Pathways and speciation of mercury in the environmental compartments of Deception Island, Antarctica

Total mercury and methyl-mercury contents and accumulation in polar microbial mats

“…Contrastingly, in an extensive study in the same island, Mao de Ferro et al (2014) indicated that volcanic activity was mainly responsible for the observed Hg concentrations in different investigated compartments. In addition to volcanic activity, these authors also indicated that marine aerosols and fumarole emissions could be responsible for the accumulation of Hg in vegetation.…”

“…In our study, we obtained samples from aquatic communities at different distances from the seashore. When comparing our data, we did not find any strong evidence of marine environments as a potential source of Hg for terrestrial/freshwater communities, which was suggested by Bargagli et al (2007) and Mao de Ferro et al (2014). The mats from the pristine McMurdo Ice Shelf, and very distant from the open water, had Hg contents of 14 to 80 ng Hg/g DW.…”

“…In polar regions, vegetation such as lichens and mosses, as well as microbial mats, which are the most abundant components of these biological communities, are likely the main sinks for Hg when the snow melts during the warm season. Previous exploration (e.g., Bargagli et al, 1993) of the accumulation of mercury in polar vegetation (i.e., mosses and lichens) has indicated that both Arctic and Antarctic vegetation can accumulate considerable concentrations of Hg and MeHg (Lindberg et al, 2002;Mao de Ferro et al, 2014). Furthermore, previous studies have suggested that microbial mats, which cover vast surfaces in the polar areas, could be important for metal accumulation in non-marine polar ecosystems (Bargagli et al, 2007).…”

“…Despite their remoteness, polar regions are exposed to different sources of natural and anthropogenic pollution from volcanic activity, atmospheric deposition, fuel spills, waste disposal and fuel combustion (Mao de Ferro et al, 2014). The residence time of gaseous elemental mercury in the troposphere facilitates its long-distance transport before it becomes incorporated into ecosystems through atmospheric deposition (Bargagli et al, 2007).…”

Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean

“…The MMHg concentration of the sediment was five orders of magnitude lower than the THg concentration (<0.001%). Although there have been no MMHg measurements of the vent sediment for comparison, recent studies on the Hg and MMHg measurements in sediment samples collected at fumaroles in Deception Island, an active volcano in Antarctica, showed that MMHg concentrations were less than the detection limit (0.01 ng g À1 ), while the Hg levels were up to 10 000 times higher than the other sampling sites (Mão de Ferro et al, 2014). The same authors suggested that low Hg methylation could be attributed to the high temperatures found in fumaroles (>80°C).…”