Environmental controls on coral skeletal δ13C in the northern South China Sea. Issue 4 (1st October 2013)

• Record Type: Journal Article
• Authors: Deng, Wenfeng; Wei, Gangjian; Xie, Luhua; Yu, Kefu
• Is Part Of: Journal of geophysical research. Volume 118:Issue 4(2013:Dec.)
• Page Start: 1359
• Page End: 1368
• Publication Date: 2013-10-01
• Subjects: Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1002/jgrg.20116
• Languages: English
• ISSNs: 2169-8953

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>[1] In this paper, we investigate the relationship between seasonal climatic and environmental variables, and the skeletal δ<sup>13</sup>C of modern and mid‐Holocene <italic>Porites lutea</italic> corals from the southern coast of Hainan Island in the northern South China Sea. No significant correlations were observed between δ<sup>13</sup>C in the modern coral and solar insolation or sea surface temperature. However, seasonal variability of δ<sup>13</sup>C in the modern coral covaries with rainfall on Hainan Island. Furthermore, the seasonal variations of δ<sup>13</sup>C in both the modern and mid‐Holocene coral are synchronous with those of the coral Δδ<sup>18</sup>O, which is a proxy for seawater δ<sup>18</sup>O and, in turn, largely controlled by local rainfall. These observations suggest that coral δ<sup>13</sup>C variations are closely associated with rainfall in this region. Given that river runoff contains dissolved inorganic carbon (DIC) with a negative δ<sup>13</sup>C, we suggest that periods of high rainfall on Hainan Island deliver increased amounts of <sup>13</sup>C‐depleted DIC to coastal seawater, resulting in an enhanced negative δ<sup>13</sup>C in the corals. Our findings, together with previous studies, appear to demonstrate that in coastal environments, coral skeletal δ<sup>13</sup>C levels are controlled mainly by terrestrial carbon input and are significantly influenced by terrestrial river runoff. Consequently, the geochemical interpretation of coral δ<sup>13</sup>C records may differ between coastal areas and offshore areas or the open ocean.</p> </abstract>