“And how was the weather?” is a standard vacation question that we can easily answer. However, it becomes much more difficult when we have to go back further than our weather archives can show. In the mud of the Holzmaar, scientists from the Geoforschungszentrum Potsdam are on the trail of prehistoric weather
The maar soil provides them with a valuable archive for this, as it has been collecting everything that lives in the lake or is washed into it for thousands of years. As algae are highly dependent on water temperature and solar radiation, scientists can now tell from the amount of algae remains and their species whether they lived in warm or cool times. The time from which humans settled here is also reflected on the lake bed.
Reforestation, deforestation and agriculture have changed the materials and nutrients that are washed into the maar. The clock of the maar bottom are the so-called “warves”. They can be recognized by the typical deposits of the different seasons and together form an annual package. If you count the warves, you can determine relatively precisely from which period the mud particles originate. So far, the scientists at Holzmaar have looked back over 15,000 years in the “weather report from the mud”.
