Research

Environmental Research: The Himalayas and Climate Change

We use long-lived radiogenic and stable isotopes to trace fluid-mediated surficial processes in the Himalayas. We focus on glacier-fed headwater streams, glacial impurities, water end-member source contributions to total river discharge, and water-rock interactions in the glacierized in Himalayan catchment. We try to address fundamental questions such as sources, pathways, and control mechanisms of surface water ionic compositions. These endeavors collectively aim to illuminate the profound impact of climate change on the delicate Himalayan ecosystem. Some key findings of our research group include:

  • Discharge-weighted average ice meltwater contribution in headwaters of the Indus, the Ganga, and the Brahmaputra, varied between 47 ± 13%, 44 ± 13%, and 29 ± 10%, respectively, which is equivalent to 33.5 ± 6.5 Gt yr-1 of melted ice mass

  • HNO3-mediated chemical weathering reactions are important processes that alter the geologic carbon cycle of high-altitude glacierized Himalayan catchments as well as on a global scale.

  • Glacier fed small Himalayan lakes (≤0.04 km2) are a significant emitter of atmospheric CO2 controlled by DIC, and is an emerging—and not an inert—component of the regional carbon budget.

  • Planetary boundary layer height dynamics in the Indo-Gangetic Plains, which are far from the Higher Himalaya, modulates pollutant transport to the high mountains of the Himalaya.

  • Biomass-derived carbon could be the only primary driver of carbon-induced glacier melting in the western Himalaya.

Publications

  • (9) Pradhan, S. *, Sen, I.S., “Metamorphic CO2 fluxes offset the geological carbon sink in the Himalayan-Tibetan orogen,” Earth and Planetary Science Letters (under revision)

  • (8) Roy, N*, Sen I.S. CO2 consumption rates in the glacierized Himalayan headwaters: The importance of sulfuric and nitric acid-mediated chemical weathering reactions in geologic carbon cycle (2023). Geochemistry, Geophysics, Geosystems, 24, e2023GC010919, https://doi.org/10.1029/2023GC010919

  • (7) Shukla, T, ** Sen, I.S.; Sundriyal S., Carbon emissions from emerging glacier-fed Himalayan lakes, Global and Planetary Changes, Volume 225, June 2023, 104134 https://doi.org/10.1016/j.gloplacha.2023.104134

  • (6) Mitra, A.,* Sen, I.S., Pandey, S.K., Velu, V., Reisberg, L., Bizimis, M., Cloquet, C., Nizam, S.* Lead Isotope Evidence for Enhanced Anthropogenic Particle Transport to the Himalayas during Summer Months; (2021) Environmental Science and Technology, 55 (20), pp. 13697-13708. https://doi.org/10.1021/acs.est.1c03830

  • (5) Nizam, S.,* Sen, I.S., Shukla, T.,** Selby, D. Melting of the Chhota Shigri Glacier, Western Himalaya, Insensitive to Anthropogenic Emission Residues: Insights from Geochemical Evidence; (2021) Geophysical Research Letters, 48 (19), art. no. e2021GL092801. https://doi.org/10.1029/2021GL092801

  • (4) Shukla, T.,** Sen, I.S. Preparing for Floods on the Third Pole; (2021) Science, 372 (6539), pp. 232-234. DOI: 10.1126/science.abh3558

  • (3) Shukla, T.,** Sundriyal, S., Sen, I.S. Contemporary Inorganic Carbon Fluxes from Rapidly Changing Glacierized Watersheds of the Himalaya; (2020) Journal of Hydrology, 587, art. no. 124972. https://doi.org/10.1016/j.jhydrol.2020.124972

  • (2) Nizam, S., * Sen, I.S., Vinoj, V., Galy, V., Selby, D., Azam, M.F., Pandey, S.K., Creaser, R.A., Agarwal, A.K., Singh, A.P., Bizimis, M. Biomass-Derived Provenance Dominates Glacial Surface Organic Carbon in the Western Himalaya; (2020) Environmental Science and Technology, 54 (14), pp. 8612-8621. https://doi.org/10.1021/acs.est.0c02710

  • (1) Boral, S.,* Sen, I.S. Tracing ‘Third Pole’ Ice Meltwater Contribution to the Himalayan Rivers using Oxygen and Hydrogen Isotopes; (2020) Geochemical Perspectives Letters, 13, pp. 48-53. doi: 10.7185/geochemlet.2013

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