Impact of changing atmospheric deposition chemistry on carbon and nutrient loading to Ganga River: integrating land–atmosphere–water components to uncover cross-domain carbon linkages Jitendra Pandey • Usha Pandey • Anand V. Singh Received: 4 July 2013 / Accepted: 14 January 2014 Ó Springer International Publishing Switzerland 2014 Abstract Terrestrial contribution of dissolved organic carbon (DOC) to riverine carbon transport remains relatively uncertain despite recent research highlighting its importance. Here we present data on changing state of atmosphere–land–water transfer and associated shift in DOC build-up in Ganga River (India) for a period of 6 years (March, 2007–February, 2013). Although the N:P stoichiometry of atmospheric depo- sition (AD) showed a declining trend, there was over 1.4 to 1.6-fold increase in AD-NO 3 - , 1.5 to 1.8-fold increase in AD-OC and, over 1.5 to 2.2-fold increase in AD-NH 4 ? and AD-PO 4 3- input over time. Water soluble organic carbon and microbial activity in sub- catchments and, DOC and nutrient concentrations in runoff increased consistently over time along the gradient of AD-input. We found a variable but strong linkage between atmospheric deposition and hydrolog- ical control of terrestrial carbon and nutrient input to the river. The results showed that the increasing input of AD-nutrients enhance primary production whereas, such input in sub-catchment enhance DOC in runoff and, the coupled effect of these favor DOC build-up in Ganga River at Varanasi. The study that forms the first report establishing trans-boundary drivers of DOC in Ganga River suggests that future climate model should consider large scale inter-regional time series data on changing atmosphere–land–water transfer and associ- ated shift in carbon balance of major rivers for more accurately predicting cross-domain carbon linkages and planning for integrated river basin management. Keywords Atmospheric deposition  Climate change  Dissolved organic carbon  Ganges basin  Integrated river basin management  Nutrients  Runoff Introduction A connective organized framework to understand carbon (C) budget is a critical challenge the scientific communities are facing both on regional and global scales. In recent years, anthropogenic activities have dramatically altered the global C cycle making it difficult to separate natural aspects of C sequestration from those induced by human perturbations. Recent studies have shown the importance of data on trans- boundary interactions in constructing a complete regional C budget (Buffam et al. 2011; Serghei et al. Responsible Editor: Karsten Kalbitz. J. Pandey (&)  A. V. Singh Environmental Science Division, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India e-mail: jiten_pandey@rediffmail.com U. Pandey Department of Botany, Faculty of Science and Technology, Mahatma Gandhi Kashividyapith University, Varanasi 221002, India e-mail: usha_pandey28@yahoo.co.in 123 Biogeochemistry DOI 10.1007/s10533-014-9957-2