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Mercury is found in Arctic marine mammals that are important in the diet of northern Indigenous peoples. The objectives of the present long‐term study, spanning a 45‐yr period, were to 1) investigate the temporal trends of total mercury (THg; muscle and liver) and selenium (Se; liver) in ringed seals (Pusa hispida) from different regions of the Canadian Arctic; and 2) examine possible relationships with age, diet, and climate parameters such as air temperature, precipitation, climatic indices, and ice‐coverage. Ringed seals were collected by hunters in northern communities in the Beaufort Sea, Central Arctic, Eastern Baffin Island, Hudson Bay, and Ungava/Nunatsiavut regions (Canada) between 1972 and 2017. Mercury levels did not change through time in seal liver, but THg levels in muscle decreased in seals from Hudson Bay (−0.91%/yr) and Ungava/Nunatsiavut (−1.30%/yr). Carbon stable isotope values in seal muscle decreased significantly through time in 4 regions. Selenium‐to‐THg ratios were found to be >1 for all years and regions. Variation partitioning analyses across regions indicated that THg trends in seals were mostly explained by age (7.3–21.7%), climate parameters (3.5–12.5%), and diet (up to 9%); climate indices (i.e., Arctic and North Atlantic Oscillations, Pacific/North American pattern) explained the majority of the climate portion. The THg levels had a positive relationship with Arctic Oscillation for multiple regions. Associations of THg with air temperature, total precipitation, and sea‐ice coverage, as well as with North Atlantic Oscillation and Pacific/North American pattern were found to vary with tissue type and geographical area. Environ Toxicol Chem 2020;39:2462–2474. © 2020 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Fisheries and Oceans Canada. [ABSTRACT FROM AUTHOR]

The spatiotemporal changes in the sea ice region albedo over the entire Arctic region and in eight subregions (the Central Arctic Ocean [CAO], the Beaufort and Chukchi Seas [BC], the East Siberian and Laptev Seas [ESL], Baffin Bay and Labrador Sea [BL], the Canadian Archipelago [CA], the Greenland Sea [GS], Hudson Bay [HB] and the Kara and Barents Seas [KB]) in the summer of 1982–2015 are analysed with CLARA‐A2‐SAL data. The results indicate that in the summer of 1982–2015, the Arctic Sea ice region albedo fluctuated with a downward trend of −1.6% per decade (significance level of 99%). The BC had the largest decline in the albedo trend of −2.7% per decade (significance level of 99%), and most other subregions had downward trends except the GS, which exhibited a slight upward trend. The mean Arctic Sea ice region albedo was 44%. The high albedo areas were mainly concentrated in the CAO and the vicinity of Greenland. The albedo decreased with decreasing latitude, while the low‐value areas were mainly concentrated in the outer sea ice area. In the Arctic region, both the sea ice concentration (SIC) and the sea ice extent (SIE) showed a decreasing trend, while the near‐surface air temperature (NSAT) and the summer Central Arctic Index (CAI) showed an increasing trend. The Arctic Sea ice region albedo was positively correlated with the SIC and the SIE (0.84, 0.78) and negatively correlated with the NSAT (−0.72), all with a statistical significance level of 99%. The correlation between sea ice region albedo and the summer CAI revealed different relationships in these regions. The BC and ESL had a significant negative correlation, and the GS showed a significant positive correlation. These findings indicated that the decrease in albedo is closely related to the reduction in Arctic Sea ice and the increase in air temperature. In addition, the sea ice region albedo variations in the BC, ESL and GS are also greatly influenced by atmospheric circulation. [ABSTRACT FROM AUTHOR]

The trends and interannual variations of summer sea ice extents ( SIEs) in both Hudson Bay and the Arctic Ocean are investigated in association with variations in atmospheric circulation and air temperature. The summer SIE variabilities of both Hudson Bay and the Arctic Ocean are well correlated and have a strong negative trend. The negative SIE trends are associated with a summer atmospheric circulation pattern that is characterized by positive anomalies over the Arctic Ocean and negative anomalies over mid-latitudes. The trends are also connected with warm air temperatures over mid- and high-latitudes. The atmospheric circulation and air temperature regressed on the summer SIEs in both Hudson Bay and the Arctic Ocean are quite similar to these trend patterns. On the other hand, the year-to-year variations of the detrended summer SIEs in both Hudson Bay and the Arctic Ocean are not correlated. The summer atmospheric circulation and air temperature over the Arctic Ocean have contributed to the detrended summer Arctic Ocean SIE. In contrast, the detrended summer Hudson Bay SIE is controlled by atmospheric circulation and air temperature in the previous spring. [ABSTRACT FROM AUTHOR]