Sydney scientists discover microscopic ocean predator that sequesters carbon

Sydney scientists discover microscopic ocean predator that sequesters carbon

By Lucy Jones  March 22nd, 2022

The species can naturally sequester carbon, even as oceans warm and become more acidic.


A team of researchers from Sydney's University of Technology have discovered a single-celled microbe they are calling "a secret weapon in battle against climate change". The microbe is abundant around the world, but hasn't been studied in depth until now.

The microbe is capable of both photosynthesis and eating prey. It can also survive in environments that are hostile to phytoplankton (the ocean's main carbon sequesters). This means the microbe could continue to absorb carbon as oceans warm and acidify.

"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," marine biologist and lead researcher on the project, Dr Michaela Larsson, said.

"However, our study organism, Prorocentrum cf. balticum, is a mixotroph, so it 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."

The study is the first to demonstrate the carbon-absorbing behaviours of microbes and could have implications for our understanding of the way carbon moves in marine environments.

How it works:

The microbe sequesters carbon naturally through the process of photosynthesis. It then forms a carbon-rich mucus shell that gets heavier as it eats other microbes. Eventually, this 'mucosphere' is shed and sinks to the ocean floor, forming part of the ocean's natural carbon pump.

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

"The natural production of extra-cellular carbon-rich polymers by ocean microbes under nutrient-deficient conditions suggest these microbes could help maintain the biological carbon pump in the future ocean."

You can read the study in full here.

Planet Ark does not take responsibility for the accuracy of the original information and encourages readers to check the references before using this information for their own purposes.


Lucy Jones

Lucy started her career working as a writer and editor in print and digital publishing. She went on to create content for Australia's leading sustainable fashion platform while completing her Master of Cultural Studies. Lucy spends her downtime at the beach, crocheting and hanging out with her cat Larry. She believes words can change the world and is stoked to help Planet Ark spread the message of positive environmental change.

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