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Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river
Author(s) -
Liu Jing,
Zhong Jun,
Ding Hu,
Yue FuJun,
Li Cai,
Xu Sen,
Li SiLiang
Publication year - 2020
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.13763
Subject(s) - weathering , biogeochemical cycle , dissolved organic carbon , carbonate , carbon cycle , environmental chemistry , carbon fibers , environmental science , tracer , geology , hydrology (agriculture) , chemistry , geochemistry , ecosystem , materials science , ecology , physics , geotechnical engineering , organic chemistry , composite number , nuclear physics , composite material , biology
Abstract To better understand the mechanisms relating to hydrological regulations of chemical weathering processes and dissolved inorganic carbon (DIC) behaviours, high‐frequency sampling campaigns and associated analyses were conducted in the Yu River, South China. Hydrological variability modifies the biogeochemical processes of dissolved solutes, so major ions display different behaviours in response to discharge change. Most ions become diluted with increasing discharge because of the shortened reactive time between rock and water under high‐flow conditions. Carbonate weathering is the main source of major ions, which shows strong chemostatic behaviour in response to changes in discharge. Ions from silicate weathering exhibit a significant dilution effect relative to the carbonate‐sourced ions. Under high temperatures, the increased soil CO 2 influx from the mineralisation of organic material shifts the negative carbon isotope ratios of DIC ( δ 13 C DIC ) during the high‐flow season. The δ 13 C DIC values show a higher sensitivity than DIC contents in response to various hydrological conditions. Results from a modified isotope‐mixing model ( IsoSource ) demonstrate that biological carbon is a dominant source of DIC and plays an important role in temporal carbon dynamics. Furthermore, this study provides insights into chemical weathering processes and carbon dynamics, highlighting the significant influence of hydrological variability to aid understanding of the global carbon cycle.