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Earth scientists can go back far in time to reconstruct the geological past and paleoclimate and better predict future climate conditions. Scientists from the Netherlands Institute of Maritime Research (NIOZ) and the University of Utrecht have successfully developed a new indicator (proxy) of the old CO.2– Levels, using the phytane organic molecule, a product of chlorophyll debris. This new organic proxy provides not only the most continuous recording of CO2-concentrations ever, it also beats a record in its span of time, spanning half a billion years. The data shows the present idea that goes up in CO2Levels that took millions of years now occur in a century. These results are published in Progress of science November 28th.
As a CO2 is increasing today, it is essential to understand the impact of these changes. To better predict the future, we need to understand the long-term changes in CO2 on geological history. Direct measurements of past CO2 are available, for example bubbles in ice cores containing old gases. However, ice cores have a limited life of one million years. To go back in time, scientists from the Earth have developed various indirect measures of CO2 from proxies, such as algae, leaves, ancient soils and chemicals stored in old sediments to restore past environmental conditions.
Phytane, a new way of traveling in time
A new proxy, using a chlorophyll degradation product, allows geochemists to derive a continuous record of CO2-the level in the deep time. NIOZ scientists have recently developed phytane as a promising new organic substitute that can discover half a billion years of CO2levels in the oceans, from the Cambrian to the recent period.
With the help of the new attorney, they were able to create the most continuous record ever recorded of old levels of carbon dioxide. "We have developed and validated a new way of traveling back in time: to go further in time and to more places," says Caitlyn Witkowski, a scientist at NIOZ. "With phytane, we now have the longest CO2-register with only one marine proxy. This new data is valuable for modelers who can now make more accurate predictions for the future. "
Witkowski and his colleagues have selected more than 300 samples of marine sediments from deep water cores and hydrocarbons from around the world, reflecting the majority of geological periods of the last 500 million years.
Fossil molecules
Past chemical reactions can be "stored" in fossil molecules and can therefore reflect various old environmental conditions. Geochemists are able to "read" these conditions, such as seawater temperature, pH, salinity, and CO2-Levels. Organic materials, such as phytane, reflect the pressure of CO2 in seawater or in the atmosphere (pCO2).
Little green miracles
Although all organic matter can reflect CO2, phytane is special. Phytane is the pigment responsible for our green world. Anything that uses photosynthesis to absorb sunlight, including plants, algae and some species of bacteria, contains chlorophyll from which phytane comes. Plants and algae absorb CO2 and produce oxygen. Without these little green miracles, our world would simply not be the same.
As chlorophyll is present throughout the world, phytane is also present everywhere and is a major constituent of decomposed and fossilized biomass. "Phytane does not change chemically over time, even if it's millions of years old," Witkowski says.
Isotopic carbon fractionation
CO2 from the past is estimated from organic matter, such as phytane, by the phenomenon of carbon isotopic fractionation during photosynthesis. When taking CO2Plants and algae prefer the isotope of light carbon (12C) to the isotope of heavy carbon (13C). They only use the heavy carbon isotope when the CO2-The surrounding water or atmosphere levels are low. The proportion between these two isotopes thus reflects the level of carbon dioxide in the environment at the time of growth.
This also explains why Witkowski did not use terrestrial plants as a source of research, using only phytane from marine sources (fossilized). The plant world is divided into so-called C3 and C4 plants, each with its own unique light / heavy carbon ratio. Phytoplankton all have 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 find high levels of carbon dioxide, reaching 1000 ppm over the current 410 ppm.In this regard, current levels are not unique, but the speed of these changes has never been seen before, changes that usually take millions of years have now passed in a century.2Data can help us understand the future of our planet. "In future research, phytane can be used to go even further back in time than the Phanerozoic, the oldest found in samples dating back two billion years.
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