Abstract. Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin) revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S) and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus) or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata). Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values) and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin.
Abstract Fauna from deep‐sea cold seeps worldwide is dominated by chemosymbiotic metazoans. Recently, investigation of new sites in the G ulf of G uinea yielded numerous new species for which symbiosis was strongly suspected. In this study, symbioses are characterized in five seep‐specialist metazoans recently collected from the G uiness site located at ∼600 m depth. Four bivalve and one annelid species belonging to families previously documented to harbor chemosynthetic bacteria were investigated using bacterial marker gene sequencing, fluorescence in situ hybridization, and stable isotope analyses. Results support that all five species display chemosynthetic, sulfur‐oxidizing γ‐proteobacteria. Bacteria are abundant in the gills of bivalves, and in the trophosome of the siboglinid annelid. As observed for their relatives occurring at deeper sites, chemoautotrophy is a major source of carbon for animal nutrition. Although symbionts found in each host species are related to symbionts found in other metazoans from the same families, several incongruencies are observed among phylogenetic trees obtained from the different bacterial genes, suggesting a certain level of heterogeneity in symbiont strains present. Results provide new insights into the diversity, biogeography, and role of symbiotic bacteria in metazoans from the G ulf of G uinea, at a site located at an intermediate depth between the continental shelf and the deep sea.
Marine environments represent an enormous biodiversity reservoir due to their numerous different habitats, being abundant in microorganisms capable of producing biomolecules, namely exopolysaccharides (EPS), with unique physical characteristics and applications in a broad range of industrial sectors. From a total of 67 marine-derived bacteria obtained from marine sediments collected at depths of 200 to 350 m from the Estremadura Spur pockmarks field, off the coast of Continental Portugal, the Brevundimonas huaxiensis strain SPUR-41 was selected to be cultivated in a bioreactor with saline culture media and glucose as a carbon source. The bacterium exhibited the capacity to produce 1.83 g/L of EPS under saline conditions. SPUR-41 EPS was a heteropolysaccharide composed of mannose (62.55% mol), glucose (9.19% mol), rhamnose (19.41% mol), glucuronic acid (4.43% mol), galactose (2.53% mol), and galacturonic acid (1.89% mol). Moreover, SPUR-41 EPS also revealed acyl groups in its composition, namely acetyl, succinyl, and pyruvyl. This study revealed the importance of research on marine environments for the discovery of bacteria that produce new value-added biopolymers for pharmaceutical and other biotechnological applications, enabling us to potentially address saline effluent pollution via a sustainable circular economy.
Deep-sea hydrothermal vents host lush chemosynthetic communities, dominated by endemic fauna that cannot live in other ecosystems. Despite over 500 active vents found worldwide, the Arctic has remained a little-studied piece of vent biogeography. Though located as early as 2001, the faunal communities of the Aurora Vent Field on the ultra-slow spreading Gakkel Ridge remained unsampled until recently, owing to difficulties with sampling on complex topography below permanent ice. Here, we report an unusual cocculinid limpet abundant on inactive chimneys in Aurora (3883–3884 m depth), describing it as Cocculina aurora n. sp. using an integrative approach combining traditional dissection, electron microscopy, molecular phylogeny, and three-dimensional anatomical reconstruction. Gross anatomy of the new species was typical for Cocculina , but it has a unique radula with broad, multi-cuspid rachidian where the outermost lateral is reduced compared to typical cocculinids. A phylogenetic reconstruction using the mitochondrial COI gene also confirmed its placement in Cocculina . Only the second cocculinid found at vents following the description of the Antarctic Cocculina enigmadonta , this is currently the sole cocculinid restricted to vents. Our discovery adds to the evidence that Arctic vents host animal communities closely associated with wood falls and distinct from other parts of the world.
Recent advances in technology have enabled an unprecedented development of underwater research, extending from near shore to the deepest regions of the globe. However, monitoring of biodiversity is not fully implemented in political agendas and biological observations in the deep ocean have been even more limited in space and time. The Foresight Workshop on Advances in Ocean Biological Observations: a sustained system for deep-ocean meroplankton was convened to to foster advances in the knowledge on deep-ocean invertebrate larval distributions and improve our understanding of fundamental deep-ocean ecological processes such as connectivity and resilience of benthic communities to natural and human-induced disturbance. This Meroplankton Observations Workshop had two specific goals: 1) review the state-of-the-art instrumentation available for meroplankton observations; 2) develop a strategy to implement technological innovations for in-situ meroplankton observation. Presentations and discussions are summarised in this report covering: i) key challenges and priorities for advancing the knowledge of deep-sea larval diversity and distribution: ii) recent developments in technology and future needs for plankton observation, iii) data integration and oceanographic modelling; iv) synergies and added value of a sustained observation system for meroplankton; v) steps for developing a sustained observation system for deep-ocean meroplankton and plans to maximise collaborative opportunities.
Abstract. Previous work in the mud volcanoes from the Gulf of Cadiz revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of those species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S) and investigate the intra-specific variation of isotope signatures within and between study sites. Twenty siboglinid and nine bivalve chemosymbiotic species have been identified and were found living in fifteen mud volcanoes during our studies. Solemyids bivalves and tubeworms of the genus Siboglinum are the most widespread, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus) or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata). Species distribution suggests that different species may adjust their position within the sediment according to their particular needs and intensity and variability of the chemical substrata supply. Isotopic values found for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values) and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge of the chemosymbiotic species in the Gulf of Cadiz, highlight the relevance of seep chemoautolithotrophic production in this area and provide a starting point for future trophic ecology studies.
Abstract In this study, we evaluated how well DNA metabarcoding of environmental samples captures changes in marine mesozooplankton community composition to optimize the use of sequencing data for studying seasonal dynamics. Although DNA metabarcoding is increasingly used to monitor the distribution of marine communities, there is a lack of standardized methods, and it remains uncertain to what extent the DNA data reflects patterns of community dynamics observed by other methods. Zooplankton net samples were collected every second week throughout 2017 in the northern Salish Sea, British Columbia. We compared metabarcoding of two genetic markers (18S targeting eukaryotes and cytochrome oxidase I targeting invertebrates) with microscopic assessments of the zooplankton collected. We also evaluated how data transformation using relative abundance, presence/absence, and the eDNA-index, affects the linearity between the morphological and genetic methods. Despite low taxonomic agreement between DNA metabarcoding and microscopy, we found most biomass dominating genera to be well represented. Using the eDNA-index, we found a generally good congruence between the seasonal cycles observed with microscopy and DNA, and that discrete water samples analyzed with DNA metabarcoding can provide information on the vertical distributions of mesozooplankton genera. We conclude by presenting guidelines for future studies that aim to use DNA to study marine zooplankton community dynamics.
Event Abstract Back to Event Macrofaunal assemblages from an inactive pockmark field in the Estremadura Spur (West Iberian margin) Sofia P. Ramalho1*, Clara F. Rodrigues1, Ascensão Ravara1, Patricia Esquete1, Luciana Génio1, Vitor Magalhães2 and Marina R. Cunha1 1 University of Aveiro, Departamento de Biologia & CESAM, Portugal 2 Estação Piloto de Piscicultura de Olhão, Instituto Português do Mar e Atmosfera, Marine Geology and Georesources Division (DivGM), Portugal The first evidence of fluid and gas escape processes in the West Iberian margin outer shelf was recently identified off the Estremadura Spur (West Iberian margin), a field which encompass more than 70 pockmarks. Depending on their seepage activity, pockmarks are known to host high abundances of distinctive macrofaunal taxa that rely in chemosynthetic derived carbon. Within the framework of the project PES, a total of eleven pockmarks were sampled between depths of 200 to 400 m, aiming to characterize the benthic macrofaunal assemblages, in terms of composition, taxonomic and trophic diversity, total biomass and respiration rates. Results showed that the studied pockmarks were overall similar in both structural as well as trophic composition, and are primarily represented by large-sized nematodes, common detritus-feeding polychaetes (e.g. Paraonidae spp., Magelona sp., Ampharetidae spp.) and bivalve species (e.g. Thyasira succisa, Kelliella miliaris). These sediments disclosed overall a low species richness but high evenness, and rarefaction curves (based on Hurlbert’s expected number of species) suggest that further sampling is required to fully assess the biodiversity of these structures. Total macrofaunal biomasses varied greatly across the stations investigated primarily due to the occasional presence of larger individuals of few species (e.g. Gasrosaccus normanii). The overall absence of typical seepage-associated fauna and the similarities found in terms of taxa encountered with both inactive pockmarks off the Gulf of Biscay and other non-seepage sediments from similar depth ranges in the Iberian margin suggest that, at the present, these seepage sites are inactive. Acknowledgements This work was supported by the project PES (PTDC/GEOFIQ/5162/2014), financed by National funding through the Portuguese Science Foundation (FCT), and additional financial support was granted by CESAM (UID/AMB/50017), by through national funds (FCT/MEC), and the co-funded by FEDER, within the PT2020 Partnership Agreement and Compete 2020. CFR, PE, AR and LG were supported by the FCT post-doctoral grants SFRH/ BPD/107805/2015, SFRH/BPD/94985/2013, SFRH/BPD/112408/2015 and SFRH/BPD/96142/2013, respectively. Keywords: Macrobenthos, community composition, Trophic structure, inactive pockmarks, continental outer shelf, West Iberian Margin Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Biodiversity, Conservation and Coastal Management Citation: Ramalho SP, Rodrigues CF, Ravara A, Esquete P, Génio L, Magalhães V and Cunha MR (2019). Macrofaunal assemblages from an inactive pockmark field in the Estremadura Spur (West Iberian margin). Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00144 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Apr 2018; Published Online: 07 Jan 2019. * Correspondence: PhD. Sofia P Ramalho, University of Aveiro, Departamento de Biologia & CESAM, Aveiro, Portugal, Portugal, sofia.pinto.ramalho@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sofia P Ramalho Clara F Rodrigues Ascensão Ravara Patricia Esquete Luciana Génio Vitor Magalhães Marina R Cunha Google Sofia P Ramalho Clara F Rodrigues Ascensão Ravara Patricia Esquete Luciana Génio Vitor Magalhães Marina R Cunha Google Scholar Sofia P Ramalho Clara F Rodrigues Ascensão Ravara Patricia Esquete Luciana Génio Vitor Magalhães Marina R Cunha PubMed Sofia P Ramalho Clara F Rodrigues Ascensão Ravara Patricia Esquete Luciana Génio Vitor Magalhães Marina R Cunha Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.
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