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δ56Fe in seabird guano reveals extensive recycling of iron in the Southern Ocean ecosystem
Citation
Wing, SR and Gault-Ringold, M and Stirling, CH and Wing, LC and Shatova, OA and Frew, RD, δ56Fe in seabird guano reveals extensive recycling of iron in the Southern Ocean ecosystem, Limnology and Oceanography, 62, (4) pp. 1671-1681. ISSN 0024-3590 (2017) [Refereed Article]
Copyright Statement
Copyright 2017 Association for the Sciences of Limnology and Oceanography
Abstract
Availability of iron limits productivity in the Southern Ocean where vast regions
of high‐nitrogen low‐chlorophyll conditions are punctuated by hotspots of production
surrounding the subAntarctic islands. Here, we compare patterns in accumulation of
iron, as indicated by [Fe] and Fe : C (from Wing et al. 2014), with proxies for uptake of iron within food webs, as indicated by Fe : Al and δ56Fe within the subAntarctic Auckland Island ecosystem. We compare these proxies for
dynamics of iron within egested material collected from six seabird species, representing
three distinct foraging guilds. Fractions of biogenic iron, estimated from Fe : Al,
were lowest in the coastal foraging guild (0.83 ± 0.01), and higher in the oceanic
and predator guilds (0.94 ± 0.01 and 0.95 ± 0.01), consistent with high rates of biological
recycling. The isotopic ratio of iron 56Fe/54Fe, reported as δ56Fe, is depleted in the heavy isotope 56Fe by recycling in the microbial loop, and is likely further depleted in 56Fe when taken up by animals within the food web. δ56Fe was most negative for the oceanic foraging group indicating intensive recycling
(−1.16 ± 0.16‰), most positive in the coastal group where direct lithogenic sources
of iron are more available (−0.14 ± 0.15‰), and intermediate
Item Details
Item Type: | Refereed Article |
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Keywords: | iron isotopes, seabirds, guano, sub-Antarctic |
Research Division: | Earth Sciences |
Research Group: | Geochemistry |
Research Field: | Geochemistry not elsewhere classified |
Objective Division: | Environmental Management |
Objective Group: | Management of Antarctic and Southern Ocean environments |
Objective Field: | Biodiversity in Antarctic and Southern Ocean environments |
UTAS Author: | Gault-Ringold, M (Dr Melanie East) |
ID Code: | 125208 |
Year Published: | 2017 |
Web of Science® Times Cited: | 5 |
Deposited By: | CRC-Antarctic Climate & Ecosystems |
Deposited On: | 2018-04-06 |
Last Modified: | 2018-05-07 |
Downloads: | 0 |
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