Biomass-derived provenance dominates glacial surface organic carbon in the western Himalaya

Nizam, Sarwar; Sen, Indra Sekhar; Vinoj, V.; Galy, Valier; Selby, David; Azam, Mohammad F.; Pandey, Satyendra Kumar; Creaser, Robert A.; Agarwal, Avinash Kumar; Singh, Akhilendra Pratap; Bizimis, Michael

Abstract

The origin, transport pathways, and spatial variability of total organic carbon (OC) on the western Himalayan glaciers is poorly understood compared to that of black carbon (BC) and dust, but it is critically important to evaluate the climatic role of OC in the region. Applying the distribution of OC activation energy, 14C activity and radiogenic isotopes of 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb in glacial debris and atmospheric particulate matter (PM10 size fraction) we demonstrate that 98.3 ± 1.6% and 1.7 ± 1.6% of the OC in western Himalayan glaciers are derived from biomass and petrogenic sources, respectively. The δ13C and N/C composition shows that the biomass is a complex mixture of C3 vegetation and autochthonous photo-autotrophic inputs modified by heterotrophic microbial activity. The dataset reveals that the studied western Himalayan glacier has negligible contributions from fossil fuel-derived particles, which contrasts to the central and eastern Himalayan glaciers that have significant contributions from fossil fuel sources. We show that this spatial variability of OC sources relates to regional differences in air-mass transport pathways and precipitation regimes over the Himalaya. Moreover, our observation suggests that biomass-derived carbon could be the only primary driver of carbon-induced glacier melting in the western Himalaya.

Citation

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. (2020). Biomass-derived provenance dominates glacial surface organic carbon in the western Himalaya. Environmental Science and Technology, 54(14), 8612-8621. https://doi.org/10.1021/acs.est.0c02710

• Journal Article Type: Article
• Acceptance Date: Jun 25, 2020
• Online Publication Date: Jun 25, 2020
• Publication Date: Jul 21, 2020
• Deposit Date: Jul 3, 2020
• Publicly Available Date: Jun 25, 2021
• Journal: Environmental Science and Technology
• Print ISSN: 0013-936X
• Electronic ISSN: 1520-5851
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 54
• Issue: 14
• Pages: 8612-8621
• DOI: https://doi.org/10.1021/acs.est.0c02710
• Public URL: https://durham-repository.worktribe.com/output/1267115