a study of diatoms seasonal distribution and biodiversity in helleh river estuary, persian gulf

the purpose of this study was to investigate the distribution and biodiversity of diatoms during different seasons and their correlation with water quality parameters in helleh river estuary, bushehr, persian gulf. samples were taken in mid-season from summer 2011 to spring 2012 during a one-year period from different stations. results showed that diatoms mostly comprised of bacillariophyceae, dictyochophyceae and chrysophyceae. the class of bacillariophyceae had the highest seasonal variation with 20 genera. the mean of diatom density obtained was 5705.8 cells l-1 in summer; 6772.5 cells l-1 in autumn; 4072.9 cells l-1 in winter; 8559.36 cells l-1 in spring. the mean of biodiversity index of shannon-wiener obtained was 2.29, 2.22, 1.49 and 1.63 in summer, fall, winter and spring, respectively. in addition, there was a significant correlation between diatom density, salinity (r= 0.469) and ph (r=0.599). the shannon-weiner diversity index showed significant correlation with salinity (r = 0.796), dissolved oxygen (r =-0.533) and temperature (r = 0.447).