Investigation of water-soluble organic constituents and their spatio-temporal heterogeneity over the Tibetan Plateau

Hewen Niu; Xixi Lu; Guotao Zhang; Chandan Sarangi

doi:10.1016/j.envpol.2022.119093

Investigation of water-soluble organic constituents and their spatio-temporal heterogeneity over the Tibetan Plateau

Environ Pollut. 2022 Jun 1:302:119093. doi: 10.1016/j.envpol.2022.119093. Epub 2022 Mar 1.

Authors

Hewen Niu¹, Xixi Lu², Guotao Zhang³, Chandan Sarangi⁴

Affiliations

¹ State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China. Electronic address: niuhw@lzb.ac.cn.
² Department of Geography, National University of Singapore, 1 Arts Link, 117570, Singapore.
³ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
⁴ Department of Civil Engineering, Indian Institute of Technology, Madras, Chennai, India; Laboratory for Atmospheric and Climate Sciences, Indian Institute of Technology Madras, Chennai, India.

PMID: 35245621
DOI: 10.1016/j.envpol.2022.119093

Abstract

Investigating the migration and transformation of carbonaceous and nitrogenous matter in the cryosphere areas is crucial for understanding global biogeochemical cycle and earth's climate system. However, water-soluble organic constituents and their transformation in multiple water bodies are barely investigated. Water-soluble organic carbon (WSOC) and organic nitrogen (WSON), and particulate black carbon (PBC) in multiple types of water bodies in eastern Tibetan Plateau (TP) cryosphere for the first time have been systematically investigated. Statistical results exhibited that from south to north and from east to west of this region, WSOC concentrations in alpine river runoff were gradually elevated. WSOC and nitrogenous matter in the alpine river runoff and precipitation in the glacier region presented distinct seasonal variations. WSON was the dominant component (63.4%) of water-soluble total nitrogen in precipitation over high-altitude southeastern TP cryosphere. Water-soluble carbonaceous matter dominated the carbon cycle in the TP cryosphere, but particulate carbonaceous matter in the alpine river runoff had a small fraction of the cryospheric carbon cycle. Analysis of optical properties illustrated that PBC had a much stronger light absorption ability (MAC-_PBC: 2.28 ± 0.37 m² g^-1) than WSOC in the alpine river runoff (0.41 ± 0.26 m² g^-1). Ionic composition was dominated by SO₄^2-, NO₃^-, and NH₄⁺ (average: 45.13 ± 3.75%) in the snow of glaciers, implying important contribution of (fossil fuel) combustion sources over this region. The results of this study have essential implications for understanding the carbon and nitrogen cycles in high altitude cryosphere regions of the world. Future work should be performed based on more robust in-situ observations and measurements from multiple environmental medium over the cryosphere areas, to ensure ecological protection and high-quality development of the high mountain Asia.

Keywords: Chemical constituents; Cryosphere; Particulate black carbon; Tibetan plateau.

MeSH terms

Aerosols / analysis
Air Pollutants* / analysis
Carbon / analysis
Environmental Monitoring / methods
Particulate Matter / analysis
Tibet
Water / analysis

Substances

Aerosols
Air Pollutants
Particulate Matter
Water
Carbon