Details:

Journal Title:
Global Change Biology
Personal Author:
Arimitsu, Mayumi L. ; Hobson, Keith A. ; Webber, D'Arcy N. ; Piatt, John F. ; Hood, Eran W. ; ... More +
Arimitsu, Mayumi L. ; Hobson, Keith A. ; Webber, D'Arcy N. ; Piatt, John F. ; Hood, Eran W. ; Fellman, Jason B. Less -
NOAA Program & Office:
NOAA General Documents
Description:
Nearly half of the freshwater discharge into the Gulf of Alaska originates from landscapes draining glacier runoff, but the influence of the influx of riverine organic matter on the trophodynamics of coastal marine food webs is not well understood. We quantified the ecological impact of riverine organic matter subsidies to glacier‐marine habitats by developing a multi‐trophic level Bayesian three‐isotope mixing model. We utilized large gradients in stable (δ13C, δ15N, δ2H) and radiogenic (Δ14C) isotopes that trace riverine and marine organic matter sources as they are passed from lower to higher trophic levels in glacial‐marine habitats. We also compared isotope ratios between glacial‐marine and more oceanic habitats. Based on isotopic measurements of potential baseline sources, ambient water and tissues of marine consumers, estimates of the riverine organic matter source contribution to upper trophic‐level species including fish and seabirds ranged from 12% to 44%. Variability in resource use among similar taxa corresponded to variation in species distribution and life histories. For example, riverine organic matter assimilation by the glacier‐nesting seabirds Kittlitz's murrelet (Brachyramphus brevirostris) was greater than that of the forest‐nesting marbled murrelet (B. marmoratus). The particulate and dissolved organic carbon in glacial runoff and near surface coastal waters was aged (12100–1500 years BP 14C‐age) but dissolved inorganic carbon and biota in coastal waters were young (530 years BP 14C‐age to modern). Thus terrestrial‐derived subsidies in marine food webs were primarily composed of young organic matter sources released from glacier ecosystems and their surrounding watersheds. Stable isotope compositions also revealed a divergence in food web structure between glacial‐marine and oceanic sites. This work demonstrates linkages between terrestrial and marine ecosystems, and facilitates a greater understanding of how climate‐driven changes in freshwater runoff have the potential to alter food web dynamics within coastal marine ecosystems in Alaska.
Keywords:
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Ecology Environmental Chemistry General Environmental Science Global And Planetary Change
Source:
Global Change Biology, 24(1), 387-398
DOI:
https://doi.org/10.1111/gcb.13875
ISSN:
1354-1013;1365-2486;
Format:
PDF
Publisher:
Wiley
Document Type:
Journal Article
License:
https://creativecommons.org/publicdomain/zero/1.0/
Rights Information:
CC0 Public Domain
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:33dc8c9b0856ab168fd4d8a8d580e2fe6ce8f40211ddd5fe54182018ce6448fc
Download URL:
https://repository.library.noaa.gov/view/noaa/59558/noaa_59558_DS1.pdf
File Type:

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