How does rising atmospheric CO2 affect marine organisms?

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Late Holocene Climate Fluctuations in the Eastern Mediterranean
Schilman, B., Ayalon, A., Bar-Matthews, M., Kagan, E.J. and Almogi-Labin, A. 2002. Sea-land paleoclimate correlation in the Eastern Mediterranean region during the late Holocene. Israel Journal of Earth Sciences 51: 181-190.

What was done
The authors analyzed high-resolution δ18O values from a speleothem in Soreq Cave, central Israel (3145'N, 3503'E), as well as from planktonic foraminifera in two marine sediment cores retrieved just off the Ashdod coast (3156.41'N, 3422.13'E and 3156.61'N, 3419.79'E), to obtain a record of climate in this region over the past 3600 years.

What was learned
The δ18O values of the speleothem and marine cores showed "striking similarity" over the period of study, according to Schilman et al., and they were determined to be primarily representative of historic changes in precipitation. Over the course of the 3600-year record, six major precipitation intervals were noted, including three that were relatively wet and three that were relatively dry. The peaks of the humid events occurred at 3200, 1300 and 700 yr BP, the latter of which was said by the researchers to be "associated with the global MWP humid event," which association is supported by additional evidence from the surrounding region in the form of (1) high Nile floods (Bell and Menzel, 1972; Hassan, 1981), (2) high Saharan lake levels (Nicholson, 1980), and (3) high water levels in the Dead Sea and Sea of Galilee (Frumkin et al., 1991). The peaks of the dry events occurred at 2100, 900 and 300 yr BP, the last of which, in the words Schilman et al., "coincides with the Little Ice Age."

What it means
Once again, evidence continues to mount for the natural and global climate oscillation that was responsible for bringing the world the Little Ice Age, Medieval Warm Period, Dark Ages Cold Period, Roman Warm Period and the set of cold and warm periods before that. Hence, it is only natural to believe that this phenomenon produced the majority of the temperature increase associated with the development of the Current Warm Period.

Bell, B. and Menzel, D.H. 1972. Toward the observation and interpretation of solar phenomena. AFCRL F19628-69-C-077 and AFCRL-TR-74-0357, Air Force Cambridge Research Laboratories, Bedford, MA, USA, pp. 8-12.

Frumkin, A., Margaritz, M., Carmi, I. and Zak, I. 1991. The Holocene climatic record of the salt caves of Mount Sedom, Israel. The Holocene 1: 191-200.

Hassan, F.A. 1981. Historical Nile floods and their implications for climatic change. Science 212: 1142-1145.

Nicholson, S.E. 1980. Saharan climates in historic times. In: Williams, M.A.J., and Faure, H., eds. The Sahara and the Nile. Balkema, Rotterdam, pp. 173-200.

Reviewed 12 April 2006