Spatial Pattern of Phytoplankton Communities from Iranian Waters of the Gulf of Oman in Pre-Monsoon Period

There is a need to increase our knowledge about phytoplankton diversity and distribution in the Iranian waters of the Persian Gulf and the Gulf of Oman. Phytoplankton samples along with environmental parameters of the Northeastern waters of the Gulf of Oman (Gordim Bay towards Gwadar Bay) were collected and recorded prior to summer monsoon (Mid of March 2013). Seven inshore and six offshore stations in two depth profile (0.5 m, 10 m) were sampled. A total of 26 genera were identified which comprised of 21 taxa from inshore and 17 taxa form offshore stations. Bacillariophyceae constituted the most dominant taxa, among which Rhizosolenia spp., Chaetoceros spp. and Pseudo-nitzschia spp. were more abundant diatoms. The dominant dinoflagellates were Ceratium furca and C. breve. The maximum and the minimum count of phytoplankton per station were 3975 and 53 cells/L. The difference in the species composition of inshore and offshore phytoplankton was significant, and the highest number of phytoplankton was recorded from the eastern coast of the study area. However, there was no significant difference between population numbers of surface water (0.5) and at 10m depth. Among the measured hydrological factors, silicate, chlorophyll a, and dissolved oxygen showed potential effect in spatial distribution of phytoplankton. Some toxic genera were observed but their occurrence was not at harmful bloom rate.