Atmospheric & Environmental Chemistry Seminar
Date and Time
"Cycling and Sources of Mercury in Terrestrial Ecosystems" with Daniel Obrist, Professor, University of Massachusetts, Lowell.
"Cycling and Sources of Mercury in Terrestrial Ecosystems" with Daniel Obrist, Professor, University of Massachusetts, Lowell.
The terrestrial environment is an important component of the global Hg cycle and is estimated to receive 3,600 Mg of atmospheric Hg deposition annually, equivalent to about half of total annual Hg emissions to the atmosphere from anthropogenic and natural sources combined (with the remainder depositing to global oceans). Atmospheric Hg deposition includes wet deposition via precipitation and snow and dry deposition, which includes removal of particulate Hg and sorption and uptake of gaseous Hg to earth’s surfaces. Multiple lines of evidence now show that dry deposition of gaseous elemental Hg (GEM) is the dominant Hg source to terrestrial environments whereby atmospheric GEM is taken up by vegetation tissues and subsequently transferred and deposited to soils when tissues are shed (litterfall), plants die off (biomass turnover), and leaf surfaces are washed off (i.e., throughfall).
Here, we present an update of our understanding of how GEM is cycling through the terrestrial environment, including: new estimates of GEM uptake by global biomes; processes and partitioning of GEM deposition in ecosystems; and emerging datasets of atmosphere-surface flux measurements to directly quantify whole ecosystem GEM sinks and sources.
Registration is required. Open to the Harvard community. For event details, visit the event page.
Contact: zhenqu@g.harvard.edu