Study of phytoplankton blooms incident in shatt al-arab river and marine coast Iraqi line

Abstract

Phytoplankton blooms, were noticed a long Shatt Al-Arab river and costal waters of north-west Arabian Gulf. The efforts were made to study this phenomena which was observed in this part of ROPME Sea Area . Phsio-chemical and biological parameters were studied to evaluate the relationship between these factors and the phytoplankton blooms which cauase the water to appear brow . The occurrence of suitable environmental factor such as water temperature(25.7-26.7)Co, salinity (39.1) ppt, calm weather, and relative increase of nutrients Nitrate(5.83 μg-at N/l), orthophosphate(0.929 μg-at PO4/l) and silicate(118.78 μg-at SiO4/l) lead to massive growth of phytoplankton achieved (4.46 x 106 cell/L) specially in the coastal area.The phytoplankton assemblage and biomass were studied. Fourty species of phytoplankton were identified (32) species belonging to diatoms and (8) species were dinoflagellates. Phytoplankton were dominated by diatoms Chaetoceros Thalassionema Rhizoslenia odentella and Coscinodiscus - Dinoflagellates were dominated by Dinophysis and Protoperdinium. Two species of Dinophysis and two species of Protoperdinium were recorded for the first time in Iraqi coastal water Dinophysis acuta, D. mitra and Protoperidinium crassipes, P. gracilie. The study clearly showed a relationship between the development of phytoplankton blooms and the input of nutrients.