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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

DOI: doi:10.3354/meps08166

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 m yr1 for 3 specimens of the genus Lepidisis and 113 17 m yr1 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:Environment
Objective Group:Climate and Climate Change
Objective Field:Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
Author:Davies, DM (Ms Diana Davies)
Author:Trull, TW (Professor Thomas Trull)
ID Code:113649
Year Published:2009
Web of Science® Times Cited:25
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2017-01-11
Last Modified:2017-03-27
Downloads:23 View Download Statistics

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