Organisms regulate their cell walls according to environmental conditions such as temperature. Some adaptations include changes in lipids that may persist for a long time after other organisms degrade. Researchers at the University of Göttingen have studied a specific group of lipids called long chains of diols, which are found in marine sediments around the world and which can be stored for millions of years. The researchers found that these lipids are produced by a hitherto unknown group of marine eustigmatophyte algae that evolved before the now known species appeared.
This discovery changes our understanding of the composition and evolution of these algae, as it was previously thought that they consisted of a relatively small group, mostly soil and freshwater species. In addition, researchers show that the ratios of these characteristic lipids, known as the long chain diol index, can be used to reconstruct summer sea surface temperatures from the past. The study was published in Proceedings of the National Academy of Sciences (PNAS).
For this study, combining the experience of the Center for Geobiology (Geobiology) of the University of Göttingen and experimental physiology and algae culture collections, researchers each month from April to October 2019 took samples of seawater from the Mediterranean and analyzed them for lipids and DNA. . DNA data showed the emergence of an early evolutionary group of marine eustigmatophyte algae that had not previously been identified. Similarities in eustigmatophyte DNA models and specific lipid concentrations combined with in-depth analysis of previously published DNA and lipid datasets indicate that these marine algae are major producers of long-chain diols. “These lipids have been found in sediments around the world from millions of years to the present. But so far no one has compared the unique lipid signature to these specific algae,” said first author Dr. Sebastian Rampen, who conducted the study. at the University of Göttingen.
“A wide range of methods can be used to draw conclusions about the ancient climate in Earth’s history,” explains Rampen. “What is interesting about our discovery is that we have demonstrated that the ratio of these unique lipids shows the temperature in the warmest months. This explains why the readings obtained by this method sometimes differ from other temperature reconstructions that give average temperatures over Combining different methods now provides additional information to help us better understand the Earth’s climate for millions of years. “
This project was made possible by funding from the German Research Foundation (DFG)
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