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Fossil algae reveals 500 million years of climate change

For its research, Witkowski collected seawater with fresh, modern algae to test the potential indicators of the past. Credit: Caitlyn Witkowski

Earth scientists are able to travel a lot ago in time to rebuild the geological and paleoclimate past in order to make better predictions about future climate conditions. Using the organic molecule mineral, chlorophyll debris, scientists at the Dutch Research Institute for the Sea (NIOZ) and Utrecht University succeeded in developing a new proxy of old CO2 levels. This new organic deputy not only provides the most sustained record of CO2 Concentrations ever, it also covers half-billion recordable years. The data confirm the idea that arises in CO2 the levels used to take millions of years now take place in a century. These findings are published in Science Feedback on November 28th.

Like CO2 is increasing today, it is essential to understand what impact these changes will have. In order to better predict the future, we have to understand long-term changes in CO2 over geological history. Direct measurements of past CO2 available, for example, bubbles in ice pools that contain ancient gases. However, there are limited periods of 1 million years of ice. To go further back in time, Earth scientists have developed various indirect CO measures2 by deputies e.g. o algae, leaves, ancient soils and chemicals stored in ancient sediments to recreate the environmental conditions of the past.

Phytane, a new way of traveling in time

A new deputy, using chlorophyll deterioration products, allows geochemists to collect a record of historical CO2 levels in deep time. Scientists at NIOZ have recently developed phytane as a new promising organic proxy that reveals half a billion years of CO2 levels in the oceans, from the Cambrian until recently.

Using the new deputy, they were able to make the most up-to-date record of everlasting carbon dioxide levels. "NICE-scientist Caitlyn Witkowski said:" We have developed and validated a new way of travel to travel further in time and for more places. " "With this, we have the longest CO now2-ord with one single marine proxy. This new data is invaluable for employees who can now make predictions of the future more accurately. "

Witkowski and colleagues selected more than 300 samples of marine sediments of deep sea light and oil from around the world, reflecting most geological periods in the last 500 million years.

Fossil Molecules

Can be stored & # 39; Past chemical reactions in fossil molecules, and therefore can reflect different ancient environmental conditions. Geochemists can collect these conditions, such as seawater temperature, pH, salinity and CO2 levels. Organic matter, such as phytaneum, reflects CO pressures2 in seawater or atmospheric (pCO2).

Although all organic issues have the potential to reflect CO2, ffytane is special. Phytane is the pigment that is responsible for our green world. There is anything that uses photosynthesis to absorb sunlight, including plants, algae and some bacteria containing chlorophyll, of which phytane is part of it. Plants and algae take CO2 and oxygen production.

Because chlorophyll is seen all over the world, there is also phytane, and has most rotten and fossil biomass. "Phytane does not change chemically over a period of time, even if it is millions of years," said Witkowski.

Isotope carbon fractionation

CO2 From the past is an estimate of organic matter, such as ffytane, through the phenomenon of the carbon isotope fraction during photosynthesis. When taking CO2, plants and algae prefer the light carbon isotope (12C) over the heavy carbon isotope (13C). They use the heavy carbon isotope only when CO2 levels in the water or surrounding atmosphere are low. The proportion between these two isotopes currently reflects the level of carbon dioxide in the environment at present.

This also explains why Witkowski did not use terrestrial plants as a source for its research, only using fossilized marine fossil sources. The plant world is split into C3- and C4-like plants, each with their own unique ratio of lightweight carbon to heavy. Phytoplankton has very similar ratios compared to their plant counterparts. Witkowski: "By choosing only marine sources, we could limit the uncertainty of the phytane source in the dataset."

"In our data, we see high levels of carbon dioxide, reaching 1000 ppm instead of 410 ppm today. In this regard, current levels are not unique, but the speed of these changes has never been seen from & # 39 In the face, millions of years now happen in a century. This additional CO2-data helps us to understand the future of our planet. "In the future, phytane can be used to return back in time more than Panoerozoic, the earliest found in two billion year samples.

Further investigation:
Study developments understand the stories about the ancient climate that small shells tell them

More information:
"Molecular fossils of phytoplankton reveal a secular PCO2 trend over the Panoerozoic" Science Feedback (2018).

Magazine reference:
Science Feedback

Provided by:
The Royal Institute of Holland for Marine Research

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