Source, processes and productivity from distribution of surface sediments, Prydz Bay, East Antarctica

Abstract

Source of sediments and depositional processes of surface sediments along the Prydz Bay were investigated through grain size, organic carbon, nitrogen, phosphorus, calcium carbonate and metal concentration. High content of sand and higher values of Al sub(2) O sub(3) and TiO sub(2) at shallow water depth indicate their terrigenous source and relatively higher hydrodynamic conditions near the coast. Al sub(2) O sub(3)/TiO sub(2) ratio ranging from 3.77- 12.73 suggests a mafic source for the sediments. C/N ratio ranging from 5.76 to 9.13 indicates autochthonous (in-situ) source for organic matter, for which phytoplanktons and algae may be the major contributors. However, N/P ratio lower than the Redfield ratio indicated a limitation of either N or P in the study area. Calcium carbonate concentration is low possibly due to increased loads of clay which must have caused the dilution of carbonates. Metals like Fe, Mn and Mg exhibit strong correlation with lithogenic elements while, the trace metals such as Cd, Co, Cu, Ni and Zn show significant correlation with organic elements indicating that lithogenic and biogenic inputs are their main sources. Trace elements namely, Cd and Zn show nutrient like behavior suggest the role of trace metal in addition to nutrients in the regulation of productivity. Thus, the present study provides an understanding of recent sedimentary environments and processes, which are used as a tool to interpret palaeoenvironmental records.