|Abstract Title:||A Synthesis of Mercury Research in the Southern Hemisphere|
|Presenter Name:||Larissa Schneider|
|Company/Institution:||Australian National University|
|Session:||Special Session - Mercury in the Southern Hemisphere|
|Day and Session:||Wednesday 27th July - Session One|
|Start Time:||06:30 UTC|
|Co-Authors:||Jenny Fisher, María Diéguez, Saul Guerrero, Anne-Hélène Fostier, Jean Guimaraes, Casper Labuschagne, Joy Leaner, Lynwill Martin, Robert Mason, Vernon Somerset, Chavon Walters|
Abstract Information :
The biogeochemical cycle of mercury (Hg) has received comprehensive attention in the Northern Hemisphere (NH) over the past two decades. In contrast, our understanding of Hg cycling in the Southern Hemisphere (SH) and tropics remains poor. Despite a wealth of NH-based studies on the Hg cycle, the environmental, geographic, and socioeconomic differences between hemispheres mean that this knowledge cannot be easily translated to the SH. In this context, we review the current literature on the Hg cycle in the SH to synthesise the key differences in Hg cycling between the hemispheres. We identify the following key differences:
(1) The ocean plays a more important role in the SH due to its larger ocean area.
(2) Atmospheric Hg deposition through litterfall to terrestrial forest ecosystems is much more significant in the SH and tropics, where most rainforest is found.
(3) Hg emission by forest fires is greater in the SH due to the prevalence of large natural fires, the reliance on slash and burn methods and the lack of regulations and law enforcement.
(4) Geogenic and volcanic Hg sources are more extensive in the SH than in the NH.
(5) Nearly all artisanal and small-scale gold mining activities using Hg occur in the SH.
(6) Most industrial activity in the SH occurs in developing countries, which lack strong regulatory controls and modern pollution control technology, resulting in larger Hg emission.
(7) The diversity in environments in the SH (e.g., Amazonian rainforest, extensive deserts) results in large variability in the natural Hg cycle across the hemisphere.
Our analysis of these NH-SH differences enables a more comprehensive understanding of the Hg cycle in the SH as well as the lingering knowledge gaps. This information will deliver guidance for policymakers, regulators, funding agencies, and researchers in the SH.