Coral cores as record of past sea surface temperature of the Talang Besar Island (South China Sea)

Content Provider	Semantic Scholar
Author	Thyartan, Revadi Devi
Copyright Year	2018
Abstract	The climate of the South China Sea (SCS) is greatly under the influence of the East Asian monsoon season. This research study focusses on reconstructing the past sea surface temperature (SST) from 2015 to 1830 (165-year record) at the Southern South China Sea, sSCS. Since very few studies regarding climate change have been undertaken in that region, this reconstruction is a significant contribution to paleoceanography in this region. It helps to understand how the climate has been changing over the past years and to identify past ENSO years. Trace elements ratios (e.g: Sr/Ca, Mg/Ca) incorporated in the skeletons of long-lived corals are considered as very useful proxies for climate reconstruction. This study is based on assessing the amount of Sr/Ca ratio (by inductively coupled plasma optical emission spectrometry) present at different intervals in a 2-metre coral core (massive Porites species) that was sampled off the Talang Besar Island, Sarawak, Borneo for long term SST reconstruction. The coral core was collected in July 2015 using a pneumatic drill. Bands observed on X ray photographs (high/low density bands) and luminescent images (bright/dull bands) of the skeleton were used to identify the annual growth of the coral core. Since the core is an equatorial one, luminescent bands are considered to be better and more visible than x ray photographs. The annual growth rate of the massive Porites coral is estimated to be ~1cm/year. The first ~25 cm (representing 25 years of growth) of the coral core were used for calibrating skeletal chemistry against 25 years of satellite data (in the absence of instrumental SST data). HadISST dataset produced better calibration equation and was used for long term SST reconstruction. Through our findings, we observed that the Southwest monsoon season calibration does not show good relationship (R2 = 0.1) with the HadISST data. Therefore, the long-term SST reconstruction focussed only on the monthly and northeast monsoon season. Based on the calibration results, it can be clearly observed that the NE monsoon reconstruction was captured reasonable well. It has also been observed that the reconstructed SST data for both monthly and northeast monsoon season were much higher than that of HadISST.
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Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article