Skip to main content
U.S. flag

An official website of the United States government

A dynamic marine calcium cycle during the past 28 million years

January 1, 2008

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 ??44/40Ca 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.

Publication Year 2008
Title A dynamic marine calcium cycle during the past 28 million years
DOI 10.1126/science.1163614
Authors E.M. Griffith, A. Paytan, K. Caldeira, T.D. Bullen, E. Thomas
Publication Type Article
Publication Subtype Journal Article
Series Title Science
Index ID 70032848
Record Source USGS Publications Warehouse