| Summary: | Paleo-sea-ice history in the Arctic Ocean was reconstructed using the sea-ice dwelling ostracode Acetabulastoma arcticum from late Quaternary sediments from the Mendeleyev, Lomonosov, and Gakkel Ridges, the Morris Jesup Rise and the Yermak Plateau. Results suggest intermittently high levels of perennial sea ice in the central Arctic Ocean during Marine Isotope Stage (MIS) 3 (25-45 ka), minimal sea ice during the last deglacial (16-11 ka) and early Holocene thermal maximum (11-5 ka) and increasing sea ice during the mid-to-late Holocene (5-0 ka). Sediment core records from the Iceland and Rockall Plateaus show that perennial sea ice existed in these regions only during glacial intervals MIS 2, 4, and 6. These results show that sea ice exhibits complex temporal and spatial variability during different climatic regimes and that the development of modern perennial sea ice may be a relatively recent phenomenon. The new 2010 database is a significant expansion and improvement over the 1995 database in several respects. It includes data from 680 samples (compared to 403 samples in 1995) from a total of 54 sources (oceanographic cruises, sampling programs, publications) described in OstArcSamples. The database has updated taxonomy given in OstArcSpecies. In addition to the census data, the OstArcCensus file also contains water temperatures for each site obtained from World Ocean Atlas 2001 (Stephens et al. 2002), and, for many samples, a second temperature value taken at the time of the cruise or obtained from early oceanographic sources. The sources for these temperatures are given in OstArcTemp. A few typographical errors from the 1995 database have been corrected and updated longitude and latitudes are provided for older samples collected in the 1930s through 1960s using new archives and the International Bathymetric Chart of the Arctic Ocean to better locate samples (IBCAO, Jakobsson et al. 2008). In addition to the surface sample ostracode data, this database provides late Quaternary sediment core records of the sea-ice dwelling species Acetabulastoma arcticum (OstArcSeaIce). The late Quaternary record of A. arcticum represents an application of the surface sample database to reconstruct paleo-sea-ice history of the central Arctic Ocean and adjacent seas during glacial, deglacial, interglacial (Holocene), and interstadial (Marine Isotope Stage 3) (Cronin et al. 2010).
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