How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic


Millennial-Scale Cycling of Climate in China's Salawusu River Valley
Reference
Lu, Y., Li, B., Wen, X., Qiu, S., Wang, F., Niu, D. and Li, Z. 2010. Millennial-centennial scales climate changes of Holocene indicated by magnetic susceptibility of high-resolution section in Salawusu River Valley, China. Chinese Geographical Science 20: 243-251.

Background
"Since the 1990s," in the words of the authors, "high-resolution paleoclimate records from the Greenland ice core (O'Brien et al., 1995) and terrestrial sediments in Afro-Asian arid areas (Guo et al., 1999) and marine sediments in the South China Sea (Wang et al., 1999) have proved one after another that climate changes on millennial-centennial scales occurred from the Late Quaternary-Holocene, and the instability of climate is similar to the Dansgaard/Oeschger oscillation."

What was done
In a study designed to further explore this millennial-centennial cycling of earth's climate, Lu et al. analyzed magnetic susceptibility measurements made on the uppermost (Holocene) segment of a stratigraphic section in the Salawusu River Valley (37°20'-37°58'N, 108°08'-108°48'E) in the southeastern margin of Mu Us Desert on the Ordos Plateau of Inner Mongolia, China.

What was learned
As a result of their work, the seven scientists delineated eleven magnetic susceptibility cycles with values alternating from low to high, in which layers of dune sands correspond to low values of magnetic susceptibility and layers of fluvio-lacustrine facies and paleosols correspond to high values. And because of this correspondence, they remark that the low and high values indicate that the climate of the region was alternately dominated by the cold-arid winter monsoon and the warm-humid summer monsoon of East Asia, respectively. In addition, they state that the cold valleys and the warm peaks of the magnetic susceptibility in the stratigraphic sequence "couple with cold peaks and warm valleys in the North Atlantic," citing the study of Bond et al. (1997), as well as with "cold-warm changes in some places of China," citing the works of Yao and Shi (1992), Liu et al. (2000), Zhou et al. (2001), Jin et al. (2002) and Jin et al. (2004).

What it means
In considering the totality of their findings, as well as the findings of many others, the Chinese researchers conclude that "climate change at millennial-centennial scales in the Salawusu River Valley and the Mu Us Desert in the Holocene was influenced by global and regional climate, and it was an integral part of global millennial-centennial scale climate fluctuations."

References
Bond, G., Showers, W., Cheseby, M., Lotti, R., Almasi, P., de Menocal, P., Priore, P., Cullen, H., Hajdas, I. and Bonani, G. 1997. A pervasive millennial-scale cycle in North Atlantic Holocene and glacial climates. Science 278: 1257-1266.

Guo, Z., Petit, N. and Liu, D. 1999. Holocene abrupt environmental changes in the arid regions in Africa and Asia. Journal of Paleogeography 1: 68-74.

Jin, H., Su, Z., Sun, L., Sun, Z., Zhang, H. and Jin, L. 2004. Climate change of Holocene in Hunshandake desert. Chinese Science Bulletin 49: 1532-1536.

Jin, Z., Shen, J., Wang, S. and Zhang, E. 2002. The medieval warm period in the Daihai area. Journal of Lake Sciences 14: 209-216.

Liu, J., Lu, H., Negendank, J. et al. 2000. Periodicity of Holocene climatic variations in the Huguangyan Maer Lake. Chinese Science Bulletin 45: 1190-1195.

O'Brien, S.R., Mayewski, P.A., Meeker, L.D., Meese, D.A., Twickler, M.S. and Whitlow, S.E. 1995. Complexity of Holocene climate as reconstructed from a Greenland ice core. Science 270: 1962-1964.

Wang, L., Sarnthein, M., Erlenkeuser, H., Grimalt, J., Grootes, P., Heilig, S., Ivanova, E., Kienast, M., Pelejero, C. and Pflaumann, U. 1999. East Asian monsoon climate during the Late Pleistocene: High-resolution sediment records from the South China Sea. Marine Geology 156: 245-284.

Yao, T. and Shi, Y. 1992. Climatic changes of Holocene reflected in the ice core from Dunde, Qilian Mountains. In: Shi, Y. et al. (Eds). The Climates and Environments of Holocene Megathermal in China. China Ocean Press, Beijing, China, pp. 206-211.

Zhou, W., Lu, X. Wu, Z., Deng, L., Jull, A.J.T., Donahue, D. and Beck, W. 2001. Peat record reflecting Holocene climatic change in the Zoige Plateau and AMS radiocarbon dating. Chinese Science Bulletin 46: 1040-1044.

Reviewed 23 February 2011