David Anderson and David Archer (Univ. Chicago) have reconstructed carbonate-ion concentration—and hence pH—of the glacial oceans, using the extent of calcium carbonate dissolution observed in foraminifer faunal assemblages. They find no evidence for a shift in the whole-ocean pH as previously inferred from boron isotopes. Instead they find a rearrangement of ocean pH, probably due to changing ocean circulation from glacial to present times. The Anderson and Archer results are significant in revealing the ocean's role in the large natural cycles in atmospheric carbon dioxide that occurred during the Quaternary ice ages. Their research is published in the 7 March issue of Nature.