BIOVOLUME AND BIOMASS OF COMMON DIATOM SPECIES FROM THE COASTAL WATERS OF KARACHI, PAKISTAN

The biovolumes of two groups of diatoms pennate and centric including thirty three common species were calculated for the estimation of carbon biomass at two stations of Manora Channel, coastal waters of Karachi, Pakistan (northern Arabian Sea). Measurements were taken during the routine cell identification by Light microscopy. Total biovolume ranged from 558µm -3 to 392500µm -3 and biomass from 1.1pgCcell -l to 3.9pgCcell -l . Total carbon biomass was higher for centric diatoms compared to pennates. Cell biovolume showed the same pattern at both stations and a positive relationship with cell carbon biomass. This is the first detailed study based on geometrical shapes of various species and their biovolume and carbon biomass calculations from northern Arabian Sea. The obtained data will help to assess the diatom community analysis and their size related contribution of carbon biomass within the study area.