| dc.description.abstract | Mercury (Hg) has been a trace metal of interest for decades due to its neurotoxic effects on humans and other organisms coupled with its ability to bioaccumulate and biomagnify. Areas like the Arctic and the ocean floor are lacking good data on Hg distribution. As the ongoing warming of the Arctic region is expected to bring unforeseeable changes to the region, it is more important than ever to establish a current baseline for the distribution of Hg in the Arctic Ocean sediments and gain more insight into its biogeochemical cycling.
In this thesis, surface sediment samples from around the eastern Arctic Ocean, the Barents Sea, Nansen Basin, Gakkel Ridge and Amundsen Basin, were analysed with direct mercury analyzer DMA-80 evo, additional 19 supporting elements were measured with ICP-MS. In addition, three sediment cores were sampled.
THg increased generally with depth, with the highest levels measured in the Nansen Basin. The average THg concentration for the whole area was calculated as 72 ± 21 ng/g (n = 58), for Barents Shelf 68 ± 19 ng/g (n = 36), for the continental slope 73 ± 13 ng/g (n = 14), and for the Eurasian Basin 89 ± 24 ng/g (n = 8). A significant difference was found between Eastern (51 ± 14 ng/g) and Western Barents Sea (79 ± 14 ng/g), which was largely attributed to mineralogy. Measured levels of THg largely agreed with previous studies from the area.
The thesis concluded that the Barents Sea and Eurasian Basin have little to no anthropogenic input. A significant correlation was found between THg and the depth, percentage of organic carbon, and Mn. Correlation with OC was only significant for the shelf area. The main factors influencing the distribution of THg in the study area are grain size, diagenesis, OC, mineralogy, and bathymetry. | |