Latitudinal gradient for mercury accumulation and isotopic evidence for post-depositional processes among three tropical forests in Southwest China

Shangwen Xia; Wei Yuan; Luxiang Lin; Xiaodong Yang; Xinbin Feng; Xianming Li; Xu Liu; Peijia Chen; Shufang Zeng; Dingyong Wang; Qizhao Su; Xun Wang

doi:10.1016/j.jhazmat.2022.128295

Latitudinal gradient for mercury accumulation and isotopic evidence for post-depositional processes among three tropical forests in Southwest China

J Hazard Mater. 2022 May 5:429:128295. doi: 10.1016/j.jhazmat.2022.128295. Epub 2022 Jan 19.

Authors

Shangwen Xia¹, Wei Yuan², Luxiang Lin³, Xiaodong Yang⁴, Xinbin Feng², Xianming Li⁵, Xu Liu⁵, Peijia Chen⁵, Shufang Zeng⁵, Dingyong Wang⁵, Qizhao Su⁶, Xun Wang⁷

Affiliations

¹ CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
² State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
³ CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China; National Forest Ecosystem Research Station at Xishuangbanna, Mengla 666300, Yunnan, China.
⁴ CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China. Electronic address: yangxd@xtbg.ac.cn.
⁵ College of Resources and Environment, Southwest University, Chongqing 400715, China.
⁶ Mengla Institute of Conservation, Xishuangbanna Administration of Nature Reserves, Mengla 666300, Yunan, China.
⁷ State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China. Electronic address: wangxun@mail.gyig.ac.cn.

PMID: 35074747
DOI: 10.1016/j.jhazmat.2022.128295

Abstract

Tropical forest contributes to > 50% of global litterfall mercury (Hg) inputs and surface soil Hg storage, while with limited understanding of Hg biogeochemical processes. In this study, we displayed the 5-m resolution of Hg spatial distribution in three 1-ha tropical forest plots across the latitudinal gradient in Southwest China, and determined Hg isotopic signatures to understand factors driving Hg spatial distribution and sequestration processes. Our results show that tropical forest at the lowest latitude has the highest litterfall Hg input (74.95 versus 34.14-56.59 μg m^-2 yr^-1 at higher latitude plots), but the smallest surface soil Hg concentration (2-3 times smaller than at higher latitude sites). Hg isotopic evidence indicates that the decreasing climate mediated microbial Hg reduction in forest floor leads to the increasing Hg accumulation along the latitudinal gradient in three tropical forests. The terrain induced indirect effects by influencing litterfall Hg inputs, soil organic matters distribution and interplays between surface and deep soils drive the heterogeneity of surface soil Hg distribution within each sampling plot. Our results highlight though the elevated litterfall Hg inputs, the distinct post-depositional reductions induced Hg loss would remarkedly decrease atmospheric Hg net sink in tropical forest.

Keywords: Climate; High resolution; Mercury isotope; Spatial distribution; Tropical forest.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China
Environmental Monitoring
Mercury* / analysis
Soil

Substances

Soil
Mercury