Are spatial variations in the diets of hydrothermal fauna linked to local environmental conditions?

Type Article
Date 2009-09
Language English
Author(s) De Busserolles F.1, Sarrazin Jozee1, Gauthier Olivier1, Gelinas Y.2, 3, Fabri Marie-Claire1, Sarradin Pierre-Marie1, Desbruyeres Daniel1
Affiliation(s) 1 : IFREMER, Ctr Brest, DEEP LEP, F-29280 Plouzane, France.
2 : Concordia Univ, GEOTOP, Montreal, PQ H4B 1R6, Canada.
3 : Concordia Univ, Dept Chem & Biochem, Montreal, PQ H4B 1R6, Canada.
Source Deep Sea Research Part II: Topical Studies in Oceanography (0967-0645) (Elsevier), 2009-09 , Vol. 56 , N. 19-20 , P. 1649-1664
DOI 10.1016/j.dsr2.2009.05.011
WOS© Times Cited 57
Keyword(s) Lucky Strike (37 degrees 17.29 ' N 32 degrees 16.45 ' W), Mid Atlantic Ridge, Food webs, Hydrothermal springs, Environmental conditions, Stable isotopes
Abstract Trophic relationships in Bathymodiolus azoricus mussel bed communities on the Tour Eiffel hydrothermal edifice (Lucky Strike) were assessed using delta C-13 and delta N-15 signatures from 14 hydrothermal species. The nutritional basis of B. azoricus was also investigated with delta S-34. Faunal samples and environmental data (temperature, pH, total dissolved sulfide, iron and copper concentrations) were collected from 12 different locations on the edifice. Chemical conditions varied between microhabitats, and were all correlated to temperature. Carbon and nitrogen isotopic results revealed the presence of two, apparently independent, trophic groups. The first was composed of symbiont-bearing fauna (B. azoricus and their associated polychaetes Branchipolynoe seepensis), while the second enclosed heterotrophic fauna (bacterivores, cletritivores, scavengers, predators). A majority of mussels displayed delta C-13 values ranging from -27 parts per thousand to -34 parts per thousand, supporting thiotrophy as the dominant nutritional pathway at Tour Eiffel, with methanotrophy and filter feeding emerging as secondary strategies. This result was corroborated by delta S-34 signatures. However, higher delta C-13 values in larger mussels suggested that, as they grow, B. azoricus mussels rely more heavily on their methanotrophic enclosymbionts. Significant spatial variability in isotopic signatures for single faunal species was observed at the scale of the edifice for three species (B. azoricus, B. seepensis, Amathys lutzi), and environmental conditions explained variation in isotopic signatures for one-third of the species. This confirms the hypothesis raised by several authors on the role of hydrothermal fluids on the trophic network at small spatial scales. We suggest that vent fluid characteristics, by influencing microbial production, are key factors in the variation of local carbon sources at vents.
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De Busserolles F., Sarrazin Jozee, Gauthier Olivier, Gelinas Y., Fabri Marie-Claire, Sarradin Pierre-Marie, Desbruyeres Daniel (2009). Are spatial variations in the diets of hydrothermal fauna linked to local environmental conditions? Deep Sea Research Part II: Topical Studies in Oceanography, 56(19-20), 1649-1664. Publisher's official version : https://doi.org/10.1016/j.dsr2.2009.05.011 , Open Access version : https://archimer.ifremer.fr/doc/00000/7312/