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| Titel |
Evidence for benthic-pelagic food web coupling and carbon export from California margin bamboo coral archives |
| VerfasserIn |
T. M. Hill, C. R. Myrvold, H. J. Spero, T. P. Guilderson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 14 ; Nr. 11, no. 14 (2014-07-22), S.3845-3854 |
| Datensatznummer |
250117520
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| Publikation (Nr.) |
 copernicus.org/bg-11-3845-2014.pdf |
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| Zusammenfassung |
| Deep-sea bamboo corals (order Gorgonacea, family Isididae) are known to
record changes in water mass chemistry over decades to centuries. These
corals are composed of a two-part skeleton of calcite internodes segmented
by gorgonin organic nodes. We examine the spatial variability of bamboo
coral organic node 13C/12C and 15N/14N from 13
bamboo coral specimens sampled along the California margin (37–32° N, 792–2136 m depth). Radiocarbon analyses of the organic
nodes show the presence of the anthropogenic bomb spike, indicating the
corals utilize a surface-derived food source (pre-bomb D14C values of
∼−100‰, post-bomb values up to
82‰). Carbon and nitrogen isotope data from the organic
nodes (δ13C = −15.9‰ to
−19.2‰; δ15N = 13.8‰ to 19.4‰) suggest selective feeding on surface-derived
organic matter or zooplankton. A strong relationship between coral δ15N and habitat depth indicates a potential archive of changing carbon
export, with decreased δ15N values reflecting reduced microbial
degradation (increased carbon flux) at shallower depths. Using four
multi-centennial-length coral records, we interpret long-term δ15N stability in the California Current. Organic node δ15C values record differences in carbon isotope fractionation dictated
by nearshore vs. offshore primary production. These findings imply strong
coupling between primary production, pelagic food webs, and deep-sea benthic
communities. |
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