Publication Abstract

Feeding relationships in Mediterranean bathyal assemblages elucidated by stable nitrogen and carbon isotope data

N.V.C. Polunin, B. Nin-Morales, W.E. Pawsey, J.E. Cartes, J.K. Pinnegar and J. Moranta

Fishes and invertebrates were collected from the continental slope southwest of the Balearic Islands, Mediterranean, in October 1996 and May 1998 from 3 faunally-distinct depth zones: 200 to 800 m (upper slope), 800 to 1425 m (middle slope) and 1425 to 1800 m (lower slope). Differences in δ15N and δ13C between October 1996 and May 1998 were observed only in the crustaceans Aristeus antennatus and Nematocarcinus exilis. There were few differences among depths in ä15N or ä13C of benthic fishes or crustaceans: the shrimps A. antennatus and Acanthephyra eximia showed higher ä15N values at greater depth, and δ13C values of the fishes Alepocephalus rostratus (Alepocephalidae) and Coelorhynchus coelorhynchus (Macrouridae) also tended to increase with increasing depth. Differences in plankton and suprabenthos were also observed among zones (at depth, greater ä15N values of gelatinous plankton, calanoid copepods and peracarids were recorded, along with smaller δ13C values of gelatinous plankton and peracarids). These are attributed to a microbially-mediated increase in ä15N and a reduction in ä13C of the particulate material remaining after preferential utilization of labile organic matter in the stable and relatively high (13°C) temperature of the Mediterranean water column. Strong positive correlations between δ15N and δ13C data for plankton, fishes and crustaceans indicated a single primary source material for these communities, which is attributed to marine snow.

Reference:

N.V.C. Polunin, B. Nin-Morales, W.E. Pawsey, J.E. Cartes, J.K. Pinnegar and J. Moranta, 2001. Feeding relationships in Mediterranean bathyal assemblages elucidated by stable nitrogen and carbon isotope data. Marine Ecology Progress Series, 220: 13-23