A team of researchers from IIT Kharagpur and Deccan College PGRI Pune has developed a new technique that can precisely retrieve data about past seasonal change in sea surface temperature from calcium carbonate continuously secreted by biological organisms like fish. These carbonates are concentrated in fish ear bones, known as otoliths.

The study, which has just been published in Rapid Communications in Mass Spectrometry, was funded by the Infosys foundation, IIT-Kharagpur said in a statement Sunday. The method can be used in any kind of biological organisms and has vast potential in climate studies, it said.

Instrumental climate record is not available at every place. If anyone wants to know, for example, how the temperature changed over week to monthly scale during the last several years in deep tiger infested creeks of Sundarban delta, one can go catch a live fish that recorded the past climate in otoliths, the statement said. The key problem in modelling past climate is lack of seasonality data, principally because geological or archaeological records do not provide that kind of resolution.