Sources and Fates of sedimentary polycyclic aromatic hydrocarbons along the East Siberian Arctic Shelf: Implications for input pathways and black carbon constraint
Description
The East Siberian Arctic Shelf (ESAS) is undergoing faster climate changes such as the decreasing sea ice, thawing permafrost and wildfires, which elevated the polycyclic aromatic hydrocarbons (PAHs) levels in the Arctic Ocean, and this region is expected to become a potential PAHs sink in sediments. Here we investigated the spatial heterogeneity of deposition and fate of PAHs together with black carbon (BC) within the ESAS. Our results explored the mixed petrogenic and pyrogenic sources of PAH. Furthermore, we found that disparate input pathways led to distinct PAH fates in coastal and open-sea regions of the ESAS, and BC likely exerts significant constraints on the behavior and fates of PAH. These carbonaceous compounds in the western ESAS is mainly affected by terrestrial inputs such as fluvial discharge and permafrost erosion, while the open-sea regions of the eastern shelf are largely driven by atmospheric delivery and biological deposition. The strong signals of emissions from permafrost along the coastal margins highlight the importance of seriously considering permafrost erosion might become a potential PAH contributor, especially with climate changes.