| Summary: | Paleoceanographical studies of Marine Isotope Stage (MIS) 11 have revealed higher-than-presentsea surface temperatures (SSTs) in the North Atlantic and in parts of the Arctic but lower-than-present SSTsin the Nordic Seas, the main throughflow area of warm water into the Arctic Ocean. We resolve thiscontradiction by complementing SST data based on planktic foraminiferal abundances with surface salinitychanges using hydrogen isotopic compositions of alkenones in a core from the central Nordic Seas. Thedata indicate the prevalence of a relatively cold, low-salinity, surface water layer in the Nordic Seasduring most of MIS 11. In spite of the low-density surface layer, which was kept buoyant by continuousmelting of surrounding glaciers, warmer Atlantic water was still propagating northward at the subsurfacethus maintaining meridional overturning circulation. This study can help to better constrain the impact ofcontinuous melting of Greenland and Arctic ice on high-latitude ocean circulation and climate.
|
|---|