Ecology of Baskandi anua, an oxbow lake of South Assam, North East India

摘要

A study was made on the physico-chemical properties of water and phyto and zooplankton communities of Baskandi anua, an oxbow lake of South Assam during March to August, 2009. Analyses of water showed acidic to slightly alkaline pH (5.4 - 7.9) with dissolved oxygen ranging from 4.26 to 11.83 mgl~(-1) and total alkalinity from 31.25 to 65 mg l~(-1), indicating the productive nature of water. Free CO_2 fluctuated from 2.93 to 15.04 mgl~(-1). PO_4 and NO_3 concentration ranged from 0.15 to 1.4 mg l~(-1) and 0.06 mg l~(-1) to 4.94 mg l~(-1) , respectively. Conductivity, pH and free CO_2 were found higher at the sites surrounded by paddy fields. Mean values of physico-chemical parameters significantly varied between the sites and were found to be influenced by one or more of the following factors viz. rainfall, depth and influx from adjacent paddy field. A total of 30 phytoplankton taxa and 12 zooplankton taxa with qualitative dominance of Chlorophyceae were recorded. The study revealed that water quality of the lake was good for aquaculture. Hence, the lake should be protected and best management practices should be implemented for sustainable production.