Diurnal and seasonal variations in the phytoplankton production of lake Kondakarla

Abstract

Variations in the phytoplankton production of lake Kondakarla were estimated at two levels (surface and at 1 m depth) during a period of 12 months. The gross production values ranged from 0·10–1·40 mg O₂l⁻¹ h⁻¹ at surface and from 0·06–0·73 mg O₂l⁻¹ h⁻¹ at 1 m depth. Peak values of gross production occurred between 9–12 h or from 12–15 h during the different months at both the levels. The seasonal variation in gross primary production ranged from 2·70 mg O₂l⁻¹ day⁻¹ during January 1984 to 9·42 mg O₂l⁻¹ day⁻¹ in September 1983 for surface waters and from 1·60 mg O₂l⁻¹ day⁻¹ during September 1983 to 5·40 mg O₂l⁻¹ day⁻¹ in February 1984 in waters at 1 m depth. The depth intergrated production varied from 4·08–13·05 g O₂m⁻² day⁻¹ while the photosynthetic efficiency ranged from 0·580–4·301%.