Potential Role of Sea Ice change in controlling Mercury in coastal Antarctic Areas
Programme: Programma Nazionale di Ricerca in Antartide (PNRA)
Duration: 11 July 2024 – 11 July 2027 (postponed)
Mercury is a toxic trace element found ubiquitously in the atmosphere where it can rapidly deposit to the hydrosphere or cryosphere and pass into nearby ecosystems. Antarctica is thought to be a sink during the polar night and a source during the polar day, although this simple scheme is complicated by atmospheric chemistry. Radicals of oxygen and bromine can enhance oxidation of atmospheric mercury to ionic forms that can deposit more rapidly. We suspect these oxidation processes are more rapid above the sea ice during the springtime when the so-called bromine explosion occurs. Our aim is to carry out atmospheric measurements of bromine and combine them with ozone and NOx measurements already taken at MZS whilst monitoring atmospheric mercury concentrations using a Tekran 2537X instrument. Complimentary to these field measurements, snow samples, ice samples, sea samples, and passive air samples at different points will allow us to start to quantify and connect between different environmental compartments, the depositional processes and metal cycling. In addition, within the same samples, we aim to investigate the presence of the mer-operon that codes for mercury resistance in bacteria as we suspect that after sea ice break up, biological processes become important in the emission of mercury from the sea surface. These measurements together with air mass back trajectories using Lagrangian models (FLEXPART and HYSPLIT) should help us make a valid contribution to understanding the role of Antarctica on the global mercury cycle.
Objectives
Objective 1) Set up a station for the continuous analysis of total gaseous mercury (TGM) in air and collection of aerosol for analysis of bromine and particulate mercury at MZS.
Objective 2) Survey the mercury concentrations in snow, sea ice, glacial melt waters and surface and subsurface seawater of Tethys Bay and the immediate vicinity of Terra Nova Bay.
Objective 3) Phylogenetic characterization of total bacterial communities and molecular detection of specific resistance genes within natural samples, and correlation of their abundance with the detected Hg concentrations.
Objective 4) Isolation of bacterial strains from the sea ice, snow and glacial melt water samples to investigate the presence of the mer-operon that codes for mercury resistance in bacteria.
Objective 5) Investigate the variables that influence the daily variations of mercury in the atmosphere, the eventual re-deposition of mercury and under what conditions, with a real estimate of how much mercury is recycled between the air and snowpack.
Objective 6) Understand how variations in sea ice at the coast can affect the mercury cycle and to what extent.
Coordinator: Cairns Warren Raymond Lee
SZN Principal Investigator: Carmen Rizzo
Partners:
National Research Council, Institute of Polar Sciences
Stazione Zoologica Anton Dohrn
University of Perugia
