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Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 15, 2629-2647, 2018
https://doi.org/10.5194/bg-15-2629-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
04 May 2018
Biodiversity and trophic ecology of hydrothermal vent fauna associated with tubeworm assemblages on the Juan de Fuca Ridge
Yann Lelièvre1,2, Jozée Sarrazin1, Julien Marticorena1, Gauthier Schaal3, Thomas Day1, Pierre Legendre2, Stéphane Hourdez4,5, and Marjolaine Matabos1 1Ifremer, Centre de Bretagne, REM/EEP, Laboratoire Environnement Profond, 29280 Plouzané, France
2Département de sciences biologiques, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec, H3C 3J7, Canada
3Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 9 CNRS/UBO/IRD/Ifremer, BP 70, 29280, Plouzané, France
4Sorbonne Université, UMR7144, Station Biologique de Roscoff, 29680 Roscoff, France
5CNRS, UMR7144, Station Biologique de Roscoff, 29680 Roscoff, France
Abstract. Hydrothermal vent sites along the Juan de Fuca Ridge in the north-east Pacific host dense populations of Ridgeia piscesae tubeworms that promote habitat heterogeneity and local diversity. A detailed description of the biodiversity and community structure is needed to help understand the ecological processes that underlie the distribution and dynamics of deep-sea vent communities. Here, we assessed the composition, abundance, diversity and trophic structure of six tubeworm samples, corresponding to different successional stages, collected on the Grotto hydrothermal edifice (Main Endeavour Field, Juan de Fuca Ridge) at 2196 m depth. Including R. piscesae, a total of 36 macrofaunal taxa were identified to the species level. Although polychaetes made up the most diverse taxon, faunal densities were dominated by gastropods. Most tubeworm aggregations were numerically dominated by the gastropods Lepetodrilus fucensis and Depressigyra globulus and polychaete Amphisamytha carldarei. The highest diversities were found in tubeworm aggregations characterised by the longest tubes (18.5 ± 3.3 cm). The high biomass of grazers and high resource partitioning at a small scale illustrates the importance of the diversity of free-living microbial communities in the maintenance of food webs. Although symbiont-bearing invertebrates R. piscesae represented a large part of the total biomass, the low number of specialised predators on this potential food source suggests that its primary role lies in community structuring. Vent food webs did not appear to be organised through predator–prey relationships. For example, although trophic structure complexity increased with ecological successional stages, showing a higher number of predators in the last stages, the food web structure itself did not change across assemblages. We suggest that environmental gradients provided by the biogenic structure of tubeworm bushes generate a multitude of ecological niches and contribute to the partitioning of nutritional resources, releasing communities from competition pressure for resources and thus allowing species to coexist.
Citation: Lelièvre, Y., Sarrazin, J., Marticorena, J., Schaal, G., Day, T., Legendre, P., Hourdez, S., and Matabos, M.: Biodiversity and trophic ecology of hydrothermal vent fauna associated with tubeworm assemblages on the Juan de Fuca Ridge, Biogeosciences, 15, 2629-2647, https://doi.org/10.5194/bg-15-2629-2018, 2018.
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Short summary
The Main Endeavour vent field, a Marine Protected Area, is a target site for the cabled observatory Ocean Networks Canada, providing unprecedented opportunities to better understand vent ecosystem functioning. We report the diversity and food webs of six faunal communities associated with siboglinid tubeworms of the Grotto edifice. Better knowledge of the ecological functioning of these communities will help in assessing the role of the MPA as a management tool for hydrothermal vents ecosystems.
The Main Endeavour vent field, a Marine Protected Area, is a target site for the cabled...
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