Boron isotope, trace elements and pH data (1990-2013) of the Porites lutea corals from Lakshadweep in the south-eastern Arabian Sea

Atmospheric CO2 rise in post-industrial era has resulted in decline in surface ocean pH, commonly known as “ocean acidification (OA)”, which has become a threat to marine calcifiers. However, ocean acidification trend and its forcing factors in different ocean basins are not well understood due to limited number of pH records. Boron isotopic composition of corals has been used to reconstruct the ocean pH. Here, we present new Boron isotopes (d11B), Sr/Ca, Li/Mg, Li/Ca and Mg/Ca data of the Porites lutea corals from the Minicoy Island, Lakshadweep in the south-eastern Arabian Sea. Data also includes estimated pKB and pH. Boron isotope analysis was performed on a ThermoScientific Neptune Plus MC-ICPMS at the NCPOR, Goa following the methods of Misra et al., 2014 (doi:10.1016/j.gca.2014.05.047). Trace element analysis was performed on a ThermoScientific Element XR ICP-MS at NCPOR, Goa using the method described by Misra et al., 2014 (doi:10.1002/2013GC005049). The dissociation constant of boric acid (pKB) was estimated using the Hadley sea surface temperature (SST) and salinity (SSS) of the study area. The pH was estimated using the calibration equation of Porites cylindrica (McCulloch et al., 2012 doi:10.1038/nclimate1473). These new dataset demonstrate that physical oceanographic processes e.g. upwelling, downwelling and convective mixing modulated by El Niño–Southern Oscillation (ENSO) largely control surface pH variability in the Arabian Sea and masked expected long-term OA trend resulting from anthropogenic CO2 rise.