The role of earthquakes and storms in the fluvial export of terrestrial organic carbon along the eastern margin of the Tibetan plateau: A biomarker perspective

Frontiers in Earth Science

Earth Science

Robert G. Hilton¹  Zhangdong Jin²  Fei Zhang²  Jin Wang³  Xiaojuan Feng⁴  Tian Ma⁵ 

[1] Department of Earth Sciences, University of Oxford, Oxford, United Kingdom;State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China;State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China;State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China;Department of Geography and Institute of Hazard, Risk and Resilience, Durham University, Durham, United Kingdom;State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China;State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China;4, State Key Laboratory of Grassland and Agro-ecosystems, and College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China;

关键词: particulate organic carbon;    landslide;    Wenchuan earthquake;    debris flow;    biomarker;    organic carbon source;   

DOI  :  10.3389/feart.2022.1090983

 received in 2022-11-06, accepted in 2022-12-01,  发布年份 2023

来源: Frontiers

【 摘 要 】

Driven by earthquakes and intense rainfall, steep tectonically active mountains are hotspots of terrestrial organic carbon mobilization from soils, rocks, and vegetation by landslides into rivers. Subsequent delivery and fluvial mobilization of organic carbon from different sources can impact atmospheric CO2 concentrations across a range of timescales. Extreme landslide triggering events can provide insight on processes and rates of carbon export. Here we used suspended sediment collected from 2005 to 2012 at the upper Min Jiang, a main tributary of the Yangtze River on the eastern margin of the Tibetan Plateau, to compare the erosion of terrestrial organic carbon before and after the 2008 Wenchuan earthquake and a storm-derived debris flow event in 2005. To constrain the source of riverine particulate organic carbon (POC), we quantified lignin phenols and n-alkanoic acids in the suspended sediments, catchment soils and landslide deposits. We found that riverine POC had higher inputs of less-degraded, discrete organic matter at high suspended sediment loads, while the source of POC seemed stochastic at low suspended sediment concentrations. The debris flow in 2005 mobilized a large amount of POC, resulting in an export of lignin within a single day equivalent to a normal year. In comparison, the 2008 Wenchuan earthquake increased the flux of POC and particulate lignin, albeit with limited impact on POC sources in comparison to seasonal variations. Our results highlight the important role of episodic events in the fluvial export of terrestrial carbon.

【 授权许可】

Unknown   
Copyright © 2023 Wang, Ma, Zhang, Hilton, Feng and Jin.