Diatom Flora of Selected Streams in the Central Alborz Region, Northern Iran

Diatoms are of high importance in systematics, ecology, genetics and bio-based industries and account for a major part of phycological researches worldwide. However, in Iran which is a large country with different aquatic ecosystems, not much investigations have been conducted on such aspects of diatoms; of which the share of the southern slope of the Central Alborz Region is quite a few. In this research, the diatom flora of the parts of the Jajrood River and some less-noticed nearby streams in northeastern Tehran (zone ۱) and Kordan and Hazarband Rivers in northwestern Tehran (zone ۲) were studied and compared. In each zone, algal periphyton samples were collected from ۵ sampling stations. Samples were treated with hot ۳۵% H۲O۲ and ۳۲% HCl to remove the minerals and organic materials and clean up the siliceous frustule of diatoms. From ۱۰ studied stations, a total of ۱۳۷ taxa were found, representing ۳۹ genera and ۲۰ families. ۳۵ taxa are new records for diatom flora of Iran. Navicula, Nitzschia and Gomphonema were the most species-rich genera and Bacillariaceae, Gomphonemataceae and Naviculaceae were the most genus-rich families recorded. Some species are known as pollution-, salinity-, and acidity-tolerant. Some other are alpine and subalpine taxa. Comparison between the data from this study and other researches in Iran, neighboring countries and other regions in Europe and North America shows that despite undeniable similarities between two studied zones and the mentioned areas, some taxa are unique to the studied areas. Also the similarities are more evident between studied zones and European and North American alpine and subalpine ecosystems than that of neighboring countries. For future studies, including more streams, and considering water physiochemical characteristics, ecological relationships of diatoms, evolution and population genetics and matching climatic and geological data with recorded species diversity could be a great step forward.

کلیدواژه ها:

Kordan River ، Hazarband River ، Jajrood River ، biodiversity ، algal periphyton