HR: 0800h
AN: PP51A-0194    [Abstracts]
TI: Spatiotemporal environmental changes in the Barents Sea during the Holocene
AU: * Ivanova, E V
EM: e_v_ivanova@ocean.ru
AF: Shirshov Institute of Oceanology RAS, 36 Nakhimovsky prosp., Moscow, 117997, Russian Federation
AU: Chistyakova, N O
EM: natal_y@mail.ru
AF: Shirshov Institute of Oceanology RAS, 36 Nakhimovsky prosp., Moscow, 117997, Russian Federation
AU: Risebrobakken, B
EM: bjorg.risebrobakken@bjerknes.uib.no
AF: Bjerknes Centre for Climate Research, 55 Allegaten, Bergen, 5007, Norway
AB: We analyzed time series of major benthic foraminiferal species, stable isotope and paleotemperature estimates for the reference sediment cores from different oceanographic settings along the SW-NE transect in order to highlight the links of paleoenvironmental changes in the Barents Sea to global variability of climate and meridional overturning circulation. The time resolution based on the oxygen isotope and AMS 14C data is ~100- 400 years. The results are compared with the other time series available in the region. Our foraminiferal records demonstrate a strong dominance of the typical arctic benthic species and subpolar planktic species in the Holocene assemblages, except for the south-western part of the Barents Sea where so-called atlantic benthic species and boreal planktic species are common since ~ 11.2 cal ka. Therefore, foraminiferal assemblages point to a relatively persistant Atlantic water input into the Barents Sea along the Norwegian coast during the last ~ 11.2 ka. However, our faunal mean annual SST estimates for the south-western Barents Sea demonstrate rather pronounced changes from ~ 6° C at the YD/Holocene transition to 13° C in the Early Holocene, i.e. the amplitude of SST changes is much higher than in the northern part of the sea where it did not exceed 2°C. These findings are consistent with spatiotemporal variations of benthic and planktic oxygen isotope ratios, and with an increase in percentage of benthic species indicative to a longer ice free season in the Northern Barents Sea during the strong Atlantic water influx along the continental slope at 7.8 to 6.9 cal ka BP. A pronounced increase in ‘atlantic' and boreal foraminifer abundance in the south-western part of the sea is established at the end of the Early Holocene. Later on, an opportunistic ‘arctic' species dominates the assemblages in several Northern Barents Sea cores thus pointing to a gradual paleoenvironmental deterioration through the Middle to Late Holocene. In total, a set of all available data points to a spatial and temporal heterogeneity of the termal optimum, and Atlantic water input via the southern (surface layer) and northern (subsurface layer) branches into the Barents Sea.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 4940 Isotopic stage
DE: 4944 Micropaleontology (0459, 3030)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting