Factors influencing distribution patterns of cyanobacteria in an upland lake of the Kumaun Himalayas, India

Abstract

We study the dynamics of bloom-forming cyanobacteria and determined the major driving forces in subtropical lake of the Kumaun Himalayas, India. Water and plankton samples from different sites and depths of the lake were analyzed. Multivariate analyses were used to evaluate the factors controlling the distribution pattern of cyanobacteria. M. aeruginosa was the most abundant species with an average density of 10.39 × 10⁶ individual/m³ and distributed throughout water depths. The geomorphic threshold modulates soil erosion processes resulting in lower transparency in the Himalayan lake; thereby limiting the growth of Chlorophycea. Effective persistence for M. aeroginosa into different depths is augmented by fluxes nutrient coupling with pigments. The ratio of nitrogen/phosphorus (N/P) had a significant negative correlation (F =-0.884; p = 0.0001) with densities. Expansion of M. aeruginosa in deep de-stratified lake is episodic and their proliferation can restrict by lowering phosphorus.

Keywords:

• Cyanobacteria
• nutrient
• N/P ratio
• Himalayas
• de-stratification

Acknowledgements

This research was, in part, of NPDF funded & supported by SERB-DST, Govt. of India with fellowship No. PDF/2015/000509. We also acknowledge the support & encouragement from Director ICAR-DCFR, Bhimtal India. We are thankful to Dr Dimpal Thakuria, Dr Prakash Sharma, Dr Deepjyoti Baruah, Mr Partha Das, Ms Annu Sharma, Mr Maneesh Dubey & Md. Sakir Baig for their help.