Aras River and Dam Reservoir Pollutions: human activities or climate change

Aras reservoir was established on the Aras River in border line of Iran and Azarbaijan. This is one the largest reservoirs in the country and deserved for its contribution in fisheries, drinking and agricultural water supply and recreational application in the region and country. This paper attempts to review Aras reservoir pollutions and phytoplankton blooms occurring in this freshwater ecosystem. The most conspicuous pollution resources of this reservoir were human activities such as agriculture (irregular use of fertilizers and pesticides), urbanization (absence of waste water purification systems), climate change and global warming. High levels of nutrients particularly phosphorous and nitrogen entered into the reservoir create harmful algal bloom particularly in warm and dry season. Cyanobacteria produced by blooms not only, have negative effects on the taste and odor of water and species diversity, but also, produce poisons that lethally impact on human and aquatic organisms. The algal species that induce blooms in the Aras reservoir were Microcystis botrys and Pseudanabaena limnetica. This review indicates that continuous monitoring of Aras reservoir and river water using physical, chemical and biological indices should be regarded as priority of research centers and related organizations.