scholarly journals Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean

Author(s):  
Sabine Stöhr ◽  
Michel Segonzac

The animal communities associated with the deep-sea reducing environment have been studied for almost 30 years, but until now only a single species of ophiuroid, Ophioctenella acies, has been found at both hydrothermal vents and methane cold seeps. Since the faunal overlap between vent and seep communities is small and many endemic species have been found among other taxa (e.g. Mollusca, Crustacea), additional species of ophiuroids were expected at previously unstudied sites. Chemical compositions at reducing sites differ greatly from the nearby bathyal environment. Generally, species adapted to chemosynthetic environments are not found in non-chemosynthetic habitats, but occasional visitors of other bathyal species to vent and seep sites have been recorded among many taxa except ophiuroids. This paper presents an analysis of the ophiuroid fauna found at hydrothermal vents and non-reducing nearby sites on the Mid-Atlantic Ridge and on methane cold seeps in the Gulf of Mexico, at Blake Ridge off South Carolina and south of Barbados. In addition to O. acies, four species were found at vents, Ophiactis tyleri sp. nov., Ophiocten centobi, Ophiomitra spinea and Ophiotreta valenciennesi rufescens. While Ophioctenella acies appears to be restricted to chemosynthetic areas, the other four species were also found in other bathyal habitats. They also occur in low numbers (mostly single individuals), whereas species adapted to hydrothermal areas typically occur in large numbers. Ophioscolex tripapillatus sp. nov. and Ophiophyllum atlanticum sp. nov. are described from nearby non-chemosynthetic sites. In a cold seep south of Barbados, three species of ophiuroids were found, including Ophioctenella acies, Amphiura sp., Ophiacantha longispina sp. nov. and Ophioplinthaca chelys. From the cold seeps at Blake Ridge and the Gulf of Mexico, Ophienigma spinilimbatum gen. et sp. nov. is described, likely restricted to the reducing environment. Ophiotreta valenciennesi rufescens occurred abundantly among Lophelia corals in the Gulf of Mexico seeps, which is the first record of this species from the West Atlantic. Habitat descriptions complement the taxonomic considerations, and the distribution of the animals in reducing environments is discussed.

2021 ◽  
Author(s):  
Long Zhang ◽  
Jian He ◽  
Peipei Tan ◽  
Zhen Gong ◽  
Shiyu Qian ◽  
...  

Cold seeps and hydrothermal vents are deep-sea reducing environments that are characterized by a lack of oxygen, photosynthesis-derived nutrients and a high concentration of reducing chemicals. Apodida is an order of deep-sea echinoderms lacking tube feet and complex respiratory trees, which are commonly found in holothurians. Chiridota heheva Pawson & Vance, 2004 (Apodida: Chiridotidae) is one of the few echinoderms that resides in deep-sea reducing environments. Unlike most cold seep and hydrothermal vent-dwelling animals, C. heheva does not survive by maintaining an epi- or endosymbiotic relationship with chemosynthetic microorganisms. The species acquires nutrients by extracting organic components from sediment detritus and suspended material. Here, we report a high-quality genome of C. heheva as a genomic reference for echinoderm adaptation to reducing environments. Chiridota heheva likely colonized its current habitats in the early Miocene. The expansion of the aerolysin-like protein family in C. heheva compared with other echinoderms might be involved in the disintegration of microbes during digestion, which in turn facilitates the species' adaptation to cold seep environments. Moreover, several hypoxia-related genes were subject to positive selection in the genome of C. heheva, which contributes to their adaptation to hypoxic environments.


2005 ◽  
Vol 85 (6) ◽  
pp. 1489-1497 ◽  
Author(s):  
Anne M. Mills ◽  
Megan E. Ward ◽  
Taylor P. Heyl ◽  
Cindy L. Van Dover

Vesicomyid clam species are abundant in many deep-sea chemosynthetic communities, including cold seeps. They rely primarily on thiotrophic (sulphide-oxidizing) gill symbionts for nutrition and thus require sulphide-rich environments. Submersible surveys of megafaunal distributions at the Blake Ridge Diapir, a deep-sea methane-hydrate seep located ∼200 miles off the coast of Charleston, South Carolina, documented massive mortalities of vesicomyid clams. The cause of these mortalities is unknown, but sulphide deprivation, sulphide toxicity, and disease are possible agents of mortality in this system. Similar redox profiles in sediment cores from live and dead clam beds do not support the hypothesis that there has been a transient shift in the flux of sulphide. To address the potential for disease as a cause of mortality, we undertook a histological survey of microparasites and other indications of disease in clam tissues. Six morphological types of parasites were identified using light microscopy, including two viral-like inclusions, Rickettsia-like gill inclusions, possible bacterial gut inclusions, bacterial gill infections, and a protistan inclusion. Of these parasites, two were pathogenic: viral-like inclusions in mantle tissues caused tissue degradation; bacterial gill infections resulted in localized disruption and degradation of gill filaments. Infection prevalence and densities were low for all parasites observed. The majority of clams examined showed intense haemocytic responses in the absence of any obvious etiologic agent, suggesting the presence of parasites not detectable by our methods. Our findings indicate that the clam population at the Blake Ridge seep was in relatively good health at the time of sampling.


2012 ◽  
Vol 9 (12) ◽  
pp. 17037-17052 ◽  
Author(s):  
C. Smith

Abstract. Chemosynthetic communities in the deep-sea can be found at hydrothermal vents, cold seeps, whale falls and wood falls. While these communities have been suggested to exist in isolation from solar energy, much of the life associated with them relies either directly or indirectly on photosynthesis in the surface waters of the oceans. The sun indirectly provides oxygen, a byproduct of photosynthesis, which aerobic chemosynthetic microorganisms require to synthesize organic carbon from CO2. Planktonic life stages of many vent and cold seep invertebrates also directly feed on photosynthetically produced organic matter as they disperse to new vent and seep systems. While a large portion of the life at deep-sea chemosynthetic habitats can be linked to the sun and so could not survive without it, a small portion of anaerobically chemosynthetic microorganisms can persist in its absence. These small and exotic organisms have developed a way of life in the deep-sea which involves the use of resources originating in their entirety from terrestrial sources.


2012 ◽  
Vol 9 (11) ◽  
pp. 16815-16875 ◽  
Author(s):  
S. Duperron ◽  
S. M. Gaudron ◽  
C. F. Rodrigues ◽  
M. R. Cunha ◽  
C. Decker ◽  
...  

Abstract. Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria which ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, East America, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous more easily accessible shallow marine species were studied. We here provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to Marmara Sea, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 51 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae), and compared among families with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions, yet relatively little is known regarding their diversity and functioning apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on Oceans, we advocate for a better assessment of bivalve symbioses diversity in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change


Zootaxa ◽  
2009 ◽  
Vol 2096 (1) ◽  
pp. 338-355 ◽  
Author(s):  
CHRISTOPH PLUM ◽  
PEDRO MARTINEZ ARBIZU

The new tegastid species Smacigastes methanophilus sp. nov. is described from cold-seep samples collected from the Gulf of Mexico in 2006. Besides Smacigastes micheli Ivanenko & Defaye, 2004 and Smacigastes barti Gollner, Ivanenko & Martínez Arbizu, 2008, this is the third species of the genus Smacigastes Ivanenko & Defaye, 2004. To date, this genus contains the only species within the family Tegastidae known from deep-sea habitats. Furthermore, S. methanophilus sp. nov. is the first species of Tegastidae found at cold seeps and associated with tubeworm aggregations. It has the same primitive features as S. micheli but can be distinguished from the latter by the setation of second and third segments of female antennule and second segment of male antennule, the setation of the mandibular palp, the ornamentation of P5 exopod in both sexes, setation of male P5 exopod, form of the female P5 baseoendopod, and the different shape and length of the P5 setae in female. Moreover, both sexes of Smacigastes methanophilus sp. nov. are much smaller than those of S. micheli. Compared to S. barti, S. methanophilus sp. nov. differs in the segmentation and setation of female antennule, the setation of male antennule, setation of mandibular palp, setation of the maxillule, number of endites of the maxilla, number of setae in P1, the ornamentation of female P5 and setation in male P5.


2013 ◽  
Vol 10 (5) ◽  
pp. 3241-3267 ◽  
Author(s):  
S. Duperron ◽  
S. M. Gaudron ◽  
C. F. Rodrigues ◽  
M. R. Cunha ◽  
C. Decker ◽  
...  

Abstract. Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.


Paleobiology ◽  
1995 ◽  
Vol 21 (4) ◽  
pp. 461-478 ◽  
Author(s):  
Kathleen A. Campbell ◽  
David J. Bottjer

Brachiopods generally have not been considered to be typical or significant faunal components of modern or ancient hydrothermal vent and cold-seep settings. The Early Cretaceous (Neocomian) rhynchonellide brachiopodPeregrinellahas long been viewed as a paleontological curiosity because of its distinctive morphology, status as the largest Mesozoic brachiopod, anomalous stratigraphic associations, and widespread, yet discontinuous paleogeographic distribution. Examination of all worldwidePeregrinellaoccurrences (14) indicates restriction of this brachiopod to ancient cold-seeps. It is probable thatPeregrinellagrew to large sizes in such great abundances at fossil cold-seep sites because of a richly organic food supply generated by localized fluid seepage and bacterial chemosynthetic activity. Living brachiopods are not known to harbor chemosymbiotic bacteria in their tissues; however, direct chemoautotrophic utilization of reduced fluids byPeregrinellacannot be rejected or demonstrated at present.Peregrinellaoccurs at widely separated cold-seeps of Neocomian age (e.g., California, Mexico, Tibet, Europe), yet its mode of dispersal and larval development is unknown. In modern hydrothermal vents of the deep-sea, organism dispersal occurs along oceanic ridges, where benthic faunas display both planktotrophic and nonplanktotrophic larval-mode types.Peregrinellamay represent a Mesozoic relic of a long-lived “lineage” of vent-seep associated rhynchonellides from the Paleozoic (e.g., ?Eoperegrinella, Dzieduszyckia), but major gaps in the stratigraphic record between these rhynchonellide occurrences, and the lack of rigorous phylogenetic analysis for these groups preclude a clear resolution of the origin(s) of vent-seep brachiopods at present.


2020 ◽  
pp. 238-292 ◽  
Author(s):  
Richard J. Léveillé ◽  
S. Kim Juniper

2020 ◽  
Author(s):  
Xiyang Dong ◽  
Jayne E. Rattray ◽  
D. Calvin Campbell ◽  
Jamie Webb ◽  
Anirban Chakraborty ◽  
...  

AbstractAt marine cold seeps, gaseous and liquid hydrocarbons migrate from deep subsurface origins to the sediment-water interface. Cold seep sediments are known to host taxonomically diverse microorganisms, but little is known about their metabolic potential and depth distribution in relation to hydrocarbon and electron acceptor availability. In this work, we combined geochemical, metagenomic and metabolomic measurements in distinct sediment redox regimes to profile microbial activities within the uppermost 350 cm of a newly discovered cold seep in the NW Atlantic deep sea (2.3 km water depth). Depth-resolved metagenomic profiling revealed compositional and functional differentiation between near-surface sediments (dominated by Proteobacteria) and deeper subsurface layers (dominated by Atribacteria, Chloroflexi, Euryarchaeota and Lokiarchaeota). Metabolic capabilities of community members were inferred from 376 metagenome-assembled genomes spanning 46 phyla (including five novel candidate phyla). In deeper sulfate-reducing and methanogenic sediments, various community members are capable of anaerobically oxidizing short-chain alkanes (alkyl-CoM reductase pathway), longer-chain alkanes (fumarate addition pathway), and aromatic hydrocarbons (fumarate addition and subsequent benzoyl-CoA pathways). Geochemical profiling demonstrated that hydrocarbon substrates are abundant in this location, thermogenic in origin, and subject to biodegradation. The detection of alkyl-/arylalkylsuccinate metabolites, together with carbon isotopic signatures of ethane, propane and carbon dioxide, support that microorganisms are actively degrading hydrocarbons in these sediments. Hydrocarbon oxidation pathways operate alongside other deep seabed metabolisms such as sulfide oxidation, hydrogen oxidation, carbon fixation, fermentation and reductive dehalogenation. Upward migrated thermogenic hydrocarbons thus sustain diverse microbial communities with activities that affect subseafloor biogeochemical processes across the redox spectrum in deep sea cold seeps.


2020 ◽  
Author(s):  
Zexin Li ◽  
Donald Pan ◽  
Guangshan Wei ◽  
Weiling Pi ◽  
Jiang-Hai Wang ◽  
...  

AbstractIn marine ecosystems, viruses exert control on the composition and metabolism of microbial communities, thus influencing overall biogeochemical cycling. Deep sea sediments associated with cold seeps are known to host taxonomically diverse microbial communities, but little is known about viruses infecting these microorganisms. Here, we probed metagenomes from seven geographically diverse cold seeps across global oceans, to assess viral diversity, virus-host interaction, and virus-encoded auxiliary metabolic genes (AMGs). Gene-sharing network comparisons with viruses inhabiting other ecosystems reveal that cold seep sediments harbour considerable unexplored viral diversity. Most cold seep viruses display high degrees of endemism with seep fluid flux being one of the main drivers of viral community composition. In silico predictions linked 14.2% of the viruses to microbial host populations, with many belonging to poorly understood candidate bacterial and archaeal phyla. Lysis was predicted to be a predominant viral lifestyle based on lineage-specific virus/host abundance ratios. Metabolic predictions of prokaryotic host genomes and viral AMGs suggest that viruses influence microbial hydrocarbon biodegradation at cold seeps, as well as other carbon, sulfur and nitrogen cycling via virus-induced mortality and/or metabolic augmentation. Overall, these findings reveal the global diversity and biogeography of cold seep viruses and indicate how viruses may manipulate seep microbial ecology and biogeochemistry.


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