“Ocean Skin”: Sliver Of Cool Surface Water Helps The Ocean Absorb More Carbon

Eddie Gonzales Jr. – MessageToEagle.com – Recent research demonstrates that slight variations in temperature at the ocean’s surface facilitate increased absorption of carbon dioxide (CO2). Scientists have focused their studies on the “ocean skin,” a layer less than 2 millimeters deep, which is marginally cooler than the underlying water.

Image credit: Schäferle – Pixabay

Theoretical and lab work suggested this temperature difference should increase ocean CO2 absorption, but it hadn’t been observed at sea before.

The new study—led by researchers from the University of Exeter’s Penryn Campus in Cornwall—used precision measurements to confirm that the temperature of the ocean skin does indeed aid carbon absorption.

The findings suggest this ocean absorbs about 7% more CO2 each year than previously thought. It might sound small, but when applied across all oceans, this additional carbon absorption is equivalent to one and half times the carbon captured by annual forest growth in the Amazon rainforest.

The global ocean absorbs about a quarter of humanity’s carbon emissions, slowing climate change while also harming the ocean, and the new findings help improve our understanding of these processes.

“Our findings provide measurements that confirm our theoretical understanding about CO2 fluxes at the ocean surface,” said lead author Dr. Daniel Ford, from the University of Exeter.

“With the COP29 climate change conference taking place next month, this work highlights the importance of the oceans, but it should also help us improve the global carbon assessments that are used to guide emission reductions.”

And the team have now included this advancement within their data submission to this year’s Global Carbon Budget assessment.

The ship observations—from two European Space Agency projects—were taken by a CO2 flux systems that measured tiny differences in CO2 in air swirling towards the ocean surface and away again, along with high-resolution temperature measurements.

Until now, global estimates of air-sea CO2 fluxes typically ignored the importance of temperature differences in the near-surface layer.

Dr. Ian Ashton, also from the University of Exeter, said, “This work is the culmination of many years of effort from an international team of scientists. The European Space Agency’s support for science was instrumental in putting together such a high-quality measurement campaign across an entire ocean.”

Dr. Gavin Tilstone, from Plymouth Marine Laboratory (PML), said, “This discovery highlights the intricacy of the ocean’s water column structure and how it can influence CO2 draw-down from the atmosphere. Understanding these subtle mechanisms is crucial as we continue to refine our climate models and predictions. It underscores the ocean’s vital role in regulating the planet’s carbon cycle and climate.”

The study’s international partners included sea temperature measurement experts from the European Space Agency and the university of Southampton.

The ship cruises were part of the Atlantic Meridional Transect (AMT) project led by PML.

Source

Paper

Enhanced ocean CO2 uptake due to near surface temperature gradients, Nature Geoscience (2024). DOI: 10.1038/s41561-024-01570-7

Written by Eddie Gonzales  Jr. – MessageToEagle.com Staff Writer