When season does not matter: summer and winter trophic ecology of Arctic amphipods

• Published in: Hydrobiologia Vol. 684; no. 1; pp. 189 - 214
• Main Authors: Legeżyńska, Joanna, Kędra, Monika, Walkusz, Wojciech
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2012; Springer; Springer Nature B.V
• Subjects: Analysis; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomedical and Life Sciences; Crustacea; Ecology; Fatty acids; Fish; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Invertebrates; Life Sciences; Primary Research Paper; Summer; Synecology; Winter; Zoology; Arctic Region; Arctic region; PN, Arctic; Trophic ecology; Arctic; Fatty acids; Stable isotopes; Seasonality; Amphipoda; Lipids; Trophic relation; Ecology; Crustacea; Aquatic environment; Hydrobiology; Seasonal variation; Arthropoda; Invertebrata; Season; Isotopes
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-011-0982-z

Polar marine ecosystems’ functioning is known to be strongly affected by the seasonality of water column production. However, a response of benthic organisms may range from close coupling to total decoupling from seasonal variability of environmental processes, depending on a feeding strategy. In this study, we used a multi-method approach (gut content, lipid and stable isotope analyses) to examine trophic ecology and major food sources of a large set of Arctic sub-littoral amphipods, and to evaluate whether their feeding strategies undergo seasonal changes. The wide range of δ 15 N values (5.45-12.43‰) indicates that amphipods form a trophic continuum from primary herbivores to carnivores/scavengers. Three main feeding modes, namely scavenging/predatory, deposit-feeding/predatory and phytodetrivory, were distinguished based on the multivariate analysis of whole fatty acid profiles. Total lipid content was low in all species and included primarily short-term energy reserves of triacylglycerols. In general, amphipods feeding habits appeared to be independent of the seasonal phytodetritial pulses. Low reliance on lipid reserves and lack of major changes in the trophic strategies over time suggest that these crustaceans feed continuously, taking advantage of a variety of food sources that are available year-round in shallow polar waters.