1,2Siamak Bagheri, 1Mashhor Mansor, 2Marzieh Makaremi, 2Alireza Mirzajani, 2Hadi Babaei,2Jalil Sabkara 2Azemat Ghandi ,2Hossein Negarestan and 1Wan Maznah W.O, 2Ali Abedini,
1School of Biological Sciences, Universiti Sains Malaysia (USM), 11800 Penang, Malaysia
2Inland Waters Aquaculture Institute, Iranian Fisheries Research Organization (IFRO), 66 Anzali, Iran
*Corresponding author: Siamak Bagheri, email: Siamakbp@gmail.com
The spatial and temporal distribution and species composition of phytoplankton in the southwestern Caspian Sea. Samples were collected from 12 stations along three transects: Lisar, Anzali and Sefidrood. A total of 79 (69 and 46 species during in 2001 and 2002, respectively) phytoplankton species were identified, the annual average phytoplankton density were calculated as 363,000 and 201,000 cells.l–1, respectively during 2001 and 2002. Dinoflagellates formed almost half of the total abundance (58%–52%) while cyanophytes were the second important group in view of contribution to total phytoplankton number (29%–24%). The study showed that dinoflagellate Prorocentrum cordatum and cyanophyte Oscillatoria sp. are numerically dominated species in the southwestern Caspian Sea. The average total phytoplankton number, phytoplankton composition and nutrients concentrations were drastically changed during 2001 and 2002 as compared to 1996–1997. The results showed that there was no correlation between comb jellyfish number with phytoplankton density during 2001 and 2002. Some studies linked drastic changes in the phytoplankton community with comb jellyfish invasion in the south of Caspian Sea after the year 2000. It was not possible to determine to what extent the fluctuation of the phytoplankton is due to the impact of comb jellyfish, and not should be disregarded is the influence of meteorological and hydrological teleconnections on the ecosystem of Caspian Sea (Bilio & Niermann 2004; Polonsky et al., 2004; Stolberg et al., 2006). The fluctuations of the phytoplankton community’s relationship to environmental parameters (chemical factors; pollutions) and nutrient upwelling were not extensively investigated up to now (Dumont, 1995; Kideys et al., 2008). Since the southern Caspian Sea is influenced to a high extent by fresh water inflow with a heavy load of artificial nutrients (Sharifi, 1990; Salmanov, 1999; CEP, 2006; Mirzajani et al., 2010; Bagheri et al., 2010), it is important to assess to which extent the increased eutrophication affects the phytoplankton abundance, and species composition in the Caspian Sea. We believed hydrology regime variations, depletion of silicate level, and increased nutrient concentration have played important roles in blooming of non–diatoms phytoplankton such as dinoflagellates and cyanophytes in the southwestern Caspian Sea.
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