Climate change may alter mercury fluxes in northern hardwood forests

Yang Yang, Linghui Meng, Ruth D. Yanai, Mario Montesdeoca, Pamela H. Templer, Heidi Asbjornsen, Lindsey E. Rustad, Charles T. Driscoll

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Soils are the largest terrestrial pool of mercury (Hg), a neurotoxic pollutant. Pathways of Hg accumulation and loss in forest soils include throughfall, litterfall, soil gas fluxes, and leaching in soil solution, all of which will likely be altered under changing climate. We took advantage of three ongoing climate-change manipulation experiments at the Hubbard Brook Experimental Forest, New Hampshire, USA: a combined growing-season warming and winter freeze-thaw cycle experiment, a throughfall exclusion to mimic drought, and a simulated ice storm experiment to examine the response of the forest Hg cycle to climatic disturbances. Across these three experiments, we compared Hg inputs in throughfall and leaf litterfall and Hg outputs in soil gas fluxes. Soil solution was measured only in the simulated ice storm experiment. We found that northern forest soils retained consistently less Hg by 16–60% in the three climate manipulations compared to the undisturbed controls (~ 7.4 µg Hg m−2 year−1), although soils across all three experiments still served as a net sink for Hg. Growing-season soil warming and combined soil warming and winter freeze-thaw cycles had little effect on litterfall and throughfall flux, but they increased soil Hg0 evasion by 31 and 35%, respectively, relative to the control plots. The drought plots had 5% lower litterfall Hg flux, 50% lower throughfall Hg flux, and 21% lower soil Hg0 evasion than the control plots. The simulated ice storm had 23% higher litterfall Hg flux, 1% higher throughfall Hg flux, 37% higher soil Hg0 evasion, and 151% higher soil Hg leaching than the control plots. These observations suggest that climate changes such as warmer soils in the growing season or more intense ice storms in winter are likely to exacerbate Hg pollution by releasing Hg sequestered in forest soils via evasion and leaching.

Original languageEnglish (US)
Pages (from-to)1-16
Number of pages16
Issue number1
StatePublished - Nov 1 2019


  • Drought
  • Freeze-thaw cycle
  • Global warming
  • Ice storm event
  • Litterfall
  • Soil drainage water
  • Soil mercury evasion
  • Soil mercury retention
  • Throughfall

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Earth-Surface Processes


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