Scientists Say Earthworm Poo Could Provide Window Into Past Climates

Posted on July 10, 2013

UK researchers say earthworm poo could provide a window into past climates. A laboratory study by researchers from the Universities of Reading and York has demonstrated that balls of calcium carbonate excreted by the earthworm Lumbricus terrestris maintain a memory of the temperature at which they were formed. The scientists say in a release that the calcite granules have the potential to reveal important information about past climates which could be used to enhance and benchmark climate change models.

Lead author Dr Emma Versteegh from the Department of Geography and Environmental Science at the University of Reading, said in a statement, "These chalk balls will allow us to reconstruct temperatures for specific time intervals in which they were formed. Reconstructions like this are interesting for archaeologists, because they give a climatic context to their finds. More importantly, climate proxies are the only means we have to study climate beyond the instrumental record, which only goes back about 150 years. This knowledge about past climates is of vital importance for developing and benchmarking climate models that make predictions for the future. Many different proxies already exist, but no proxy is perfect, or is available in every location, so it is good to have many different ones."

Dr. Stuart Black, from the University of Reading's Department of Archaeology, added. "We believe this new method of delving into past climates has distinct advantages over other biological proxies. For example, we believe it will work for the full seasonal range of temperatures, whereas methods such as tree rings, do not 'record' during winter. In addition, because the chalk balls are found in direct context with archaeological finds, they will reveal temperatures at the same location. At present, links are often attempted with climate proxies many hundreds or even thousands of miles away."

The research was published the journal Geochimica et Cosmochimica Acta.