Hydrothermal vent food webs on East Diamante submarine volcano, Mariana Arc

Hydrothermal vent-endemic invertebrates are being found at increasingly shallow depths, in some cases within the photic zone. The degree to which these organisms utilize chemosynthetic versus photosynthetic food sources is a compelling question. On East Diamante submarine volcano (Mariana Arc), deep-sea hydrothermal vent invertebrates are found in close proximity to both macroalgae and bacterial mats, and active venting occurs in the photic zone. Samples were taken at the summit (179 m) and on the slopes (247-288 m) of a hydrothermally-active volcanic cone in East Diamante’s caldera, and at two deeper sites to the east (349 and 461 m). At the summit of the cone, the community was composed of non-vent fauna, predominantly soft corals. On the slopes, large numbers of vent fauna were observed, primarily assemblages of snails/sponges and limpets/crabs. Vent barnacles and crabs dominated at the deepest eastern site (461 m) while a variety of vent fauna (e.g., snails, limpets, copepods) were found at a shallower site close by (349 m). The combined techniques of stable isotopes and fatty acid biomarkers indicate an increased use of photosynthetic material by local invertebrates, as sampling becomes shallower. For the most part, this trend holds in spite of the disparate taxonomies and feeding strategies of the sampled organisms. Vent invertebrates at the deepest site appear to rely solely on chemosynthetic food sources, non-vent fauna at the summit on photosynthetic material, while the remaining vent organisms, with an approximate depth range of 100 m (247-349 m), had mixed diets.

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First Name: 
Catherine
Last Name: 
Stevens
Telephone: 
778-440-1970
Affiliation: 
School of Earth & Ocean Sciences and Department of Biology, University of Victoria, PO Box 3020, Victoria, BC, V8W 3N5 Canada
First Name: 
Kim
Last Name: 
Juniper
Affiliation: 
School of Earth & Ocean Sciences and Department of Biology, University of Victoria, PO Box 3020, Victoria, BC, V8W 3N5 Canada
First Name: 
Helene
Last Name: 
Limén
Affiliation: 
Research Service, The Riksdag Administration, The Swedish Parliament, SE-100 12 Stockholm, Sweden
First Name: 
David
Last Name: 
Pond
Affiliation: 
Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Dunbeg, Oban, Argyll PA37 1QA, UK
Choose keywords that are most applicable to your abstract. (Three maximum.): 
Trophic relations (including symbiosis)
Ecological Interactions
Abstract ID: 
CBE5-138