A recent study led by Anne Willem Omta highlights the pivotal role of biological processes in regulating carbon storage in the ocean during the Last Glacial Maximum.
Reporting by Helen Hill for CBIOMES
The Last Glacial Maximum or LGM, which occurred approximately 20,000 years ago, was a period when ice sheets were at their maximum extension, covering large parts of North America, Europe, and Asia. This epoch is crucial for understanding past climate dynamics and the mechanisms that controlled atmospheric CO2 levels. In a recent Nature Communications paper titled “Carbon isotope budget indicates biological disequilibrium dominated ocean carbon storage at the Last Glacial Maximum,” CBIOMES members Anne Willem Omta, Christopher Follett, and Jonathan Lauderdale together with Raphael Ferrari (MIT) delve into the carbon isotopic signatures of different water masses to unravel the complexities of oceanic carbon storage during this time.
“Our analysis shows that biologically sequestered carbon in the ocean can explain 75±40 ppmv of the observed 90 ppmv change in atmospheric CO2,” Omta explains. “This is based on a mass balance calculation using published carbon isotopic measurements”. This revelation underscores the significance of biological activity in modulating carbon levels in the ocean, challenging previous assumptions that physical processes were the main drivers.
The implications of this research could be profound for the field of climate science. Understanding the mechanisms that controlled carbon storage during the LGM can provide valuable insights into how current and future climate change might impact oceanic carbon sequestration. In Omta’s words: “Since we can’t travel into the future to test our climate models, we need to test them in other ways. One method is to simulate past climates such as the LGM and see how well the models represent them. Such simulations have had persistent problems, which means that there are parts of the climate system that we still don’t understand well. One of these persistent problems has been accounting for the lower CO2 at the LGM. Where was the excess stored and why? This is the question we addressed in our article.”
The study highlights the need to consider biological processes in climate models, which have traditionally focused more on physical factors.
“Studies such as ours will not immediately lead to revised future climate projections,” says Omta. “Such revisions could occur down the line, as we gain more insight into climates of the past. Regardless, being able to explain climates of the past will put our future projections on a stronger footing”.
The study opens up new avenues for research into the role of biological processes in ocean carbon storage. Future studies could explore how different types of marine organisms contribute to carbon sequestration and how these processes might be affected by changing environmental conditions. Additionally, the integration of biological and physical data could lead to more comprehensive models of oceanic carbon dynamics.
Publication:
Omta, A.W., Follett, C.L., Lauderdale, J.M., Ferrari, R. (2024), Carbon isotope budget indicates biological disequilibrium dominated ocean carbon storage at the Last Glacial Maximum, Nat. Commun., doi: 10.1038/s41467-024-52360-z