TAILIEUCHUNG - Temporal changes in environmental characteristics and diversity of net phytoplankton in a freshwater lake
Temporal changes in the species composition, seasonal abundance, and diversity of net phytoplankton (NPP) were investigated in relation to some environmental characteristics of the water and sediment of Lake Krishnasayer, an ancient man-made shallow freshwater lake, located at Burdwan, India, between January and December 2003. | Turk J Bot 31 (2007) 287-296 © TÜB‹TAK Research Article Temporal Changes in Environmental Characteristics and Diversity of Net Phytoplankton in a Freshwater Lake C. CHATTOPADHYAY*, T. C. BANERJEE Ecology Research Unit, Department of Zoology, Burdwan University, Burdwan-713104, INDIA Received: Accepted: Abstract: Temporal changes in the species composition, seasonal abundance, and diversity of net phytoplankton (NPP) were investigated in relation to some environmental characteristics of the water and sediment of Lake Krishnasayer, an ancient man-made shallow freshwater lake, located at Burdwan, India, between January and December 2003. In all, 43 species and 7 genera were identified from the weekly samples taken from a 1 × 1 × 1-m water column at sites I and II. The most abundant taxa were Cyanophyta () and Bacillariophyta (), whilst Euglenophyta was the least abundant (4%). The relationships (r) were significant (P 1 m) water temperature and pH were measured in situ with a certified mercury-filled Celsius thermometer sensitive to ºC and a digital pH meter (Hanna instruments, Portugal), respectively. Secchi depths were measured once on each sampling date at 1200 IST with a 20-cm diameter black and white Secchidisc. All water samples for chemical analysis were taken at approximately the same time of the day (. between 0800 and 0900 IST). Water samples for dissolved oxygen, combined carbon dioxide, dissolved chlorides, and silica were analysed following the methods outlined by Wetzel & Likens (1991) and Clesceri et al. (1998). Furthermore, one portion (15-20 ml) of each water sample was filtered through Whatman No. 41 filter paper, and the filtrate was used for determining concentrations of total dissolved nitrate-nitrogen and phosphate (orthophosphorus) using a UV-Vis spectrophotometer (Chemito 2100) with standardised chemicals and procedures (Solorzano & Sharp, 1980; Clesceri et al., 1998). The percentage .
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