Trophic Relationships between Macroinvertebrate and Fish Communities in St. Petersburg Methane Seep in the Abyssal Zone of Lake Baikal
T. Ya. SITNIKOVA1, I. V. MEKHANIKOVA1, V. G. SIDILEVA2, S. I. KIYASHKO3, T. V. NAUMOVA1, T. I. ZEMSKAYA1, O. M. KHLYSTOV1
1Limnological Institute, SB RAS, 664033, Irkutsk, Ulan-Batorskaya str., 3
2Zoological Institute, RAS, 199034, St. Petersburg, Universitetskaya emb., 1
3A. V. Zhirmunsky Institute of Marine Biology, FEB RAS, 690041, Vladivostok, Palchevsky str., 17
Keywords: метановый сип, озеро Байкал, макробеспозвоночные, коттоидные рыбы, стабильные изотопы, трофические связи, methane seep, Lake Baikal, macroinvertebrates, cottoid fish, stable isotopes, trophic relationships
Abstract
Traphic relationships were examined for macroinvertebrates and fish inhabiting St. Petersburg methane seep (Central part of lake Baikal, ~1400 m depth). The analyses of the values of carbon and nitrogen stable isotopes showed that all animals associated with the seep were heterotrophs with different feeding strategies, symbiotrophs were absent. Seep enimals consumed combined food with different portion of methane derived carbon ranged from 2.7 to 89 %. The average values of the δ13С varied from -26.2 ‰ (in benthopelagic amphipods) to -64.5 ‰ (in gastropods). The trophic food web of the methane seep consisted of filter feeders (pelagic amphipods TP 1.9), detritophages (gastropods TP 2.2 and burrowing amphipods TP 2.1), polyphages (nectobenthic and bentho-pelagic amphipods TP 2.8-3.2), and predators (flat worms TP 3.6-4.2 and cottoid fish TP 3.0-3.8). Animals occupying the similar trophic positions differed significantly in the δ13С values and utilized partly overlapping different food components.
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