Tracing basal resource use across sea‐ice, pelagic, and benthic habitats in the early Arctic spring food web with essential amino acid carbon isotopes. Issue 4 (9th February 2023)

• Record Type: Journal Article
• Authors: Vane, Kim; Cobain, Matthew R. D.; Trueman, Clive N.; Vonnahme, Tobias R.; Rokitta, Sebastian; Polunin, Nicholas V. C.; Flores, Hauke
• Is Part Of: Limnology and oceanography. Volume 68:Issue 4(2023)
• Page Start: 862
• Page End: 877
• Publication Date: 2023-02-09
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; Océanographie; Limnologie; Limnology; Oceanography; Computer network resources; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); Periodicals; 551.4805
• DOI: 10.1002/lno.12315
• Languages: English
• ISSNs: 0024-3590

Abstract

Abstract: A rapidly warming Arctic Ocean and associated sea‐ice decline is resulting in changing sea‐ice protist communities, affecting productivity of under‐ice, pelagic, and benthic fauna. Quantifying such effects is hampered by a lack of biomarkers suitable for tracing specific basal resources (primary producers and microorganisms) through food webs. We investigate the potential of δ 13 C values of essential amino acids (EAAs) (δ 13 CEAA values) to estimate the proportional use of diverse basal resources by organisms from the under‐ice ( Apherusa glacialis ), pelagic ( Calanus hyperboreus ) and benthic habitats (sponges, sea cucumber), and the cryo‐pelagic fish Boreogadus saida . Two approaches were used: baseline δ 13 CEAA values, that is, the basal resource specific δ 13 CEAA values, and δ 13 CEAA fingerprints, or mean‐centred baseline δ 13 CEAA values. Substantial use of sub‐ice algae Melosira arctica by all studied organisms suggests that its role within Arctic food webs is greater than previously recognized. In addition, δ 13 CEAA fingerprints from algae‐associated bacteria were clearly traced to the sponges, with an individually variable kelp use by sea cucumbers. Although mean‐centred δ 13 CEAA values in A. glacialis, C. hyperboreus, and B. saida tissues were aligned with microalgae resources, they were not fully represented by the filtered pelagic‐ and sea‐ice particulate organic matter constituting the spring diatom‐dominated algal community. Under‐ice and pelagic microalgae use could only be differentiated with baseline δ 13 CEAA values as similar microalgae clades occur in both habitats. We suggest that δ 13 CEAA fingerprints combined with microalgae baseline δ 13 CEAA values are an insightful tool to assess the effect of ongoing changes in Arctic basal resources on their use by organisms.