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. (January 2021)

• Record Type: Journal Article
• Authors: Amiraux, Rémi; Archambault, Philippe; Moriceau, Brivaela; Lemire, Mélanie; Babin, Marcel; Memery, Laurent; Massé, Guillaume; Tremblay, Jean-Eric
• Is Part Of: Organic geochemistry. Volume 151(2021)
• Publication Date: 2021-01
• Subjects: Arctic shelves -- Sympagic-benthic coupling -- IP25 -- HBI -- n-3 PUFA -- EPA -- DHA -- Mya truncata -- Serripes groenlandicus -- ice-derived HBI III; Organic geochemistry -- Periodicals; Biogeochemistry -- Periodicals; Géochimie organique -- Périodiques; 553.205
• DOI: 10.1016/j.orggeochem.2020.104160
• Languages: English
• ISSNs: 0146-6380

Abstract

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