Bok
06-14-2012, 07:27 PM
Ocean acidification during Permian period may have caused the Great Dying
More... (http://www.sciencenews.org/view/generic/id/341465/title/Calcium_offers_clues_in_mass_extinction)
More... (http://www.sciencenews.org/view/generic/id/341465/title/Calcium_offers_clues_in_mass_extinction)