The health of benthic diatom assemblages in lower stretch of a lesser Himalayan glacier-fed river, Mandakini

Journal of Earth system science

Jyoti Verma2¹  Asheesh Shivam Mishra1²  Prakash Nautiyal1² 

[1] Department of Zoology, University of Allahabad, Uttar Pradesh 211 002, India.$$;Aquatic Biodiversity Unit, Department of Zoology and Biotechnology, HNB Garhwal University, Srinagar, Uttarakhand 246 174, India.$$

关键词: Achnanthidium spp.;    anthropogenic eutrophication;    degradation;    ecosystem health;    mésotraphentic;    PCA;    spatial distribution.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

This study examines the ecological state of epilithic diatom assemblages along the lower stretch of Mandakini, a glacier-fed Himalayan river. The diatoms were sampled at four stations during winter and summer, only once in each season. Valve counts were obtained from Naphrax mounts prepared from each sample. Assemblages were recorded for each location. The software OMNIDIA Ver. 5.3 was used for computing the ecological values from the sample counts. Normally Achnanthidium spp. dominated the assemblages, except Nitzschia fonticola (Grunow) at S1 (Kund) and Encyonema minutum (Hilse in Rabh) at S4 (Rudraprayag), only during summer. The ecological values revealed that the assemblages were in 𝛽-mesosaprobic and mésotraphentic states. However, at S4, trophic state was observed to be eutraphentic. Louis Leclercq index indicated that organic pollution was nonexistent, while the anthropogenic eutrophication was low except at S2 (Tilwara) and S3 (Medanpur) in summer and was moderate at S4 in winter characterized by a lean flow. The most abundant indicator taxa for anthropogenic eutrophication are varied; Cymbella tumida (Brebisson-Van Heurck) at S1, Encyonema minutum at S2, S4 while Surirella aungusta (Kutzing) at S3. Ordination showed that the taxa indicating degradation and anthropogenic eutrophication figured as characteristic taxa at respective locations.

【 授权许可】

Unknown