Water mass processes on Arctic shelves as revealed from δ18O of H2O

The water masses of the Arctic Ocean shelf regions are significantly influenced by river water and sea-ice processes. Since river water is highly depleted in δ18O relative to marine waters as well as to sea-ice, the δ18O composition and salinity of a water sample can be used to separate the different water sources. In this paper the freshwater distribution on the Kara, Laptev and the Beaufort shelves are discussed based on δ18O and salinity data. Depending on the average depth the observed fields of salinity and δ18O values are different for each region. But comparing the overall δ18O and salinity correlations reveals a remarkable similarity for these three Arctic shelf regions. On all discussed Arctic shelves bottom water masses are formed by sea-ice processes. And remnants of these bottom water masses are found on all shelves during summer at a similar salinity of about 30.