FN Archimer Export Format PT J TI Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps BT AF PORTAIL, Marie OLU, Karine DUBOIS, Stanislas ESCOBAR-BRIONES, Elva GELINAS, Yves MENOT, Lenaick SARRAZIN, Jozee AS 1:1;2:1;3:2;4:3;5:4,5;6:1;7:1; FF 1:PDG-REM-EEP-LEP;2:PDG-REM-EEP-LEP;3:PDG-ODE-DYNECO-LEBCO;4:;5:;6:PDG-REM-EEP-LEP;7:PDG-REM-EEP-LEP; C1 Inst Carnot Ifremer EDROME, Ctr Bretagne, REM EEP, Lab Environm Profond, Plouzane, France. IFREMER, Ctr Bretagne, DYNECO, Lab Ecol Benth, Plouzane, France. Univ Nacl Autonoma Mexico, Inst Ciencias Mary & Limnol, Mexico City, DF, Mexico. Concordia Univ, Geotop, Montreal, PQ, Canada. Concordia Univ, Dept Chem & Biochem, Montreal, PQ, Canada. C2 IFREMER, FRANCE IFREMER, FRANCE UNIV UNAM, MEXICO UNIV CONCORDIA, CANADA UNIV CONCORDIA, CANADA SI BREST SE PDG-REM-EEP-LEP PDG-ODE-DYNECO-LEBCO IN WOS Ifremer jusqu'en 2018 DOAJ copubli-int-hors-europe copubli-sud IF 2.806 TC 32 UR https://archimer.ifremer.fr/doc/00353/46390/46018.pdf https://archimer.ifremer.fr/doc/00353/46390/46019.pdf https://archimer.ifremer.fr/doc/00353/46390/46020.pdf LA English DT Article CR BIG BO L'Atalante AB 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. PY 2016 PD SEP SO Plos One SN 1932-6203 PU Public Library Science VL 11 IS 9 UT 000384171400007 DI 10.1371/journal.pone.0162263 ID 46390 ER EF