Not just humans, ocean critters also contribute to global warming - This is how

New Delhi: Amid the continuing heated discourse on climate change and its effects on the globe, a new study has found that ocean clams and worms release a huge amount of harmful greenhouse gas into the atmosphere, which is almost equivalent to that of 20,000 dairy cows.

While researchers are putting in every effort to find ways and means of reducing the emission of harmful greenhouse gases, this study brings to light how methane gas finds its way into the water and then finally out into the atmosphere, thus contributing to global warming.

Methane has 28 times greater warming potential than carbon dioxide.

Researchers from Cardiff University in the UK and Stockholm University in Sweden, have shown that the ocean critters are producing large amounts of the strongest greenhouse gases – methane and nitrous oxides – from the bacteria in their guts.

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

The researchers estimate that this nearly amounts to as much methane given off as 20,000 dairy cows.

This is approximately 10 percent of the entire Welsh dairy cow population and one 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.

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

"What is puzzling is that the Baltic Sea makes up only about 0.1 percent 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," said Ernest Chi Fru, from Cardiff University.

"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," said Stefano Bonaglia, from Stockholm University.

"These small yet very abundant animals may play an important, but so far neglected, role in regulating the emissions of greenhouse gases in the sea," said Bonaglia, lead author of the study published in the journal Scientific Reports.

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 methane production by a factor of eight compared to completely bare sediments.

(With PTI inputs)