High resolution Oxygen and Carbon Isotopic
High-resolution Oxygen and Carbon Isotopic Records of a Modern and a Fossil Coral from the Lakshadweep Archipelago.
Stable isotopic signature of modern coral vs 400 years old fossil coral is compared in this study to understand seasonal variation in Lakshadweep Archipelago. Monsoon induced upwelling in the Lakshadweep sea induces upwelling resulting in cooling which is reflected in the seasonal band of the modern coral. Temperature plays a dominant role in the stable oxygen isotope variation of the modern coral. This study also points at anthropogenic effect “suess effect” on the modern coral. Both modern and fossil coral species revealed monsoon-induced seasonal changes in carbon isotope related to changes in total dissolved inorganic carbon. We observed a high amplitude changes in isotopic signature of both the corals which is mainly attributed to the genus difference.
Top left: (a) X-radiograph from a slab of modern drilled coral, and (b) X-radiograph of fossil coral (>400 yrs old coral).
Top right: Carbon (δ 13 C) and oxygen (δ 18 O) isotopes of fossil coral plotted against depth. Bottom: The δ 18 O and δ 13 C values of modern coral are plotted against time.