posted on 2023-11-03, 05:03authored byZhaohan Chu, Yunzhuo Zhou, Maodian Liu, Huiming Lin, Menghan Cheng, Han Xie, Liuliang Yuan, Zhihao Zhang, Qianru Zhang, Chengcheng Li, Yuang Chen, Yanpei Guo, Long Chen, Xuejun Wang
Mercury, a pervasive global pollutant,
primarily enters
the atmosphere
through human activities and legacy emissions from the land and oceans.
A significant portion of this mercury subsequently settles on land
through vegetation uptake. Characterizing mercury storage and distribution
within vegetation is essential for comprehending regional and global
mercury cycles. We conducted an unprecedented large-scale aboveground
vegetation mercury survey across the expansive Tibetan Plateau. We
find that mosses (31.1 ± 0.5 ng/g) and cushion plants (15.2 ±
0.7 ng/g) outstood high mercury concentrations. Despite exceptionally
low anthropogenic mercury emissions, mercury concentrations of all
biomes exceeded at least one-third of their respective global averages.
While acknowledging the role of plant physiological factors, statistical
models emphasize the predominant impact of atmospheric mercury on
driving variations in mercury concentrations. Our estimations indicate
that aboveground vegetation on the plateau accumulates 32–12+21 Mg
(interquartile range) mercury. Forests occupy the highest biomass
and store 82% of mercury, while mosses, representing only 3% of the
biomass, disproportionally contribute 13% to mercury storage and account
for 43% (2.5–1.4+3.0 Mg/year) of annual mercury assimilation by vegetation.
Additionally, our study underscores that extrapolating aboveground
vegetation mercury storage from lower-altitude regions to the Tibetan
Plateau can lead to substantial overestimation, inspiring further
exploration in alpine ecosystems worldwide.