Recordings On Sea Surface Temperature And Metals Pollution From Coral Reefs Sclerochronology

Abstract

The aragonite skeleton of massive reef-building corals contain a record of the oceanic environment in which they grow. This proxy measurement is very important to understand past environmental condition due to the lack of instrumental records, and as basis how to manage it in the present and in the future. This research objectives are to find out the ability U/Ca ratio in showing SST fluctuations and to know metals fluctuation in the waters from corals sclerochronology. The robustness of U/Ca ratio was assessed by comparing it with local SST data set achieved by NOAA satellite due to period of 1983-2002. Porites stephensoni is used as samples, took from Seribu Islands – Jakarta, in specific Bokor Island, Tikus Island, and Tidung Island. Samples are analyzed with neutron activation analyses (NAA) to measure elements concentration, except for Pb and Cd we used atomic absorbance spectrometer (AAS). The U/Ca ratio show very weak correlation with yearly SST variations, with r2 = -0.23 (Tikus Island), r2 = -0.35 (Tidung Island), and r2 = -0.39 (Bokor Island). U/Ca ratio can not be used for showing SST variation at Seribu Islands waters. Sclerochronology show that metals pollution did happen, noticed by metal/Ca ratio that higher then its background value. Arsenic (As) is not naturally habits in corals skeleton, while the other metals (Sb, Pb, Cd, Co, Cr) seem naturally habit in it. Applying principal component analysis to all samples data set has resulted in categorizing them into one group. It show that those three island has similar water quality or they were influenced by the same water-mass. They have one general source for all the metals, except arsenic (As).