New research has shown that an invisible film on the surface of the world’s oceans may be greatly reducing carbon absorption from the atmosphere, according to The Guardian. The study, by scientists at the universities of Heriot-Watt, Newcastle, and Exeter, will impact future climate change forecasts. It was published in the journal Nature Geoscience on Monday.
As the planet’s greatest long-term sink of carbon dioxide, oceans absorb roughly a quarter of all carbon dioxide emissions generated from human activity. Higher levels of sea turbulence lead to a greater exchange of gases between the ocean and atmosphere.
Now, researchers have calculated the impact of “biological surfactants” on this process, which has been difficult to quantify. The study, by researchers with the European Space Agency, the Natural Environment Research Council, and the Leverhulme Trust, provides real-time comparisons of this “surfactant effect” in different parts of the world’s oceans. Their findings showed that surfactants can cut down on the ocean’s carbon absorption by as much as 50 percent.
Such a significant reduction could prove to be a problem – especially since warming temperatures spark a corresponding rise in surfactants.
The researchers collected samples from various areas of the Atlantic Ocean in 2014. According to Heriot-Watt University Lyell research fellow Dr. Ryan Pereira:
“As surface temperatures rise, so too do surfactants, which is why this is such a critical finding. The warmer the ocean surface gets, the more surfactants we can expect, and an even greater reduction in gas exchange. What we discovered at 13 sites across the Atlantic Ocean is that biological surfactants suppress the rate of gas exchange caused by the wind.”
This scum on the ocean surface can arise from a variety of biological sources. Sometimes, surfactants like an oil slick or sea foam can be easy to see, yet researchers say surfactants can be invisible in some cases, which makes it difficult to gauge using satellite monitoring. Scientists say they need to an accurate way to measure the buildup of this layer of organic matter, in order to make predictions about the exchange of greenhouse gases like carbon dioxide and methane.
“These latest results build on our previous findings that, contrary to conventional wisdom, large sea surface enrichments of natural surfactants counter the effects of high winds,” says Newcastle University marine biogeochemistry professor Rob Upstill-Goddard.
And Exeter University’s Dr. Ian Ashton noted:
“Combining this new research with a wealth of satellite data available allows us to consider the effect of surfactants on gas exchange across the entire Atlantic Ocean, helping us to monitor carbon dioxide on a global scale.”