Assessment of the primary production statues of the international Gavkhooni Wetland, Iran

Wetlands are of the unique and productive ecosystems in the world. The present study was conducted to determine primary production statues of the international Gavkhooni Wetland, based on chlorophyll-a. Sampling was performed seasonally from March 2017 to February 2018. Four sampling stations were assigned based on latitude and longitude. Water salinity, temperature, pH, nitrate, phosphate, BOD5, TDS, EC, TSS and dissolved oxygen were determined in triplicate in each station. Trophy level was determined using index TSI. The results showed that there was no significant difference in mean chlorophyll-a content between the seasons. The highest and lowest chlorophyll-a contents were observed in spring and winter, respectively; and the significantly highest content was measured in the station A (Shakh Kenar). There was no significant difference in the water physicochemical parameters between the seasons (P>0.05). The mean water nitrate level of the sampling stations was 4.255 mg/l; the highest (5.07 mg/l) and lowest (3.35 mg/l) levels were recorded in the summer and autumn, respectively. The mean water phosphate level of the sampling stations was 1.082 mg/l; the highest (1.75 mg/l) and lowest (0.57 mg/l) levels were recorded to the winter and summer, respectively. The mean dissolved oxygen level during the study was 5.64 mg/l. According to the results, nitrate is the limiting factor for production in the Gavkhooni Wetland. Based on index TSI, the wetland is oligotrophic in the spring, autumn and winter, but mesotrophic in the summer.