Changing climate alters inputs and pathways of mercury deposition to forested ecosystems

Bradley D Blackwell,John A Maxwell,Thomas M Holsen,Charles T Driscoll

doi:10.1007/s10533-014-9961-6

Bradley D Blackwell, John A Maxwell + Show 2 more

Open Access

https://doi.org/10.1007/s10533-014-9961-6

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Journal: Biogeochemistry	Publication Date: Feb 21, 2014
Citations: 95	License type: CC BY 2.0

Affiliation: Clarkson University, Syracuse University

Abstract

Although land cover and meteorological conditions are known to impact mercury (Hg) deposition processes, few studies have addressed how changes in forest cover and shifting climatic conditions will impact the Hg cycle. The purpose of this study was to examine the effects of forest type (hardwood vs. conifer) and meteorological variation on atmospheric Hg deposition in two forest stands in Huntington Wildlife Forest in upstate New York, USA. Mercury deposition associated with litterfall was similar between the hardwood and conifer stands, but total Hg deposition was greater in the coniferous stand due to larger throughfall Hg. Soil evasion losses of Hg were significantly higher in the hardwood plot. Although Hg deposition was greater and evasion losses were lower in the conifer plot, soil Hg pools were smaller than in the hardwood plot. Annual variability in meteorological conditions was substantial between 2009 and 2010, and changes in Hg deposition over this period appear to be related to variation in temperature and precipitation quantity. The results from this study suggest that projected increases in temperature and precipitation in the northeastern United States could alter Hg deposition and availability by decreasing litterfall Hg inputs and increasing throughfall Hg inputs.

Highlights

Mercury (Hg) contamination is an environmental issue that impacts ecosystems across the globe, even in remote, pristine locations (Fitzgerald et al.1998; Driscoll et al 2013)
The purpose of this study was to examine the effects of forest type and meteorological variation on atmospheric Hg deposition in two forest stands in Huntington Wildlife Forest in upstate New York, USA
The forest has been the site of numerous biogeochemical studies (e.g., Selvendiran et al 2008; Mitchell et al 1992; Johnson and Lindberg 1992), and serves as a monitoring station for the National Atmospheric Deposition Program (NADP) National Trends Network (NTN), Mercury Deposition Network (MDN), and EPA Clean Air Status and Trends Network (CASTNET) programs

Summary

Introduction

Mercury (Hg) contamination is an environmental issue that impacts ecosystems across the globe, even in remote, pristine locations (Fitzgerald et al.1998; Driscoll et al 2013). Hg emissions and deposition in North America have declined since the mid-1980s, global emissions are increasing and many ecosystems experience symptoms of Hg contamination (Driscoll et al 2013; Drevnick et al 2012; Schmeltz et al 2011). Production of methyl-mercury (MeHg) largely takes place in reducing environments, and it subsequently biomagnifies and bioaccumulates in aquatic food chains (Wiener et al 2003). As human and wildlife exposure to Hg occurs primarily through consumption of MeHg contaminated fish and shellfish, past research has mainly focused on aquatic environments. Forest is the predominant land cover category in North America and likely receives greater atmospheric Hg deposition than any other land cover category

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