Seasonal variations in response of periphytic algal community to nutrient enrichment in the river Ganga (Varanasi, India)

Annales de Limnologie: International journal of limnology

article

Arpana Yadav¹  Dhananjay Kumar²  Ram Sharan Singh³  Lalit K. Pandey⁴  Jyoti Rai¹ 

[1] Laboratory of Algal Biology, Department of Botany, Institute of Science, Banaras Hindu University;Department of Botany, School of Life Sciences, H.N.B. Garhwal University;Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU);Department of Plant Science, Faculty of Applied Sciences, MJP Rohilkhand University

关键词: periphyton;    chemical diffusing substrate;    nutrient limitation;    nitrogen;    phosphorus;   

DOI  :  10.1051/limn/2018025

学科分类：地球科学(综合)

来源: EDP Sciences

【 摘 要 】

Effect of nutrient enrichment on periphyton was studied using chemical diffusing substrates that released, singly or in combination, PO 4 3− -P and nitrogen, both NO 3 − -N and NH 4 + -N. The study was carried out in March and June 2014 as these two time periods showed abundance of different groups of algae. Whereas diatoms and green algae were abundant in March, cyanobacteria dominated in June. Nitrogen was primarily growth limiting in river water as its enrichment enhanced the growth of periphyton. Phosphate limitation was secondary in nature. Enrichment of NH 4 + -N caused greater enhancement of periphytic growth than that of NO 3 − -N. Nutrient enrichment reduced species diversity, further enhancing total biovolume of the periphytic group that was predominant at that particular point of time. Nutrient enrichment markedly increased cyanobacterial populations in June due inter alia to high temperature. In spite of nutrient enrichment, the periphytic biomass did not reach the level (chl a ≥ 100–150 mg m −2 ) considered as the nuisance, except in March when combined enrichment of PO 4 3− -P and NO 3 − -N greatly enhanced the periphytic biomass.

【 授权许可】

CC BY