Stable isotope signatures and distribution of deepwater sponges in Lake Baikal

摘要: To better understand the species composition and nutrition of deepwater sponges in Lake Baikal, we determined depth, habitat, stable isotopic signatures for sponges. All sponge specimens except one were collected at depths below photic zone a variety benthic habitats including methane seeps hydrothermal vents. The freshwater Baikal generally occurred aggregations (fields, carpets, belts), mainly on hard substrates (different types bedrock argillite, bitumen). New maximum depth records established three species. clustered into two groups, based their values, with members group assimilating organic carbon from photosynthetic sources exhibiting δ13C values (−32 to −26.9‰) similar those reported previously littoral Members second group, distinguished by highly depleted (−65 −37.3‰), participate chemosynthetic food web. δ15N ranged widely (2.1–16.7‰) suggesting that they assimilate nitrogen environmental possibly microbial symbionts. Conservation diversity is therefore, likely dependent resources found different habitats.