The oceans hide a well-kept secret: natural mechanisms that trap organic carbon in their depths. A recent study lifts the veil on these processes, offering keys to better fight global warming.
Marine sediments play an essential role in climate regulation by storing immense quantities of carbone organic. However, the mechanisms allowing this preservation remained poorly understood until now. An international team of researchers, led by the Universities of Manchester and Leeds, have identified two key processes: sorption and molecular transformation. These findings, published in Nature Geosciencecould well shake up our approach to carbon sequestration.
Sorption, an invisible shield
Sorption consists ofadsorption of carbon molecules on the mineral surfaces of sediments. This phenomenon creates a chemical barrier that protects organic carbon from degradation by microbes and enzymes. Without this mechanism, a large part of the carbon would return to theatmosphere in the form of CO₂.
This process is particularly effective in the surface layers of sediments. It helps stabilize the carbon before it is buried deeper, where it is even better protected. Thus, sorption acts as a first filter essential for long-term preservation.
Molecular transformation, a natural alchemy
Molecular transformation changes the chemical structure of carbon molecules. Small, reactive compounds transform into larger, stable molecules, called geopolymers. The latter are more resistant to degradation, which prolongs their storage in sediments.
This process completes sorption by reinforcing the stability of the organic carbon. Together, they form an effective protection system, preventing carbon from quickly returning to the atmospheric cycle.
-A digital model to better understand
To explore these mechanisms, the researchers developed an innovative numerical model. This integrates processes such as burial, hydrolysis of dissolved organic carbon, sorption and molecular transformation. Thanks to Monte Carlo simulations andartificial intelligencethe model was refined to match the observations real.
The results show that up to 43.8% of organic carbon could be preserved, a figure much higher than previous estimates. This advance allows us to better understand the complex interactions between the different sequestration processes.
Implications for the climate
These discoveries open up promising perspectives for the fight against climate change. By reproducing or amplifying these natural processes, it would be possible to improve carbon sequestration in oceans. For example, the fertilisation of the oceans could be optimized to stimulate the growth of phytoplankton and increase carbon storage.
Additionally, this work could guide the development of more effective environmental policies. By aligning human strategies with the natural capacities of marine ecosystems, we could limit CO₂ emissions while preserving natural balances.
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