Biodiversity Data Journal :
Taxonomic Paper
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Corresponding author: Klaas Gerdes (kgerdes@ines-solutions.eu)
Academic editor: Danwei Huang
Received: 10 Jun 2021 | Accepted: 06 Aug 2021 | Published: 28 Sep 2021
© 2021 Klaas Gerdes, Terue Kihara, Pedro Martínez Arbizu, Thomas Kuhn, Ulrich Schwarz-Schampera, Christopher Mah, Jon Norenburg, Thomas Linley, Kate Shalaeva, Enrique Macpherson, Dennis Gordon, Sabine Stöhr, Charles Messing, Simon Bober, Theresa Guggolz, Magdalini Christodoulou, Andrey Gebruk, Antonina Kremenetskaia, Andreas Kroh, Karen Sanamyan, Kathrin Bolstad, Leon Hoffman, Andrew Gooday, Tina Molodtsova
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Gerdes K, Kihara TC, Martínez Arbizu P, Kuhn T, Schwarz-Schampera U, Mah CL, Norenburg JL, Linley TD, Shalaeva K, Macpherson E, Gordon D, Stöhr S, Messing CG, Bober S, Guggolz T, Christodoulou M, Gebruk A, Kremenetskaia A, Kroh A, Sanamyan K, Bolstad K, Hoffman L, Gooday AJ, Molodtsova T (2021) Megafauna of the German exploration licence area for seafloor massive sulphides along the Central and South East Indian Ridge (Indian Ocean). Biodiversity Data Journal 9: e69955. https://doi.org/10.3897/BDJ.9.e69955
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The growing interest in mineral resources of the deep sea, such as seafloor massive sulphide deposits, has led to an increasing number of exploration licences issued by the International Seabed Authority. In the Indian Ocean, four licence areas exist, resulting in an increasing number of new hydrothermal vent fields and the discovery of new species. Most studies focus on active venting areas including their ecology, but the non-vent megafauna of the Central Indian Ridge and South East Indian Ridge remains poorly known.
In the framework of the Indian Ocean Exploration project in the German license area for seafloor massive sulphides, baseline imagery and sampling surveys were conducted yearly during research expeditions from 2013 to 2018, using video sledges and Remotely Operated Vehicles.
This is the first report of an imagery collection of megafauna from the southern Central Indian- and South East Indian Ridge, reporting the taxonomic richness and their distribution. A total of 218 taxa were recorded and identified, based on imagery, with additional morphological and molecular confirmed identifications of 20 taxa from 89 sampled specimens. The compiled fauna catalogue is a synthesis of megafauna occurrences aiming at a consistent morphological identification of taxa and showing their regional distribution. The imagery data were collected during multiple research cruises in different exploration clusters of the German licence area, located 500 km north of the Rodriguez Triple Junction along the Central Indian Ridge and 500 km southeast of it along the Southeast Indian Ridge.
deep-sea mining, INDEX, fauna catalogue, video imagery, photographs, biodiversity
The Central Indian Ridge (CIR) and South East Indian Ridge (SEIR) are part of a global oceanic ridge system with high magmatic activity, which creates new seafloor, volcanoes and hydrothermal vent fields (
Along the spreading axes of the Indian Ocean, exploration licences for SMS deposits as potential mineral resources are issued by the International Seabed Authority (ISA; www.isa.org.jm). The ISA manages the areas beyond national jurisdiction (
Possible future mining events at inactive hydrothermal vents will physically remove hard substrates and the local fauna, thereby flattening the vertical topography and permanently reducing habitat heterogeneity (
Such mining-related activities and disturbances will likely affect the hydrothermal vent fields and their surrounding areas, making taxonomic and ecological baseline studies essential for describing undisturbed environmental conditions and assessing potential mining impacts (
Deep-sea megafauna are important components of biodiversity and play significant roles in ecosystem functioning, as pointed out for megafauna occurring in nodule areas (
Environmental research has been conducted in the framework of the German Indian Ocean Exploration (INDEX) project and includes biological benthic baseline studies in accordance with ISA environmental guidelines (www.isa.org.jm (ISBA/25/LTC/6/Rev.1);
Locations of imagery stations within the INDEX exploration area. a) Overview map of the southwestern Indian Ocean showing the ridge spreading axes (red line). b) Cluster 1-12 of the GLA for polymetallic massive sulphide exploration. The red boxes show the areas enlarged in C-F; each includes imagery transects conducted in each area. c) MESO area and Cluster 4. d) Cluster 5 and 6. e) Cluster 8 and 9. f) Cluster 11 and 12. Bathymetry data provided by the Federal Institute for Geoscience and Natural Resources (BGR).
This study combined the existing imagery of the taxa observed within the GLA to create a taxonomic expert-revised faunal catalogue with consistent identifications for the six years of exploration. The goal of the image analysis was to assess the species richness of benthic megafauna within the GLA, covering active and inactive hydrothermal vent fields and their surrounding non-vent areas, namely the abyssal deep-sea areas along the spreading axis of the southern CIR, the Rodriguez Triple Junction (RTJ) and the northern SEIR.
Six expeditions in consecutive years from 2013 to 2018 were used for this imagery study and covered a cumulative bottom track distance of 220,983 m. A total of 122,918 photographs and 367 hours 10 minutes of video imagery were collected. All photographs were reviewed and faunal occurrences annotated and extracted; video imagery was only used when additional imagery was necessary to clarify the imagery-based identification. The study area has a bathymetrical range of 2,280 – 3,770 m and spanned a geographical range from the MESO areas (after RV Meteor and RV Sonne;
All imagery transects were conducted using three different video sledges and three Remotely Operated Vehicles (ROVs). The towed video platforms were the Multifunctional Tool (MFT) and the STROMER (STR), both belonging to the BGR and the video sledge (VS) of the Royal Netherlands Institute for Sea Research (NIOZ). The ROVs were the Kiel 6000 from the GEOMAR, the Remotely Operated Platform for Ocean Science (ROPOS) of the Canadian Scientific Submersible Facility (CSSF) and the ROV Victor 6000 of the IFREMER. Table
Detailed information of each expedition, including gear used, number of stations, photographs and video collected and distance covered. EGS = Edmond-vent site 2-vent site 7, SEIR = South East Indian Ridge, RTJ = Rodriguez Triple Junction, MFT = Multifunctional Tool, ROV = Remotely Operated Vehicle, VS = Video Sledge, ROPOS = Remotely Operated Platform for Ocean Science, STR = STROMER.
Expedition |
Vessel |
Year |
Time period |
Cluster |
Locality |
Gear |
No. of Stations |
Photographs |
Video (h: min) |
Distance (m) |
INDEX 2013 |
RV Sonne |
2013 |
23Oct – 21Dec |
4,5 |
MESO, Kairei, EGS |
MFT |
4 |
15,124 |
- |
11,529 |
ROV Kiel 6000 |
11 |
595 |
105:57 |
18,617 |
||||||
INDEX 2014 |
RV Pelagia |
2014 |
11Nov – 9Dec |
6,8,9 |
SEIR, Pelagia |
VS |
11 |
64,606 |
- |
33,820 |
INDEX 2015 |
RV Pelagia |
2015 |
12Oct – 12Dec |
4 |
vent site 1, EGS |
VS |
8 |
15,243 |
- |
28,529 |
ROV ROPOS |
11 |
5,608 |
68:36 |
22,541 |
||||||
INDEX 2016 |
RV Pourquoi pas? |
2016 |
3Jan – 3Feb |
5,8 |
Kairei, Pelagia |
ROV Victor 6000 |
5 |
3,402 |
81:52 |
38,277 |
INDEX 2017 |
RV Sonne |
2017 |
25Aug – 13Oct |
11,12 |
SEIR, vent site 5 |
STR |
4 |
4,522 |
- |
16,460 |
INDEX 2018 |
RV Pelagia |
2018 |
10Oct – 17Dec |
5,11,12 |
RTJ, vent sites 3-6 |
ROV ROPOS |
16 |
4,817 (9,001 frame grabs) |
110:45 |
51,210 |
Detailed information of each sampling gear, including altitude above seafloor, speed range during imagery collection, camera angle, camera system, interval of taking still photos and information regarding the resolution (dots per inch (dpi); Megapixel (mp); Bit rate (kBits sec-1); Size of video imagery in pixel X pixel). All gears used flat port pressure bottles for video and still cameras with the exception of the ROV Victor 6000, which used dome port pressure bottles.
Gear specifications |
Camera specifications |
Video specifications |
|||||||||
Gear |
Altitude |
Speed range |
Angle |
Camera system |
Interval |
Dots per inch |
Megapixel |
Frame rate |
Bit rate |
Pixel resolution |
Megapixel |
MFT |
0.5-5 m |
0.3-1 knots |
90°/ 45° |
Canon Power Shot G9 |
10 sec |
180 dpi |
12 mp |
25 fps |
8,555 kBits sec-1 |
1440X1080 |
1.6 mp |
STR |
0.5-5 m |
0.3-1 knots |
90°/ 90° |
Canon Power Shot G15 |
10 sec |
180 dpi |
12 mp |
29 fps |
15,186 kBits sec-1 |
1920X1080 |
2.1 mp |
VS |
0.5-5 m |
0.3-1.5 knots |
-/ 90° |
- |
- |
- |
- |
25 fps |
171,355 kBits sec-1 |
1920X1080 |
2.1 mp |
ROV Kiel 6000 |
0.5-5 m |
0.1-1 knots |
10-90° |
Canon Power Shot G5 |
- |
180 dpi |
5 mp |
25 fps |
4,128 kBits sec-1 |
704X576 |
0.4 mp |
ROV Victor 6000 |
0.5-5 m |
0.1-1 knots |
10-90° |
Video frame grabs |
- |
72 dpi |
2.1 mp |
25 fps |
768 kBits sec-1 |
1440X1080 |
2.1 mp |
ROV Ropos |
0.5-8 m |
0.1-1 knots |
10-90° |
Nikon D700/ D810 |
- |
300 dpi |
12 mp/ 36 mp |
30 fps |
50,384 kBits sec-1 |
1920X1080 |
2.1 mp |
All taxa visible in photographs and video were annotated, cut out, and the individuals identified to the lowest taxonomic level possible. Photographic analysis was carried out using Adobe Photoshop Lightroom 5.7 (©2019 Adobe Systems Software Ireland Ltd.; www.adobe.com). Photographs were imported and automatically white-balanced and tone-corrected; year and station were added to the metadata for standardisation purposes and use in an imagery database.
Each photograph was magnified until identification was impossible due to pixelation and each section searched for both sessile and motile animals (
The metadata of the processed photographs were exported and included taxon, abundance, expedition, year, station, GPS coordinates and technical information about the camera using the plug-in ListView (www.lightroomsolutions.com) for Adobe Photoshop Lightroom; the fauna catalogue shows selected images of each taxon.
The video imagery analysis was carried out with the video processing programme Magix Video deluxe 2014 Premium (©2003-2020 MAGIX Software GmbH; www.magix.com) primarily using video tracks from the ROVs; MFT video imagery was only processed in addition to photographs, if supporting the identification.
Both frame grabs from the video and short video films were exported and the frame grabs were used for the extension of the fauna catalogue. Short video films were cut out and added if the movement was characteristic for the animal and, therefore, helpful for identification (pers. comm. H. Singh Woods Hole Oceanographic Institute, Massachusetts, USA). The identification process was carried out in the same way as for the photographs. Detailed metadata information, such as sample locations, gear, depth, sampled specimens and camera information are listed in Suppl. material
A total of 89 specimens were collected throughout the expeditions using ROVs, mainly within active hydrothermal vent fields. Megafaunal specimens were quickly transferred to chilled seawater and photographed, and tissue subsamples or the entire animal were preserved in 96% ethanol for molecular analysis. Onboard photographs of the sampled specimens were included in this manuscript if they showed characteristic details helpful for taxonomic identification. In the laboratory, the specimens were assigned to the lowest taxonomic level possible using a sequenced segment of approximately 650 bp of the cytochrome oxidase subunit I (COI) gene. Molecular samples were used to verify identifications based on images.
Note: Scaling of photographs was, in most cases, not possible due to missing lasers or lasers visible on a different focal plane. Only size estimates, based on samples or in relation to known sizes of taxa, are given. The identification of taxa, based only on imagery, is very difficult and many of the taxa presented herein might be new species. Llife traces and the phylum Porifera, with the exception of a single trace listed as poriferan taxon, Paleodictyon nodosum, are excluded from this catalogue. The phylum Porifera was excluded from this megafauna catalogue because of the high diversity of this group and the difficulties to discriminate these morphologically very similar taxa from one another, based on imagery alone without physical samples within the INDEX area.
Some putative taxa presented have an asterisk followed by an additional taxon name in squared brackets as, for example, “Genus species *[Genus species sp. inc.]”. This means that the image shown in the catalogue has the “Genus species” identification level, even though there do exist certain images in Suppl. material
Several abbreviations were used in this fauna catalogue following the recommendations for standardisation of imagery-based annotations by
Table
List of all taxa in this fauna catalogue including phylum and the scientific name authority for the taxon. The asterisk and species names in squared brackets means that a taxon has been identified in several images, but a given identification level could not be supported in all images because not every single observation could be supported by morphological or molecular methods or contradictory results of different methods exist. Some putative taxa presented have an asterisk followed by an additional taxon name in squared brackets, as, for example, “Genus species *[Genus species sp. inc.]”, meaning that the image shown in the catalogue has the “Genus species” identification level, with further images, where the species level identification remains uncertain, indicated by “*[Genus species sp. inc.]”. The taxonomic ranks ˈcl.ˈ (“class”), ˈord.ˈ (“order”), ˈfam.ˈ (“family”), ˈgen.ˈ (“genus”) and ˈsp.ˈ (species) indicate the taxonomic rank and are always combined with the open nomenclature (ON) signs ˈindet.ˈ, ˈinc.ˈ according to
Phylum |
Taxon |
Authority |
Annelida |
Archinome jasoni *[Archinome jasoni sp. inc.] |
Borda, Kudenov, Chevaldonné, Blake, Desbruyères, Fabri, Hourdez, Pleijel, Shank, Wilson, Schulze & Rouse, 2013 |
Polynoidae gen. indet. |
Kinberg, 1856 |
|
Branchipolynoe gen. inc. |
Pettibone, 1984 |
|
Lepidonotopodium gen. inc. (DZMB_2021_0001) |
Pettibone, 1983 |
|
Lepidonotopodium gen. inc. (DZMB_2021_0002) |
Pettibone, 1983 |
|
Lepidonotopodium gen. inc. (DZMB_2021_0003) |
Pettibone, 1983 |
|
Sabellidae gen. indet. |
Latreille, 1825 |
|
Oasisia gen. inc. |
Jones, 1985 |
|
Alvinella gen. inc. |
Desbruyeres & Laubier, 1980 |
|
Arthropoda |
Glyptelasma gen. inc. |
Pilsbry, 1907 |
Neolepas marisindica sp. inc. |
Watanabe, Chen & Chan, 2018 |
|
Regioscalpellum regium sp. inc. |
(Wyville Thomson, 1873) |
|
Verrucidae fam. inc. |
Darwin, 1854 |
|
Amphipoda ord. inc. |
Latreille, 1816 |
|
Anomura fam. indet. |
MacLeay, 1838 |
|
Galatheidae fam. inc. |
Samouelle, 1819 |
|
Munidopsis aries sp. inc. |
(A. Milne Edwards, 1880) |
|
Munidopsis pallida sp. inc. |
Alcock, 1894 |
|
Paguroidea superfam. inc. |
Latreille, 1802 |
|
Thymopides laurentae sp. inc. |
Segonzac & Macpherson, 2003 |
|
Austinograea rodriguezensis |
Tsuchida & Hashimoto, 2002 |
|
Alvinocaris solitaire sp. inc. *[Alvinocaris solitaire] |
Yahagi, Watanabe, Kojima & Beedesse, 2014 |
|
Mirocaris indica sp. inc. |
Komai, Martin, Zala, Tsuchida & Hashimoto, 2006 |
|
Rimicaris kairei |
Watabe & Hashimoto, 2002 |
|
Nematocarcinus gen. inc. (DZMB_2021_0004) |
A. Milne-Edwards, 1881 |
|
Nematocarcinus gen. inc. (DZMB_2021_0005) |
A. Milne-Edwards, 1881 |
|
Dendrobranchiata subord. inc. |
Bate, 1888 |
|
Cerataspis monstrosus sp. inc. |
Gray, 1828 |
|
Munnopsidae fam. inc. (DZMB_2021_0006) |
Lilljeborg, 1864 |
|
Munnopsidae fam. inc. (DZMB_2021_0007) |
Lilljeborg, 1864 |
|
Pantopoda ord. inc. |
Gerstaecker, 1863 |
|
Bryozoa |
Cheilostomatida fam. indet. (DZMB_2021_0008) |
Busk, 1852 |
Cheilostomatida fam. indet. (DZMB_2021_0009) |
Busk, 1852 |
|
Bifaxaria gen. inc. |
Busk, 1884 |
|
Tessaradoma gen. inc. |
Norman, 1869 |
|
Chordata |
Synaphobranchidae gen. indet. |
Johnson, 1862 |
Histiobranchus gen. inc. |
Gill, 1883 |
|
Synaphobranchidae Ilyophis brunneus fam. inc. |
Gilbert, 1891 |
|
Bathysaurus mollis sp. inc. |
Günther, 1878 |
|
Bathypterois sp. indet. |
Günther, 1878 |
|
Ipnops agassizii sp. inc. |
Garman, 1899 |
|
Gadiformes Macrouridae ord. inc. (DZMB_2021_0010) |
Bonaparte, 1831 |
|
Gadiformes Macrouridae ord. inc. (DZMB_2021_0011) |
Bonaparte, 1831 |
|
Coryphaenoides gen. inc. (DZMB_2021_0012) |
Gunnerus, 1765 |
|
Coryphaenoides gen. inc. (DZMB_2021_0013) |
Gunnerus, 1765 |
|
Coryphaenoides armatus sp. inc. |
(Hector, 1875) |
|
Coryphaenoides longifilis sp. inc. |
Günther, 1877 |
|
Antimora rostrata |
(Günther, 1878) |
|
Chaunacops gen. inc. |
Garman, 1899 |
|
Notacanthiformes ord. inc. |
L. S. Berg, 1947 |
|
Aldrovandia affinis gen. inc. |
(Günther, 1877) |
|
Halosauropsis macrochir gen. inc. |
(Günther, 1878) |
|
Ophidiidae gen. indet. (DZMB_2021_0014) |
Rafinesque, 1810 |
|
Ophidiidae gen. indet. (DZMB_2021_0015) |
Rafinesque, 1810 |
|
Ophidiidae fam. inc. (DZMB_2021_0016) |
Rafinesque, 1810 |
|
Acanthonus armatus gen. inc. |
Günther, 1878 |
|
Barathrites iris gen. inc. |
Zugmayer, 1911 |
|
Bassozetus gen. inc. |
Gill, 1883 |
|
Spectrunculus crassus sp. inc. |
(Vaillant, 1888) |
|
Spectrunculus grandis sp. inc. |
(Günther, 1877) |
|
Xyelacyba myersi gen. inc. |
Cohen, 1961 |
|
Pachycara angeloi |
Thiel, Knebelsberger, Kihara & Gerdes, 2021 |
|
Octacnemidae gen. indet. |
- |
|
Culeolus spp. indet. |
Herdman, 1881 |
|
Bathyraja tunae sp. inc. |
Stehmann, 2005 |
|
Cnidaria |
Cnidaria cl. indet. |
Hatschek, 1888 |
Ceriantharia ord. indet. |
Perrier, 1893 |
|
Spirularia fam. indet. |
den Hartog, 1977 |
|
Actiniaria fam. indet. (DZMB_2021_0017) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0018) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0019) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0020) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0021) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0022) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0023) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0024) |
Hertwig, 1882 |
|
Actiniaria fam. indet. (DZMB_2021_0025) |
Hertwig, 1882 |
|
Actinoscyphiidae gen. indet. (DZMB_2021_0026) |
Stephenson, 1920 |
|
Actinoscyphiidae gen. indet. (DZMB_2021_0027) |
Stephenson, 1920 |
|
Actinoscyphia sp. indet. |
Stephenson, 1920 |
|
Actinostolidae gen. indet. |
Carlgren, 1932 |
|
Actinostola sp. indet. (DZMB_2021_0028) |
Verrill, 1883 |
|
Actinostola sp. indet. (DZMB_2021_0029) |
Verrill, 1883 |
|
Actinostola sp. indet. (DZMB_2021_0030) |
Verrill, 1883 |
|
Actinostola sp. indet. (DZMB_2021_0031) |
Verrill, 1883 |
|
Bathyphellia sp. indet. (DZMB_2021_0032) |
Carlgren, 1932 |
|
Bathyphellia sp. indet. (DZMB_2021_0033) |
Carlgren, 1932 |
|
Chondrophellia sp. indet. |
Carlgren, 1925 |
|
Maractis sp. indet. |
Fautin & Barber, 1999 |
|
Relicanthus daphneae sp. inc. |
(Daly, 2006) |
|
Alcyonacea fam. indet. |
Lamouroux, 1812 |
|
Alcyonacea Anthomastus gen. inc. |
Verrill, 1878 |
|
Anthomastus sp. indet. |
Verrill, 1878 |
|
Chrysogorgia sp. indet. (DZMB_2021_0034) |
Duchassaing & Michelotti, 1864 |
|
Chrysogorgia sp. indet. (DZMB_2021_0035) |
Duchassaing & Michelotti, 1864 |
|
Iridogorgia magnispiralis sp. inc. |
Watling, 2007 |
|
Clavulariidae gen. indet. (DZMB_2021_0036) |
Hickson, 1894 |
|
Clavulariidae gen. indet. (DZMB_2021_0037) |
Hickson, 1894 |
|
Clavulariidae fam. inc. (DZMB_2021_0038) |
Hickson, 1894 |
|
Clavulariidae fam. inc. (DZMB_2021_0039) |
Hickson, 1894 |
|
Isididae gen. indet. (DZMB_2021_0040) |
Lamouroux, 1812 |
|
Isididae gen. indet. (DZMB_2021_0041) |
Lamouroux, 1812 |
|
Isididae gen. indet. (DZMB_2021_0042) |
Lamouroux, 1812 |
|
Isididae gen. indet. (DZMB_2021_0043) |
Lamouroux, 1812 |
|
Isididae fam. inc. (DZMB_2021_0044) |
Lamouroux, 1812 |
|
Isididae gen. indet. (DZMB_2021_0045) |
Lamouroux, 1812 |
|
Isididae Acanella gen. inc. |
Gray, 1870 |
|
Isididae Bathygorgia gen. inc. |
Wright, 1885 |
|
Isididae Jasonisis gen. inc. |
Alderslade & McFadden, 2012 |
|
Isididae Keratoisis gen. inc. (DZMB_2021_0046) |
Wright, 1869 |
|
Isididae Keratoisis gen. inc. (DZMB_2021_0047) |
Wright, 1869 |
|
Isididae Lepidisis gen. inc. |
Verrill, 1883 |
|
Lepidisis spp. indet. |
Verrill, 1883 |
|
Paragorgiidae fam. inc. |
Kükenthal, 1916 |
|
Primnoidae gen. indet. (DZMB_2021_0048) |
Milne Edwards, 1857 |
|
Primnoidae gen. indet. (DZMB_2021_0049) |
Milne Edwards, 1857 |
|
Stalk of Alcyonacea or Antipatharia ord. inc. |
Lamouroux, 1812/ - |
|
Heteropathes sp. indet. |
Opresko, 2011 |
|
Heteropathes americana sp. inc. |
(Opresko, 2003) |
|
Bathypathes sp. indet. (DZMB_2021_0050) |
Brook, 1889 |
|
Bathypathes gen. inc. (DZMB_2021_0051) |
Brook, 1889 |
|
Bathypathes patula sp. inc. |
Brook, 1889 |
|
Schizopathes spp. indet. |
Brook, 1889 |
|
Pennatulacea ord. inc. (DZMB_2021_0052) |
Verrill, 1865 |
|
Pennatulacea fam. indet. (DZMB_2021_0053) |
Verrill, 1865 |
|
Pennatulacea Kophobelemnon ord. inc. |
Asbjörnsen, 1856 |
|
Umbellula sp. indet. (DZMB_2021_0054) |
Gray, 1870 |
|
Umbellula sp. indet. (DZMB_2021_0055) |
Gray, 1870 |
|
Zoantharia fam. indet. (DZMB_2021_0056) |
Gray, 1832 |
|
Zoantharia fam. indet. (DZMB_2021_0057) |
Gray, 1832 |
|
Zoantharia fam. indet. (DZMB_2021_0058) |
Gray, 1832 |
|
Epizoanthus sp. indet. |
Gray, 1867 |
|
Hydrozoa ord. indet. (DZMB_2021_0059) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0060) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0061) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0062) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0063) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0064) |
Owen, 1843 |
|
Hydrozoa ord. indet. (DZMB_2021_0065) |
Owen, 1843 |
|
Candelabrum sp. indet |
de Blainville, 1830 |
|
Corymorphidae gen. indet. |
Allman, 1872 |
|
Siphonophorae Rhodaliidae Thermopalia gen. inc. |
Pugh, 1983 |
|
Echinodermata |
Hymenodiscus gen. inc. |
Perrier, 1884 |
Freyellidae fam. inc. |
Downey, 1986 |
|
Freyastera gen. inc. |
Downey, 1986 |
|
Freyella gen. inc. |
Perrier, 1885 |
|
Styracaster gen. inc. |
Sladen, 1883 |
|
Henricia gen. inc. |
Gray, 1840 |
|
Goniasteridae gen. indet. (DZMB_2021_0066) |
Forbes, 1841 |
|
Goniasteridae gen. indet. (DZMB_2021_0067) |
Forbes, 1841 |
|
Circeaster gen. inc. |
Koehler, 1909 |
|
Evoplosoma gen. inc. |
Fisher, 1906 |
|
Lydiaster johannae sp. inc. |
Koehler, 1909 |
|
Solasteridae fam. inc. |
Viguier, 1878 |
|
Asthenactis gen. inc. |
Fisher, 1906 |
|
Hymenaster sp. indet. |
Wyville Thomson, 1873 |
|
Pteraster gen. inc. |
Müller & Troschel, 1842 |
|
Antedonidae gen. indet. (DZMB_2021_0068) |
Norman, 1865 |
|
Antedonidae fam. inc. (DZMB_2021_0069) |
Norman, 1865 |
|
Bathymetra gen. inc. |
AH Clark, 1908 |
|
Pentametrocrinus sp. indet. |
AH Clark, 1908 |
|
Hyocrinidae gen. indet. |
Carpenter, 1884 |
|
Irregularia infracl. inc. |
Latreille, 1825 |
|
Cidaroida fam. indet. |
Claus, 1880 |
|
Hapalosoma sp. indet. |
Mortensen, 1903 |
|
Salenocidaris sp. indet. |
Agassiz, 1869 |
|
Chiridota hydrothermica sp. inc. |
Smirnov & Gebruk, 2000 |
|
Elpidiidae gen. indet. (DZMB_2021_0070) |
Théel, 1882 |
|
Elpidiidae gen. indet. (DZMB_2021_0071) |
Théel, 1882 |
|
Elpidiidae gen. indet. (DZMB_2021_0072) |
Théel, 1882 |
|
Peniagone purpurea |
(Théel, 1882) |
|
Laetmogonidae gen. indet. |
Ekman, 1926 |
|
Enypniastes eximia |
Théel, 1882 |
|
Benthodytes sp. indet. |
Théel, 1882 |
|
Benthothuria gen. inc. |
Perrier R., 1898 |
|
Pseudostichopus gen. inc. (DZMB_2021_0073) |
Théel, 1886 |
|
Pseudostichopus sp. indet. (DZMB_2021_0074) |
Théel, 1886 |
|
Oneirophanta sp. indet. |
Théel, 1879 |
|
Synallactidae gen. indet. (DZMB_2021_0075) |
Ludwig, 1894 |
|
Synallactidae gen. indet. (DZMB_2021_0076) |
Ludwig, 1894 |
|
Synallactidae gen. indet. (DZMB_2021_0077) |
Ludwig, 1894 |
|
Synallactidae gen. indet. (DZMB_2021_0078) |
Ludwig, 1894 |
|
Synallactidae fam. inc. (DZMB_2021_0079) |
Ludwig, 1894 |
|
Synallactes sp. indet. |
Ludwig, 1894 |
|
Amphilepidida ord. inc. |
O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017 |
|
Asteronyx gen. inc. |
Müller & Troschel, 1842 |
|
Ophiacanthida ord. inc. |
O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017 |
|
Ophiophyllum petilum sp. inc. |
Lyman, 1878 |
|
Ophiosphalma gen. inc. |
H.L. Clark, 1941 |
|
Ophiosphalma armigerum sp. inc. |
(Lyman, 1878) |
|
Hemichordata |
Torquaratoridae fam. inc. |
Holland, Clague, Gordon, Gebruk, Pawson & Vecchione, 2005 |
Mollusca |
Bathymodiolus septemdierum *[Bathymodiolus septemdierum sp. inc.] |
Hashimoto & Okutani, 1994 |
Bathypolypus sp. indet. |
Grimpe, 1921 |
|
Cirroteuthis sp. indet. |
Eschricht, 1838 |
|
Grimpoteuthis gen. inc. |
Robson, 1932 |
|
Magnapinna sp. indet. |
Vecchione & Young, 1998 |
|
Abyssochrysoidea superfam. inc. |
Tomlin, 1927 |
|
Speculator gen. inc. |
Waren & Bouchet, 2001 |
|
Alviniconcha marisindica |
Okutani, 2014 |
|
Lepetodrilidae fam. inc. |
McLean, 1988 |
|
Lepetodrilus gen. inc. |
McLean, 1988 |
|
Lepetodrilidae Lepetodrilus sp. indet. *[Lepetodrilidae Lepetodrilus gen. inc.] |
McLean, 1988 |
|
Phymorhynchus sp. indet. |
Dall, 1908 |
|
Phymorhynchus sp. indet. (Egg capsules) |
Dall, 1908 |
|
Melanodrymiidae fam. inc. |
Salvini-Plawen & Steiner, 1995 |
|
Chrysomallon squamiferum |
C. Chen, Linse, Copley & Rogers, 2015 |
|
Scaphopoda ord. indet. |
Bronn, 1862 |
|
Solenogastres ord. indet. |
Gegenbaur, 1878 |
|
Nemertea |
Thermanemertes gen. inc. |
Rogers, Gibson & Tunnicliffe, 1996 |
Platyhelminthes |
Polycladida fam. indet. *[Polycladida ord. inc.] |
Lang, 1884 |
Porifera |
Paleodictyon nodosum |
Seilacher, 1977 |
Foraminifera |
Monothalamea ord. indet. (DZMB_2021_0080) |
Haeckel, 1862 (as emended by Pawlowski et al., 2013) |
Monothalamea ord. indet. (DZMB_2021_0081) |
Haeckel, 1862 (as emended by Pawlowski et al., 2013) |
|
Monothalamea ord. indet. (DZMB_2021_0082) |
Haeckel, 1862 (as emended by Pawlowski et al., 2013) |
|
Luffammina gen. inc. |
Kamenskaya, Bagirov & Simdianov, 2002 |
|
Psammina gen. inc. (DZMB_2021_0083) |
Haeckel, 1889 |
|
Psammina gen. inc. (DZMB_2021_0084) |
Haeckel, 1889 |
|
Stannoma gen. inc. |
Haeckel, 1889 |
The following Table
Brief description of the 78 fields of the Suppl. material
Field name |
Field data description |
Field ID |
Unique ID for each data entry |
Cruise Name |
Name of the research expedition |
Research Vessel |
Name of the vessel on which the expedition took place |
Leg Number |
Contains the leg of a single expedition during which the data were generated |
Geographical Area |
Mid Ocean Ridge segment where the data were collected |
Area sector |
Contains information if the data were collected within or outside a cluster and in which cluster the data were collected. The clusters are within the German licence area for the exploration of polymetallic sulphide occurrences and were issued by the Federal Institute for Geosciences and Natural Resources (www.bgr.de) on behalf of the International Seabed Authority (www.isa.org.jm) |
Year |
Year of the expedition |
Sampling Date |
Date of data collection (year-month-day) |
Time stamp (on video/still photo) |
Time (hours:minutes:seconds) of the data collection in UTC |
Sampling start time |
Start time of the individual transect (hours:minutes) |
Sampling start depth |
Depth (m) at the starting point of the transect |
Sampling start latitude |
Latitude at the starting point of the transect |
Sampling start longitude |
Longitude at the starting point of the transect |
Sampling end time |
End time of the individual transect (hours:minutes) |
Sampling end depth |
Depth (m) at the end point of the transect |
Sampling end latitude |
Latitude at the end point of the transect |
Sampling end longitude |
Longitude at the end point of the transect |
Area or Volume sampled (m) |
Length (m) of the entire transect |
Locality |
Local name of the sampling area or hydrothermal vent field name |
Geodetic Datum |
Global reference frame for precisely measuring locations on Earth |
Coordinate uncertainty in Meters |
Accurracy deviation of the underwater acoustic Ultra-short-baseline (USBL) positioning in metres |
Station ID |
Name of individual station including the year of expedition |
Transect ID |
Name of the individual transect |
Sample ID |
Name of the individual sample collected |
Voucher Specimen Code |
Unique code for each sampled specimen |
Marker |
Genetic marker targeted |
PCR Result |
Descriptor for the success of extracting DNA with the Polymerase chain reaction (PCR) |
Sequence Result |
Descriptor for the successful sequencing result of the extracted DNA |
Photograph frame code of sampled specimen |
Photograph name of the sampled specimen |
Sampling Gear (code) |
Abbreviation of the tool or gear used for the data collection |
Preparations |
Descriptor for the preparation of collected data including information of the fixation of sampled specimens |
Institution Storing Imagery and Samples |
Abbreviation of Institute where samples are stored |
Recorded By |
Abbreviation of Institute that has the copyright of imagery |
Occurrence Status |
Indication for the occurrence status of the identified taxon in the data |
Identification Remarks |
Indicating potential limitations related to the available material and data type used for the identification (imagery, physical sample or both) |
Language |
Language of the data entry |
Basis of Record |
Descriptor if the identification record was based on Human observtaion (indirect, imagery only) or Preserved Specimen (direct, including physical samples) |
Dataset Name |
Name of the Dataset, equivalent with the project name INDEX (Indian Ocean Exploration Project) |
Number of sampled individuals |
Indicating how many of the photographed individuals were collected and are present as a physical sample |
Number of counted individuals |
Number of individuals of a specific taxon that were counted in the photograph present. The number "0" indicates different photograph or sample of an identical specimen, the number "100" indicates that precise counting was not possible and an uncountable number of individuals was present. |
Frame Code (on video/still photo) |
Name of the photograph or frame grab showing the identified taxon |
Area of image |
Showing the total area of each photograph or frame grab in pixels (length x width) |
Video/photo sled ID code |
Name of the tool or gear used for the data collection |
Technical specifications of camera equipment |
Specification of the camera used or if a frame grab was extracted from a high definition (hd) or standard definition (sd) video |
Kingdom |
Taxonomic classification hierarchy level: Kingdom |
Identification: Phylum |
Taxonomic classification hierarchy level: Phylum |
Identification: Class |
Taxonomic classification hierarchy level: Class |
Identification: Order |
Taxonomic classification hierarchy level: Order |
Identification: Family |
Taxonomic classification hierarchy level: Family |
Identification: Genus |
Taxonomic classification hierarchy level: Genus |
Identification: Species |
Taxonomic classification hierarchy level: Species |
Taxon rank |
Lowest possible identification level |
Identification Qualifier |
Descriptor for the confidence of the identification level |
Scientific Name authorship |
Authority and year of the original taxon description |
Identification: putative species name or number |
Putative taxon name regardless the identification level including the identification qualifier |
Identification Molecular |
Result of the molecular identification if present |
Morphological Taxonomist |
Responsible taxonomist who identified the taxon the putative taxon name or number |
Morphological Taxonomist E-mail |
Current email adress of the taxonomist |
Morphological Taxonomist Institution |
Current Institution of the taxonomist |
Behaviour |
Behaviour of the observed and identified individual |
Specimen Details: Life Stage |
Life stage of the identified individual, if possible |
Specimen Details : Tissue Descriptor |
Tissue used for the molecular DNA extraction |
Specimen Details: Associated Taxa |
Associated taxa in the close vicinity of the identified taxon |
Specimen Details : Associated Specimens |
Associated specimens in symbiosis or attached to the identified individual |
Hydrothermal activity |
Indicating if the identified taxon was observed in an area with hydrothermal activity or not |
Activity of hydrothermal vent site (active/inactive/dormant/diffuse flow) |
Indicating the level of hydrothermal activity from high to low/no activity in the categories "active", "diffuse flow", "inactive", "dormant", "non-vent", respectively |
Age of hydrothermal vent (100 - >10,000 years) |
Estimated and categorised age of hydrothermal vent field from young (100 years) to old (10,000 years) |
Water Body |
Ocean in which data or samples were collected |
Water Temperature (°C) |
Water temperature in degrees Celsius at the location of the observed individual (if measured) |
Salinity (ppt) |
Salinity in parts per thousand at the location of the observed individual (if measured) |
Depth (m) |
Depth (m) at the location of the observed individual |
Image Type |
Indicating if the data were derived from a photograph or from video imagery |
Exposure |
Exposure time of the camera used |
ISO-speed |
Indicating the sensitivity of the CMOS sensor towards light. A higher ISO speed indicates higher sensitivity to light. |
Focal length |
Measure of how strongly the camera converges the light |
Use of picture |
Descriptor of which photographs were extracted for identification, were extracted and send to taxonomists for precise identification and extracted, identified and shown in the publication as an example of that taxon |
Latitude |
Latitude in decimal degrees of the observed individual |
Longitude |
Longitude in decimal degrees of the observed individual |
Fig.
Culeolus sp. indet. in situ in the surrounding area of the vent site 4 hydrothermal vent field in Cluster 5 of the INDEX area. The individual is an example for the species complex Culeolus spp. indet., with more images and entries in the supplementary imagery and data table. Image corresponds with the data (Image attribution: BGR).
Fig.
Lepidisis sp. indet. in situ at the South East Indian Ridge within Vent site 5 in Cluster 11 of the INDEX area. The individual is an example for the species complex Lepidisis spp. indet., with more images and entries in the supplementary imagery and data table. Image corresponds with the data (Image attribution: BGR).
Fig.
Schizopathes sp. indet. in situ at the Rodriguez Triple Junction at the border of Vent site 4 in Cluster 5 of the INDEX area. The individual is an example for the species complex Schizopathes spp. indet., with more images and entries in the supplementary imagery and data table. Image corresponds with the data (Image attribution: BGR).
Remarks: The animal seen in Fig.
Remarks: The echinoid seen in Fig.
Less detail can be recognszed in an individual seen in images R1915_00209 and R1915_00213, but the high similarity to the specimen in Fig.
Remarks: The presence of relatively few, long and slender spines with upturned distal ends characterise the observed echinoids as saleniids. This is further supported by the excentric position of the periproct and large apical disc seen in Fig.
Despite the majority of the 218 taxa identified solely on imagery and physical samples existing for a considerably lower number, this is the first image atlas of the deep-sea benthic megafauna for the GLA, covering the southern CIR and northern SEIR in the Indian Ocean. Specifically, the atlas consists of the first collection of imaged taxon occurrences within active hydrothermal vents and their periphery, inactive vent sites and the non-vent areas in a region potentially exposed to mining and, thus, presents valuable biological baseline information.
Amongst the 218 taxa, the phylum Cnidaria are represented by the most taxa (77), followed by the phyla Echinodermata (48), Chordata (30), Arthropoda (22), Mollusca (17), Annelida (9) and Bryozoa (4). The phyla Hemichordata, Nemertea, Platyhelminthes and Porifera are each represented by one taxon. However, the latter phylum was excluded from this catalogue as noted in the Methods section, but has a considerably higher number of taxa (Table
Number of taxa/species in each phylum at the Central Indian Ridge (CIR), the South East Indian Ridge (SEIR) and the Rodriguez Triple Junction (RTJ). Numbers include active vent taxa, inactive vent taxa and non-vent taxa. Note, that the phylum Porifera was excluded from this catalogue, with the exception of a single species.
Phylum |
Taxa CIR |
Taxa SEIR |
Taxa RTJ |
Taxa total |
Annelida |
5 |
8 |
3 |
9 |
Arthropoda |
15 |
17 |
12 |
22 |
Bryozoa |
3 |
4 |
1 |
4 |
Chordata |
16 |
19 |
16 |
30 |
Cnidaria |
42 |
47 |
28 |
77 |
Echinodermata |
26 |
37 |
12 |
48 |
Hemichordata |
- |
1 |
- |
1 |
Mollusca |
8 |
14 |
10 |
17 |
Nemertea |
- |
- |
1 |
1 |
Platyhelminthes |
1 |
- |
1 |
1 |
Porifera |
1 |
1 |
- |
1 |
Foraminifera |
5 |
4 |
2 |
7 |
Total |
122 |
152 |
86 |
218 |
In the Kingdom Chromista, protists, belonging to phylum Foraminifera, contributed seven taxa that could be distinguished, based on imagery. Some are tentatively identified to genus level, but these identifications cannot be confirmed from photographs alone. The identification of xenophyophores from photographs is particularly problematic. Nevertheless, these protistan taxa were consistently identified in all years and by all sampling gear.
A total of 93 megafaunal taxa were recognised from the active hydrothermal vents, based on imagery (Table
List of active vent species for the Central Indian Ridge (CIR), the South East Indian Ridge (SEIR) and the Rodriguez Triple Junction (RTJ) within active hydrothermal vent fields in each region. Presence of each taxon indicated as low ('+'), medium ('++') or high ('+++') density. Low density = 1 specimen, medium = 2-9 specimens and high ≥ 10 specimens. Endemic active vent taxa are highlighted in bold.
Phylum |
Active vent taxa |
CIR |
SEIR |
RTJ |
Annelida |
Archinome jasoni *[Archinome jasoni sp. inc.] |
+++ |
+++ |
+++ |
Branchipolynoe gen. inc. |
+ |
|||
Lepidonotopodium gen. inc. (DZMB_2021_0001) |
++ |
++ |
++ |
|
Oasisia gen. inc. |
+++ |
+++ |
||
Alvinella gen. inc. |
+++ |
|||
Arthropoda |
Neolepas marisindica sp. inc. |
+++ |
+++ |
+++ |
Regioscalpellum regium sp. inc. |
+++ |
|||
Verrucidae fam. inc. |
+++ |
+++ |
||
Munidopsis pallida sp. inc. |
++ |
|||
Austinograea rodriguezensis |
+++ |
+++ |
+++ |
|
Alvinocaris solitaire sp. inc. |
+++ |
+++ |
+++ |
|
Mirocaris indica sp. inc. |
+++ |
++ |
++ |
|
Rimicaris kairei |
+++ |
+++ |
+++ |
|
Pantopoda ord. inc. |
++ |
|||
Chordata |
Synaphobranchidae gen. indet. |
+ |
++ |
|
Synaphobranchidae Ilyophis brunneus fam. inc. |
+ |
|||
Coryphaenoides gen. inc. (DZMB_2021_0012) |
+ |
+ |
||
Coryphaenoides armatus sp. inc. |
+ |
+ |
||
Halosauropsis macrochir gen. inc. |
+ |
|||
Spectrunculus crassus sp. inc. |
++ |
|||
Spectrunculus grandis sp. inc. |
++ |
+ |
||
Pachycara angeloi |
++ |
++ |
++ |
|
Cnidaria |
Ceriantharia ord. indet. |
+ |
||
Actiniaria fam. indet. (DZMB_2021_0017) |
+++ |
|||
Actiniaria fam. indet. (DZMB_2021_0018) |
++ |
|||
Actiniaria fam. indet. (DZMB_2021_0019) |
+++ |
++ |
+++ |
|
Actiniaria fam. indet. (DZMB_2021_0020) |
+++ |
+ |
||
Actiniaria fam. indet. (DZMB_2021_0021) |
+++ |
++ |
||
Actiniaria fam. indet. (DZMB_2021_0022) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0023) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0024) |
++ |
|||
Actiniaria fam. indet. (DZMB_2021_0025) |
++ |
|||
Actinoscyphiidae gen. indet. (DZMB_2021_0026) |
+ |
+ |
||
Actinoscyphia sp. indet. |
+ |
++ |
||
Actinostolidae gen. indet. |
++ |
++ |
+++ |
|
Actinostola sp. indet. (DZMB_2021_0028) |
+++ |
+ |
||
Actinostola sp. indet. (DZMB_2021_0029) |
+ |
|||
Actinostola sp. indet. (DZMB_2021_0030) |
+ |
+++ |
||
Actinostola sp. indet. (DZMB_2021_0031) |
+ |
|||
Bathyphellia sp. indet. (DZMB_2021_0032) |
++ |
++ |
||
Bathyphellia sp. indet. (DZMB_2021_0033) |
+++ |
|||
Maractis sp. indet. |
+++ |
+++ |
+++ |
|
Relicanthus daphneae sp. inc. |
+ |
+ |
||
Alcyonacea Anthomastus gen. inc. |
+ |
|||
Iridogorgia magnispiralis sp. inc. |
++ |
|||
Clavulariidae gen. indet. (DZMB_2021_0036) |
+++ |
+++ |
+++ |
|
Clavulariidae gen. indet. (DZMB_2021_0037) |
+ |
|||
Clavulariidae fam. inc. (DZMB_2021_0038) |
++ |
|||
Clavulariidae fam. inc. (DZMB_2021_0039) |
++ |
|||
Isididae gen. indet. (DZMB_2021_0040) |
+ |
|||
Isididae gen. indet. (DZMB_2021_0041) |
+ |
|||
Isididae gen. indet. (DZMB_2021_0043) |
+ |
+ |
||
Isididae fam. inc. (DZMB_2021_0044) |
+ |
|||
Isididae Bathygorgia gen. inc. |
++ |
+ |
||
Isididae Jasonisis gen. inc. |
++ |
|||
Isididae Keratoisis gen. inc. (DZMB_2021_0047) |
++ |
|||
Isididae Lepidisis gen. inc. |
++ |
|||
Lepidisis spp. indet. |
+++ |
++ |
||
Paragorgiidae fam. inc. |
+ |
|||
Primnoidae gen. indet. (DZMB_2021_0048) |
+ |
|||
Primnoidae gen. indet. (DZMB_2021_0049) |
++ |
|||
Stalk of Alcyonacea or Antipatharia ord. inc. |
+ |
|||
Heteropathes americana sp. inc. |
+ |
|||
Bathypathes sp. indet. (DZMB_2021_0050) |
+ |
|||
Bathypathes patula sp. inc. |
++ |
++ |
++ |
|
Schizopathes spp. indet. |
+ |
+ |
||
Umbellula sp. indet. (DZMB_2021_0054) |
++ |
|||
Umbellula sp. indet. (DZMB_2021_0055) |
++ |
|||
Zoantharia fam. indet. (DZMB_2021_0056) |
+++ |
+++ |
||
Zoantharia fam. indet. (DZMB_2021_0057) |
+++ |
+++ |
+++ |
|
Hydrozoa ord. indet. (DZMB_2021_0060) |
+++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0061) |
+++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0062) |
+ |
|||
Hydrozoa ord. indet. (DZMB_2021_0063) |
++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0064) |
+++ |
|||
Candelabrum sp. indet. |
+++ |
+ |
++ |
|
Corymorphidae gen. indet. |
+ |
|||
Siphonophorae Rhodaliidae Thermopalia gen. inc. |
++ |
|||
Echinodermata |
Freyella gen. inc. |
+ |
||
Chiridota hydrothermica sp. inc. |
++ |
+++ |
||
Mollusca |
Bathymodiolus septemdierum *[Bathymodiolus septemdierum sp. inc.] |
+++ |
+++ |
+++ |
Abyssochrysoidea superfam. inc. |
+++ |
|||
Alviniconcha marisindica |
+++ |
+++ |
+++ |
|
Lepetodrilidae fam. inc. |
+++ |
+++ |
||
Lepetodrilus gen. inc. |
+++ |
|||
Lepetodrilidae Lepetodrilus sp. indet. *[Lepetodrilidae Lepetodrilus gen. inc.] |
+++ |
+++ |
||
Phymorhynchus sp. indet. |
+++ |
+++ |
+++ |
|
Phymorhynchus sp. indet. (Egg capsules) |
+++ |
+++ |
+++ |
|
Melanodrymiidae fam. inc. |
+++ |
|||
Chrysomallon squamiferum |
+++ |
+++ |
||
Solenogastres ord. indet. |
+ |
+ |
||
Nemertea |
Thermanemertes gen. inc. |
+++ |
||
Platyhelminthes |
Polycladida ord. inc. |
+++ |
+++ |
Of the total of 93 taxa found within and in close proximity to hydrothermal vents, 29 identified megafaunal taxa were considered endemic at active vent fields. This number is comparable to the total of 46 megafaunal taxa identified from imagery or physical sampling at Dodo, Solitaire, Edmond and Kairei vent fields, stretching along the CIR and at Longqi and Tiancheng along the South West Indian Ridge (SWIR) (
We recognised a total of 69 taxa at inactive vent fields and inactive parts of active vent fields (Table
List of inactive vent species for the Central Indian Ridge (CIR), the South East Indian Ridge (SEIR) and the Rodriguez Triple Junction (RTJ) within inactive hydrothermal vent fields in each region. Presence of each taxon indicated as low ('+'), medium ('++') or high ('+++') density. Low density = 1 specimen, medium = 2-9 specimens and high ≥ 10 specimens. Taxa found exclusively within or in close proximity to inactive hydrothermal vent fields are highlighted in bold, taxa observed only within inactive vent fields are additionally indicated by a plus.
Phylum |
Inactive vent taxa |
CIR |
SEIR |
RTJ |
Annelida |
Polynoidae gen. indet. |
++ |
++ |
|
Lepidonotopodium gen. inc. (DZMB_2021_0002) + |
+ |
|||
Lepidonotopodium gen. inc. (DZMB_2021_0003) + |
+ |
|||
Arthropoda |
Glyptelasma gen. inc. |
+++ |
+ |
|
Amphipoda ord. inc. + |
+ |
|||
Munidopsis aries sp. inc. |
+ |
|||
Munidopsis pallida sp. inc. |
++ |
++ |
||
Thymopides laurentae sp. inc. |
+ |
|||
Nematocarcinus gen. inc. (DZMB_2021_0004) |
+ |
|||
Nematocarcinus gen. inc. (DZMB_2021_0005) |
+ |
+ |
||
Cerataspis monstrosus sp. inc. |
++ |
|||
Munnopsidae fam. inc. (DZMB_2021_0007) + |
+++ |
|||
Bryozoa |
Cheilostomatida fam. indet. (DZMB_2021_0009) + |
+++ |
||
Chordata |
Synaphobranchidae gen. indet. |
++ |
++ |
+ |
Histiobranchus gen. inc. |
+ |
|||
Coryphaenoides longifilis sp. inc. |
+ |
++ |
||
Halosauropsis macrochir gen. inc. |
++ |
|||
Ophidiidae gen. indet. (DZMB_2021_0014) |
+ |
|||
Bassozetus gen. inc. |
+ |
|||
Spectrunculus grandis sp. inc. |
++ |
|||
Cnidaria |
Spirularia fam. indet. |
++ |
||
Actiniaria fam. indet. (DZMB_2021_0017) |
++ |
|||
Actiniaria fam. indet. (DZMB_2021_0018) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0020) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0021) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0022) |
++ |
|||
Actinoscyphia sp. indet |
++ |
+ |
||
Actinostolidae gen. indet. |
+ |
++ |
||
Actinostola sp. indet. (DZMB_2021_0028) |
+ |
+ |
||
Bathyphellia sp. indet. (DZMB_2021_0032) |
++ |
|||
Chondrophellia sp. indet. + |
++ |
|||
Alcyonacea fam. indet. + |
++ |
|||
Anthomastus sp. indet. + |
++ |
|||
Chrysogorgia sp. indet. (DZMB_2021_0034) + |
+ |
|||
Chrysogorgia sp. indet. (DZMB_2021_0035) + |
++ |
|||
Iridogorgia magnispiralis sp. inc. |
+++ |
|||
Clavulariidae gen. indet. (DZMB_2021_0036) |
+ |
++ |
||
Clavulariidae gen. indet. (DZMB_2021_0037) |
+ |
|||
Isididae gen. indet. (DZMB_2021_0040) |
+ |
|||
Isididae gen. indet. (DZMB_2021_0042) |
++ |
|||
Isididae gen. indet. (DZMB_2021_0045) + |
+ |
|||
Isididae Acanella gen. inc. |
++ |
|||
Isididae Bathygorgia gen. inc. |
++ |
++ |
||
Isididae Jasonisis gen. inc. |
++ |
|||
Isididae Lepidisis gen. inc. |
++ |
|||
Lepidisis spp. indet. |
++ |
++ |
||
Primnoidae gen. indet. (DZMB_2021_0049) |
++ |
|||
Stalk of Alcyonacea or Antipatharia ord. inc. |
++ |
|||
Heteropathes sp. indet. |
++ |
|||
Bathypathes gen. inc. (DZMB_2021_0051) |
+ |
|||
Bathypathes patula sp. inc. |
++ |
|||
Pennatulacea ord. inc. (DZMB_2021_0052) |
+ |
|||
Pennatulacea Kophobelemnon ord. inc. |
+ |
|||
Zoantharia fam. indet. (DZMB_2021_0056) |
+++ |
+++ |
||
Zoantharia fam. indet. (DZMB_2021_0057) |
+++ |
+++ |
||
Zoantharia fam. indet. (DZMB_2021_0058) + |
+++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0059) + |
+++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0062) |
++ |
|||
Echinodermata |
Freyellidae fam. inc. |
+ |
||
Freyella gen. inc. |
++ |
|||
Goniasteridae gen. indet. (DZMB_2021_0066) |
+ |
|||
Circeaster gen. inc. + |
+ |
++ |
||
Hapalosoma sp. indet. |
+ |
|||
Synallactidae gen. indet. (DZMB_2021_0077) |
+ |
|||
Synallactes sp. indet. |
++ |
|||
Ophiosphalma gen. inc. + |
+ |
|||
Ophiosphalma armigerum sp. inc. |
++ |
+ |
||
Mollusca |
Abyssochrysoidea superfam. inc. |
+++ |
||
Phymorhynchus sp. indet. (Egg capsules) |
+++ |
The few studies focusing on megafauna at inactive vent fields found that most taxa are known from other hard substrates and were not endemic or strictly dependent on inactive hydrothermal areas (
Some species were found exclusively at inactive vents, including two limpet species from the East Pacific Rise (
In the Pacific Ocean aggregations of non-vent fauna, such as solitary tunicates, brisingid sea stars, crinoids, sponges, anemones and brachiopods are found on inactive hydrothermal sulphides at Gorda Ridge (
On inactive chimney complexes at Longqi,
A total of 134 megafauna taxa were identified in the non-vent areas (Table
List of non-vent species for the Central Indian Ridge (CIR), the South East Indian Ridge (SEIR) and the Rodriguez Triple Junction (RTJ). Presence of each taxon indicated as low ('+'), medium ('++') or high ('+++') density. Low density = 1 specimen, medium = 2-9 specimens and high ≥ 10 specimens.
Phylum |
Non-vent taxa |
CIR |
SEIR |
RTJ |
Annelida |
Polynoidae gen. indet. |
++ |
||
Sabellidae gen. indet. |
++ |
+++ |
||
Arthropoda |
Anomura fam. indet. |
++ |
||
Galatheidae fam. inc. |
++ |
+ |
||
Munidopsis aries sp. inc. |
++ |
+ |
+ |
|
Munidopsis pallida sp. inc. |
++ |
++ |
||
Paguroidea superfam. inc. |
++ |
|||
Thymopides laurentae sp. inc. |
+ |
|||
Nematocarcinus gen. inc. (DZMB_2021_0004) |
+++ |
++ |
++ |
|
Nematocarcinus gen. inc. (DZMB_2021_0005) |
+++ |
|||
Dendrobranchiata subord. inc. |
+ |
|||
Cerataspis monstrosus sp. inc. |
++ |
+++ |
++ |
|
Munnopsidae fam. inc. (DZMB_2021_0006) |
+++ |
|||
Bryozoa |
Cheilostomatida fam. indet. (DZMB_2021_0008) |
++ |
++ |
|
Bifaxaria gen. inc. |
++ |
++ |
+ |
|
Tessaradoma gen. inc. |
+++ |
+ |
||
Chordata |
Synaphobranchidae gen. indet. |
++ |
++ |
|
Bathysaurus mollis sp. inc. |
++ |
++ |
++ |
|
Bathypterois sp. indet. |
++ |
+ |
||
Ipnops agassizii sp. inc. |
++ |
+ |
||
Gadiformes Macrouridae ord. inc. (DZMB_2021_0010) |
+ |
|||
Gadiformes Macrouridae ord. inc. (DZMB_2021_0011) |
+ |
|||
Coryphaenoides gen. inc. (DZMB_2021_0013) |
++ |
|||
Coryphaenoides armatus sp. inc. |
++ |
+ |
||
Antimora rostrata |
++ |
|||
Chaunacops gen. inc. |
+ |
|||
Notacanthiformes ord. inc. |
++ |
|||
Aldrovandia affinis gen. inc. |
++ |
+++ |
||
Halosauropsis macrochir gen. inc. |
+++ |
++ |
||
Ophidiidae gen. indet. (DZMB_2021_0015) |
+ |
|||
Ophidiidae fam. inc. (DZMB_2021_0016) |
+ |
++ |
||
Acanthonus armatus gen. inc. |
+ |
++ |
+ |
|
Barathrites iris gen. inc. |
++ |
|||
Bassozetus gen. inc. |
+ |
++ |
||
Spectrunculus crassus sp. inc. |
++ |
+ |
||
Spectrunculus grandis sp. inc. |
+ |
++ |
||
Xyelacyba myersi gen. inc. |
++ |
|||
Octacnemidae gen. indet. |
+ |
|||
Culeolus spp. indet |
++ |
|||
Bathyraja tunae sp. inc. |
++ |
|||
Cnidaria |
Cnidaria cl. indet. |
+ |
||
Spirularia fam. indet. |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0017) |
+ |
+ |
||
Actiniaria fam. indet. (DZMB_2021_0018) |
++ |
|||
Actiniaria fam. indet. (DZMB_2021_0020) |
+ |
|||
Actiniaria fam. indet. (DZMB_2021_0022) |
+ |
|||
Actinostolidae gen. indet. |
++ |
|||
Actinostola sp. indet. (DZMB_2021_0028) |
++ |
+ |
||
Bathyphellia sp. indet. (DZMB_2021_0032) |
++ |
|||
Bathyphellia sp. indet. (DZMB_2021_0033) |
++ |
|||
Alcyonacea Anthomastus gen. inc. |
+ |
|||
Iridogorgia magnispiralis sp. inc. |
+ |
|||
Clavulariidae gen. indet. (DZMB_2021_0037) |
+ |
|||
Clavulariidae fam. inc. (DZMB_2021_0038) |
+ |
|||
Isididae gen. indet. (DZMB_2021_0042) |
+ |
|||
Isididae fam. inc. (DZMB_2021_0044) |
+ |
|||
Isididae Acanella gen. inc. |
+ |
|||
Isididae Bathygorgia gen. inc. |
+ |
+ |
||
Isididae Jasonisis gen. inc. |
+ |
|||
Isididae Keratoisis gen. inc. (DZMB_2021_0046) |
+ |
|||
Isididae Lepidisis gen. inc. |
+ |
|||
Lepidisis spp. indet. |
++ |
|||
Paragorgiidae fam. inc. |
+ |
|||
Primnoidae gen. indet. (DZMB_2021_0049) |
++ |
++ |
||
Heteropathes sp. indet. |
+ |
|||
Heteropathes americana sp. inc. |
+ |
|||
Bathypathes patula sp. inc. |
+ |
+ |
||
Schizopathes spp. indet. |
+ |
|||
Pennatulacea fam. indet (DZMB_2021_0053) |
+ |
|||
Umbellula sp. indet. (DZMB_2021_0054) |
+ |
|||
Umbellula sp. indet. (DZMB_2021_0055) |
+ |
|||
Epizoanthus sp. indet. |
++ |
|||
Hydrozoa ord. indet. (DZMB_2021_0065) |
++ |
|||
Siphonophorae Rhodaliidae Thermopalia gen. inc. |
+ |
|||
Echinodermata |
Hymenodiscus gen. inc. |
++ |
+ |
|
Freyellidae fam. inc. |
++ |
++ |
||
Freyastera gen. inc. |
++ |
++ |
++ |
|
Freyella gen. inc. |
++ |
++ |
+ |
|
Styracaster gen. inc. |
++ |
|||
Henricia gen. inc. |
+ |
+ |
||
Goniasteridae gen. indet. (DZMB_2021_0066) |
+ |
++ |
||
Goniasteridae gen. indet. (DZMB_2021_0067) |
++ |
|||
Evoplosoma gen. inc. |
++ |
|||
Lydiaster johannae sp. inc. |
+ |
|||
Solasteridae fam. inc. |
+ |
|||
Asthenactis gen. inc. |
+ |
|||
Hymenaster sp. indet. |
+ |
|||
Pteraster gen. inc. |
+ |
|||
Antedonidae gen. indet. (DZMB_2021_0068) |
++ |
++ |
||
Antedonidae fam. inc. (DZMB_2021_0069) |
++ |
++ |
||
cf. Bathymetra sp. |
+ |
+ |
||
Pentametrocrinus sp. indet. |
++ |
++ |
||
Hyocrinidae gen. indet. |
++ |
|||
Irregularia infracl. inc. |
+ |
|||
Cidaroida fam. indet. |
+ |
|||
Hapalosoma sp. indet. |
++ |
+ |
||
Salenocidaris sp. indet. |
++ |
|||
Elpidiidae gen. indet. (DZMB_2021_0070) |
+ |
++ |
||
Elpidiidae gen. indet. (DZMB_2021_0071) |
+ |
|||
Elpidiidae gen. indet. (DZMB_2021_0072) |
++ |
|||
Peniagone purpurea |
+ |
|||
Laetmogonidae sp. indet. |
++ |
++ |
||
Enypniastes eximia |
++ |
|||
Benthodytes sp. indet. |
++ |
+ |
+ |
|
Benthothuria gen. inc. |
+ |
|||
Pseudostichopus gen. inc. (DZMB_2021_0073) |
+ |
|||
Pseudostichopus sp. indet. (DZMB_2021_0074) |
++ |
|||
Oneirophanta sp. indet. |
++ |
|||
Synallactidae gen. indet. (DZMB_2021_0075) |
++ |
+++ |
||
Synallactidae gen. indet. (DZMB_2021_0076) |
+++ |
++ |
++ |
|
Synallactidae gen. indet. (DZMB_2021_0077) |
++ |
++ |
||
Synallactidae gen. indet. (DZMB_2021_0078) |
++ |
|||
Synallactidae fam. inc. (DZMB_2021_0079) |
+ |
|||
Synallactes sp. indet. |
++ |
++ |
||
Amphilepidida ord. inc. |
+ |
|||
Asteronyx gen. inc. |
++ |
|||
Ophiacanthida ord. inc. |
++ |
+ |
||
Ophiophyllum petilum sp. inc. |
+ |
|||
Ophiosphalma armigerum sp. inc. |
++ |
++ |
++ |
|
Hemichordata |
Torquaratoridae fam. inc. |
+ |
||
Mollusca |
Bathypolypus sp. indet. |
++ |
||
Cirroteuthis sp. indet. |
+ |
+ |
++ |
|
Grimpoteuthis gen. inc. |
+ |
|||
Magnapinna sp. indet. |
+ |
|||
Speculator gen. inc. |
++ |
|||
Scaphopoda ord. indet. |
++ |
+ |
||
Porifera |
Paleodictyon nodosum |
+++ |
+++ |
|
Foraminifera |
Monothalamea ord. indet. (DZMB_2021_0080) |
++ |
||
Monothalamea ord. indet. (DZMB_2021_0081) |
++ |
++ |
||
Monothalamea ord. indet. (DZMB_2021_0082) |
+++ |
|||
Luffammina gen. inc. |
+++ |
+++ |
||
Psammina gen. inc. (DZMB_2021_0083) |
+++ |
+ |
+ |
|
Psammina gen. inc. (DZMB_2021_0084) |
+++ |
|||
Stannoma gen. inc. |
+ |
Information on the benthic deep-sea megafauna of the Indian Ocean from both samples and imagery are rather scarce (
These seven taxa were observed at similar depths to those recorded here from the CIR and SEIR area, all on soft substrates (
The GLA covers three regions; the southern CIR, the RTJ and the northern SEIR, a distance spanning 1000 km from the northern to the southern border. Several taxa are widespread throughout the INDEX area and others have restricted distribution patterns (Tables
The widespread distribution throughout the INDEX area of many typical active vent field taxa found in this study confirms the Indian Ocean as a standalone biogeographic province (
At inactive hydrothermal vent fields, the majority of taxa were shared with active vent fields and non-vent areas and only 22 of the 69 taxa were observed only within - or close to - inactive areas. Fifteen taxa were observed exclusively within inactive areas on sulphides. Of the 22 taxa observed at inactive sites, 19 showed a restricted occurrence in one region, including the isopod Munnopsidae fam. inc. (DZMB_2021_0007) at the RTJ, the Bryozoan Cheilostomatida fam. indet. (DZMB_2021_0009) on the SEIR and the fish Histiobranchus gen. inc. on the CIR; the remaining three taxa were restricted to two regions each (Table
The non-vent area showed the highest species diversity in medium to low abundance with a high number of locally-restricted taxa (Table
In the Indian Ocean, three additional licence areas for polymetallic sulphides have been issued to China on the SWIR, India on the southern CIR and SWIR and Korea on the CIR, with a number of shared species between the licence areas and hydrothermal vent fields outside exploration claims (
Other taxa, such as Rimicaris kairei, show a greater connectivity and a more widespread distribution across spatially-separated vent fields in this yet undisturbed environment (
Although potential mining activities are focusing on inactive hydrothermal vents, they could affect nearby active hydrothermal vents and the surrounding non-vent area (
Mitigation strategies to avoid 'serious harm' to the environment include Environmental Impact Assessment studies (EIA), which require baseline studies for time series and monitoring to understand and explain succession, resilience and the recovery potential of the fauna against anthropogenic disturbances (
The impact of mining activities for inactive hydrothermal vent sites is far from understood due to a lack of qualitative and quantitative studies as pointed out in several reviews addressing the potential consequences of mining-related disturbances (
This megafauna catalogue is a valuable baseline study that offers an impression of the diversity present within the GLA, which can serve as a basis for monitoring the deep-sea benthic megafauna in the context of potential SMS mining activities. A drawback of this fauna catalogue is that the occurrences of taxa are based chiefly on imagery alone; additional physical samples are needed for taxonomic and molecular confirmation.
This study was funded by the Federal Institute for Geosciences and Natural Resources. Pictures and samples, presented in this study, originate from the INDEX exploration project for marine polymetallic sulphides by the Federal Institute for Geosciences and Natural Resources (BGR) on behalf of the German Federal Ministry for Economic Affairs and Energy. Exploration activities are carried out in the framework and under the regulations of an exploration licence with the International Seabed Authority.
Many thanks to the captain and crew of the “RV Sonne”, “RV Pelagia” and “RV Porquoi pas?”. The ROV teams from the GEOMAR (ROV Kiel6000), the Canadian Scientific Submersible Facility (ROPOS) and the IFREMER (ROV Victor 6000) made this study possible with their expertise in gaining the video imagery and photographs. Thanks to the GRG who participated to the acquisition, processing and interpretation of the data shown and discussed in this paper.
KHG sampled specimens, participated at several expeditions, extracted faunal occurrences from video- and photograph transects, prepared the database, did the initial identification and wrote the manuscript. PMA contributed to the database work, the imagery collection and processing. TK and USS funded the project, made data collection possible and are the principle investigators of the INDEX project. CM identified the sea stars, JN identified the nemertean taxa, TDL identified all fish, KS identified cirripedians, EM identified lobster and squat lobster, DG identified the bryozoans, TM identified cnidarians, SS identified brittle stars, CGM identified crinoids, SB identified Munnopsidae, TMG identified all Annelida MC identified crabs, anomuran crabs, shrimps and sea spiders, AG and AK1 identified sea cucumbers, AK2 identified sea urchins, KS identified ascideans, KB identified cephalopods, LH identified shell-bearing molluscs, AJG identified Foraminifera, TCK sampled specimens, participated at all expeditions and did the initial identification. All authors reviewed the manuscript.