2008/12/12 by Elizabeth M. Griffith, Adina Paytan, Ken Caldeira +2 · 2 citations
Earth and Planetary Sciences · Environmental Science · #Geology and Paleoclimatology Research #Isotope Analysis in Ecology #Paleontology and Stratigraphy of Fossils
paper · doi:10.1126/science.1163614
openalex publication_date 2008/12/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
Multiple lines of evidence have shown that the isotopic composition and concentration of calcium in seawater have changed over the past 28 million years. A high-resolution, continuous seawater calcium isotope ratio curve from marine (pelagic) barite reveals distinct features in the evolution of the seawater calcium isotopic ratio suggesting changes in seawater calcium concentrations. The most pronounced increase in the delta44/40Ca value of seawater (of 0.3 per mil) occurred over roughly 4 million years following a period of low values around 13 million years ago. The major change in marine calcium corresponds to a climatic transition and global change in the carbon cycle and suggests a reorganization of the global biogeochemical system.