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Multi-century time-series of 15N and 14C in bamboo corals from deep Tasmanian seamounts: evidence for stable oceanographic conditions
Citation
Sherwood, OA and Thresher, RE and Fallon, SJ and Davies, DM and Trull, TW, Multi-century time-series of 15N and 14C in bamboo corals from deep Tasmanian seamounts: evidence for stable oceanographic conditions, Marine Ecology - Progress Series, 397 pp. 209-218. ISSN 0171-8630 (2009) [Refereed Article]
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Copyright Statement
Copyright 2009 Inter-Research
Abstract
Bamboo corals (Family Isididae) are an important component of seamount benthos south of Tasmania. Besides having lifespans of up to 400 yr, little is known about their basic ecology, nor how to decode potential climate signals encoded in their skeletons. We explored the stable nitrogen isotope and radiocarbon compositions of the skeletal organic fraction of the genera Isidella, Keratoisis and Lepidisis collected from 3 Tasmanian seamounts. Analyses were performed on tissues and organic node growth rings sampled at a temporal resolution of 1 to 4 yr. Radiocarbon chronologies exhibited nuclear bomb signals characteristic of surface waters and constrained radial growth rates to ~35 ± 10 µm yr–1 for 3 specimens of the genus Lepidisis and 113 ± 17 µm yr–1 for 1 specimen of Isidella. δ15N values of the living tissue and underlying gorgonin were similar and averaged 9 to 12‰. Records of δ15N from 8 different specimens showed subtle, quasi-decadal patterns over the last ~100 yr, although the amplitude of these features (~1‰) was similar to the average intra- and intercolony reproducibility. These results demonstrate the utility of deep-sea corals to track seamount biogeochemical processes over long time scales, and suggest that the extent of nutrient depletion of surface waters and associated trophic dynamics have remained relatively constant in this region over centuries. This provides an important baseline for the evaluation of the impacts of anthropogenic climate change.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | Tasmanian seamounts, deep-sea corals, stable isotopes, radiocarbon, biogeochemistry |
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Chemical oceanography |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Understanding climate change |
| Objective Field: | Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts) |
| UTAS Author: | Davies, DM (Ms Diana Davies) |
| UTAS Author: | Trull, TW (Professor Thomas Trull) |
| ID Code: | 113649 |
| Year Published: | 2009 |
| Web of Science® Times Cited: | 32 |
| Deposited By: | CRC-Antarctic Climate & Ecosystems |
| Deposited On: | 2017-01-11 |
| Last Modified: | 2017-03-27 |
| Downloads: | 152 View Download Statistics |
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