Natural Greenhouse Gas Emissions from streams and lakes are strongly linked to water discharge and temperature according to a new study by Tamil Nadu Agricultural University. This knowledge is necessary to assess how man-made climate change is altering Greenhouse emissions from natural landscapes and has large Implications for climate change mitigation measures.
“Our new study shows that with increased precipitation, a larger amount of carbon may be washed into streams and lakes and an increased share of this carbon also ends up in the atmosphere. Hence, landscape carbon sinks may become less effective in the future,” said Sivakiruthika Balathandayuthabani, Ramanujan Fellow at the School of Post Graduate Studies at TNAU and the lead author of the study.
However, human use of fossil fuels has added a carbon flux to the atmosphere driving climate change. A great concern now is how the changed climate affects the balance of the natural greenhouse gas fluxes. If natural emissions increase faster than natural sinks, we get a vicious circle, i.e. a self-reinforcing effect by which increased emissions affect the climate resulting in greater emissions. This would accelerate climate change even further.
“The natural greenhouse gas fluxes are in the process of becoming partly anthropogenic because they are being impacted by anthropogenic climate change”, said David Bastviken.“It is clear that such measurements are not sufficiently representative and do not fully tell how large the fluxes are, nor how they are regulated”, says Sivakiruthika Balathandayuthabani.
Consequently, a team of researchers from TNAU and the Swedish universities Linköping University, the Swedish University of Agricultural Sciences, Stockholm University and the University of Gothenburg, have now applied a new approach by which a large number of measurement points were used over a longer period in both streams and lakes across an entire catchment area. In the study, published in the scientific journal Limnology and Oceanography Letters, the researchers quantified the amounts of carbon transported from the soil in a catchment area to streams and lakes, and to the atmosphere.
The researchers were able to demonstrate that greenhouse gas emissions from streams over time were dependent on water discharge which in turn depended on the amount of precipitation.“The integration across a full catchment with large amounts of data shows that the relationships between fluxes and environmental factors influenced by the climate may be simpler than we think. This gives us hope that we will be able to predict emissions from larger areas, helping us quantify climate feedback and include such information when planning climate change mitigation efforts,” says SivakiruthikaBalathandayuthabani.
This study was made possible by funding from the Swedish Research Council FORMAS, the Swedish Research Council, the European Research Council and the Swedish Nuclear Fuel and Waste Management Company and the Ramanujan Fellowship from the Science and Engineering Research Board of the Government of India. Sivakiruthika Balathandayuthabani is currently studying the emission of greenhouse gases methane, carbon dioxide and nitrous oxides from man-made water bodies in south India such as farm ponds, irrigation canals, irrigation tanks and open wells primarily used for agriculture. Her project aims to estimate their contribution to our national greenhouse gas inventory, and their impact on ongoing climate change and to explore strategies to reduce emissions from them.