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Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps

In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assem...

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Autores principales: Portail, Marie, Olu, Karine, Dubois, Stanislas F., Escobar-Briones, Elva, Gelinas, Yves, Menot, Lénaick, Sarrazin, Jozée
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5040445/
https://www.ncbi.nlm.nih.gov/pubmed/27683216
http://dx.doi.org/10.1371/journal.pone.0162263
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author Portail, Marie
Olu, Karine
Dubois, Stanislas F.
Escobar-Briones, Elva
Gelinas, Yves
Menot, Lénaick
Sarrazin, Jozée
author_facet Portail, Marie
Olu, Karine
Dubois, Stanislas F.
Escobar-Briones, Elva
Gelinas, Yves
Menot, Lénaick
Sarrazin, Jozée
author_sort Portail, Marie
collection PubMed
description In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to partly release the competitive pressure within communities of low fluid-flux habitats. Finally, ecosystem functioning in vents and seeps was highly similar despite environmental differences (e.g. physico-chemistry, dominant basal sources) suggesting that ecological niches are not specifically linked to the nature of fluids. This comparison of seep and vent functioning in the Guaymas basin thus provides further supports to the hypothesis of continuity among deep-sea chemosynthetic ecosystems.
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spelling pubmed-50404452016-10-27 Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps Portail, Marie Olu, Karine Dubois, Stanislas F. Escobar-Briones, Elva Gelinas, Yves Menot, Lénaick Sarrazin, Jozée PLoS One Research Article In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to partly release the competitive pressure within communities of low fluid-flux habitats. Finally, ecosystem functioning in vents and seeps was highly similar despite environmental differences (e.g. physico-chemistry, dominant basal sources) suggesting that ecological niches are not specifically linked to the nature of fluids. This comparison of seep and vent functioning in the Guaymas basin thus provides further supports to the hypothesis of continuity among deep-sea chemosynthetic ecosystems. Public Library of Science 2016-09-28 /pmc/articles/PMC5040445/ /pubmed/27683216 http://dx.doi.org/10.1371/journal.pone.0162263 Text en © 2016 Portail et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Portail, Marie
Olu, Karine
Dubois, Stanislas F.
Escobar-Briones, Elva
Gelinas, Yves
Menot, Lénaick
Sarrazin, Jozée
Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title_full Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title_fullStr Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title_full_unstemmed Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title_short Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
title_sort food-web complexity in guaymas basin hydrothermal vents and cold seeps
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5040445/
https://www.ncbi.nlm.nih.gov/pubmed/27683216
http://dx.doi.org/10.1371/journal.pone.0162263
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