Efficiency of sympagic-benthic coupling revealed by analyses of n-3 fatty acids, IP25 and other highly branched isoprenoids in two filter-feeding Arctic benthic molluscs: Mya truncata and Serripes groenlandicus

The aim of this work was to determine the impact sympagic (ice-associated) algal primary production on quality Arctic filter-feeding bivalves. For purpose, we investigated sea ice lipids (including omega-3 polyunsaturated fatty acids (n-3 PUFA) and highly branched isoprenoids (HBI)), as well their subsequent incorporation into truncate softshell clam (Mya truncata) Greenland cockle (Serripes groenlandicus), during melting periods two consecutive years in Baffin Bay. Lipid exhibited seasonal variability overall contrasts between years, a result distinct physical forcings ensuing biological responses. Whilst less productive terms total or chlorophyll a, spring 2016 more than 2015 for n-3 PUFA, which are essential benthic fauna. diatom HBI biomarker IP25 quantified from both years. Interestingly, such preceded by hitherto ‘pelagic’ biomarker, III, ice. In bivalves, contents correlations confirmed tightness sympagic-benthic coupling highlighted that S. groenlandicus can be used sentinel species assessing degree coupling. confirmation bivalves incorporate sea-ice derived III not only IP25, may introduce uncertainties use some HBI-based indices. Monitoring acid allowed identification spawning suggests M. truncata did store enough PUFA sustain its reproductive effort.