Reading ancient climate from plankton shells

Climate changes from millions of years ago are recorded at daily rate in ancient sea shells, new research shows. For slow-growing plankton it opens the way to seeing seasonal variations in ocean temperatures - Simon Redfern A huge X-ray microscope has revealed growth bands in plankton shells that show how shell chemistry records the sea temperature. The results could allow scientists to chart short timescale changes in ocean temperatures hundreds of millions of years ago. Plankton shells show features like tree rings, recording historical climate. It's important to understand current climate change in the light of how climate has varied in the geological past. One way to do this, for the last few thousand years, is to analyse ice from the poles. The planet's temperature and atmosphere are recorded by bubbles of ancient air trapped in polar ice cores.