Refining Forams as Past Ocean Thermometer (IMAGE) University of California - Davis Caption The shells of plankton called foraminifera are a record of past ocean chemistry and therefore past climate. New work led by UC Davis and OSU scientists shows that mysterious bands of magnesium in the shells of foraminifera are caused by daily day/night cycles, helping to better define this model for measuring past climate. Credit Jennifer Fehrenbacher, OSU Usage Restrictions May be used with acknowledgement. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.