primary productivity and phytoplankton diversity of the golestan dam reservoir, golestan province, iran

Golestan dam lake is located 12 kilometers east of gonbad city and was constructed in 1379. the volume of the golestan dam reservoir is 52 million cubic meters and its area is 1500 hectares, which was built for the purposes of agricultural and aquaculture operations. the present study on phytoplankton biodiversity and its relationship with the primary productivity of the golestan dam reservoir was conducted from april to july 2019. furthermore, water quality parameters such as transparency, ph, alkalinity, free carbon dioxide, air and water temperature, dissolved oxygen, primary productivity, conductivity, nitrate-nitrogen, and orthophosphate were analyzed along with the qualitative and quantitative estimation of phytoplankton. the results indicated that the average primary productivity or gross primary production (gpp) was 0.399 ± 0.081 gcm3h-1, net primary production (npp) (0.307±0.061 gcm3h-1), and community respiration (cr) 0.094±0.024 gcm3h-1 in the surface. algae in freshwater have numerous environmental functions and are based upon the recycling of nutrients. totally 73 species of phytoplankton belonging to the different taxonomic groups were identified. which belong to 32 genera among these 32 genera, 12 belong to cyanophyceae,8 belong to chlorophyceae, 10 belong to bacillariophyceae, and 2 belong to euglenophyta. on the basis of mean primary productivity, the fish production potential of reservoir golestan dam showed considerable scope for the enhancement of current average production.