Baltic clams and worms release as much greenhouse gas as 20,000 dairy cows

October 13, 2017
Credit: CC0 Public Domain

Scientists have shown that ocean clams and worms are releasing a significant amount of potentially harmful greenhouse gas into the atmosphere.

The team, from Cardiff University and Stockholm University, have shown that the critters are producing large amounts of the strongest - and nitrous oxides - from the bacteria in their guts.

Methane gas is making its way into the water and then finally out into the atmosphere, contributing to global warming - methane has 28 times greater warming potential than carbon dioxide.

A detailed analysis showed that around 10 per cent of total methane emissions from the Baltic Sea may be due to clams and worms.

The researchers estimate that this is equivalent to as much methane given off as 20,000 dairy cows. This is as much as 10 per cent of the entire Welsh dairy cow population and 1 per cent of the entire UK dairy cow population.

The findings, which have been published in the journal Scientific Reports, point to a so far neglected source of greenhouse gases in the sea and could have a profound impact on decision makers.

It has been suggested that farming oysters, mussels and clams could be an effective solution against human pressures on the environment, such as eutrophication caused by the run-off of fertilisers into our waters.

The authors warn that stakeholders should consider these potential impacts before deciding whether to promote shellfish farming to large areas of the ocean.

Co-author of the study Dr Ernest Chi Fru, from Cardiff University's School of Earth and Ocean Sciences, said: "What is puzzling is that the Baltic Sea makes up only about 0.1% of Earth's oceans, implying that globally, apparently harmless bivalve animals at the bottom of the world's oceans may in fact be contributing ridiculous amounts of greenhouse gases to the atmosphere that is unaccounted for."

Lead author of the study Dr Stefano Bonaglia, from Stockholm University, said: "It sounds funny but small animals in the seafloor may act like cows in a stable, both groups being important contributors of methane due to the bacteria in their gut.

"These small yet very abundant animals may play an important, but so far neglected, role in regulating the emissions of gases in the sea."

To arrive at their results the team analysed trace gas, isotopes and molecules from the worms and clams, known as polychaetes and bivalves respectively, taken from ocean sediments in the Baltic Sea.

The team analysed both the direct and indirect contribution that these groups were having on methane and nitrous oxide production in the sea. The results showed that sediments containing clams and worms increased by a factor of eight compared to completely bare sediments.

Explore further: Researchers tackle methane emissions with gas-guzzling bacteria

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10 comments

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TheGhostofOtto1923
1.7 / 5 (6) Oct 13, 2017
Huh. Another significant natural source of these gasses that scientists knew nothing about.

And I thought AGW was conclusive?

What else dont they have in their models?
JongDan
1 / 5 (3) Oct 13, 2017
No to aquaculture then?
cantdrive85
1.8 / 5 (5) Oct 13, 2017
We should tax the clams, there is no other way to solve this environmental atrocity!
hrfJC
4 / 5 (3) Oct 13, 2017
Interesting study on a potent greenhouse gas, methane from natural or theogenic causes out of man's control. But this methane may well be far less than the huge plumes released during insane fracking producing not only methane, a long term global warming threat, but far worse enormous increases in local earthquakes and irreversible contamination of precious ground water with toxic chemicals. Fracking for GREED DRIVEN profit is sheer insanity with enormous IMMEDIATELY harmful environmental consequences.
rrrander
not rated yet Oct 13, 2017
Latest left-lib fad is snorting nitrous oxide at parties. No guilt...
tblakely1357
5 / 5 (1) Oct 14, 2017
Sooo, would you prefer to jail frackers or just kill them for crimes against Gia?
SamB
1 / 5 (1) Oct 14, 2017
Huh. Another significant natural source of these gasses that scientists knew nothing about.

And I thought AGW was conclusive?

What else dont they have in their models?


humility
mackita
5 / 5 (2) Oct 14, 2017
Baltic Sea is in a critical condition and in danger of dying unless pollution from the Russian city of St Petersburg is drastically cut. This pollution is also main source of greenhouse gases formation in Baltic swamp - not the worms and clams which are purifying water instead.
hrfJC
2 / 5 (2) Oct 14, 2017
Another liberal Russiagate fabrication! Correction: as a native East Prussian, let me point out that Kaliningrad, formerly Koenigsberg, not St Petersburg, is located on the coast of the Baltic Sea and would be your suspected source of methane outgassing from sewage, bog and marsh gases. Also methane is a powerful greenhouse gas, lighter than air, thus rising into the atmosphere. But at these low levels it is odorless and non toxic to fish or humans.
dnatwork
not rated yet Oct 16, 2017
Wow, these comments. It seems you folks think the problem is all the wildlife, that has been key to keeping the carbon cycle in balance throughout the history of the planet. So we should eradicate all the animals so you can keep driving your coal-fired SUVs?

Clams and cows other things that belch have been around for hundreds of millions of years. Whatever they've been doing was already in the mix when climate was more stable. Obviously the thing that has changed in the last 200 years is the burning of fossil fuels by humans. Correcting the balance means correcting the source of the imbalance.

The researchers make the point (kind of late in the article) that what they are cautioning against is trying to solve one problem (water pollution) by creating another (clams that generate more greenhouse gas than you realized). They don't say anything to indicate that clams caused global warming in the first place.

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