Glacial sea surface temperature of the East Sea (Japan Sea) inferred from planktonic foraminiferal assemblage

In order to reconstruct the last glacial sea surface temperature (SST) of the East Sea, we investigated planktonic foraminiferal assemblage in the marine sediments of a piston core recovered from the Ulleung Basin, East Sea. For core top, the most dominant species is right coiling Neogloboquadrina incompta, while left coiling Neogloboquadrina pachyderma and Globigerina bulloides clearly dominate the glacial assemblages. Based on fauna count, we reconstructed past SST using modern analog technique (MAT) with a global dataset. However, the application of the global dataset may hinder the reconstruction of regional SST. In order to validate this, we tested for the foraminiferal assemblages of 51 surface sediments in the East Sea with MAT and the global dataset. The results show that the estimated MAT temperatures were completely different from the real SST of core top sites, indicating that MAT with the global dataset may not be applicable for the East Sea SST reconstruction. Therefore, we developed new statistical calculation method using East Sea fauna dataset only. According to this method, the glacial SST was 2 °C lower than today for August, and 6 °C lower for February. This glacial-interglacial change of August temperature is relatively smaller than other results, while February temperature is comparable.