Max, Lars, Riethdorf, Jan-Rainer, Tiedemann, Ralf, Nürnberg, Dirk and Abelmann, Andrea (2011) Late Pleistocene to Holocene sea surface temperature development in the NW-Pacific and its marginal seas. [Poster] In: AGU Fall Meeting 2011. , 05.12.-09.12.2011, San Francisco, California, USA .

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Abstract

ABSTRACT FINAL ID: PP41C-1785
The subarctic N-Pacific acts as terminus of the modern ocean circulation with water masses highly enriched in dissolved nutrients and carbon dioxide. Today a permanent halocline results in strong upper-ocean stratification, which hampers the atmospheric-oceanic gas exchange and the supply of nutrients into the photic zone. Past changes in sea surface conditions in the subarctic Pacific are proposed to impact climate but are less well known than in the N-Atlantic. The onset and timing of past oceanographic changes are suggested to be driven by changes in oceanic circulation and/or atmospheric teleconnections.
Here, we present a suite of sediment records from the continental slope off Kamchatka (NW-Pacific), the western Bering Sea and the Sea of Okhotsk. All cores were obtained well above the shallow carbonate compensation depth (CCD) and provide sufficient material for detailed late Pleistocene to Holocene reconstructions of past changes in oceanographic conditions. The stratigraphy is based on high-resolution X-ray fluorescence scans (XRF) together with spectrophotographic measurements (color b*), which were aligned to the NGRIP oxygen isotope record and further confirmed by AMS 14C ages. Alkenone measurements were applied to reconstruct sea surface temperatures (SST) by use of the Uk'37 index (Müller et al., 1998). Our SST reconstructions span the last ∼15 ka BP. Prior alkenone concentrations were below the detection limit and thus indicate the absence of coccolithophoride blooms during the last glacial. After ∼14.7 ka BP the SST records in the NW-Pacific and western Bering Sea indicate an early increase in SST (Bolling/Allerod), followed by a cold spell at ∼12.8 ka BP (Younger Dryas) and the onset of warm Holocene climate conditions around ∼10.7 ka BP. During the early Holocene the SST increased by up to 4°C. This pronounced warming is interpreted as amplified stratification of the upper water column, which is paralleled by laminae formation at the sea floor. The SST record, derived from the Sea of Okhotsk, shows a slightly different pattern and indicates a more gradual warming towards the Holocene. Finally, a drop in SST by ca. 2°C is observed towards the middle Holocene, which also challenges the proposed idea of a SST seesaw pattern between the N-Atlantic and N-Pacific (Kim et al., 2004).

References
Kim, J.-H., Rimbu, N., Lorenz, S.J., Lohmann, G., Nam, S.-I., Schouten, S., Rühlemann, C. & Schneider, R.R. (2004): North Pacific and North Atlantic sea-surface temperature variability during the Holocene. – Quaternary Science Reviews 23, 2141-2154.
Müller, P.J., G. Kirst, G. Ruhland, I. von Storch & A. Rosell-Melé, (1998): Calibration of the alkenone paleotemperature index (UK'37) based on core-tops from the eastern South Atlantic and the global ocean (60 degrees N - 60 degrees S) – Geochimica Et Cosmochimica Acta 62, 1757-1772.

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