Mercury (Hg) is one of the primary contaminants of concern in the Arctic marine ecosystem. Methyl Hg (MeHg) is known to biomagnify in food webs. During the International Polar Year - Circumpolar Flaw Lead study, sea ice, seawater, bottom ice algae, phytoplankton and the herbivorous copepods were collected from the Amundsen Gulf to test whether ice algae and phytoplankton assimilate Hg from their habitat, and whether Hg bioaccumulates from the seawater to the primary consumers. Sea ice algae were found to accumulate Hg primarily from the bulk bottom ice, and the sea ice algae bloom depleted Hg stored within the bottom section of the ice. Furthermore, biodilution of Hg was observed to occur in sea ice algae. Higher concentrations of Hg were also found in phytoplankton and in grazing copepods. A positive correlation between MeHg and trophic level suggests the occurrence of MeHg biomagnification even at these low trophic positions.

Mercury (Hg) is one of the primary contaminants of concern in the Arctic marine ecosystem. Methyl Hg (MeHg) is known to biomagnify in food webs. During the International Polar Year - Circumpolar Flaw Lead study, sea ice, seawater, bottom ice algae, phytoplankton and the herbivorous copepods were collected from the Amundsen Gulf to test whether ice algae and phytoplankton assimilate Hg from their habitat, and whether Hg bioaccumulates from the seawater to the primary consumers. Sea ice algae were found to accumulate Hg primarily from the bulk bottom ice, and the sea ice algae bloom depleted Hg stored within the bottom section of the ice. Furthermore, biodilution of Hg was observed to occur in sea ice algae. Higher concentrations of Hg were also found in phytoplankton and in grazing copepods. A positive correlation between MeHg and trophic level suggests the occurrence of MeHg biomagnification even at these low trophic positions.

Marine phytoplankton are known to produce UV-absorbing compounds (UVACs) for protection against UV radiation. To assess whether the same strategy applies to sea ice-associated algal communities, MAAs were measured in algae associated with surface melt ponds, sea ice, sea ice−water interface, and underlying seawater in a coastal bay of the Canadian Arctic Archipelago during the 2011 spring melt transition. Six UVACs were detected as the spring melt progressed, namely shinorine, palythine, and porphyra-334 and three unknowns (U1, U2 and U3). U1 was most likely palythene, another MAA. The molecular identities of the other two UVACs, U2 and U3, which have an absorption maximum of 363 and 300 nm, respectively, remain to be structurally elucidated. The results confirm that Arctic sea ice-associated algal communities are capable of producing photoprotectants and that spatial and temporal variations in MAA and other UVAC synthesis are affected by snow cover and UV radiation exposure. / May 2016