Mapping the forest litterfall mercury deposition in China

Area of Science:

• Environmental Science
• Ecosystem Ecology
• Biogeochemistry

Background:

• Litterfall mercury (Hg) deposition is a significant input to forest ecosystems.
• Quantifying this deposition in China has been limited by data availability.

Purpose of the Study:

• To model forest litterfall production across China.
• To compile a nationwide dataset of litterfall Hg concentration.
• To quantify forest litterfall Hg flux and deposition in China.

Main Methods:

• Utilized the random forest (RF) method and multi-source datasets to model litterfall production.
• Compiled a comprehensive nationwide dataset of litterfall Hg concentration.
• Integrated litterfall production and Hg concentration data to estimate Hg flux.

Main Results:

• Nationwide litterfall Hg concentration averaged 51.99 ± 34.23 ng g⁻¹.
• Mean litterfall production was simulated at 5.07 Mg ha⁻¹ yr⁻¹, varying regionally.
• Forest litterfall Hg flux averaged 25.88 ± 12.53 μg m⁻² yr⁻¹, higher in the south than the north.
• Total Hg deposition from forest litterfall in China was estimated at 27.0 ± 13.0 Mg yr⁻¹.

Conclusions:

• This study provides the first comprehensive quantitative evaluation of forest litterfall Hg deposition in China.
• Findings are crucial for understanding China's role in the global Hg cycle.
• Results highlight regional variations in Hg deposition and inform ecosystem management.