Spatial Distribution of Atmospheric Mercury Species in the Southern Ocean

Abstract

Antarctica and the surrounding Southern Ocean act as an important sink in the global mercury cycle; however, corresponding studies of atmospheric mercury species in these regions are still scarce. Here, we report large‐scale observations of atmospheric gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Antarctic marine boundary layer (MBL) taken during a summer cruise. There is large variability in the spatial distribution of GOM, which is likely attributable to the diverse land surface types, including coastal Antarctica, sea‐ice region, and oceanic region, along the cruise route. In coastal Antarctica, the highest GOM level (56.23 ± 47.74 pg·m−3) might be attributed to the significant in‐situ oxidation there. Significant in‐situ oxidation of GEM could also occur in the sea‐ice region, causing the significant increase of GOM (up to 87.01 pg·m−3), while the uptake of the high content of sea‐salt aerosols in sea‐ice regions might efficiently eliminate GOM in the air, resulting in generally lower content of GOM (13.10 ± 14.48 pg·m−3) in the sea‐ice region. In the oceanic region, the lowest level of GOM (3.95 ± 4.69 pg·m−3) is due to both the uptake of sea‐salt aerosols and the seasonal melting of first‐year sea‐ice. This study provides insight to understand the mechanisms of the atmospheric mercury cycle in various land surface types in the Antarctic MBL.

Latitudinal Distribution of Gaseous Elemental Mercury in Tropical Western Pacific: The Role of the Doldrums and the ITCZ

“…This investigation suggests that the regional transport can further intensify the accumulation of GEM under the wind weakening condition when getting closer to the doldrums. The steadily rising trend of GEM without synchronize rise of BC near the doldrums (8°S∼2°S) is likely to reflect the large differences in the residence time of GEM (from months up to 1 year) and BC (3.3∼10.6 days) in the air, , and further the different “accumulation effect” of doldrums on gaseous and particulate pollutants. Whether this potential “accumulation effect” is widely existed need further investigation.…”

Increased Contribution of Circumpolar Deep Water Upwelling to Methylmercury in the Upper Ocean around Antarctica: Evidence from Mercury Isotopes in the Ornithogenic Sediments

“…7−9 The marginal waters of Antarctica are located at the intersection of atmosphere, ocean, land, ice and snow, where Hg undergoes intricate physicochemical processes. 10,11 Moreover, Antarctic coastal regions are often accompanied by the presence of polynyas (open water within sea ice), which serve as hotspots for biological activity due to their higher primary productivity. 12 Therefore, it is crucial to clarify the source and fate of Hg in Antarctic coastal waters to understand its impact on the fragile Antarctic ecosystem.…”

“…As a worldwide pollutant, mercury (Hg) has the ability to travel long distances through atmospheric and oceanic currents, and settle in distant polar regions . In aquatic environments, Hg can be microbially and abiotically methylated to form highly toxic methylmercury (MeHg), posing a serious threat to ecosystems. − In the Southern Ocean, high concentrations of total Hg and MeHg have been found south of the polar front, which may explain the high Hg accumulation in predators at medium and high trophic levels. − The marginal waters of Antarctica are located at the intersection of atmosphere, ocean, land, ice and snow, where Hg undergoes intricate physicochemical processes. , Moreover, Antarctic coastal regions are often accompanied by the presence of polynyas (open water within sea ice), which serve as hotspots for biological activity due to their higher primary productivity . Therefore, it is crucial to clarify the source and fate of Hg in Antarctic coastal waters to understand its impact on the fragile Antarctic ecosystem.…”

The Marginal Ice Zone as a dominant source region of atmospheric mercury during central Arctic summertime

“…GEM has a long residence time in the air (0.5–1 year) due to its high volatility, low water solubility and low chemical reactivity and accounts for more than 90% of the total content of Hg in the surface air 4 – 6 . Gaseous and particulate divalent Hg, which can be formed by GEM oxidation, have a shorter lifetime (hours to weeks) and can be effectively eliminated from the air via dry and wet deposition 2 , 4 , 7 .…”