Climate change

Microscopic ocean predator with taste for carbon discovered

Written by Oceanographic Staff

Scientists discovered a single-celled microscopic ocean predator that might be able to sequester carbon naturally. The microbe could prove invaluable for the fight against warming oceans and ocean acidification.

As the climate gets warmer and ocean temperatures rise due to global warming, a microscopic ocean predator in the form of a single-celled marine microbe might hold crucial answers on how to delay and alleviate the impacts of climate change.

A team of scientists at the University of Sydney recently discovered a new microbe species that “could be a secret weapon in the battle against climate change”, according to the team. It thinks that the microbe could be cultivated to help offset carbon emissions.

After studying the new microbe that has never before been studied in such detail, the team of researchers found that it is abundant around the world, uses photosynthesis and secretes a carbon-rich mucus that attracts and immobilises other microbes. After eating and trapping some of these microbes, the carbon-rich mucus is passed and sinks to the bottom of the ocean where it forms part of the natural biological carbon pump.

Dr Michaela Larsson, a marine biologist who led the research published in the journal Nature Communications, said: “Most terrestrial plants use nutrients from the soil to grow, but some, like the Venus flytrap, gain additional nutrients by catching and consuming insects. Similarly, marine microbes that photosynthesise, known as phytoplankton, use nutrients dissolved in the surrounding seawater to grow.”

“Having the capacity to acquire nutrients in different ways means this microbe can occupy parts of the ocean devoid of dissolved nutrients and therefore unsuitable for most phytoplankton,” she added.

The team of researchers believes that the species could be capable of sinking up to 0.15 gigaton of carbon annually. This is an interesting find that comes after many studies have suggested that 10 gigaton of CO2 would have to be removed from the atmosphere annually until 2050 to meet climate goals.

“This is an entirely new species, never before described in this amount of detail,” said Professor Martina Doblin, the study’s senior author.

She added: “The implication is that there’s potentially more carbon sinking in the ocean than we currently think, and that there is perhaps greater potential for the ocean to capture more carbon naturally through this process, in places that weren’t thought to be potential carbon sequestration locations.”

“The natural production of extra-cellular carbon-rich polymers by ocean microbes under nutrient-deficient conditions, which we’ll see under global warming, suggest these microbes could help maintain the biological carbon pump in the future ocean.

“The next step before assessing the feasibility of large-scale cultivation is to gauge the proportion of the carbon-rich exopolymers resistant to bacteria breakdown and determine the sinking velocity of discarded mucospheres.”

“This could be a game-changer in the way we think about carbon and the way it moves in the marine environment,” she concluded.

For more from our Ocean Newsroom, click here.

Photography courtesy of The Ocean Agency, Renata Romeo and Shaun Wolfe.

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