Bubbles enhance the ocean’s CO2 uptake more strongly than previously assumed

New study provides first direct measurement evidence for a long-overlooked effect in air–sea gas exchange

Helmholtz Centre for Ocean Research Kiel (GEOMAR)

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In strong winds and rough seas, gas exchange between the air and the sea is asymmetrical: air bubbles are literally pushed into the water by breaking waves. Consequently, more gases, such as carbon dioxide, are absorbed than released.

Photo: Ming-Xi Yang, Plymouth Marine Laboratory

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Credit: Dr Ming-Xi Yang, Plymouth Marine Laboratory

The exchange of carbon dioxide between the ocean and the atmosphere is a key component of the global carbon cycle. Acting as a vast buffer, the ocean absorbs a substantial share of human-made CO2 emissions, thereby slowing the pace of climate change.

How effective this buffering is, depends on how efficiently CO2 is transferred between air and water. Until now, most calculations assumed that this exchange is symmetric – meaning that CO2 enters and leaves the ocean at the same rate.

“With our study, we fundamentally challenge this assumption, known as the symmetric flux formulation,” says lead author Dr Yuanxu Dong, a Humboldt Fellow at the GEOMAR Helmholtz Centre for Ocean Research Kiel and Heidelberg University. Because this assumption is widely used in carbon cycle and climate models, many previous estimates may be systematically biased.

When waves swallow air

In regions with strong winds and heavy wave action, breaking waves entrain air bubbles into the water. These bubbles act like tiny transport capsules: under increased pressure below the surface, CO2 dissolves particularly efficiently into the ocean. Put simply, the gas is not just exchanged, but actively “pushed” into the water.

This bubble-mediated gas transfer favours CO2 uptake much more strongly than outgassing – an asymmetric effect that had previously been hypothesised but never directly demonstrated using field data.

First direct evidence from observations

In the study, an international research team led by Plymouth Marine Laboratory and GEOMAR Helmholtz Centre for Ocean Research Kiel, in collaboration with the Heriot-Watt University, analysed a total of 4,082 hours of high-quality measurements of air–sea CO2 flux measurements. The data were collected during 17 research cruises across a wide range of ocean regions.

Using a newly developed two-dimensional analysis method, the researchers were able for the first time to demonstrate directly from observational data that air–sea gas exchange is indeed asymmetric. Based on this approach, the team recalculated global air–sea CO2 fluxes for the period from 1991 to 2020. The result: on average, the global ocean absorbed around 0.3 to 0.4 petagrams more carbon per year – about 15 per cent more than previous estimates.

Particularly strong effect in the Southern Ocean

The effect varies regionally. The additional CO2 uptake is especially pronounced in regions with frequent strong winds and breaking waves, such as the Southern Ocean – an area where some of the most severe impacts of climate change are already being observed.

Seasonal differences also play a role: during winter, when storms are more frequent, the asymmetric effect becomes even stronger. Overall, the revised calculations significantly increase the fraction of the ocean surface that acts as a net sink for CO2.

Implications for climate models and the global carbon budget

The findings suggest that the ocean’s role as a CO2 sink has so far been underestimated. At the same time, the gap between observation-based estimates and the results of many global climate models becomes even more apparent.

“We therefore strongly advocate that future CO2 flux assessments should adopt the asymmetric formulation,” says Yuanxu Dong. Co-author Dr Ming-Xi Yang, chemical oceanographer at the Plymouth Marine Laboratory, adds: “Accounting for this asymmetry means that ocean CO2 flux estimates derived from observations diverge even further from those produced by global models. This points to shortcomings in the models – and these models need to be as realistic as possible in order to make reliable future CO2 and climate projections.”

Open questions and future research needs

Despite the robustness of the results, the researchers emphasise that uncertainties remain. In particular, measurements of CO2 outgassing under extreme wind and wave conditions are still scarce, as they are technically challenging to obtain. Additional data are needed to further constrain the asymmetric effect and to better integrate it into global models.

What is already clear, however, is that the ocean plays an even more important role in the climate system than previously assumed – and that seemingly small processes, such as air bubbles in breaking waves, can have global consequences.

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Journal

Nature Communications

DOI

10.1038/s41467-025-66652-5 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Asymmetric bubble-mediated gas transfer enhances global ocean CO2 uptake

 

Why swearing makes you stronger

Swearing boosts performance by helping people feel focused, disinhibited, study finds

Peer-Reviewed Publication

American Psychological Association

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Letting out a swear word in a moment of frustration can feel good. Now, research suggests that it can be good for you, too: Swearing can boost people’s physical performance by helping them overcome their inhibitions and push themselves harder on tests of strength and endurance, according to research published by the American Psychological Association.

“In many situations, people hold themselves back – consciously or unconsciously – from using their full strength,” said study author Richard Stephens, PhD, of Keele University in the U.K.  “Swearing is an easily available way to help yourself feel focused, confident and less distracted, and ‘go for it’ a little more.” 

The article was published in the journal American Psychologist.

Previous research by Stephens and others has found when people swear, they perform better on many physical challenges, including how long they can keep their hand in ice water and how long they can support their body weight during a chair push-up exercise.

“That is now a well replicated, reliable finding,” Stephens said. “But the question is -- how is swearing helping us? What's the psychological mechanism?”

He and his colleagues believed that it might be that swearing puts people in a disinhibited state of mind. “By swearing, we throw off social constraint and allow ourselves to push harder in different situations,” he said. 

To test this, the researchers conducted two experiments with 192 total participants. In each, they asked participants to repeat either a swear word of their choice, or a neutral word, every two seconds while doing a chair pushup. After completing the chair pushup challenge, participants answered questions about their mental state during the task. The questions included measures of different mental states linked to disinhibition, including how much positive emotion participants felt, how funny they found the situation, how distracted they felt and how self-confident they felt. The questions also included a measure of psychological “flow,” a state in which people become immersed in an activity in a pleasant, focused way.

Overall, and confirming earlier research, the researchers found that participants who swore during the chair pushup task were able to support their body weight significantly longer than those who repeated a neutral word. Combining the results of the two experiments as well as a previous experiment conducted as part of an earlier study, they also found that this difference could be explained by increases in participants’ reports of psychological flow, distraction and self-confidence – all important aspects of a disinhibition.

 “These findings help explain why swearing is so commonplace,” said Stephens. “Swearing is literally a calorie neutral, drug free, low cost, readily available tool at our disposal for when we need a boost in performance.”

In the future, the researchers plan to explore whether this boost from swearing works in any context where success depends on overcoming hesitancy, according to study co-author Nicholas Washmuth, DPT, of the University of Alabama in Huntsville. “Our labs are now studying how swearing influences public speaking and romantic approach behaviors, two situations where people tend to hesitate or second-guess themselves," he said. 

Article: “Don’t Hold Back: Swearing Improves Strength Through State Disinhibition,” by Richard Stephens, PhD, Harry Dowber, MSc, and Christopher Richardson, MSc, Keele University; and Nicholas Washmuth, DPT, University of Alabama in Huntsville. American Psychologist, published online Dec. 18, 2025. 
 
CONTACT: Richard Stephens, PhD, can be reached at rstephens@keele.ac.uk. 
 

The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States. APA’s membership includes  173,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance the creation, communication and application of psychological knowledge to benefit society and improve lives.

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Journal

American Psychologist

DOI

10.1037/amp0001650 

Method of Research

Experimental study

Subject of Research

People

Article Title

“Don’t Hold Back”: Swearing Improves Strength Through State Disinhibition

Article Publication Date

18-Dec-2025

 

A delicate Antarctic balance crucial to global climate

University of Queensland

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A diagram of the influences on Antarctic Bottom Water at Cape Darnley

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Credit: The University of Queensland

New findings about ocean processes in the Antarctic show melting ice shelves and changes to sea ice could have catastrophic implications for the global climate.

A team of Australian researchers led by Dr David Gwyther at The University of Queensland has identified competing forces that control the formation of some of the coldest, densest – and most important – water on the planet.

“This very cold, salty water, called Antarctic Bottom Water, is formed by the freezing of the ocean surface in sea ice factories that we call polynyas,” Dr Gwyther said.

“This dense water sinks to the ocean floor where it flows northwards acting like a giant conveyor belt driving currents around the planet which influence the climate worldwide.

“Our study shows the formation of bottom water is a fine balance between strong coastal winds, sea-ice growth and the volume of fresh water released by melting ice shelves.

“The interaction between these processes determines how much dense water is formed and this balance could shift under climate change.

“Increased ice shelf melt, or reduced sea ice growth can weaken dense water production.

“This is important, as changes to dense water production might over time impact global ocean circulation and affect climate patterns such as rainfall in Africa or temperatures in Europe.”

Antarctic Bottom Water is formed at 4 known locations, and the research led by the School of the Environment focussed on Cape Darnley in East Antarctica, roughly 3,000 km from the Australian mainland.

“Until now we haven’t had a clear picture of what controls Antarctic Bottom Water formation at Cape Darnley,” Dr Gwyther said.

“We built an advanced regional ocean simulation that includes salinity, temperature, water currents, sea ice and wind data.

“We found 2 neighbouring systems played opposing and very delicately balanced roles in the production of bottom water.

“Meltwater flowing from beneath the Amery Ice Shelf freshens the water flowing northwards to Cape Darnley and suppresses dense water formation.

“Conversely, sea ice production in the nearby Mackenzie Polynya region between the Amery Ice Shelf and Cape Darnley increases salinity and strengthens dense water formation.

“These 2 systems influence Cape Darnley’s dense water formation in opposite directions.

“If the balance were to shift through more melting ice or a reduction in polynya activity, we could see major changes in how much dense water forms and flows into the global ocean.”

The team found that if Amery Ice Shelf melting doubles, dense water export decreases by about 7 per cent, while if sea ice production at Mackenzie Polynya shuts down, export decreases by around 36 per cent.

The research is published in Geophysical Research Letters.

It was completed in collaboration with the Australian Antarctic Division and the Australian Antarctic Program Partnership.

Iceberg at Cape Danley, East Antarctica

Credit

Sienna Blanckensee

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Journal

Geophysical Research Letters

DOI

10.1029/2025GL118187 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

What controls the formation of Antarctic Bottom Water at Cape Darnley, East Antarctica?

Article Publication Date

18-Dec-2025