water Article Anthropogenic Impact on Tropical Perennial River in South India: Snapshot of Carbon Dynamics and Bacterial Community Composition Katrin Premke 1,* , Gunasekaran Dharanivasan 2,3, Kristin Steger 4, Kai Nils Nitzsche 5 , Vijayan Jayavignesh 6, Indumathi M Nambi 6 and Sundaram Seshadri 3 1 Department of Chemical Analytics and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany 2 Department of Sensing, Information and Mechanization System, Institute of Agricultural Engineering, Agricultural Research Organization, Volcani Center, Rishon LeZion 7528809, Israel;
[email protected] 3 Indigenous and Frontier Technology Research Centre (IFTR), Chennai 600061, India;
[email protected] 4 Faculty of Environment and Natural Resources, Chair of Soil Ecology, University of Freiburg, 79085 Freiburg im Breisgau, Germany;
[email protected] 5 Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan;
[email protected] 6 Environmental and Water Resources Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600036, India;
[email protected] (V.J.);
[email protected] (I.M.N.) * Correspondence:
[email protected] Received: 10 March 2020; Accepted: 5 May 2020; Published: 11 May 2020 Abstract: Riverine systems play an important role in the global carbon cycle, and they are considered hotspots for bacterial activities such as organic matter decomposition. However, our knowledge about these processes in tropical or subtropical regions is limited. The aim of this study was to investigate anthropogenically induced changes of water quality, the distribution of selected pharmaceuticals, and the effects of pollution on greenhouse gas concentrations and bacterial community composition along the 800 km long Cauvery river, the main river serving as a potable and irrigation water supply in Southern India.