Microbial processes at the land–water interface, and cross‐domain causal relationships, as influenced by atmospheric deposition of pollutants in three freshwater lakes in India

Abstract

The effects of long-term atmospheric deposition of pollutant elements on the trans-surface causative relationships at three lake sites having different catchment characteristics were investigated in this study. The selected determinants included lake productivity, bottom sediment quality, and a suite of microbial variables (microbial biomass (C mic ); basal respiration; substrate-induced respiration; bacterial:fungal ratio; metabolic quotient; and alkaline phosphatase and FDAase activities) measured at the land-water interface, in relation to atmospheric deposition of phosphate; nitrate; ammonium; sulphate; calcium; and magnesium. The results indicated significant between-site differences (P < 0.001) in the atmospheric deposition of phosphate (0.21-1.96 kg.h -1 .year -1 ); nitrate (2.77-28.05 kg.h -1 .year -1 ); ammonium (0.58-11.60 kg.h -1 .year -1 ); sulphate (5.64-32.15 kg.h -1 .year -1 ); calcium (4.50-30.00 kg.h -1 .year -1 ); and magnesium (1.50-12.15 kg.h -1 .year -1 ), as well as a consistently increasing input of these ions across time. The catchment vegetation had important effects on microbial variables that, in turn, affected lake productivity. Interfaces of woodland lake were found to be rich in phenolics, supporting low C mic and activities. Except for alkaline phosphatase, which declined over time, atmospheric deposition of pollutant elements increased the C mic and activities at the land-water interface. The time lag correlation analysis indicated the C mic and lake productivity relationships were significantly altered by atmospherically driven nitrogen and phosphorus inputs, with a time lag of 2-3 years. Despite being supportive, aerial nutrient inputs appeared to have a destabilizing effect on both, microbial biomass and lake productivity variables. These observations indicate that if present atmospheric deposition trends of pollutant elements continue, it will modify the cross-domain causative relationships of inland lentic systems over the long term. These study results are relevant for the formulation of strategies for managing freshwater tropical lakes.

Determination of Drinking Water Quality: A Case Study on Saline Prone South-West Coastal Belt of Bangladesh

“…The potassium exhibits negative correlation with sulfate. The concentration of phosphate in harvested rainwater was similar to those reported at some other locations of India (Das et al, 2005;Pandey and Pandey, 2009). The maximum permissible limit of phosphate in drinking water 6 ppm, ADB proposed water quality standard for Bangladesh (ADB, 1994).…”

The Role of Catchment Vegetation in Reducing Atmospheric Inputs of Pollutant Aerosols in Ganga River

“…Atmospheric deposition, clearfall and run-off waters were analyzed for SO 4 2-, NO 3 -, NH 4 ? and PO 4 3-as described by Pandey and Pandey (2009) and Na ? , K ?…”

Atmospheric Deposition of Nutrients Shifts Carbon Capture and Storage Trends in Freshwater Tropical Lakes in India

“…Role of such trans-boundary linked changes becomes important in areas characterized by unprecedented increase in atmospheric deposition. Studies have indicated atmospheric deposition of reactive N as high as 20 to 60 kg ha 1 yr 1 in many ecosystems of Europe (Bobbink and Lamers, 2002) and 12 to 46 kg ha 1 yr 1 in many parts of India (Pandey and Pandey, 2009;Pandey et al, 2014). Nitrate concentrations in Norwegian lakes doubled in less than a decade due to air-driven deposition (Vitousek et al, 1997).…”

“…Significant correlations (R 2 0.9735 0.9764; P 0.001) between AD-nutrients and microbial activity indicated the influence of AD-nutrients on microbial processes in lake catchment. It is possible that AD-nutrients improve the poor substrate quality of OM to enhance microbial colonization (Wedin and Tilman, 1996;Elser et al, 2000;Pandey and Pandey, 2009). …”

“…To date, no data so for is available from Indian tropics addressing explicitly the human-induced changes in atmosphere-land-water transfer and subsequent influence on C balance of freshwater lakes. Recent studies have indicated that Indian surface waters are receiving increasingly high input of atmospherically deposited (AD) nutrients (Pandey and Pandey, 2009;2014). The AD-nutrients may alter ecosystem attributes via direct deposition to water surface and via deposition on land surface and subsequent modifications in the catchment (Whitall et al, 2003;Pandey, 2011).…”