Tracing basal resource use across sea-ice, pelagic, and benthic habitats in the early Arctic spring food web with essential amino acid carbon isotopes
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https://hdl.handle.net/10037/30151Date
2023-02-09Type
Journal articleTidsskriftartikkel
Peer reviewed
Author
Vane, Kim; Cobain, Matthew R. D.; Trueman, Clive N.; Vonnahme, Tobias R.; Rokitta, Sebastian; Polunin, Nicholas V. C.; Flores, HaukeAbstract
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 δ13C values of essential amino acids (EAAs) (δ13CEAA 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 δ13CEAA values, that is, the basal resource specific δ13CEAA values, and
δ13CEAA fingerprints, or mean-centred baseline δ13CEAA 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, δ13CEAA fingerprints from algae-associated bacteria were clearly traced to the sponges, with an individually variable kelp use by sea cucumbers. Although mean-centred δ13CEAA 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 δ13CEAA values as similar microalgae clades occur in both habitats. We suggest that δ13CEAA fingerprints combined with microalgae baseline
δ13CEAA values are an insightful tool to assess the effect of ongoing changes in Arctic basal resources on their
use by organisms.
Publisher
WileyCitation
Vane, Cobain, Trueman, Vonnahme, Rokitta, Polunin, Flores. Tracing basal resource use across sea-ice, pelagic, and benthic habitats in the early Arctic spring food web with essential amino acid carbon isotopes. Limnology and Oceanography. 2023;68:862-877Metadata
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