Understanding the Cyclicity of Chemical Weatheringand Associated CO2Consumption in the BrahmaputraRiver Basin (India): The Role of Major Rivers in ClimateChange Mitigation Perspective
2016 (English)In: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 22, no 3, 225-251 p.Article in journal (Refereed) Published
Weathering of rocks that regulate the water chemistry of the river has been used to evaluate the CO2 consumption rate which exerts a strong influence on the global climate. The foremost objective of the present research is to estimate the chemical weathering rate (CWR) of the continental water in the entire stretch of Brahmaputra River from upstream to downstream and their associated CO2 consumption rate. To establish the link between the rapid chemical weathering and thereby enhance CO2 drawdown from the atmosphere, the major ion composition of the Brahmaputra River that drains the Himalaya has been obtained. Major ion chemistry of the Brahmaputra River was resolved on samples collected from nine locations in pre-monsoon, monsoon and post-monsoon seasons for two cycles: cycle I (2011-2012) and cycle II (2013-2014). The physico-chemical parameters of water samples were analysed by employing standard methods. The Brahmaputra River was characterized by alkalinity, high concentration of Ca2+ and HCO3 (-) along with significant temporal variation in major ion composition. In general, it was found that water chemistry of the river was mainly controlled by rock weathering with minor contributions from atmospheric and anthropogenic sources. The effective CO2 pressure (log) for pre-monsoon, monsoon and post-monsoon has been estimated. The question of rates of chemical weathering (carbonate and silicate) was addressed by using TDS and run-off (mm year(-1)). It has been found that the extent of CWR is directly dependent on the CO2 consumption rate which may be further evaluated from the perspective of climate change mitigation The average annual CO2 consumption rate of the Brahmaputra River due to silicate and carbonate weathering was found to be 0.52 (x10(6) mol Km(-2) year(-1)) and 0.55 (x10(6) mol Km(-2) year(-1)) for cycle I and 0.49 (x10(6) mol Km(-2) year(-1)) and 0.52 (x10(6) mol Km(-2) year(-1)) for cycle II, respectively, which were significantly higher than that of other Himalayan rivers. Estimation of CWR of the Brahmaputra River indicates that carbonate weathering largely dominates the water chemistry of the Brahmaputra River.
Place, publisher, year, edition, pages
2016. Vol. 22, no 3, 225-251 p.
IdentifiersURN: urn:nbn:se:uu:diva-289174DOI: 10.1007/s10498-016-9290-6ISI: 000376579000004OAI: oai:DiVA.org:uu-289174DiVA: diva2:924800