Scientists have discovered a microscopic ocean predator with a taste for carbon

The single-celled microbe, which is capable of photosynthesis as well as hunting and eating prey, could be "a secret weapon in battle against climate change".

Sky News, Monday 14 March 2022

https://news.sky.com/story/scientists-have-discovered-a-microscopic-ocean-predator-with-a-taste-for-carbon-12565919

Scientists have found what could be a 'secret weapon' in the battle against climate change

Scientists have discovered a new and tiny marine predator which is capable of naturally sequestering carbon.

They say the single-celled microbe could be "a secret weapon in the battle against climate change" as oceans get warmer and more acidic.

According to the team at the University of Technology Sydney, in Australia, the critter could be cultivated to help offset carbon emissions.

What does it do?

The microbe uses photosynthesis and secretes a carbon-rich mucus that attracts and traps other microbes.

The predator eats some of these microbes before abandoning the heavy carbon-rich mucus which sinks to the bottom of the ocean, contributing to the natural carbon pump.

According to marine biologist Dr Michaela Larsson, who led the research published in the journal Nature Communications, the behaviour has never been demonstrated before.

"Most terrestrial plants use nutrients from the soil to grow, but some, like the Venus flytrap, gain additional nutrients by catching and consuming insects," said Dr Larsson.

"Similarly, marine microbes that photosynthesise, known as phytoplankton, use nutrients dissolved in the surrounding seawater to grow," she added.

"However, our study organism, Prorocentrum cf. balticum, is a mixotroph, so is also able to eat other microbes for a concentrated hit of nutrients, like taking a multivitamin.

"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."

Professor Martina Doblin, the study's senior author, said the microbe could be enormously significant for how we think about the ocean balancing the amount of carbon dioxide in the atmosphere.

The species, which was isolated from waters off of the coast of Sydney, is estimated to be capable of sinking up to 0.15 gigaton of carbon every year.

Studies have suggested that in order to meet climate goals, humanity will need to find a way to remove 10 gigaton of CO2 from the atmosphere every year until 2050.

"This is an entirely new species, never before described in this amount of detail," said Professor Doblin.

"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 added.