Collaborative Research: MEGA - Mercury biogeochemical cycling and export from Greenland to the Arctic

Mercury is a toxic element that is of concern for the health of the environment and humans. There are particularly high amounts of mercury in Arctic food webs due to the transport of mercury in the atmosphere to the Arctic, primarily from mining and industrial regions. The main source of mercury to the Arctic is thought to be human emissions to the atmosphere (for example, from processing of material in gold mining and fossil fuel burning), but there may also be large natural sources of mercury that could change with climate warming.

Glaciers and ice sheets, large rivers of ice, have recently been identified in Greenland as possible sources of mercury to the Arctic through glacier physical grinding (as they bulldoze their way through the landscape) and melt, but data is still sparse and these existing datasets highlight significant uncertainty. In the MEGA project, the investigators will sample (i) a range of glacial meltwater rivers across Greenland, (ii) the oceans these meltwaters flow into, and (iii) the air next to the water sampling sites, to understand whether these natural mercury inputs are important and/or are likely to change with increased glacier melting in a warming climate.

This new data will improve our knowledge of the importance of glaciers and ice sheets in the Earth System, and provide critical process information using modern measurement techniques. The MEGA project will ultimately help us understand how mercury moves and changes through Arctic systems. MEGA will support two PhD students, several undergraduates, and a number of early career scientific researchers.

It will establish an international collaboration between US, Danish, German, Czech and Greenlandic researchers, and provide unique opportunities for teachers from under resourced high schools in West Philadelphia to participate in Arctic research.

Mercury is a toxic element that accumulates and magnifies in food webs, making it of particular concern to human populations. Concentrations of mercury in the Arctic region are of particular concern for policymakers because they are high in Arctic marine organisms. This is important for Arctic communities that rely on fishing and hunting for significant proportions of their diet.

The major source of mercury to the Arctic is atmospheric deposition of anthropogenic mercury from lower latitudes (for example, from artisanal gold mining and fossil fuel burning), transported to the polar regions by prevailing atmospheric circulation. More recently, natural sources of mercury, such as from permafrost melting, have received attention as potentially important components of the Arctic mercury cycle that could change in a warming climate.

However, large gaps in scientific knowledge surround these climatically sensitive but potentially significant natural sources of mercury, particularly glaciers and ice sheets. The Greenland Ice Sheet is by far the largest ice mass in the northern hemisphere, covering over 20% of the land surface in the Arctic. Recent research suggests the ice sheet may be an important source of mercury to surrounding ocean ecosystems, but the data is limited and additional research is needed.

The MEGA project will produce the first complete model of mercury mobilization, movement and transformations from source (ice) to sink (ocean). The investigators will develop a robust numerical budget for mercury in Greenland by sampling (i) meltwater rivers flowing from the ice sheet, (ii) the coastal areas these rivers enter, and (iii) the atmosphere from where mercury can be deposited/transported.

MEGA will use innovative methodological techniques like the chemical fingerprint of the mercury (e.g., mercury isotope ratios) to provide information that contextualizes the importance of the Greenland Ice Sheet processes in the Arctic mercury cycle. The MEGA project will support a diverse range of researchers, including undergraduate students, two graduate students, an early career postdoctoral researcher, and four early career faculty.

The project will also develop collaborations, networking and capacity building between US researchers/institutions and researchers/institutions from Greenland, Denmark, the Czech Republic and Germany. MEGA will also embed two K-12 educators from Philadelphia in fieldwork to cultivate interests in STEM, Arctic research, and Earth systems science, helping inspire their teaching curriculum and their students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.