SOURCES OF PRIMARY PRODUCTION, BENTHIC-PELAGIC COUPLING, AND TROPHIC RELATIONSHIPS WITHIN THE NORTHEAST WATER POLYNYA - INSIGHTS FROM DELTA-C-13 AND DELTA-N-15 ANALYSIS

We used stable carbon (C-13/C-12) and nitrogen (N-15/N-14) isotope ana lysis to investigate linkages between sources of primary production an d the pelagic and benthic components oi the Northeast Water (NEW) Poly nya off northeastern Greenland. Ice algae was enriched in C-13 (mean d elta(13)C = -18.6 vs -27.9 parts per thousand) and N-15 (mean delta(15 )N = 8.3 vs 4.9 parts per thousand) over particulate organic matter (P OM) suggesting that the relative importance of these sources might be traced isotopically. Most grazing crustaceans and filter-feeding bival ves had delta(13)C and delta(15)N values in the range of -21 to -23 pa rts per thousand and 7 to 9 parts per thousand, respectively, indicati ng a direct pathway from POM. Close benthic-pelagic coupling was also confirmed for other benthic organisms examined with the exception of t he predatory or deposit feeding echinoderms Ophioctin, Ophiacantha and Pontaster. Compared with other Arctic and temperate marine food webs, stable-carbon isotope values for the NEW Polynya were depleted in C-1 3. A delta(15)N trophic model that incorporated taxon-specific isotopi c fractionation factors indicated that the NEW Polynya consisted of 4. 5 to 5 trophic levels. Stable-isotope analysis may be well suited to e stablishing the importance of polynyas as sites of high primary produc tivity and tight benthic-pelagic coupling relative to regions of more permanent ice cover.