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

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 d15N and more depleted d13C values than the same stages inhabiting the black smokers themselves. The shrimps R. exoculata and Chorocaris chacei demonstrate ontogenetic changes in d13C (the former also in d15N), with smaller individuals showing higher d15N and more depleted d13C values than larger shrimps. Benthopelagic and benthic components of the vent community differ significantly in d13C and d15N, the benthic fauna being less dependent upon chemosynthetic production