Oxygen Isotope Composition in Porites Coral from the Northern Gulf of Thailand: an Implication for Its Skeletal Growth

Abstract

To elucidate the skeletal growth of a Porites coral from the Gulf of Thailand, oxygen isotope ratio (δ¹⁸O) in coral aragonite was measured by mass spectrometry. Two cyclic changes in δ¹⁸O were observed from the coral sample analyzed every 1mm from the top to a depth of 40mm. A cyclic change in δ¹⁸O is assumed to record an annual change in seawater salinity, and the coral growth rate is estimated at -20mm/year.