How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

Lago Sarmiento, Torres del Paine Drainage Basin, Southern Chile
Solari, M.A., Herve, F., Le Roux, J.P., Airo, A. and Sial, A.N. 2010. Paleoclimatic significance of lacustrine microbialites: A stable isotope case study of two lakes at Torres del Paine, southern Chile. Palaeogeography, Palaeoclimatology, Palaeoecology 297: 70-82.

Working along the shore of Lago Sarmiento (51°03'00"S, 72°45'01"W) in southern Chile, where massive dead carbonate microbialites are exposed, Solari et al. obtained a δ18O record stretching back in time about 1200 years, to which they applied a "well-established, temperature-dependent oxygen isotope equilibrium fractionation equation between calcite and water" that yielded values of surface water temperature at a number of different dates, the two oldest of which (AD 800 and 1100) bracketed the MWP at that location. The warmest of these values was 9.5°C, which is 1.26°C greater than the mean surface water temperature of 8.24°C that they calculated from actual temperature measurements made every 20 minutes from April 1, 2003 to March 15, 2004. However, a δ18O-based surface water temperature of 8.9°C is indicated fairly close to the present. Thus, to be conservative, we calculate the peak temperature of the MWP to have been only 0.6°C greater than the peak temperature of the CWP.