MEPS 220:13-23 (2001)  -  doi:10.3354/meps220013

ABSTRACT: 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 δ¹⁵N or δ¹³C of benthic fishes or crustaceans: the shrimps A. antennatus and Acanthephyra eximia showed higher δ¹⁵N 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 δ¹⁵N 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 δ¹⁵N and a reduction in δ¹³C 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.

KEY WORDS: Deep-sea · Mesozooplankton · Fishes · Crustaceans · Suprabenthos · Mediterranean · Bathyal