Dynamics of physico-chemical limnology of a shallow wetland in Kashmir Himalaya (India)

Abstract

The variability in surface water chemistry within and between aquatic ecosystems is regulated by many factors operating at several spatial and temporal scales. The present study was carried out on one of the famous shallow wetlands of Kashmir known as Hokersar wetland. As the wetland is under tremendous pressure of anthropogenic activities besides suffering from internal wetland processes, it becomes imperative to study the seasonal dynamics of various physico-chemical characteristics of water. For this purpose, six study sites were chosen for the collection of water samples from September 2013 to August 2014. Among the parameters recorded, lower values of depth (0.9 m), dissolved oxygen (2.4 mg/L), higher values of chloride (44 mg/L), ammonical nitrogen (251 µg/L), nitrate nitrogen (688 µg/L) and both the forms of phosphorus reflect that the wetland is under the heavy influence of sewage, silt and unmanaged agricultural activities in the surrounding catchment which seems to be the foremost cause of deterioration of the wetland waters. When the present study is compared with the previous studies in terms of physico-chemical characteristics of water, it clearly reveals that some aspects depict distinct variations while some showed close proximity. Further, some of the recorded parameters of water were in range with national standards while some portray wide variations. Principal component analysis revealed that component 1 explains 82.157% of the variation, component 2 with 8.345% variation and component 3 having 3.26% variation. Among various parameters, nitrate nitrogen, total alkalinity and total hardness contribute strongly towards the seasonality of the remaining parameters in the wetland. From the present study, it seems that the wetland has still the capacity to absorb major nutrients especially the nitrogen and phosphorus that drain from the immediate catchment into the Queen wetland of Kashmir.