Abstract:
The present research aims to study the species diversity, abundance and spatial distribution of diatom from the coastal waters of Sindh coast (Sandspit) and Baluchistan coast (Gadani ship breaking area). The Seawater samples were collected monthly from Gadani ship breaking area and Sandspit for analysis of phytoplankton (Diatom) on board using Niskin bottles. A total of 109 phytoplankton species are identified from two sites. Eight dominant species of Bacillariophyceae observed in all stations on both sites such as Bacillaria paxillifer, Coscinodiscus spp., Cymatosira lorenziana, Guinardia delicatula, Melosira arctica, Nitzschia longissima, Rhizosolenia Setigera and Rhizosolenia imbricata. Diverse species of phytoplankton in Gadani compared to Sandspit were observed. In the Gadani area, 85 species of diatoms and from Sandspit 74 species of diatom were recorded. Thirty-four genera were observed in Gadani, whereas 27 genera were observed in Sandspit. The results showed quite variation in the species composition of phytoplankton in two coastal sites and along with the difference of nearshore and offshore zones. Diatom communities are susceptible to change in their environment; the pollution due to anthropogenic substances in the coastal waters and changing climatic conditions trigger HAB forming species, which is perilous for marine fauna particularly, fishes.