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Comparison between 1960–1961 and 1997 of the maximum abundance scores in each of the three profiles: (a) Profile I, (b) Profile II and (c) Profile III. Taxa with the same or only one abundance score difference were left out. For abbreviations, see section ‘Abbreviations used’.
Source publication
The algal vegetation at three rocky-shore localities on the Swedish Skagerrak coast with different environmental conditions was studied in 1960–1961 by SCUBA diving. The same localities were revisited in the summer of 1997, using the same methods for recording the vegetation. Detailed descriptions of the vegetation profiles are presented to allow t...
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Context 1
... number of algal taxa found in 1960–1961 was 65, and in 1997 this was 72. Out of the in total 78 taxa which occurred in the 1960’s and/or 1997, 49 did not show a major difference in maximum abundance for the two periods ( Figure 7a), and 29 showed differences (Figure 7b). Six species were not observed in 1997: Asperococcus bullosus (dominant in Profile I in 1960-1961), Sporochnus pedunculatus , Spermothamnion repens , Griffithsia corallinoides , Polyides rotundus , and Porphyra umbilicalis (all common in 1960–1961). Fur- thermore, three species were significantly more abundant in the 1960’s: Mesogloia vermiculata , Dasya baillouviana and Codium fragile . The latter two are species introduced to the Skagerrak earlier this century. All these species were present and recognised in Pedersén’s herbarium, so there is no doubt that they did occur in the 1960’s. Also the abundance differences were confirmed by Pedersén’s herbarium: his specimens of M. vermiculata , D. baillouviana and C. fragile were much larger and much more numerous than the single small specimens we found in 1997. Thirteen species were found in the profiles in 1997, but not by Pedersén in the 1960’s. These are: Urospora sp., Dumontia contorta , Apoglossum ruscifolium , Asperococcus fistulosus , Blidingia minima , Giffordia sandriana , Membranoptera alata , Odonthalia dentata , Plumaria plumosa , Sargassum muticum (recently introduced from Japan), Scagelia pusilla (?Syn . An- tithamnion boreale var. droebachense ), Stictyosiphon soriferus and cf. Dilsea carnosa . Seven species were clearly more abundant in 1997: Cystoclonium purpureum , Delesseria sanguinea , Phycodrys rubens , Polysiphonia urceolata , Lomentaria clavellosa , Desmarestia viridis and Laminaria digitata . Figure 8 shows the algal taxa that differed in abundance by more than one abundance scale unit between 1960–1961 and 1997 for each of the three profiles separately. There were larger differences between the periods in Profiles I and II than in Profile III, but in Profile III more species had arrived relative to the ones that had disappeared. Thus, there was a drastic increase in the number of taxa in Profile III, from 35 in 1960–1961 to 52 in 1997. Also Profile II had more newcomers than disappearances, and species richness increased from 49 to 58. Contrarily, Profile I lost more species than the new ones coming in, and species richness decreased from 56 to 51. The disappearance or large decrease of some species since 1960–1961 from more than one profile is a strong argument for a possible general disappear- ance/decrease in the area. This was the case for Asperococcus bullosus , Chondrus crispus , Mesogloia vermiculata , Spermothamnion repens , Griffithsia corallinoides , Porphyra umbilicalis and Codium fragile . Some species also showed opposite trends in different profiles, e.g. Leathesia difformis disappeared from Profiles I and II, but was newly found in Profile III in 1997, and Polysiphonia brodiaei decreased in Profile I but increased in Profile II (Figure 8). Increased abundance of the red algae Cystoclonium purpureum , Delesseria sanguinea , Phycodrys rubens , Lomentaria clavellosa , and the brown alga Desmarestia viridis is a trend that was found in more than one profile. In Profile II this was accompanied by large increases of Bonnemaisonia hamifera , two Ceramium species ( C. rubrum , C. strictum ), and three Polysiphonia species ( P. brodiaei , P. nigrescens , P. urceolata ). It should be noted that these six filamentous species also showed increasing trends in the other profiles, but only by one step in the abundance scale used. Also some other filamentous algae ( Bryopsis plumosa , Elachista fucicola ), and some foliaceous algae ( Phyllophora truncata , Phyllophora pseudoceranoides , Ulva lactuca ), showed increasing trends throughout (in all profiles). Decreasing trends in Profiles I and II (but not in Profile III) were shown by Chondrus crispus (from ‘abundant’ to ‘rare’), Furcellaria lumbricalis (from ‘abundant’ to ‘common’) and Chorda filum (from ‘abundant’ or ‘common’ to ‘rare’). Of the 78 taxa that occurred in 1960–1961 and/or 1997, 39 belonged to the Rhodophyta (= Bangio- phyceae = red algae), 29 to the Phaeophyta (= Fuco- phyceae = brown algae), and 12 to the Chlorophyta (= Chlorophyceae = green algae). The red algae were the most dynamic group with differences in abundance scale by two or more units between 1960–1961 and 1997 for 46% of the taxa. For the brown and green algae, this figure was 31% and 25%, respectively. Gen- erally, the changes in community composition were towards increased cover scales in 1997 as can be seen from the skewed distribution in Figure 9a, and the red algae were mainly responsible for this increase. When relating the differences in abundance scores between 1960–1961 and 1997 to thallus shape and size, it appeared that the increases were mainly caused by 5–50 cm long algae with thin filamentous thalli belonging to all three taxonomic groups, and red and green algae with foliaceous thalli (Figures 9b–h). The plots for the smallest algae ( < 5 cm long, mainly thin ...
Context 2
... number of algal taxa found in 1960–1961 was 65, and in 1997 this was 72. Out of the in total 78 taxa which occurred in the 1960’s and/or 1997, 49 did not show a major difference in maximum abundance for the two periods ( Figure 7a), and 29 showed differences (Figure 7b). Six species were not observed in 1997: Asperococcus bullosus (dominant in Profile I in 1960-1961), Sporochnus pedunculatus , Spermothamnion repens , Griffithsia corallinoides , Polyides rotundus , and Porphyra umbilicalis (all common in 1960–1961). Fur- thermore, three species were significantly more abundant in the 1960’s: Mesogloia vermiculata , Dasya baillouviana and Codium fragile . The latter two are species introduced to the Skagerrak earlier this century. All these species were present and recognised in Pedersén’s herbarium, so there is no doubt that they did occur in the 1960’s. Also the abundance differences were confirmed by Pedersén’s herbarium: his specimens of M. vermiculata , D. baillouviana and C. fragile were much larger and much more numerous than the single small specimens we found in 1997. Thirteen species were found in the profiles in 1997, but not by Pedersén in the 1960’s. These are: Urospora sp., Dumontia contorta , Apoglossum ruscifolium , Asperococcus fistulosus , Blidingia minima , Giffordia sandriana , Membranoptera alata , Odonthalia dentata , Plumaria plumosa , Sargassum muticum (recently introduced from Japan), Scagelia pusilla (?Syn . An- tithamnion boreale var. droebachense ), Stictyosiphon soriferus and cf. Dilsea carnosa . Seven species were clearly more abundant in 1997: Cystoclonium purpureum , Delesseria sanguinea , Phycodrys rubens , Polysiphonia urceolata , Lomentaria clavellosa , Desmarestia viridis and Laminaria digitata . Figure 8 shows the algal taxa that differed in abundance by more than one abundance scale unit between 1960–1961 and 1997 for each of the three profiles separately. There were larger differences between the periods in Profiles I and II than in Profile III, but in Profile III more species had arrived relative to the ones that had disappeared. Thus, there was a drastic increase in the number of taxa in Profile III, from 35 in 1960–1961 to 52 in 1997. Also Profile II had more newcomers than disappearances, and species richness increased from 49 to 58. Contrarily, Profile I lost more species than the new ones coming in, and species richness decreased from 56 to 51. The disappearance or large decrease of some species since 1960–1961 from more than one profile is a strong argument for a possible general disappear- ance/decrease in the area. This was the case for Asperococcus bullosus , Chondrus crispus , Mesogloia vermiculata , Spermothamnion repens , Griffithsia corallinoides , Porphyra umbilicalis and Codium fragile . Some species also showed opposite trends in different profiles, e.g. Leathesia difformis disappeared from Profiles I and II, but was newly found in Profile III in 1997, and Polysiphonia brodiaei decreased in Profile I but increased in Profile II (Figure 8). Increased abundance of the red algae Cystoclonium purpureum , Delesseria sanguinea , Phycodrys rubens , Lomentaria clavellosa , and the brown alga Desmarestia viridis is a trend that was found in more than one profile. In Profile II this was accompanied by large increases of Bonnemaisonia hamifera , two Ceramium species ( C. rubrum , C. strictum ), and three Polysiphonia species ( P. brodiaei , P. nigrescens , P. urceolata ). It should be noted that these six filamentous species also showed increasing trends in the other profiles, but only by one step in the abundance scale used. Also some other filamentous algae ( Bryopsis plumosa , Elachista fucicola ), and some foliaceous algae ( Phyllophora truncata , Phyllophora pseudoceranoides , Ulva lactuca ), showed increasing trends throughout (in all profiles). Decreasing trends in Profiles I and II (but not in Profile III) were shown by Chondrus crispus (from ‘abundant’ to ‘rare’), Furcellaria lumbricalis (from ‘abundant’ to ‘common’) and Chorda filum (from ‘abundant’ or ‘common’ to ‘rare’). Of the 78 taxa that occurred in 1960–1961 and/or 1997, 39 belonged to the Rhodophyta (= Bangio- phyceae = red algae), 29 to the Phaeophyta (= Fuco- phyceae = brown algae), and 12 to the Chlorophyta (= Chlorophyceae = green algae). The red algae were the most dynamic group with differences in abundance scale by two or more units between 1960–1961 and 1997 for 46% of the taxa. For the brown and green algae, this figure was 31% and 25%, respectively. Gen- erally, the changes in community composition were towards increased cover scales in 1997 as can be seen from the skewed distribution in Figure 9a, and the red algae were mainly responsible for this increase. When relating the differences in abundance scores between 1960–1961 and 1997 to thallus shape and size, it appeared that the increases were mainly caused by 5–50 cm long algae with thin filamentous thalli belonging to all three taxonomic groups, and red and green algae with foliaceous thalli (Figures 9b–h). The plots for the smallest algae ( < 5 cm long, mainly thin ...
Citations
... These high levels of nutrient during summer could explain the high macroalgal biomass observed in this site during October 2021, dominated by fine foliaceous and cartilaginous blade species (e.g. C. ramosa and S. interruptum). Species in both sites are known to thrive under Moderate eutrophication (Johansson et al., 1998;Eriksson et al., 2002), especially as rhodophytes are highly resistant to sedimentation (Fraser et al., 2017). However, while the flora associated with both eutrophic sites showed similarities, the two sites exhibited different community compositions, with a higher species richness in the Moderate eutrophication bed. ...
Background and Aims:
Maerl-associated communities have received considerable attention due to their uniqueness, biodiversity and functional importance. Although the impacts of human activities are well documented for maerl-associated macrofauna, the spatio-temporal variations of macroalgae have comparatively been neglected, and the drivers that influence their dynamics are poorly known. We investigate the links between maerl-associated macroalgal communities, anthropogenic pressures and environmental conditions, and hypothesize that sites under human pressure would exhibit different dynamics when compared to reference site.
Methods:
In order to better understand community variation through space and time, four subtidal maerl beds under different pressures were consistently monitored over one year in the bay of Brest, Brittany, France. Both macroalgae communities monitoring and environmental data were acquired through field sampling and
available models.
Key Results:
Higher macroalgal biomass was observed within eutrophic sites, especially in summer (more than 10 times higher than in Unimpacted site), caused by free-living forms of opportunistic red macroalgae. The Dredged site also exhibited distinct macroalgal communities during summer from the Unimpacted site. Nutrient concentrations and seasonality proved to be key factors affecting the macroalgal community composition, although dredging and its effects on granulometry also had strong influence. Over the long term, less than half of the species identified during historical surveys were found, indicating major temporal changes.
Conclusions:
Human pressures have strong impact on maerl-associated macroalgal communities. Nutrient concentrations and dredging pressure appear as the main anthropogenic factors shaping maerl-associated macroalgal communities. Additionally, our results suggest historical changes in maerl-associated macroalgal
communities over 25 years in response to changes in local human pressure management. This study suggests that maerl-associated macroalgal communities could be used as indicators of anthropogenic-driven changes in this habitat
... In other European seas the species has been proven to determine negative impacts as an ecosystem engineer by forming dense epiphytic growth on host algae (e.g. Johansson et al. 1998), and by preventing competing algae to colonize (Svensson et al. 2013). Its high surface to volume ratio and associated greater potential for rapid uptake of nutrients in comparison to their host algae is perceived as a negative impact on ocean nourishment (Katsanevakis et al. 2014a). ...
Biological invasions have become a defining feature of marine Mediterranean ecosystems with significant impacts on biodiversity, ecosystem services, and human health. We systematically reviewed the current knowledge on the impacts of marine biological invasions in the Mediterranean Sea. We screened relevant literature and applied a standardised framework that classifies mechanisms and magnitude of impacts and type of evidence. Overall, 103 alien and cryptogenic species were analysed, 59 of which were associated with both negative and positive impacts, 17 to only negative, and 13 to only positive; no impacts were found for 14 species. Evidence for most reported impacts (52%) was of medium strength, but for 32% of impact reports evidence was weak, based solely on expert judgement. Only 16% of the reported impacts were based on experimental studies. Our assessment allowed us to create an inventory of 88 alien and cryptogenic species from 16 different phyla with reported moderate to high impacts. The ten worst invasive species in terms of reported negative impacts on biodiversity include six algae, two fishes, and two molluscs, with the green alga Caulerpa cylindracea ranking first. Negative impacts on biodiversity prevailed over positive ones. Competition for resources, the creation of novel habitat through ecosystem engineering, and predation were the primary reported mechanisms of negative effects. Most cases of combined negative and positive impacts on biodiversity referred to community-level modifications. Overall, more positive than negative impacts were reported on ecosystem services, but this varied depending on the service. For human health, only negative impacts were recorded. Substantial variation was found among Mediterranean ecoregions in terms of mechanisms of impact and the taxonomic identity of impacting species. There was no evidence that the magnitude of impact increases with residence time. Holistic approaches and experimental research constitute the way forward to better understanding and managing biological invasions.
... In Iceland, B. hamifera was first reported in Dýrafjörður, Northwest Iceland (Munda, 1978) and later in Hvalfjörður, Southwest Iceland (Gunnarsson and Egilsdóttir, 2010) (Fig. 1). This alga has a greater potential for rapid uptake of nutrients in comparison to their host algae through its dense epiphytic growth that can also reduce light availability significantly for those algae (Wallentinus, 1984;Johansson et al., 1998;Svensson et al., 2013;Katsanevakis et al., 2014). ...
In the last decades, there has been an increase of macroalgal species appearing in new geographic regions. These new records are being linked to non-intentional global human-mediated transport. In Iceland three macroalgae species have been reported as non-indigenous. We updated the number of non-indigenous macroalgae to 8 species, 4 of which are potentially invasive. Pathways and vectors of each macroalga introduction are identified. The red algae group does not stand out in Iceland as in the nearest territories. The number of non-indigenous macroalgae will probably increase in the near future due to (1) secondary spread of species via shipping vector; (2) the growing trend of aquaculture in Norway, where surface currents will probably allow the spread of algae to Iceland; and (3) the increase of studies focusing on this matter. To address the problem, we suggest that local monitoring and mitigation programs should be implemented across Iceland, and that regulatory and preventive measures for the maritime traffic vector should be developed.
... Coastal urbanization has increased during the last decades and, as a result, the biota from coastal ecosystems has been increasingly impacted by anthropogenic activities (Martins et al., 2012;De Vasconcelos et al., 2019;Gaglioti et al., 2020). Pollution is one of the most serious problems affecting benthic communities and has been intensifying since the 1960s (Johansson et al., 1998;Díez et al., 2009). Due to pollution, problems such as eutrophication, turbidity, toxicity, and siltation have been increasing in marine ecosystems, which change the structures of the communities by altering species occurrence and distribution (Johansson et al., 1998;Díez et al., 2009). ...
... Pollution is one of the most serious problems affecting benthic communities and has been intensifying since the 1960s (Johansson et al., 1998;Díez et al., 2009). Due to pollution, problems such as eutrophication, turbidity, toxicity, and siltation have been increasing in marine ecosystems, which change the structures of the communities by altering species occurrence and distribution (Johansson et al., 1998;Díez et al., 2009). ...
Guanabara Bay, the second largest bay on the Brazilian coast, has tropical to subtropical, hypereutrophic water conditions. A survey of the macroalgae flora conducted over the past 200 years (1800–2013) yielded a list of 245 species, which represents 15.7% of the total macroalgae recorded in the Tropical Western Atlantic, while comprehends 29.9% and 50.2% of the marine flora in Brazil and Rio de Janeiro, respectively. When evaluating the macroalgal list throughout different periods, it is noticeable the gradual loss of biodiversity as anthropization increased over the last two centuries. The use of phytogeographic indexes and beta diversity confirmed the negative changes in macroalgae assemblages as a response to increasing environmental degradation. The use of floristic surveys to establish the reference conditions employing historical data and/or regionally referenced prove to be an efficient tool using macroalgae as an ecological indicator for water quality.
... Tolerance to sediment deposition is dependent on algal morphology. Species that propagate vegetatively or regenerate from basal thallus parts are the most resistant to sedimentation effects [101][102][103]. Most of the algal species in our study area are prostrate, bladed species that are more susceptible to scouring and burial [102,104]. ...
... Species that propagate vegetatively or regenerate from basal thallus parts are the most resistant to sedimentation effects [101][102][103]. Most of the algal species in our study area are prostrate, bladed species that are more susceptible to scouring and burial [102,104]. In addition, while kelp gametes can survive for long periods in some settings [90], most only live a few weeks [92,105], decreasing their chances of survival when conditions are unfavorable (e.g., subject to ephemeral sedimentation) for long periods of time. ...
The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth). Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.
... Common practice (Munda, 1993;Schories et al., 1997;Sagarin et al., 1999;Bartsch and Kuhlenkamp, 2000;Piriz et al., 2003;Schiel et al., 2004;Lima et al., 2007;Tribollet and Vroom, 2007;Hawkins et al., 2008;Kinzie, 2008;Barrett et al., 2009;Mumby, 2009;Vroom and Timmers, 2009;Svane and Gröndahl, 1988;Eriksson et al., 1998Eriksson et al., , 2002Johansson et al., 1998;Schutte et al., 2010;Trowbridge et al., 2011Trowbridge et al., , 2013, as well as our previous studies (Titlyanov et al., 2011а,b, 2014a(Titlyanov et al., 2011а,b, ,b, 2015aTitlyanova, 2012b, 2013;Titlyanova et al., 2014), comparing the diversity and species composition of two or more algal collections in order to clarify the historical (decadal) changes in the marine flora associated with long-term climate changes, or the influence of anthropogenic factors, suggests observance of the following four basic rules (conditions) for making such comparisons: ...
Coral Reef Marine Plants of Hainan Island summarizes the literature on the role and use of marine plants in coral reef ecosystems, especially in China and countries in the Asia-Pacific Region. The first chapter of the book focuses on the description of coral reef ecosystems, their architecture, and status of Hainan coral reefs. The second chapter focuses on common knowledge surrounding marine plants, such as their classification, identifying characteristics of different phyla, morphology, reproduction, life forms, main algal communities on coral reefs, distribution of algae on coral reefs and their roles, and the use of seaweeds in cookery, medicine, industry, and agriculture. The third chapter on the seaweed flora of Hainan Island contains species composition of the marine benthic flora, the complete list of marine plants found by researchers from all studies, and historical changes in the flora and seasonal changes. The final chapter shows how to identify common species of marine plants on coral reefs of Hainan Island. This excellent work will help readers identify relevant plants, also teaching them how to use plant resources to assess endangered states and create conservation strategies. Presents the first publication devoted to the description of marine plants of Hainan Island Describes marine plants, including the role of their communities in ecosystems of coral reef Discusses seasonal and decadal changes in biodiversity and the composition of the marine flora of the island Combines fundamental morphology with utilization and related products. © 2017 China Science Publishing & Media Ltd. Published by Elsevier Inc. All rights reserved.
... B. hamifera has a negative impact as an ecosystem engineer by forming dense epiphytic growth on host algae (e.g. Johansson et al. 1998), thus reducing light and nutrient availability for those algae, in addition to preventing competing algae to colonize (Svensson et al. 2013 E ). ...
... fragile, and that no displacement or elimination of native congeners has occurred. A reduction in abundance between the early 1960s and 1997 was also reported from the Swedish west coast (Johansson et al. 1998). Positive effects of C. fragile subsp. ...
... B. hamifera has a negative impact as an ecosystem engineer by forming dense epiphytic growth on host algae (e.g. Johansson et al. 1998), thus reducing light and nutrient availability for those algae, in addition to preventing competing algae to colonize (Svensson et al. 2013 E ). ...
... fragile, and that no displacement or elimination of native congeners has occurred. A reduction in abundance between the early 1960s and 1997 was also reported from the Swedish west coast (Johansson et al. 1998). Positive effects of C. fragile subsp. ...
A good understanding of the mechanisms and magnitude of the impact of invasive alien species on ecosystem services and biodiversity is a prerequisite for the efficient prioritisation of actions to prevent new invasions or for developing mitigation measures. In this review, we identified alien marine species that have a high impact on ecosystem services and biodiversity in European seas, classified the mechanisms of
impact, commented on the methods applied for assessing the impact and the related inferential strength, and reported on gaps in available information. Furthermore, we have proposed an updated inventory of 87 marine species in Europe, representing 13 phyla, which have a documented high impact on ecosystem services or biodiversity. Food provision was the ecosystem service that was impacted by the greatest number of alien species (in terms of both positive and negative impacts). Following food provision, the ecosystem services that were negatively affected by the highest number of alien species were ocean nourishment, recreation and tourism, and lifecycle maintenance, while the ecosystem services that were most often positively impacted were cognitive benefits, water purification, and climate regulation. In many cases, marine aliens were found to impact keystone/protected species and habitats. Thirty percent of the assessed species had an impact on entire ecosystem processes or wider ecosystem functioning, more often in a negative fashion. Forty-nine of the assessed species were reported as being ecosystem engineers, which fundamentally modify, create, or define habitats by altering their physical or chemical properties. The positive impacts of alien species are probably underestimated, as there is often a perception bias against alien species. Among the species herein assessed as high-impact species, 17 had only negative and 7 only positive impacts; for the majority (63 species), both negative and positive impacts were reported; the overall balance was often unknown. Although there is no doubt that invasive species have modified marine ecosystems, evidence for most of the reported impacts is weak, as it is based on expert judgement or dubious correlations, while only 13% of the reported impacts were inferred via manipulative or natural experiments. A need for stronger inference is evident, to improve our knowledge base of marine biological invasions and better inform environmental managers.
... Spirulina spp. have been recorded on natural hard substrates in other parts of the Baltic Sea, e.g. on boulders in the Asko area (Wallin et al. 2011), on ascidians in Gullmar Fjord, Skagerrak (Johansson et al. 1998) or on barnacles Balanus improvisus off the island of Rügen, where they formed small mat-like patches up to 3 cm in diameter (Rathsack-Künzenbach 1961). Rose-pink trichomes of Spirulina rosea Crouan were found on experimental colonisation plates deployed in the Gulf of Gdańsk at locations close to Gdynia and Gdańsk (Dziubińska & Janas 2007) and Hel (Dziubińska & Szaniawska 2010). ...
We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other cyanobacteria, diatoms and nematode species were also present. After a few days in the laboratory, the red trichomes of S. subsalsa started to turn blue-green in colour, suggesting the strong chromatic acclimation abilities of this species.
... Spirulina spp. have been recorded on natural hard substrates in other parts of the Baltic Sea, e.g. on boulders in the Asko area (Wallin et al. 2011), on ascidians in Gullmar Fjord, Skagerrak (Johansson et al. 1998) or on barnacles Balanus improvisus off the island of Rügen, where they formed small mat-like patches up to 3 cm in diameter (Rathsack-Künzenbach 1961). Rose-pink trichomes of Spirulina rosea Crouan were found on experimental colonisation plates deployed in the Gulf of Gdańsk at locations close to Gdynia and Gdańsk (Dziubińska & Janas 2007) and Hel (Dziubińska & Szaniawska 2010). ...
We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other cyanobacteria, diatoms and nematode species were also present. After a few days in the laboratory, the red trichomes of S. subsalsa started to turn blue-green in colour, suggesting the strong chromatic acclimation abilities of this species.
