Ice Age temperatures and precipitation reconstructed from earthworm granules


Earthworm Calcite Granules (ECGs) might be present in loess sequences. Credit score: Charlotte Prud’homme

Scientists from a global analysis venture led by Johannes Gutenberg College Mainz (JGU) have utilized a brand new methodology to reconstruct previous local weather. As they report within the present difficulty of Communications Earth & Setting, they’ve decided temperatures and precipitation over the last Ice Age, which peaked about 25,000 years in the past, by analyzing earthworm granules.

“The new method was discovered at Université Paris 1 Panthéon-Sorbonne and further developed at the Max Planck Institute for Chemistry,” mentioned Dr. Peter Fischer of JGU’s Institute of Geography, who was the lead investigator of the TerraClime venture during which the research is embedded.

“In cooperation with other scientists, including researchers from the University of Lausanne and Römisch-Germanisches Zentralmuseum, we used the method to reconstruct the climate at Schwalbenberg near Remagen and Nußloch near Heidelberg.”

The 2 websites kind well-developed last-glacial mud deposits. The so-called loess incorporates sequences courting from 45,000 to 22,000 years in the past, during which the earthworm granules (as much as about solely 2.5 millimeters in measurement) might be discovered. These calcitic granules, technically generally known as Earthworm Calcite Granules (ECGs), are secreted each day by earthworms.

Utilizing the so-called radiocarbon methodology, which is predicated on the decay of the naturally occurring radioactive carbon isotope (14C), researchers can exactly decide their age. Moreover, by analyzing the ratios of steady oxygen and carbon isotopes within the ECGs, it’s then attainable to reconstruct how heat or how humid it was on the time of their formation.

Summer time temperatures had been greater than beforehand thought and humidity was considerably decreased

“Analysis of the data obtained from the ECGs shows that from 45,000 to 22,000 years before present it was much drier in Central Europe than it is today, with up to 70 percent less humidity,” mentioned Dr. Charlotte Prud’homme from the College of Lausanne, the research’s lead writer. “This allows us for the first time to quantify previous findings about this period.” The novelty in these investigations on ECGs is that summer time temperatures on the time had been considerably greater than beforehand thought.

“Although summers during the cold maximum of the last glacial were about four to eleven degrees Celsius colder than today, they were only one to four degrees below the values of short milder climatic phases that occurred during the last glacial,” defined Fischer.

“Given these summer temperatures, we cannot exclude that Ice Age human populations may have made a seasonal living in Central Europe during the cold maximum, at a time for which it is generally assumed that humans could not survive here,” added Dr. Olaf Jöris of Römisch-Germanisches-Zentralmuseum, who was additionally concerned within the research.

“Until now, reconstructions of Ice Age climate have been mainly based on the analyses of microorganisms in deep-sea deposits,” acknowledged Fischer.

For the continents, corresponding complete information have been missing thus far, which might be modified with the brand new methodology: “Since ECGs can be found in many loess sequences, temperatures and precipitation of the past can now be determined on land over a large area. One main aim is to build a database that can be used to precisely quantify past climate changes on land and to identify force feedback mechanisms. Incorporating land-based climate data will increase the database and contribute to improve existing climate modeling and thus provide valuable insights for future climate change.”

Extra data:
Charlotte Prud’homme et al, Millennial-timescale quantitative estimates of local weather dynamics in central Europe from earthworm calcite granules in loess deposits, Communications Earth & Setting (2022). DOI: 10.1038/s43247-022-00595-3

Ice Age temperatures and precipitation reconstructed from earthworm granules (2022, November 21)
retrieved 21 November 2022

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