Carbon and nitrogen isotopic composition of the fauna from the Broken Spur hydrothermal vent field

Abstract

 The carbon and nitrogen isotopic composition of 18 faunistic groups collected during the 39th cruise of the R.V. “Akademik Mstislav Keldysh” in September 1996 at the Broken Spur vent field, MAR, was studied. The trophic structure of the Broken Spur vent community is considered. All age stages of the shrimp Rimicaris exoculata living 5 m below the main aggregations at black smokers show higher δ¹⁵N and more depleted δ¹³C values than the same stages inhabiting the black smokers themselves. The shrimps R. exoculata and Chorocaris chacei demonstrate ontogenetic changes in δ¹³C (the former also in δ¹⁵N), with smaller individuals showing higher δ¹⁵N and more depleted δ¹³C values than larger shrimps. Benthopelagic and benthic components of the vent community differ significantly in δ¹³C and δ¹⁵N, the benthic fauna being less dependent upon chemosynthetic production.