Reading source and processes from the distribution of suspended particulate matter and its selected elemental chemistry in the Southern and Indian Oceans

Abstract

Analysis of surface suspended particulate matter (SPM) from 28 to 69 degrees S at 1 degrees interval reveals a more or less decreasing trend with increasing latitude at two distinct sections in the north and south of 54 degrees S which are marked by relatively steady and a highly fluctuating trends respectively. Vertical as well as horizontal profiles of SPM, temperature and salinity at six selected stations were used in conjunction with associated trace metals to understand their association, distribution and possible source. The southern Antarctic zone is characterized by low salinity and temperature, variable SPM with high Fe and Mn, and the northern Subtropical zone is with high SPM of mainly biogenic material, high salinity and temperature and high Ca, whereas the Sub Antarctic zone in between is of moderate salinity and temperature but low SPM. The terrigenous input through melt water of ice is probably responsible for the high SPM and low salinity near surface waters, and also high SPM waters at 1000 m depth which are with high Fe and Mn in the Antarctic zone. The temperature and salinity controlled primary productivity probably controls the concentration and distribution of near surface high SPM and associated trace metals in the subtropical zone whereas the primary productivity and the melt water play a role in contributing SPM in the middle convergence zone.