Survey on chlorophyll-a changes in Persian Gulf and the Gulf of Oman

Chlorophyll-a indicates the biomass of phytoplankton as the primary production. Chlorophyll-a changes indicate the situation of the ecosystem. The present study was conducted for monitoring it in the northern part of the Persian Gulf and ​​Oman Gulf. For this purpose, CTD and NASA site information was used. Samplings were done from January-March 2018-2021. Mean southern waters chlorophyll-a in 2018 was (0.97±0.84 mg/m3) mean southern water’s surface chlorophyll-a was (1.98±1.48 mg/m3) in 2019. The mean su rface chlorophyll-a of Oman Gulf in 2020 was (0.92±0.334 mg/m3). The mean of chlorophyll-a in the Persian Gulf in 2021 was (0.23±0.13mg/m3). The data result of NMDS showed significant differences between the two groups: (Bushehr, Hormozgan, Sistan & Blochestan, 2019) in comparison (Bushehr and Khuzestan, 2021). Mean surface chlorophyll-a in the first and second groups were (1.09±1.5 mg/m3) and (0.13±0.16 mg/m3), respectively. This significant difference and the greater biomass amount of the first group were due to floods and discharge of nutrients in March-April of 2019, and Nutrients will provide suitable conditions for phytoplankton’s growth.