. 6 (2750) Sta. 10 (2897) Sta. 16 (2690) Sta. 17 (2776) Sta. 19 (3088 wire) Sta. 20 (3088) Sta. 23 (2926) Sta. 27 (2900wire) Sta. 52 (2237) Sta. 57 (2640) Sta. 64 (3140) Sta. 92 (2826) Sta. 108 (2736) Sta. 114 (2387 Sta. 116 (2928) PCA-H Axis 1 (22 %) 6.5 Chaetodermamorpha spp. Levinsenia flava 6.0 Shannon Diversity H' 0.5 PCA-H Axis 2 (12%) Nemertea sp. A 0 5.5 5.0 4.5 Mendicula ferruginosa Prionospio delta Aricidea simplex - type 2 Ophelina sp. 1 2.03 4.0 1999 Aricidea simplex - type 1 -0.5 -0.5 0 PCA-H Axis 1 (22 %) 2000 2001 2002 2003 2004 Sta. 6 Sta. 10 Sta. 16 Sta. 17 Sta. 19 Sta. 20 Sta. 23 Sta. 52 Sta. 57 Sta. 64 Sta. 92 Sta. 108 Sta. 114 Sta. 116 Sta. 27 0.5 60 Fig. 9. (A) Metric scaling of samples from January 1996 to October 1999, based on CNESS distances with m ¼ 10 and (B) Gabriel Euclidean distance biplot showing the eight species that contributed 42% of the variation. The benthic infauna in the vicinity of SF-DODS is rich and diverse. The 810 species of benthic invertebrates were identified from a relatively small geographic area, within a limited depth range of approximately 2160–3140 m, and from a total of only 12 m2 of the seafloor. When these records of a lower continental slope assemblage are taken together with species identified from middle and upper slope depths during the 1990–1991 baseline programs (Blake et al., 1992), the overall slope fauna rivals that described from the US Atlantic Slope (Maciolek et al., 1987a, b; Blake et al., 1986; Grassle and Maciolek, 1992; Blake and Grassle, 1994). In addition, we believe that some taxa such as small crustaceans may be undersampled, possibly because of bow wave effects that can move away small organisms found at the sediment–water interface during entry of the box core into the sediment. Despite the long list of species, most are rare; only 28 taxa had more than 500 occurrences and of these, only 13 were represented by more than 1000 individuals. Remarkably, of these 28 taxa, about half are believed to be new to science. When the entire fauna is considered, our conservative estimate is that 64% are new to science. By way of comparison, Blake and Grassle (1994) Fisher's alpha 4.1. Benthic communities on the Northern California slope 50 40 30 20 10 1999 Sta. 6 Sta. 20 Sta. 64 2000 2001 Sta. 10 Sta. 23 Sta. 92 2002 Sta. 16 Sta. 27 Sta. 108 2003 Sta. 17 Sta. 52 Sta. 114 2004 Sta. 19 Sta. 57 Sta. 116 Fig. 10. Benthic community parameters for SF-DODS stations sampled in 1999–2004. recorded 1202 species from 150 box core samples from off the Carolinas in a study that encompassed a much greater geographic area, a wide array of sedimentary and topographic types, and a greater depth range (550–3500 m). Of those 1202 taxa, 43% were believed new to science. Most of the polychaete families that were common in the California samples were also speciose off the Carolinas (Blake and Grassle, 1994): Spionidae (26 species in California v 62 species off the Carolinas), Paraonidae (38 v 35), Ampharetidae (25 v 33), Author's personal copy ARTICLE IN PRESS 1787 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Sanders-Hurlbert Rarefaction Diversity Curves 180 57-04 114-04 160 16-04 50-02 52-03 57-01 140 114-03 E(Sn) 120 6-0417-03 17-04 24-00 52-04 16-02 16-00 64-03 100 116-02 7-99 92-02 80 116-01 19-03 10-99 13-02 11-99 12-99 60 40 20 0 0 200 400 600 800 1000 1200 Rarefied sample size Fig. 11. Rarefaction curves for samples from SF-DODS stations sampled 1999–2004. Some samples are labeled with the station year. Cirratulidae (25 v 31), Phyllodocidae (17 v 29), and Dorvilleidae (30 v 28). The much higher number of species of Spionidae off the Carolinas is probably due to the greater diversity of sediment and habitat types together with the greater depth range. It is very interesting, however, that regardless of the total number of species recorded in the two studies, the number of species and relative importance of Paraonidae, Ampharetidae, Dorvilleidae, and Cirratulidae are very similar in two study areas in two different oceans. Among the four major crustacean orders, the Amphipoda with 89 species (11.3% of the total fauna) were the most speciose. Isopoda (9.8%), Tanaidacea (7.4%), and Cumacea (6.2%) had fewer species, but often were more abundant. The high number of amphipod species on the California slope differs from that in the Atlantic studies of Blake and Grassle (1994) where the tanaidaceans were the most dominant crustacean group with 8.3% of the total fauna, followed by amphipods (6.2%), isopods (4.9%), and cumaceans (2.4%). With a few exceptions, species diversity was high throughout the study area and comparable to the 1990–1991 regional baseline studies (Blake et al., 1992) and the US Atlantic slope (Grassle and Maciolek, 1992; Blake and Grassle, 1994). Exceptions included stations where dredged material deposits were heavy or isolated samples where anomalously high densities of one or two species reduced the diversity. Light or moderate amounts of dredged material did not appear to significantly affect diversity indices except at stations within SF-DODS where dredged material deposits were the deepest. The baseline studies of 1990–1991 demonstrated a distinct Zonation of benthic communities by depth (SAIC, 1992; Blake et al., 1992; unpublished). In the earlier studies distinct assemblages identified using NESS at four depth intervals: 600–800, 800–1500, 1500–2200, and 2400–3100 m. The latter lower slope assemblage has the same faunal characteristics as in the present monitoring study. Further Zonation within the lower slope assemblage is evident, however, in the present SF-DODS data because faunal assemblages identified at 2800–3150 m are more similar to one another than to those at stations shallower than 2800 m. 4.2. Impacts of dredged material disposal The large disposal events in 1997 and 1998 clearly affected stations in the center of the disposal site; Stations 13 and 53 were heavily impacted as evidenced by the low abundances and diversities recorded there following major disposal events. Faunal assemblages on the boundary of the site were affected to varying degrees depending on location. Dredged material was clearly seen in SPI images taken at Station 17 (see Section 4.5 below), and shifts from more-or-less ambient fine-grained sediments to a coarse dredged material cover and then back to fine-grained sediments were obvious. Although the fauna remained rich and diverse in spite of this cover of dredged material, species composition differed subtly from reference stations at similar depths as well as from other years at the same site. Most of the stations outside the boundaries of SF-DODS did not exhibit any Author's personal copy ARTICLE IN PRESS 1788 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 CNESS Level (m=30) 0.48 0.60 0.74 0.89 Sta.-Year outlier sample 19-03 Sta: Target Depth (m) 16: 2500 33: 2300 50: 2200 52: 2350 114: 2550 1.03 1.18 1 16-00 31-00 33-00 50-02 52-03 52-04 114-03 114-04 114-02 2 6-99 7-99 6-00 6-01 6-03 6-04 108-04 108-03 17-02 17-03 6: 2750 7: 2850 16: 2500 17: 2675 24: 2700 57: 2850 108: 2700 10: 2950 11: 3075 12: 3025 13: 3000 18: 2950 19: 3100 20: 3125 22: 3000 23: 2950 27: 2750 64: 3250 92: 2800 116: 3000 6-02 17-99 16-02 16-03 57-02 16-04 17-00 17-04 17-01 24-01 24-00 24-99 57-99 57-01 57-03 57-04 57-00 4.3. Opportunistic species 3 10-99 23-99 10-01 10-02 92-02 23-02 10-03 27-03 92-03 116-02 116-03 27-02 23-03 116-01 27-00 27-01 27-99 10-00 19-00 20-00 22-00 19-99 20-99 20-02 19-01 19-02 20-01 20-03 10-04 23-04 27-04 116-04 19-04 20-04 92-04 11-99 64-02 64-03 64-04 18-99 12-99 13-02 effect of dredged material disposal on year-to-year assemblage patterns. The fauna that appeared to be colonizing stations affected by dredged material was dominated by polychaetes, nemertean worms, and wormlike aplacophorans, while crustaceans and mollusks were less important at this stage. Initial colonizers were long, thin-bodied forms. For example, in 2002 at Station 13, slender polychaetes of the families Spionidae, Paraonidae, Cossuridae, Cirratulidae, and Capitellidae comprised most of the fauna. However, the actual species at this site were for the most part taxa that would normally be there regardless of the presence of dredged material, suggesting that recolonization was largely by ambient taxa rather than any unusual opportunistic species (but see Section 4.3). For example, P. delta, one of the common and dominant spionid polychaetes in lower slope assemblages, appeared to be one of the early colonizers and more abundant at impacted than at non-impacted stations. 4 Fig. 12. Similarity and cluster analysis for samples taken at SF-DODS 1999–2004 based on CNESS with m ¼ 30. One possible infaunal opportunistic species is Ophelina sp. 1, a small opheliid polychaete that appeared to be abundant in coarse dredged material sediments (e.g., Station 17). However, this species was found throughout the study area and it may merely be a species that prefers sediments with a higher sand fraction. No purely opportunistic infaunal species, i.e., one not already known to the study area, was identified. The occurrence of 900+ specimens of Sphaerosyllis sp. 1 at Station 19 in 2003 was considered anomalous and not an example of an opportunistic species; it was entirely absent from Station 19 the following year. A small, unknown capitellid polychaete was found at Station 13 in 2002, but in small numbers. Foraminifera of the genus Bathysiphon may be potential or early colonizers on dredged material. While not infaunal, these organisms were found in the biology samples, but due to the fragile nature of their tests, were usually damaged during sample processing. At least two species were often seen in the SPI images. Both species produce stick-like tests. In one species, the test consists of cemented or agglutinated sand grains and minerals (Fig. 14A). The second species is white or gray in color with the test consisting of delicate sponge spicules imbedded in a cemented matrix. Within each test is a unicellular organism that feeds essentially like an amoeba, using pseudopodia to capture and engulf the prey. How these organisms colonize areas of fresh dredged material is not known, but it is likely that asexually produced gamonts and sexually produced schizonts are dispersed by currents near the seabed. It is not known if there is any selectivity in the settlement of the dispersive stages. Dr. A. Gooday (personal communication, March 2005) indicated that one study from the western Pacific suggested that Bathysiphon colonized fresh volcanic sediment. These organisms do not burrow or deposit feed and are not part of processes that contribute to bioturbation; therefore they do not have any modifying effects on the sediment except that they selectively cement larger sand grains and minerals to their tests, thus producing concentrated ‘‘sticks’’ of coarser sediment in an otherwise fine-grained area of dredged material. Further study is required in order to understand the role of large foraminiferans such as Bathysiphon in the recolonization of dredged material. 4.4. Role of large epifaunal organisms in colonization and reworking of dredged material Other organisms that may be important in the early recolonization or reworking of dredged material include deposit-feeding Author's personal copy ARTICLE IN PRESS 1789 PCA-H Axis 2 (8%) J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 0 -0.5 -0.5 0 0.5 PCA-H Axis 2 (8%) PCA-H Axis 1 (22%) 0 -0.5 -0.5 0 PCA-H Axis 1 (22%) 0.5 Fig. 13. PCA-H results for SF-DODS stations sampled 1999–2004. (A) Metric scaling of samples. Squares indicate stations within or on the boundary of SF-DODS, circles indicate reference stations outside the disposal site and (B) Gabriel Euclidean biplot indicating the species that contributed 2% or more to the CNESS variation. holothurians. Four specimens of Scotoplanes globosa, an elasapoid holothurian, were collected at Stations 1, 9, and 14 (Appendix B). Stations 9 and 14 are within SF-DODS and Station 1 is to the NW in an area subject to fallout of sediment drift from dredged material disposal. Two of these specimens were collected in 1997 (Stations 1 and 14); another specimen was elegantly photographed in a SPI image from Station 9 in that same year (Fig. 14B). S. globosa is reported to travel in dense ‘‘herds’’ feeding on surficial sediments like a vacuum cleaner (Barham et al., 1976; Gage and Tyler, 1991). These animals walk over the sediment on their lateral podia, but in very soft sediments appear to bulldoze their way through the mud. They are capable of eating sediment, including dredged material, and are capable of passing it rapidly through their guts, producing fecal trails on the surface. Through their feeding and bulldozing activities, elasapoids, if present in high densities, are capable of reworking significant amounts of sediment. Their bulldozing activities also serve to disrupt resident benthic infauna as evidenced in Fig. 14B, where several polychaete tubes are entangled on the specimen’s lead podia. The fact that two specimens were collected in box cores and another imaged at Author's personal copy ARTICLE IN PRESS 1790 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Fig. 14. (A) Sediment profile image of agglutinated foraminiferans of the genus Bathysiphon in 2003 at Station 13 in the middle of SF-DODS. Arrow denotes feeding void of infaunal worm; (B) sediment profile image of the elasapoid holothurian Scotoplanes globosa at Station 9 in 1997. Sediment is dredged material. Anterior is to the right, polychaete tubes are entangled around the leading podial arm. an adjacent station suggests that a sizeable population of S. globosa was present within and adjacent to SF-DODS in October–November 1997. Another moderately large holothurian found throughout the study area is Ypsilothuria bitentaculata. This species is also a deposit feeder, but lacks the mobility of S. globosa. Y. bitentaculata was encountered in virtually every benthic sample taken within and around the disposal site and it is obvious that this species must play an important role in processing the sediments ingested as part of its feeding activities. Specimens of Y. bitentaculata were collected from one box core taken at the mid-site Station 13, suggesting that either it is able to burrow upwards out of fresh dredged material or can move to the site from adjacent locations. annual basis. More importantly, they demonstrate that benthic organisms are rapidly reworking this sediment. The infaunal results indicate that the resident species are the ones coping with the dredged material and that non-ambient opportunistic species are effectively absent. These observations are important because they demonstrate that dredged material received at sites on the boundary and outside SF-DODS are not degrading the resident infauna because the same species are present year after year, although the assemblages of these organisms may shift. Images taken from within SF-DODS such as at Station 13 in the center are heavily impacted, but even there, the images and occasional infaunal collections show that polychaetes and holothurians are usually evident, albeit in reduced numbers. 4.5. Bioturbation and reworking of dredged material by benthic infauna 4.6. Colonization and succession of disturbed deep-sea sediments In annual images taken 1999–2002 at Station 17 on the SW border of SF-DODS (Figs. 15A–D), dredged material was evident as granular coarse-grained sediment overlying finer muds. Tubes of benthic polychaetes are visible at the surface and oxic voids of burrowing organisms are clearly seen at depth, as well as the body of a polychaete (Fig. 15D). Over time, deposit-feeding infauna can move dredged material to depth, ingest it, and redeposit the particles in fecal pellets. Eventually, old dredged material becomes nearly indistinguishable from fine-grained ambient sediments. A Pennatulid, an ophiuroid, and a foraminiferan are visible on the surface at Station 6 (Fig. 15E), which is approximately 1 nm NE of the boundary of the disposal site; normally, only fine-grained dredged material reaches this station. Large numbers of the foraminiferan Bathysiphon are present at the surface of Station 10 (Fig. 15F), which is on the opposite side of SF-DODS from Station 6 and also approximately 1 nm from the site boundary. Dredged material was more evident at this station because fine-grained particles are carried NW from the site by prevailing currents. Large oxic voids of burrowing infauna can be seen at Station 19 (Fig. 15G) on the SW boundary; this is a station where dredged material is routinely evident. Station 27 is located approximately 2 nm NW of the site boundary; occasional deposits of dredged material are observed at this site due to the direct NW transport of fine-grained sediment. Numerous oxic voids and small polychaete tubes can be seen at the surface (Fig. 15H). SPI images provide a means to record the amount of dredged material that different sites in and around SF-DODS receive on an The majority of literature that refers to recolonization of disturbed deep-sea sediments is derived from small-scale experiments in which azoic sediments were placed in or on the seabed, usually in boxes or trays of various designs. The experiments were usually designed so that treatments would be recovered at different time intervals in order to estimate the rates of recolonization. Initial investigations of infaunal succession were carried out in the western North Atlantic by deploying deep-sea sediments in trays lying on the seabed. Grassle (1977) observed infaunal colonization after 2 and 26 months in trays at a depth of 1760 m (Station DOS-1) in the Northwest Atlantic. These were the first experiments to suggest that recolonization rates following disturbance were very slow for macrobenthos. The density of colonizing invertebrates was low, with most species not previously reported from the study area. Among the most common taxa were dorvilleid and capitellid polychaetes, priapulids, woodboring bivalves, and snails that were ectoparasitic on echinoderms. Later tray recolonization studies in the Northwest Atlantic conducted by Grassle and Morse-Porteous (1987) at DOS-l, and at 3600 m (DOS-2), for periods ranging from 2 to 59 months, supported Grassle’s initial findings of slow recolonization. After 59 months, faunal densities were still lower than those in background sediments. Trays that were covered with screens had higher densities of colonizers, suggesting that predation might affect recolonizing organisms (Grassle and Morse-Porteous, 1987). Desbruyères et al. (1980) reported more rapid colonization of defaunated sediments after 6 months at a 2160 m site in the Bay of Biscay when sediments were organically enriched. Experiments Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 1791 Fig. 15. Sediment profile images: (A–D) Station 17 (A, 1999; B, 2000; C, 2001; D, 2002); (E) Station 6 (2003); (F) Station 10 (2002); (G) Station 19 (2003); (H) Station 27 (2002). Arrows point to oxic voids or burrowing worms, details explained in text. Images are approximately 15 cm wide. with non-enriched sediments conducted for 6 and 11 months at depths of 2160 and 4150 m were slow to recolonize and supported Grassle’s findings (Desbruyères et al., 1985). As in Grassle’s experiments, many of the recruits in the Bay of Biscay belonged to species that were not present in the control or ambient sediments. These early sediment-tray experiments were considered to have hydrodynamic artifacts that modified boundary layer water flow and as such were considered unrealistic because the experimental substrata were separated from natural sediments (Smith, 1985; Snelgrove et al., 1995). Subsequent deployments of sediment-tray arrays that provided an unrestricted water flow over the sediments were made by Snelgrove et al. (1992, 1994, 1996) for 23 days and 28 months at a depth of 900 m near St. Croix, US Virgin Islands. Results indicated that colonizing macrofauna can attain or exceed ambient densities in 2 or more years. However, as in the earlier studies, the colonizing species were the ones that were relatively rare in background sediments (Snelgrove et al., 1996). Organically enriched sediments were colonized by dense numbers of capitellid and hesionid polychaetes, cumaceans, and leptostracans that were not observed in the ambient sediments. There are few comparable studies of infaunal recolonization of deep-sea sediments in the eastern Pacific. However, in those studies, the initial colonizers to disturbed or azoic sediments appear to be species that are relatively common in the background community (Levin and Smith, 1984; Kukert and Smith, 1992; Levin and DiBacco, 1995). Opportunists such as capitellid polychaetes were not reported from these deep-water experiments in the Pacific, although Capitella and leptostracans are known from adjacent ambient sediments in shallow submarine canyons (Vetter and Dayton, 1998). These results suggest, on a preliminary basis, that the pattern of recolonization of disturbed or treated sediments in deep-sea habitats differs between the Atlantic and Pacific continental slopes. In the Atlantic, the initial colonizers appear to be opportunists that are either rare or entirely absent in the adjacent ambient control sediments. In contrast, initial colonizers of disturbed sediments in the eastern Pacific are species from the ambient fauna found at control locations. The results of long-term monitoring at SF-DODS reported here strongly support this hypothesis. With one exception, rapid recolonization of sediments at SF-DODS that received dredged material was by infaunal species that were characteristic of adjacent ambient sediments at the same depth intervals. Early arrivals were typically polychaetes with long, thin bodies representing the families Paraonidae, Spionidae, and Cirratulidae. All of the species, however, are those that were present in the baseline pre-disposal surveys (Blake et al., 1992, unpublished). In addition to these small polychaetes, larger macrobenthic species such as the holothurian, Y. bitentaculata, are invariably found in the same samples. A one-time occurrence of high densities of the syllid polychaete Sphaerosyllis sp. 1 at Station 19 in 2003 was considered to be anomalous. The only potential candidate for an opportunistic macrofaunal species was Ophelina sp. 1, a small opheliid polychaete that appeared to prefer coarse sediments because it appeared in high densities when the silt+clay fraction was replaced by sandy dredged material such as at Station 17 in 1999. Rates of recolonization reported from experimental studies in the eastern Pacific differ depending on the type and duration of the experiments. Sediment-tray experiments at 1300 m in the Santa Catalina Basin yielded very low rates of recolonization, with macrofaunal densities attaining only 3% of that in the background community after 4.5 months (Levin and Smith, 1984). Sedimenttray colonization rates may be biased due to altered boundary layer water flow along the seafloor and on the tray (Kukert and Smith, 1992). In contrast, experimental sites where an artificial mound of sediment 5-cm high was placed over ambient sediment was colonized much more rapidly than sediment trays, with macrofaunal community abundance approaching background levels after 11 months (Kukert and Smith, 1992). However, after 23 months, infaunal community structure on the artificial mounds, although having high species richness, still differed in Author's personal copy ARTICLE IN PRESS 1792 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 structure from that found in the surrounding sediments. These results suggest that the reestablishment of the ambient community at the experimental sites required at least 2 years following a small-scale burial disturbance. The only previous example of a large anthropogenic disturbance was the DISCOL experiment on the abyssal equatorial seafloor in the southeastern Pacific Ocean (Borowski and Thiel, 1998). This study was designed to assess the potential effects of manganese-nodule mining on abyssal benthic communities. A sled, 8-m wide and equipped with a plow, was towed 78 times through a study area 3.6-km in diameter at a depth of 4160 m. Furrows were dug to a depth of 10–15 cm with a disturbance created over approximately 20% of the study area. Benthic samples were taken immediately after the disturbance, and then after 6 months and 3 years afterwards. The immediate result was a reduction of infaunal species by 39% within the plowed tracks. Polychaetes appeared to be the most heavily disturbed taxa. After 3 years most of the taxa had returned to densities similar to that of the background community, but diversity was depressed, suggesting that a longer interval was required to fully restore the disturbed habitat. These data did suggest that, unexpectedly, the plowed tracks were rapidly recolonized, probably by movement of organisms from adjacent undisturbed areas rather than by larval settlement (Borowski and Thiel, 1998). One of the findings of the SF-DODS long-term monitoring is that after a moderate degree of recolonization as evidenced at Station 13 between 1998 and 2002, the same faunal constituents that occurred at stations of similar depths outside the disposal site were present at this central site station. A similar example is found at Station 16 located outside of the SF-DODS boundary on the southeast. In October 2000, SPI images at Station 16 revealed that 414 cm of dredged material were deposited at the site, suggesting that at least 10 cm had been deposited between October 1999 and October 2000. At the same time, 876 specimens of benthic invertebrates were present in the benthic sample, of which 109 were identified taxa. Although diversity and evenness were lower than in earlier and subsequent years, it is evident that 10 cm of dredged material had not obliterated the fauna. The dominant species in 2000 was the large paranoid A. simplex type II, a species that was also prevalent in 2002 and 2003. The one indication of recolonization similar to that found at Station 13 was the presence of L. flava as the second most abundant species. This polychaete was neither among the dominant species in previous years nor among such in subsequent years. In the community analysis for Station 16, the 2000 sample has a high similarity to samples from 2002 to 2003, suggesting that the overall community structure at the site had not changed despite 414 cm being recorded at the site in 2000. Examination of the results from SF-DODS suggests that the grain size of anthropogenic sediments may influence the structure of the benthic community. Station 17 on the SE boundary of the SF-DODS changed from surficial sediments having 495% silt+clay in January 1996 to sediments having o50% silt+clay in 1998–2000, after which finer sediments returned. During the 10 years that this site was monitored from January 1996 through September 2004, five distinct faunal assemblages were identified, all of which may be correlated with the changes in sediment texture. Unlike the experimental tray and mound studies, however, the resident macrofauna at Station 17 was never removed, but instead changed from year to year as varying amounts of anthropogenic sediments were received. Although these results from a single station suggest that localized anthropogenic impacts of dredged material disposal result in shifts in faunal assemblages, there may also be a larger natural regional pattern because when Station 17 is compared with other samples taken in the same years, samples from those years usually cluster together. The present results suggest that the benthic infauna of SFDODS and vicinity is highly resilient and that if dredged material disposal were to end for any prolonged interval, the infauna within SF-DODS would return to a pre-disposal assemblage within a relatively short period of time, perhaps 2–3 years. This hypothesis differs from the experimental results of Grassle and Morse-Porteous (1987) and other studies in the North Atlantic where recolonization rates were estimated to be much slower. 4.7. Methods of recolonization In order for benthic organisms to recolonize disturbed sediments, recruits must arrive either as larvae or adults. Although there are few data on the reproduction and larval development of deep-sea benthic infauna, there is plenty of speculation that deep-sea invertebrates breed continuously and have direct or lecithotrophic development (Young, 2003). Planktotrophic larvae and thus broad-scale dispersal of planktic larvae would be rare. We know of no direct observations on the life history of any of the benthic invertebrates that are dominant at SF-DODS. The presence of fully developed adults of polychaetes and other benthic invertebrates at sites heavily impacted by dredged material suggests that they arrived by migration from adjacent marginally impacted sites along the site boundaries. Movement of adults in benthic boundary layer currents should be feasible because SPI images clearly showed sessile sea pens bent over by water movement. Dauer et al. (1982), working in shallowwater habitats, documented that adult benthic invertebrates that normally live within the sediments are capable of being carried from one location to another by currents. Blake and Narayanaswamy (2004), working in Antarctic slope sediments, reported that benthic organisms disturbed by the impact of a camera frame were dislodged from the mud and carried away by bottom currents. 4.8. Food supply, seasonality, and recolonization Transects from the upper to the lower continental slope were sampled as part of baseline surveys to support the SF-DODS site designation process (Blake et al., 1992; SAIC, 1992). These studies clearly indicated that densities of benthic infauna from 1500 to 3000 m depth off California were an order of magnitude higher than at the same depths in the western North Atlantic. The high productivity of the benthic infauna on the California slope is most certainly linked to seasonal upwelling events, which result in phytoplankton production in surface waters and subsequent phytodetrital falls that provide pulses of organic matter to the infaunal benthos. Patterns of species richness, dominance, and even taxonomic composition have been shown to be related to the supply of organic matter to the seabed (Grassle and Grassle, 1994; Levin and Gooday, 2003). Smith et al. (1998), working at a site in 4100 m off southern California (Station M), found that pulses of phytodetritus arrived on the seabed between July and December. This phytodetritus was richer in organic carbon, total nitrogen, and phaeopigments than the underlying ambient sediments. Additional observations by these workers suggested that, while the aggregates of phytodetritus were visible only for 2–3 days, it was actually metabolized over a longer timeframe, perhaps for 25–50 days. Although such studies have not been conducted in the vicinity of SF-DODS, samples of sediments were analyzed for chlorophyll and phaeopigments in 1991 (Blake et al., 1992). Chlorophyll a concentrations measured 5.3–17.0 mg/g (dry wt.) and phaeopigments 35.2–76.20 mg/g (dry wt.) at 12 stations. Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 A review of the literature at that time suggested that these results were among the highest ever recorded in the deep sea. Changes in benthic community structure linked to seasonality or climatology are difficult to study in the deep sea because of the long-term nature of the data required. The 14-year program at Station M in 4100 m off Southern California has provided data suggesting that large-scale climatological events such as El Niño and La Niña may influence the benthos even at abyssal depths (Ruhl and Smith, 2004). These authors observed that certain megafaunal holothurians including S. globosa increased in abundance after the El Niño and La Niña events of 1997 and 1999. It is noteworthy that S. globosa has neither been seen in the SPI images nor collected since 1997 at SF-DODS, suggesting that processes that enhanced populations at a deeper site off southern California may have had the opposite effect in Northern California. There are no data that conclusively demonstrate that seasonality or climatology influences colonization processes at SF-DODS. Monitoring surveys were carried out in all seasons. Infaunal densities and species richness were lower in winter (January and December 1996), but those samples were not sorted and identified until 2001. Long-term storage of the samples in ethanol and subsequent degradation of calcium carbonate in the shells of small molluscs and crustaceans may have been responsible for fewer taxa being identified from those samples rather than any real temporal effect. It is virtually impossible to identify molluscs that have decalcified. 4.9. Effects of long-term use of SF-DODS This study has demonstrated that dredged material disposal at SF-DODS has not caused regional degradation outside of the disposal site nor even on the boundaries of the site. The data clearly indicated that benthic communities in the vicinity of SFDODS are highly resilient and capable of reworking small amounts of dredged material and recovering rapidly from larger deposits. Heavy deposits of dredged material 414 cm observed in SPI images at Station 16 outside of SF-DODS in October 2000 were shown to be colonized by 109 species of benthic invertebrates, which for the most part were the same species observed in previous and subsequent years. Data clearly indicated that even at Station 13 in the center of the disposal site, fresh dredged material was colonized by species that are the same as those from adjacent non-impacted sediments. Part of this resilience may be reflected in the fact that the entire slope itself is relatively steep and subject to periodic slumping and turbidity flows. A prominent turbidity flow was observed near the center of the current location of SFDODS during a camera sled transect in 1991 (Hecker, 1992). Organisms living in such an environment may be pre-adapted to colonize disturbed sediments. The use of the continental slope for disposal of noncontaminated dredged material obviously depends upon economics and distance of the site from the source of dredging. Off Northern California the continental shelf is narrow, allowing tugs and their barges to make a round trip to SF-DODS in a single day. Given the results of this study, it should be reasonable to propose 1793 using additional continental slope sites off California for similar purposes. Acknowledgements On the occasion of this special issue, we are pleased to dedicate this paper to Dr. J. Frederick Grassle, deep-sea ecologist and longtime colleague. Dr. Grassle’s approach to compiling high-quality benthic and biodiversity data continues to inspire our work and the present study is such an effort. Over the 10 years of field work reported for this project, several key individuals were responsible for planning and implementing the box coring task. For most of those years, Hovie Clifford (WHOI) maintained the box cores in Woods Hole and prepared them for shipment to California. In the field, George Hampson (WHOI), Brigitte Hilbig, Pamela Neubert, Russ Winchell (Oceans Taxonomic Services), and Howard Jones (Marine Taxonomic Services) have at different times played important roles in the collection and shipboard processing of the biology samples. Other important field leaders including Kim Brown (Tetra Tech), Mark Herrenkohl (SAIC), John Nakayama (SAIC), and Michael Cole (SAIC). The officers and crew of the R/V Point Sur assisted in all phases of sample collection, sometimes under difficult conditions. The taxonomic team included: Gene Ruff (polychaetes), Stacy Doner (polychaetes and ophiuroids), James Blake (polychaetes), Nancy Maciolek (polychaetes), Les Watling (cumaceans), Isabelle Williams (molluscs, crustaceans, and holothurians), Pamela Neubert (aplacophorans and ophiuroids), and Paula Winchell (sipunculans and nemerteans). Dmitry Ivanov (Moscow State University, Russia) identified the Chaetodermamorpha collections for 2004. Marymegan Daly (Ohio State University) identified the anemones and provided working keys. USEPA Region 9 provided the financial support to complete the laboratory work for the 1996–2001 samples, data analysis, and report preparation as part of GSA Contract No. GS-10F-0115 K, Delivery Order 0900 to ENSR Corporation, now AECOM. Michael Donnelly (USACE, San Francisco District) supported analysis of the 2002–2004 databases and the field surveys since 1999 as part of annual contracts for field, laboratory, and reporting tasks. Finally, we thank Rich Lutz, Rutgers University, the guest editor of this issue, for his support. Appendix A See Table A1. Appendix B See Table B1. Appendix C See Table C1. Author's personal copy ARTICLE IN PRESS 1794 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table A1 Station coordinates and depths for 135 benthic box core samples collected at SF-DODS (January 1996–September 2004). Box core station Target location Date Latitude (N) Longitude (W) 1 37141.000 123131.000 2 37141.00 123130.00 3 37141.000 123129.000 6 37140.000 123127.000 7 37140.000 123128.000 8 37140.000 123129.000 9 37140.000 123130.000 10 37140.000 123131.000 11 37139.000 123131.000 12 37139.000 123130.000 13 37139.000 123129.000 14 37139.000 123128.000 15 37139.000 123127.000 16 37138.000 123127.000 17 37138.000 123128.000 0 0 11-Dec-96 29-Oct-97 11-Dec-96 29-Oct-97 12-Oct-98 21-Jan-96 5-Dec-96 29-Oct-97 13-Oct-99 16-Oct-00 22-Oct-01 22-Sep-02 26-Sep-03 03-Oct-04 19-Jan-96 11-Dec-96 30-Oct-97 11-Oct-98 13-Oct-99 23-Jan-96 5-Dec-96 29-Oct-97 11-Oct-98 19-Jan-96 5-Dec-96 30-Oct-97 11-Dec-96 30-Oct-97 8-Oct-99 16-Oct-00 23-Oct-01 22-Sep-02 26-Sep-03 02-Oct-04 23-Jan-96 11-Dec-96 3-Nov-97 9-Oct-99 21-Jan-96 5-Dec-96 29-Oct-97 8-Oct-98 8-Oct-99 4-Dec-96 28-Oct-97 08-Oct-98 29-Sep-02 23-Jan-96 11-Dec-96 29-Oct-97 08-Oct-98 23-Jan-96 12-Dec-96 12-Dec-96 03-Nov-97 08-Oct-98 15-Oct-00 21-Sep-02 23-Sep-03 02-Oct-04 19-Jan-96 11-Dec-96 03-Nov-97 07-Oct-98 13-Oct-99 15-Oct-00 21-Oct-01 21-Sep-02 24-Sep-03 02-Oct-04 Sampling position Latitude (N) Longitude (W) Depth (m) 37141.100 37141.100 37141.010 37141.010 37140.960 37141.010 37141.050 37140.970 37140.050 37139.970 37140.000 37140.020 37140.080 37139.930 37140.000 37140.070 37139.990 37140.000 37139.990 37140.000 37140.110 37140.050 37140.030 37139.980 37140.010 37140.040 37140.020 37140.040 37139.960 37140.010 37140.020 37140.000 37140.000 37139.940 37139.000 37139.090 37139.100 37139.000 37139.000 37138.920 37139.050 37138.990 37138.910 37139.150 37138.990 37138.970 37138.920 37139.000 37139.060 37139.000 37138.970 37139.020 37139.050 37138.000 37138.070 37138.040 37137.900 37138.020 37138.010 37137.970 37138.020 37137.980 37137.970 37138.000 37138.020 37137.940 37138.000 37138.010 37138.050 37137.980 123131.030 123130.980 123129.900 123129.970 123129.930 123129.030 123128.990 123129.000 123126.970 123126.950 123126.910 123127.000 123127.030 123126.920 123127.990 123128.000 123128.000 123128.000 123127.970 123128.990 123128.980 123128.980 123129.010 123130.000 123130.000 123129.980 123130.970 123130.960 123131.060 123131.030 123131.000 123131.000 123130.980 123130.940 123130.990 123130.990 123131.030 123131.030 123130.000 123129.850 123129.920 123129.970 123129.890 123129.040 123129.020 123128.950 123128.950 123128.000 123127.950 123128.020 123127.980 123126.990 123126.990 123127.080 123127.050 123126.880 123126.890 123126.950 123126.980 123127.040 123128.010 123127.930 123127.950 123127.990 123120.000 123127.910 123128.030 123127.940 123127.940 123127.990 2799 2665 2600 2603 2592 2500 2452 2740 2765 2730 2770 2697 2710 2750 2800 2775 2850 2820 2805 2726 2850 2843 2910 2890 2906 2927 2954 2920 3015 3065 2985 2739 2736 2897 3070 2990 2955 3045 3015 3000 3025 3070 2989 2930 2945 2987 2902 2790 2850 2878 2750 2835 2830 2650 2690 2749 2670 2693 2694 2690 2800 2800 2795 2830 2770 2780 2862 2775 2750 2776 Author's personal copy ARTICLE IN PRESS 1795 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table A1 (continued ) Box core station Target location Date Latitude (N) Longitude (W) 18 37138.000 123129.000 19 37138.000 123130.000 20 37138.000 123131.000 22 23 37137.000 37137.000 123130.000 123129.000 24 37137.000 123128.000 26 27 37140.000 37141.000 123132.000 123132.000 31 33 50 52 37142.010 37142.000 37143.000 37143.000 123129.000 123127.000 123126.000 123128.000 53a 37139.500 123129.500 57 37143.000 123133.000 64 37136.000 123133.000 92 37145.000 123135.000 108 37139.000 123125.000 114 37135.000 123127.000 116 37135.000 123129.000 10-Dec-96 30-Oct-97 7-Oct-98 8-Oct-99 20-Jan-96 07-Oct-98 09-Oct-99 15-Oct-00 22-Oct-01 22-Sep-02 24-Sep-03 02-Oct-04 13-Oct-99 15-Oct-00 23-Oct-01 22-Sep-02 24-Sep-03 02-Oct-04 19-Oct-00 21-Jan-96 10-Dec-96 03-Nov-97 06-Oct-98 09-Oct-99 26-Sep-02 24-Sep-03 02-Oct-04 08-Oct-99 19-Oct-00 22-Oct-01 13-Oct-98 08-Oct-99 16-Oct-00 22-Oct-01 23-Sep-02 26-Sep-03 02-Oct-04 16-Oct-00 20-Oct-00 24-Sep-02 26-Sep-03 03-Oct-04 12-Dec-96 03-Nov-97 13-Oct-99 16-Oct-00 22-Oct-01 23-Sep-02 26-Sep-03 01-Oct-04 25-Sep-02 26-Sep-03 03-Oct-04 24-Sep-02 23-Sep-03 01-Oct-04 26-Sep-03 03-Oct-04 27-Sep-02 26-Sep-03 26-Sep-03 17-Oct-01 25-Sep-02 26-Sep-03 03-Oct-04 Sampling position Latitude (N) Longitude (W) Depth (m) 37138.040 37137.950 37137.950 37137.860 37138.000 37138.040 37137.940 37137.950 37137.980 37138.010 37137.970 37137.970 37138.130 37137.960 37138.040 37138.060 37137.940 37137.990 37137.000 37137.000 37137.130 37137.060 37137.230 37136.960 37136.950 37136.860 37136.980 37136.900 37136.970 37136.940 37140.000 37141.000 37140.970 37140.980 37140.960 37140.920 37140.940 37142.010 37142.010 37142.950 37142.940 37144.000 37139.570 37139.580 37143.000 37142.990 37142.960 37142.970 37142.970 37143.010 37136.010 37135.980 37135.980 37145.000 37145.000 37144.960 37138.950 37138.980 37135.080 37135.070 37134.970 37135.030 37134.990 37135.080 37135.000 123128.990 123128.89 123128.930 123128.860 123130.000 123130.020 123129.940 123129.950 123130.030 123130.000 123130.040 123129.960 123131.090 123131.060 123131.010 123131.010 123130.970 123131.020 123130.020 123128.990 123129.080 123129.150 123129.180 123128.930 123129.020 123128.850 123127.000 123127.920 123127.920 123127.930 123132.000 123132.000 123131.980 123131.950 123131.940 123131.930 123131.900 123129.000 123127.010 123125.900 123127.940 123128.000 123129.450 123129.610 123133.000 123132.990 123132.970 123132.940 123132.950 123132.980 123133.010 123132.960 123132.980 123135.000 123134.980 123134.960 123124.940 123124.970 123126.960 123126.900 123126.980 123128.990 123128.980 123129.060 123128.990 2920 2905 2950 2900 2947 3030 3020 2940 3123 3000 2983 2838 3060 3060 3142 3050 3035 3088 3010 2875 2950 2950 2970 2970 2954 2821 2926 2900 2650 2680 2915 2929 2740 2770 2825 2750 2840 2380 2400 2160 2240 2237 2950 2875 2668 2650 2750 2709 2750 2640 3136 3130 3140 2850 2805 2826 2670 2736 2420 2505 2387 3071 2975 2730 2928 a This was a special location within SF-DODS intended for detailed mapping of dredged material and is not the station currently designated as Sta. 53 on the SF-DODS site grid. Author's personal copy ARTICLE IN PRESS 1796 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table B1 Infaunal species identified from SF-DODS stations (January 1996–September 2004). CNIDARIA Class Anthozoa Anemonactis cf. mazeli (Jourdan, 1880) Ceriantharia spp. indet. Edwardsia sp. 3 Kophobelemnon cf. affine Studer, 1894 Paraedwardsia sp. 1 Pennatula phosphorea (Linnaeus, 1758) NEMERTEA Cerebratulus sp. 1 Carinomella sp. 1 Nemertea sp. 5, 6, 7, 8, 9, 10, 11, 12, 13 PRIAPULIDA Family Priapulidae Priapulidae sp. 1 ANNELIDA–POLYCHAETA Family Aberrantidae Aberranta sp. 1 Family Acrocirridae Flabelligella sp. 1, 2, 3 Family Ampharetidae Amage perfecta Moore, 1923 Ampharete finmarchica (Sars, 1864) Ampharete nr. longipaleolata Uschakov, 1955 Amphicteis mucronata Moore, 1923 Amphicteis scaphobranchiata Moore, 1906 Amphicteis vestis Hartman, 1965 Anobothrus gracilis (Malmgren, 1866) Anobothrus sp. 2, 3 Eclysippe sp. 2 Glyphanostomum pallescens (Théel, 1878) Lysippe labiata Malmgren, 1866 Melinna heterodonta Moore, 1923 Mugga wahrbergi Eliason, 1955 Paralysippe annectens (Moore, 1923) Paramage scutata (Moore, 1923) Sabellides sp. 1 Sosanides sp. 1 Sosanopsis wireni Hessle, 1917 Ampharetidae sp. 1, 2, 3, 4, 5, 6 Family Amphinomidae Paramphinome sp. 1 Family Aphroditidae Aphrodita nr. parva Moore, 1905 Aphrodita sp. 1 Family Apistobranchidae Apistobranchus ornatus Hartman, 1965 Family Capitellidae Capitella capitata complex (Fabricius, 1780) Heteromastus spp. indet. Mediomastus californiensis Hartman, 1944 Neoheteromastus lineus Hartman, 1960 Neomediomastus glabrus (Hartman, 1960) Neonotomastus glabrus Fauchald, 1972 Notomastus abyssalis Fauchald, 1972 Notomastus latericeus Sars, 1851 Notomastus lineatus Claparède, 1870 Notomastus precosis Hartman, 1960 Notomastus profundus Eisig, 1887 Notomastus sp. 1, 2, 3, 4 Capitellidae n. gen. n. sp. 1 Family Chaetopteridae Phyllochaetopterus limicolus Hartman, 1960 Spiochaetopterus costarum (Claparède, 1870) Family Chrysopetalidae Dysponetus sp. 1 Family Cirratulidae Aphelochaeta cf. glandaria Blake, 1996 Aphelochaeta monilaris (Hartman, 1960) Aphelochaeta sp. 1, 2, 4, 7, 8, 9, 10, 11 Aphelochaeta X Chaetozone allanotai Blake, 2006 Chaetozone brunnea Blake, 2006 Chaetozone pallaea Blake, 2006 Chaetozone spinosa (Moore, 1905) Chaetozone sp. 3, 8, 9, 10 Table B1. (continued ) Chaetozone sp. unk Dodecaceria sp. 1 Monticellina sp. 2, 3 Tharyx kirkegaardi Blake, 1991 Family Cossuridae Cossura brunnea Fauchald, 1972 Cossura candida Hartman, 1955 Cossura modica Fauchald & Hancock, 1981 Cossura pygodactylata Jones, 1956 Cossura rostrata Fauchald, 1972 Family Dorvilleidae Anchidorvillea moniliformis Hilbig & Blake, 1991 Exallopus intermedius Hilbig & Blake, 1991 Exallopus sp. 1 Ophryotrocha labidion Hilbig & Blake, 1991 Ophryotrocha cf. maciolekae Hilbig & Blake, 1991 Ophryotrocha obtusa Hilbig & Blake, 1991 Ophryotrocha pachysoma Hilbig & Blake, 1991 Ophryotrocha sp. 1, 3, 4, 5, 6, 7, 8, 9, 10, 11 Ophryotrocha n. sp. unknown Parophryotrocha sp. 1, 2 Parougia sp. 1, 2 Pettiboneia bathyalis Hilbig & Ruff, 1990 Pettiboneia brevipalpa Hilbig & Ruff, 1990 Pettiboneia dibranchiata Blake, 1979 Pettiboneia sp. 1 Pseudophryotrocha serrata Hilbig & Blake, 1991 Dorvilleidae sp. 1, 2, 3 Family Fauveliopsidae Fauveliopsis glabra (Hartman, 1960) Family Flabelligeridae Brada pilosa Moore, 1906 Brada pleurobranchiata (Moore, 1923) Brada villosa (Rathke, 1843) Diplocirrus sp. 1, 2, 3 Flabelligera infundibularis Johnson, 1901 Flabelligera sp. 1 Ilyphagus spp. indet. Pherusa spp. indet. Family Glyceridae Glycera americana Leidy, 1855 Glycera nana Johnson, 1901 Family Goniadidae Bathyglycinde cedroensis Fauchald, 1972 Goniada brunnea Treadwell, 1906 Goniada maculata Ørsted, 1843 Family Hesionidae Gyptis hians Fauchald, 1981 Gyptis sp. 1, 2 Hesione spp. indet. Kefersteinia sp. 1 Microphthalmus sp. 1,2 Nereimyra sp. 1, X Ophiodromus sp. 1 Hesionidae sp. 1, 2, 3, 4 Family Lacydoniidae Lacydonia hampsoni Blake, 1994 Lacydonia sp. 1 Family Lumbrineridae Augeneria cf. tentaculata Monro, 1930 Cenogenus sp. 1, 2 Eranno sp. 1, 2 Lumbrineris californiensis Hartman, 1944 Lumbrineris cruzensis Hartman, 1944 Lumbrineris latreilli Audouin & Milne Edwards, 1834 Lumbrineris pallida Hartman, 1944 Lumbrineris sp. 1, 2 Ninoe gemmea Moore, 1911 Ninoe sp. 1, C Family Maldanidae Asychis sp. 1 Axiothella cf. rubrocincta (Johnson, 1901) Clymenura gracilis Hartman, 1961 Clymenura sp. 1 Euclymene sp. 1 Lumbriclymene lineus Hartman, 1960 Macroclymene sp. 1 Maldane cristata Treadwell, 1923 Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table B1. (continued ) Maldane monilata Fauchald, 1972 Maldane sp. 1 Microclymene cf. caudata Imajima & Shiraki, 1982 Nicomache spp. indet. Notoproctus abyssus Hartman & Fauchald, 1971 Notoproctus nr. pacificus (Moore, 1906) Notoproctus oculatus Sars, 1851 Praxillella gracilis (Sars, 1861) Praxillella sp. 1, 2 Rhodine bitorquata Moore, 1923 Family Nephtyidae Aglaophamus paucilamellata Fauchald, 1972 Aglaophamus nr. eugeniae Fauchald, 1972 Aglaophamus nr. surrufa Fauchald, 1972 Family Nereididae Ceratocephale pacifica Hartman, 1960 Nereis sp. 1, 2 Family Oenonidae ( ¼ Arabellidae) Drilonereis falcata Moore, 1911 Family Onuphidae Kinbergonuphis nr. nannognathus Chamberlin, 1919 Kinbergonuphis proalopus Chamberlin, 1919 Nothria sp. 1 Onuphis affinis Hilbig, 1995 Onuphis geophiliformis (Moore, 1903) Onuphis iridescens (Johnson, 1901) Onuphis mexicana (Fauchald, 1968) Onuphis pallida (Moore, 1991) Onuphis nr. vibex Fauchald, 1972 Onuphis sp. 1 Paradiopatra sp. 1 Family Opheliidae Ophelina acuminata Ørsted, 1843 Ophelina breviata (Ehlers, 1913) Ophelina abranchiata Støp-Bowitz, 1948 Ophelina sp. 1, 2, 3 Travisia brevis Moore, 1923 Travisia pupa Moore, 1906 Family Orbiniidae Califia calida Hartman, 1957 Leitoscoloplos sp. 1, 5 Leodamas sp. 1 Orbiniella sp. 1 Family Oweniidae Galathowenia pygidialis (Hartman, 1960) Myriochele gracilis Hartman, 1955 Myriochele olgae Blake, 2000 Myriochele sp. 1, 3 Myriowenia sp. 1 Family Paralacydoniidae Paralacydonia paradoxa Fauvel, 1913 Family Paraonidae Aricidea cf. catherinae Laubier, 1967 Aricidea cf. hartleyi Blake, 1996 Aricidea cf. pseudoarticulata Hobson, 1972 Aricidea quadrilobata Webster & Benedict, 1887 Aricidea ramosa Annenkova, 1934 Aricidea simplex Day, 1963 Aricidea simplex Type 2 Aricidea wassi Pettibone, 1965 Aricidea sp. 1, 3, 4, 5, 10, 12, 13, 14, 15, 16, 17 Cirrophorus branchiatus Ehlers, 1908 Cirrophorus furcatus (Hartman, 1957) Cirrophorus sp. 1 Levinsenia flava Strelzov, 1973 Levinsenia gracilis (Tauber, 1879) Levinsenia oculata (Hartman, 1957) Levinsenia sp. 1, 3, 4, 5, 6, A Paradoneis lyra (Southern, 1914) Paradoneis sp. 1, 3, 4 Paraonella monilaris (Hartman & Fauchald, 1971) Paraonella monilaris Type 2 Paraonella sp. 1 Family Pholoidae Pholoe sp. 1 Family Phyllodocidae Chaetoparia careyi Fauchald & Hancock, 1981 Eulalia sp. 1, 2 Table B1. (continued ) Eumida sp. 1, 2 Lugia sp. 1 Mystides caeca Langerhans, 1880 Mystides rarica (Uschakov, 1958) Paranaitis sp. 1, 2 Phyllodoce sp. 1 Protomystides sp. 1 Pterocirrus sp. 1 Sige bifoliata Sige brunnea (Fauchald, 1972) Sige sp. 1 Phyllodocidae sp. 1 Family Pilargidae Ancistrosyllis groenlandica McIntosh, 1879 Ancistrosyllis cf. hamata (Hartman, 1960) Sigambra setosa Fauchald, 1972 Sigambra tentaculata (Treadwell, 1941) Family Poecilochaetidae Poecilochaetus sp. 1 Family Polynoidae Harmothoe spp. indet. Herdmanella spp. indet. Iphione spp. indet. Subadyte sp. 1 Harmothoinae sp. 1 Macellicephalinae sp. 1 Family Sabellidae Chone gracilis Moore, 1906 Euchone incolor McIntosh, 1885 Euchone velifera Banse, 1972 Jasmineira sp. 2, 3 Laonome spp. indet. Potamethus mucronatus (Moore, 1923) Sabellinae spp. indet. Family Scalibregmatidae Asclerocheilus beringianus Uschakov, 1955 Asclerocheilus sp. 1, 3, 4 Hyboscolex sp. 1 Pseudoscalibregma sp. 1, 2 Scalibregma californicum Blake, 2000 Scalibregma sp. 1 Family Sigalionidae Ehlersileanira sp. 1, 2 Family Sphaerodoridae Amacrodorum sp. 1 Clavodorum fusum (Hartman, 1967) Clavodorum sp. 2, 3 Commensodorum sp. 3 Sphaerephesia sp. 1 Sphaerodoropsis biserialis (Berkeley & Berkeley, 1944) Sphaerodoropsis furca Fauchald, 1974 Sphaerodoropsis sphaerulifer Moore, 1909 Sphaerodorum nr. gracilis (Rathke, 1843) Sphaerodoropsis sp. 1, 4, 5, 6, 7, 8 Sphaerodorum sp. 1 Family Spionidae Aurospio dibranchiata Maciolek, 1981 Laonice nr. antarcticae Hartman, 1953 Laonice sp. 1, 2, 4, 5, 6, 7 Prionospio anuncata Fauchald, 1972 Prionospio delta Hartman, 1965 Prionospio fauchaldi Maciolek, 1985 Prionospio nr. steenstrupi Malmgren, 1867 Prionospio sp. 3, 6, 8, 9, 11, 12, 13, 14, 15 Scolelepis sp. 1 Spiophanella sp. 1 Spiophanes anoculata Hartman, 1960 Spiophanes kroyeri Grube, 1860 Spiophanes nr. wigleyi Pettibone, 1962 Family Sternaspidae Sternaspis spp. indet. Family Syllidae Braniella palpata Hartman, 1967 Braniella sp. 1 Exogone sp. 1 Sphaerosyllis sp. 1 Family Terebellidae Amaeana sp.1 1797 Author's personal copy ARTICLE IN PRESS 1798 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table B1. (continued ) Table B1. (continued ) Amphitrite cirrata Müller, 1771 Artacama coniferi Moore, 1905 Lanassa venusta (Malm, 1874) Lanassa gracilis (Moore, 1923) Laphania sp. 1 Leaena sp. 1 Lysilla loveni Malmgren, 1866 Lysilla pacifica Hessle, 1917 Phisidia sanctaemariae Hilbig, 2000 Pista percyi Hilbig, 2000 Polycirrus spp. indet. Proclea cf. graffii (Langerhans, 1884) Amphitritinae sp. 1, 3 Family Trichobranchidae Terebellides sp. 1, 2, 3, 4 Trichobranchus sp. 1 Trichobranchidae sp. 7 Family Trochochaetidae Trochochaeta sp. 1 Family Unknown Polychaeta sp. 1 ANNELIDA–OLIGOCHAETA Tubificidae sp. 1 ANNELIDA–POGONOPHORA Heptabrachia nr. beringianus Ivanov, 1960 Polybrachia canadensis (Ivanov, 1962) Polybrachia sp. 1 Sclerolinium sp. 1 Siboglinoides sp. 1 Siboglinum sp. 1, 2 SIPUNCULA Nephasoma diaphanes (Gerould, 1913) Nephasoma sp. 1 Sipuncula sp. 1, 2, 3 ECHIURA Echiura sp. 1, 2, 3, 4, 5, 6 MOLLUSCA – APLACOPHORA Order Chaetodermamorpha Family Chaetodermatidae Chaetoderma sp. A, B, C Falcidens sp. A, B, C, D, E Family Limifossoridae Scutopus sp. A, B Family Prochaetodermatidae Claviderma sp. A, B Prochaetoderma sp. A Spathoderma sp. A Order Neomeniomorpha Family Dondersiidae Nematomenia sp. 1 Family Epimeniidae Epimenia sp. 1 Family Perimeniidae Elutheromenia sp. 1 Family Simrothiellidae Plawenia sp. 1, 2 Spiomenia sp. 1 Simrothiellidae sp. 1, 2, 3 Family unknown Neomeniod sp. A, B, C, D, E, F, G, H, I MOLLUSCA – BIVALVIA Family Arcidae Bathyarca nucleator (Dall, 1908) Bathynearra tillamookensis (Dall, 1916) Family Cuspidariidae Cardiomya planetica (Dall, 1908) Cuspidaria variola Bernard, 1979 Cuspidariidae sp. 1 Myonera garretti Dall, 1908 Family Hiatellidae Saxicavella sp. 1 Family Kelliidae Kelliella galatheae (Knudsen, 1970) Family Lasaeidae Mysella nr. planata (Krauss, 1885) Neaeromya compressa (Dall, 1899) Family Malletiidae Malletia talama Dall, 1916 Family Neilonellidae Austrotindaria gibbsii (Dall, 1897) Neilonella mexicana (Dall, 1908) Family Nuculanidae Yoldiella nr. capsa (Dall, 1916) Yoldiella nr. derjugini Scarlato, 1981 Yoldiella nr. Frigida (Torell, 1859). Yoldiella nr. minuscula Verrill & Bush, 1898 Yoldiella orcia (Dall, 1916) Yoldiella sp. 1, 2 Family Nuculidae Deminucula nr. atacellana (Schenck, 1939) Nucula carlottensis Dall, 1897 Family Pectinidae Cyclopecten bistriatus (Dall, 1916) Family Pholadidae nr. Xylophaga sp. 1 Family Solemyidae Acharax johnsoni (Dall, 1891) Solemya sp. 1, 2 Family Thyasiridae Adontorhina lynnae Coan, Scott & Bernard, 2000 Axinopsida sp. 1 (2002) Leptaxinus cf. minutus Verrill & Bush, 1898 Mendicula ferruginosa (Forbes, 1844) Thyasira (Axinulus) sp. 1 Thyasira cf. cygnus Dall, 1916 Thyasira flexuosa (Montagu, 1803) Thyasira orecta Bernard, 1982 Thyasira sp. 1, 2 Thyasiridae sp. 1, 3, 4 Family Verticordiidae Dalliocordia alaskana (Dall, 1895) MOLLUSCA – GASTROPODA Family Acteonidae Acteonidae sp. 1 Family Buccinidae Buccinum diplodetum Dall, 1907 Colus cf. glyptus (Verrill, 1882) Colus cf. jordani (Dall, 1913) Colus cf. trophius (Dall, 1919) Family Cancellariidae Agatrix sp. 1 Family Lepetidae Lepetidae sp. 1 Family Naticidae Polinices pallidus Broderip & Sowerby, 1829 Family Neptuneidae nr. Mohnia frielei (Dall, 1891) Family Scaphandridae nr. Scaphander punctostriatus Mighels, 1841 Family Scissurellidae Scissurella crispata (Fleming, 1828) Family Turridae Pleurotomella sp. 2 Propebela sp. 1, 2, 3 Turridae sp. 2 (1998) Order Nudibranchia Nudibranchia spp. indet. MOLLUSCA – SCAPHOPODA Family Dentaliidae Rhabdius rectius (Carpenter, 1864) Family Siphondentaliidae Cadulus tolmei Dall, 1897 Siphonodentalium sp. 1 CRUSTACEA – AMPHIPODA Family Aoridae Lembos sp. 1 Family Ampeliscidae Ampelisca eoa Gurjanova, 1951 Ampelisca plumosa Holmes, 1908 Ampelisca sp. 1, 3 Byblis nr. barbarensis Barnard, 1960 Byblis nr. crassicornis Barnard, 1971 Haploops lodo Barnard, 1961 Family Amphilochidae Amphilochida sp. 1, 2 Family Argissidae Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table B1. (continued ) Table B1. (continued ) Argissa sp. 1 Family Caprellidae Mayerella banksia Laubitz, 1970 Caprellidae (nr. Leuconacia) sp. 1 Family Eusiiridae Eusiridae sp. 1 Family Gammaridae Gammaridae sp. 1, 2, 3 Family Isaeidae Photis typhlops Conlan, 1994 Family Ischyroceridae Bonnierella linearis Barnard, 1964 Bonnierella sp. 1 Family Lepechinellidae Lepechinella sp. 2, 3, 4, 5, 6 Family Liljeborgiidae Liljeborgia cota Barnard, 1962 Family Lysianassidae Acidostoma sp. 1 Hippomedon sp. 2 Lepidepecreum sp. 1 Lepidepecreum sp. 2 nr. Uristes sp. 1 Uristes sp. 2 Lysianassidae sp. 1, 2, 3, 4 Family Oedicerotidae Aceroides nr. callida Barnard, 1967 Aceroides sp. 1 Bathymedon caino Barnard, 1967 Bathymedon flebilis Barnard, 1967 Bathymedon nr. saussurei (Boeck, 1871) Bathymedon sp. 1, 2 Deflexilodes sp. 1, 2, 3 Deflexilodes sp. 2 Monoculodes latissimanus Stephensen, 1931 Monoculodes necopinus Barnard, 1967 Oedicerotidae sp. 1, 2, 3, 4, 5 Family Pardaliscidae nr. Halice sp. 1 nr. Pardiliscella sp. 1 Parpano sp. 1 Pardaliscidae sp. 1, 2, 3, 4 Family Phoxocephalidae Harpinia mucronata Sars, 1885 Harpiniopsis emeryi Barnard, 1960 Harpiniopsis nr. galerus Barnard, 1960 Harpiniopsis profundis Barnard, 1960 Harpiniopsis sp. 1, 2, 4, 5, 6, 7 Paraphoxus oculatus (Sars, 1895) Pseudharpinia excavata Chevreux, 1887 Pseudharpinia sp. 1 Family Pleustidae Pleusymtes nr. subglaber Baranard & Given, 1960 Pleustidae sp. 1, 2 Family Podoceridae Dulichiopsis nr. abyssi Stephensen, 1944 Dulichiopsis remis (Barnard, 1964) Paradulichia sp. 1 Family Stenothoidae Stenothoidae sp. 1 Family Synopiidae nr. Austrosyrrhoe sp. 1 Bruzelia tuberculata Sars, 1895 Bruzelia nr. popolocan Barnard, 1972 nr. Ileraustroe sp. 1 Ileraustroe sp. 2 Syrrhoe crenulata Goës, 1886 Syrrhoe sp. 2 Syrrhoites sp.2 CRUSTACEA–CUMACEA Family Bodotriidae Bathycuma longicaudatum Calman, 1912 Vaunthompsoniinae n.g. n.sp. 1 Family Diastylidae Diastylis sp. 1, 3, 4, 5, 6 Leptostylis sp. 1, 2 Makrokylindrus sp. 1, 3 Family Lampropidae Hemilamprops sp. 1, 2 ? Paralamprops sp. 1 Family Leuconidae Eudorella sp. 1, 3 Leucon (Crymoleucon) sp. 1, 3, 4, 6 Leucon (Leucon) sp. 1, 5 Leucon (Macroleucon) sp. 1 Family Nannastracidae Atlantocuma (?) sp. 1 Campylaspis sp. 5, 6, 8, 10, 11, 13, 14, 15 Cumella sp. 1, 5 Cumella (Styloptocuma) sp. 1, 3, 4 Procampylaspis sp. 1, 2, 3 CRUSTACEA–ISOPODA Family Arcturidae Arcturus sp. 1 Family Cryptoniscidae Cryptoniscidae spp. indet. Family Dendrotiidae Dendromunna sp. 1 Dendrotion sp. 1 Family Desmosomatidae Balbidocolon sp. 1 Chelator sp. 1, 2, 3 Desmosoma sp. 1, 2 Disparella sp. 2 Eugerda sp. 1, 3, 4, 5, 6, 7 Eugerdella cf. pugilator Hessler, 1970 Eugerdella sp. 1, 3, 4 Mirabilicoxa cf. richardsoni Mezhov, 1986 Mirabilicoxa sp. 1, 2, 3, 4, 5, 6, 7 Momedossa symmetrica (Schultz, 1966) Oecidiobranchus sp. 1 Prochelator sp. 1, 4, 6, 7 Family Gnathiidae Gnathia sp. 2 Family Haploniscidae Haploniscus sp. 1, 2, 3, 4 Family Ischnomesidae Haplomesus nr. insignis Hansen, 1916 Haplomesus sp. 2, 3 Ischnomesus sp. 3, 4 Family Janirellidae Janirella cf. ornata Birstein, 1960 Janirella sp. 1 Family Katianiridae Katianira sp. 1 Family Mesosignidae Mesosignum cf. asperum Menzies & Frankenburg, 1968 Family Munnopsidae Acanthomunna sp. 1, 2 Bathybadistes sp. 1 Betamorpha cf. indentifrons Menzies, 1962 Betamorpha cf. megista Thistle & Hessler, 1977 Betamorpha cf. profunda (Menzies & George, 1972) Disconectes sp. 2 Eurycope sp. 5 Ilyarachna cf. acarina Menzies & Barnard, 1959 Ilyarachna cf. profunda Schultz, 1966 Munnopsoides nr. tattersalli Birstein, 1973 Munnopsurus sp. 1, 4 Pseudarachna sp. 1 Munnopsidae sp. 1, 3, 4, 5, 6 Family Nannoniscidae Exiliniscus sp. 1, 2 Hebefustis sp. 1 Nannoniscoides sp. 1 Nannoniscus cristatus Mezhov, 1986 Nannoniscus sp. 2 Family Paramunnidae Notoxenoides sp. 1, 2, 3 Paramunna sp. 1 Pleurogonium cf. californiense Menzies, 1951 Pleurogonium sp. 1 CRUSTACEA–MYSIDACEA Family Mysidae Paramblyops sp. 1 Pseudomma sp. 1 1799 Author's personal copy ARTICLE IN PRESS 1800 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table B1. (continued ) Table B1. (continued ) CRUSTACEA–TANAIDACEA Family Anarthuridae Agathotanais sp. 1 Akanthophoreus sp. 1 Araphura sp. 2 nr. Chaulipleona dentate Dojiri & Sieg, 1991 Cryptocope sp. 1, 2 Leptognathia sp. 2 Leptognathiella nr. abyssi Hansen, 1913 Leptognathoides sp. 1 Nematotanais sp. 1 Paragathotanais sp. 1 Paranarthrura sp. 1 Scoloura sp. 1 Siphonolabrum sp. 1, 2 Tanaella forcifera (Lang, 1968) Akanthophoreinae sp. 1, 6, 7, 8, 9, 10, 11, 12 Anarthrurinae sp. 1, 2, 4, 5, 6, 7, 8, 9 Leptognathiinae sp. 1 Family Colletteidae Collettea sp. 1 Family Neotanaidae Neotanais armiger Wolff, 1956 Family Pseudotanaidae Pseudotanais nr. affinis Hansen, 1886 Pseudotanais sp. 1, 2, 3, 4, 5, 7, 8 Family Typhlotanaidae Peraeospinosus sp. 1, 3, 4, 5 Typhlotanais sp. 2 Typhlotanaidae sp. 1, 2, 3, 5, 6, 7, 8, 9, 11 Family Whiteleggiidae Carpoapseudes sp. 1, 2, 3 ARTHROPODA – PYCNOGONIDA Family Ammotheidae Ammotheidae sp. 1 Family Callipallenidae Nymphon aculeatum Child, 1994 Pallenopsis (Bathypallenopsis) nr. comosa Stock, 1975 Family Colletteidae Collettea sp. 1 Family Neotanaidae Neotanais armiger Wolff, 1956 Family Pseudotanaidae Pseudotanais nr. affinis Hansen, 1886 Pseudotanais sp. 1, 2, 3, 4, 5, 7, 8 Family Typhlotanaidae Peraeospinosus sp. 1, 3, 4, 5 Typhlotanais sp. 2 Typhlotanaidae sp. 1, 5, 6, 7, 8, 9, 11 Family Whiteleggiidae Carpoapseudes sp. 1, 2, 3 ECHINODERMATA–ASTEROIDEA Porcellanasteridae sp. 1 ECHINODERMATA–ECHINOIDEA Spatangoida sp. 1 ECHINODERMATA–HOLOTHUROIDEA Family Cucumariidae Thyone sp. 1 Family Elpidiidae Scotoplanes globosa Théel, 1882 Family Laetmogonidae Laetmogonidae sp. 1, 2 Family Molpadiidae Molpadia intermedia (Ludwig, 1894) Molpadia musculus Risso, 1826 Molpadia sp. 1 Family Synaptidae Labidoplax nr. buski (McIntosh, 1866) Myriotrochus sp. 1, 2, 3, 4 Protankyra nr. abyssicola Théel, 1886 Synaptidae (1998) sp. 1 Synallactes aenigma (Ludwig, 1893) Family Ypsilothuriidae Ypsilothuria bitentaculata Ludwig, 1894 ECHINODERMATA–OPHIUROIDEA Family Amphiuridae Amphilepis platytata Clark, 1911 Amphiura carchara Clark, 1911 Amphiura diomedeae Lyman, 1882 Dougaloplus gastracantha (Lütken & Mortensen, 1899) Family Ophiacanthidae Ophiacantha diplasia Clark, 1911 Ophiacantha macrarthra Clark, 1911 Ophiacantha normani Lyman, 1879 Ophiolimna bairdi (Lyman, 1883) Ophiophura sp. 1 Family Ophiuridae Ophiura leptoctenia Clark, 1911 Ophiura sp. 1 Family unknown Ophiuroidea sp. 1 HEMICHORDATA Enteropneusta sp. 1, 2, 3 Hemichordata sp. 1 Stereobalanus sp. 1 Taxa marked ‘‘spp. indet.’’ are included because they are the only representatives of the genus. Author's personal copy ARTICLE IN PRESS 1801 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table C1 Benthic community parameters for 135 benthic biology samples collected from SF-DODS (1996–2004). Station/year Total indiv. (0.1 m2) No. valid species 01/Dec 1996 01/1997 02/Dec 1996 02/1997 02/1998 03/Jan 1996 03/Dec 1996 03/1997 06/1999 06/2000 06/2001 06/2002 06/2003 06/2004 07/Jan 1996 07/Dec 1996 07/1997 07/1998 07/1999 08/Jan 1996 08/Dec 96 08/1997 08/1998 09/Jan 1996 09/Dec 1996 09/1997 10/Dec 1996 10/1997 10/1999 10/2000 10/2001 10/2002 10/2003 10/2004 11/Jan 1996 11/Dec 1996 11/1997 11/1999 12/Jan 1996 12/Dec 1996 12/1997 12/1998 12/1999 13/Dec 1996 13/1997 13/1998 13/2002 14/Jan 1996 14/Dec 1996 14/1997 14/1998 15/Jan 1996 15/Dec 1996 16/Dec96 16/1997 16/1998 16/2000 16/2002 16/2003 16/2004 17/Jan 1996 17/Dec 1996 17/1997 17/1998 17/1999 17/2000 17/2001 17/2002 17/2003 17/2004 18/Dec 1996 18/1997 18/1998 18/1999 706 449 699 189 326 542 649 546 540 541 695 582 691 766 76 655 452 305 663 282 663 357 307 129 406 625 463 409 374 408 510 648 697 793 219 453 536 307 161 393 364 103 252 176 100 15 273 135 255 637 328 206 633 642 576 451 876 1066 774 1068 243 314 508 502 703 690 524 713 817 882 229 449 553 254 127 94 114 55 71 94 106 107 112 94 108 91 115 130 29 123 82 58 93 62 114 79 62 44 76 88 85 74 68 76 86 104 109 115 51 80 76 54 45 60 59 35 48 47 21 9 57 39 53 72 61 47 104 113 116 103 109 123 136 162 56 67 99 109 102 103 101 123 125 132 58 102 92 67 Total indiv. Pielou’s (J0 ) valid species 574 426 577 115 282 438 590 502 490 498 634 531 647 707 75 572 421 267 597 268 589 346 274 111 311 579 422 385 330 372 460 565 655 731 201 406 482 286 156 372 346 100 235 172 100 15 256 129 247 593 308 202 599 550 479 388 742 949 726 976 236 287 447 433 644 629 481 641 756 793 222 437 507 241 0.85 0.84 0.86 0.92 0.88 0.84 0.81 0.85 0.87 0.85 0.83 0.82 0.84 0.87 0.90 0.85 0.83 0.83 0.85 0.80 0.86 0.85 0.83 0.90 0.83 0.76 0.79 0.82 0.82 0.75 0.81 0.83 0.82 0.79 0.84 0.79 0.75 0.70 0.85 0.69 0.74 0.89 0.74 0.78 0.49 0.90 0.83 0.71 0.75 0.70 0.79 0.72 0.77 0.85 0.88 0.82 0.66 0.79 0.82 0.83 0.83 0.80 0.87 0.88 0.77 0.81 0.85 0.86 0.83 0.88 0.81 0.85 0.80 0.84 Fisher’s log- Shannon’s series a H0 (log2) ESN (50) ESN (100) ESN (200) ESN (400) ESN (500) 50.50 37.32 42.57 41.36 30.52 36.73 37.69 41.65 45.38 34.27 37.40 31.61 40.67 46.76 17.34 48.12 30.39 22.82 30.87 25.30 42.11 31.99 24.97 26.94 32.07 28.88 32.07 27.24 25.98 28.90 31.20 37.43 37.32 38.35 22.03 29.83 25.37 19.69 21.19 20.24 20.44 19.14 18.25 21.32 8.11 9.50 22.75 19.00 20.71 21.46 22.81 19.25 36.35 43.10 48.67 45.82 35.23 37.67 49.39 55.40 23.21 27.49 39.39 46.85 34.12 35.00 38.99 45.23 42.67 45.20 25.53 41.85 32.87 30.75 32.2 28.9 32.1 32.0 29.2 29.8 28.3 30.3 32.4 29.2 29.5 27.2 30.4 33.6 23.5 31.9 27.6 24.2 29.3 23.8 32.1 28.8 25.7 27.2 27.8 23.5 25.9 26.1 25.1 23.1 27.0 29.1 28.6 27.9 24.6 25.7 22.7 19.7 25.2 19.5 21.7 24.7 21.2 22.2 13.1 * 24.5 20.1 21.9 20.6 23.6 20.3 25.6 31.5 33.2 30.2 22.6 28.9 31.8 32.8 24.8 24.8 31.6 33.4 25.8 27.8 30.1 32.6 30.5 34.8 24.7 30.7 26.4 26.2 51.7 44.9 50.0 50.5 43.5 46.8 43.9 45.8 50.6 44.0 44.7 40.5 45.8 52.6 * 50.9 42.1 35.0 43.9 36.0 50.3 44.2 38.7 41.4 42.6 35.3 40.2 38.6 37.3 35.7 41.2 44.2 43.2 43.8 36.3 39.6 34.7 30.0 37.0 30.0 32.1 35.0 31.7 34.2 21.0 * 36.4 32.7 32.7 31.1 35.2 31.4 40.1 48.7 51.7 48.4 36.8 44.7 51.1 52.6 36.6 38.4 49.0 52.1 39.7 42.7 47.1 50.7 46.9 54.7 37.3 47.3 40.2 39.7 77.8 66.4 72.6 * 61.5 68.0 64.6 66.6 73.9 63.1 64.4 57.6 65.8 76.6 * 76.3 60.1 49.8 61.4 53.0 73.1 62.8 54.4 * 61.3 51.9 59.1 54.9 53.1 53.7 59.2 63.8 62.2 64.6 50.9 57.8 50.3 44.6 * 44.4 45.2 * 44.6 * * * 51.4 * 47.4 44.9 49.8 46.7 59.9 70.6 76.4 73.0 56.9 63.6 76.4 79.2 51.7 55.9 70.7 76.3 58.1 61.9 68.9 73.8 68.4 78.6 54.8 68.9 58.9 59.9 109.1 91.7 98.6 * * 91.0 90.2 95.4 102.5 85.9 88.5 80.0 92.3 104.8 * 106.6 80.4 * 81.0 * 99.2 * * * * 74.0 83.0 * * * 80.9 88.9 86.7 89.8 * 79.5 70.0 * * * * * * * * * * * * 61.5 * * 85.5 98.0 107.4 103.0 82.6 86.1 106.8 112.0 * * 94.9 105.6 81.8 84.9 93.8 101.5 95.2 104.5 * 97.5 82.7 * 120.0 * 107.7 * * * 99.2 106.8 112.0 94.0 97.6 88.6 102.4 114.5 * 116.8 * * 87.6 * 107.8 * * * * 82.3 * * * * * 98.5 96.1 98.8 * * * * * * * * * * * * * * * 67.3 * * 95.3 108.3 * * 91.9 94.4 117.3 123.7 * * * * 90.8 93.5 * 111.4 105.0 113.1 * * 91.4 * 5.92 5.49 5.89 5.32 5.40 5.52 5.45 5.70 5.91 5.56 5.63 5.33 5.74 6.09 4.39 5.89 5.28 4.85 5.55 4.75 5.87 5.35 4.94 4.89 5.20 4.89 5.09 5.11 4.96 4.70 5.23 5.55 5.53 5.40 4.79 5.02 4.69 4.03 4.68 4.10 4.38 4.55 4.11 4.32 2.17 2.84 4.86 3.75 4.29 4.35 4.71 3.98 5.13 5.82 6.01 5.52 4.46 5.47 5.84 6.12 4.80 4.83 5.77 5.98 5.11 5.41 5.63 5.98 5.78 6.22 4.74 5.69 5.24 5.08 Author's personal copy ARTICLE IN PRESS 1802 J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Table C1 (continued ) Station/year Total indiv. (0.1 m2) No. valid species Total indiv. Pielou’s (J0 ) valid species Fisher’s log- Shannon’s H0 (log2) series a ESN (50) ESN (100) ESN (200) ESN (400) ESN (500) 19Jan 1996 19/1998 19/1999 19/2000 19/2001 19/2002 19/2003 19/2004 20/1999 20/2000 20/2001 20/2002 20/2003 20/2004 22/2000 23/Jan 1996 23/Dec 1996 23/1997 23/1998 23/1999 23/2002 23/2003 23/2004 24/1999 24/2000 24/2001 26/1998 27/1999 27/2000 27/2001 27/2002 27/2003 27/2004 31/2000 33/2000 50/2002 52/2003 52/2004 53/Dec 1996 53/1997 57/1999 57/2000 57/2001 57/2002 57/2003 57/2004 64/2002 64/2003 64/2004 92/2002 92/2003 92/2004 108/2003 108/2004 114/2002 114/2003 114/2004 116/2001 116/2002 116/2003 116/2004 405 540 391 349 379 484 1280 288 416 337 403 434 490 526 440 214 538 385 487 403 569 726 619 496 457 551 334 349 577 606 564 604 594 759 651 1180 1068 961 778 209 452 623 787 462 801 1044 537 788 691 548 551 434 594 699 591 727 1092 441 691 480 527 70 92 77 70 79 94 64 79 80 75 85 90 90 101 93 46 109 79 90 86 101 118 113 99 116 107 68 92 94 97 109 103 124 127 109 154 150 144 102 36 93 125 142 113 134 178 100 107 113 82 94 94 108 122 107 135 176 74 98 98 114 355 471 363 328 347 428 1264 253 384 300 362 385 457 498 413 207 499 327 450 389 522 672 592 426 420 496 302 315 523 559 511 573 562 647 584 999 1000 907 719 208 398 546 729 412 749 1000 494 736 671 528 518 404 562 641 541 661 971 411 631 465 493 26.11 34.15 29.89 27.27 31.94 37.22 14.23 39.42 30.75 32.10 35.00 36.96 33.55 38.25 37.36 18.34 43.02 33.10 33.83 34.18 37.30 41.48 41.44 40.51 52.99 41.93 27.31 43.70 33.43 33.90 42.45 36.63 49.22 47.26 39.51 50.87 48.94 48.22 32.46 12.56 38.18 50.70 52.63 51.38 47.54 62.99 37.83 34.43 38.91 27.18 33.59 38.49 39.74 44.67 39.98 51.32 62.85 26.34 32.49 37.91 46.51 25.7 26.6 26.6 26.5 27.4 28.5 10.6 31.8 25.8 28.2 29.4 28.9 28.9 26.9 28.5 20.9 29.9 28.3 26.8 28.7 27.0 28.4 29.4 30.9 33.4 33.7 24.0 30.4 26.3 25.6 31.2 29.1 33.0 28.7 25.0 33.9 28.8 27.3 26.3 19.0 31.4 30.2 30.0 33.1 30.9 30.6 26.2 28.6 30.7 24.9 28.2 26.6 30.7 31.9 27.0 30.1 33.5 25.9 26.9 29.7 32.73 38.6 41.3 40.6 40.1 42.1 44.2 17.0 49.4 39.4 42.9 44.7 45.1 45.0 42.2 44.2 31.5 47.4 43.7 40.8 44.4 41.7 44.4 45.5 48.0 53.0 52.2 37.5 48.1 40.6 39.5 48.1 44.7 51.5 47.1 41.0 53.3 45.9 44.2 39.6 27.5 48.2 48.9 48.6 52.9 49.0 46.6 41.2 44.0 46.6 38.0 42.8 42.4 47.4 49.5 43.8 49.3 55.3 39.1 40.7 45.5 51.07 54.4 60.2 58.5 56.4 60.9 64.8 26.0 71.6 57.5 61.6 64.5 66.0 65.2 63.7 64.7 45.2 71.1 62.8 59.8 63.7 62.0 66.0 66.9 70.0 79.7 74.4 55.5 72.3 59.5 58.0 70.1 64.6 76.0 72.3 63.7 77.9 68.4 67.5 57.1 35.6 69.4 74.9 74.6 78.7 73.4 76.4 62.4 63.1 67.2 55.0 61.3 64.2 68.7 72.3 66.6 75.9 85.0 55.1 58.3 65.9 74.2 * * * * * 91.1 37.7 * * * * * 86.0 91.2 91.6 * 99.5 * 84.8 * 88.9 93.6 94.2 96.3 113.4 98.9 * * 83.4 82.2 97.9 88.8 107.1 103.0 92.1 107.1 97.4 98.3 79.4 * * 107.9 107.6 111.4 103.4 112.9 90.1 84.8 92.3 74.5 83.8 93.5 94.1 100.2 94.3 108.7 134.9 73.2 80.4 91.6 103.3 * * * * * * 42.1 * * * * * * 101 * * * * * * * 103.8 104.5 * * * * * 92.2 91.7 108.0 97.4 118.2 113.9 102.0 117.6 108.4 109.9 87.6 * * 120.0 119.7 * 114.0 139.2 * 92.5 108.4 80.6 92.5 * 103.1 110.2 103.7 120.2 146.0 * 88.6 * 114.0 0.82 0.78 0.81 0.83 0.83 0.82 0.34 0.89 0.80 0.84 0.86 0.83 0.84 0.79 0.82 0.77 0.83 0.84 0.81 0.84 0.80 0.80 0.82 0.86 0.88 0.89 0.78 0.85 0.79 0.77 0.85 0.83 0.86 0.77 0.71 0.85 0.76 0.73 0.79 0.69 0.87 0.82 0.80 0.87 0.83 0.79 0.78 0.81 0.84 0.79 0.83 0.77 0.85 0.85 0.75 0.79 0.83 0.80 0.80 0.84 0.87 References Barham, E., Ayer, N.J., Boyce, R.E., 1976. Megabenthos of the San Diego Trough: photographic census and observations from the bathyscaphe Trieste. Deep-Sea Research 14, 23–128. Blake, J.A., 1993. Chapter 3. In: Blake, J.A., Lissner, A.L. (Eds.), Taxonomic Atlas of the Santa Maria Basin and Western Santa Barbara Channel. Introduction, Benthic Ecology, Oceanography, Platyhelminthes, and Nemertea, vol. 1. Santa Barbara Museum of Natural History, pp. 35–47. Blake, J.A., Grassle, J.F., 1994. Benthic structure on the US South Atlantic Slope off the Carolinas: spatial heterogeneity in a current dominated system. Deep-Sea Research II 41, 835–874. 5.03 5.12 5.10 5.08 5.22 5.40 2.03 5.59 5.06 5.25 5.49 5.40 5.43 5.27 5.37 4.27 5.65 5.27 5.26 5.38 5.33 5.51 5.58 5.69 6.01 6.00 4.74 5.52 5.20 5.11 5.77 5.52 6.01 5.35 4.77 6.20 5.46 5.23 5.25 3.59 5.72 5.71 5.73 5.91 5.85 5.92 5.19 5.49 5.76 5.00 5.42 5.07 5.73 0.85 5.08 5.59 6.17 5.00 5.28 5.58 5.93 Blake, J.A., Narayanaswamy, B.E., 2004. Benthic infaunal communities across the Weddell Sea Basin and South Sandwich Slope, Antarctica. Deep-Sea Research II 51, 1797–1815. Blake, J.A., Hecker, B., Grassle, J.F., Brown, B., Wade, M., Boehm, P., Baptiste, E., Hilbig, B., Maciolek, N.J., Petrecca, R., Ruff, R.E., Starczak, V., Watling, L.E., 1986. Study of biological processes on the US South Atlantic slope and rise. Phase 2. Prepared for the US Department of the Interior, Minerals Management Service, Washington, DC, under Contract No. 12-12-0001-30054. National Technical Information Service (NTIS) Nos. PB 87-214342 and PB 87-214359. Vol. 1, Executive Summary, ii+58 pp.; vol. 2, Final Report, ii+414 pp. and 13 appendices. /http://www.gomr.mms.gov/PI/PDFImages/ ESPIS/0/491.pdfS Author's personal copy ARTICLE IN PRESS J.A. Blake et al. / Deep-Sea Research II 56 (2009) 1775–1803 Blake, J.A., Muramoto, J.A., Hilbig, B., Williams, I.P., 1992. 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