Microscopic ocean predator with a taste for carbon capture

A single-celled marine microbe capable of photosynthesis and hunting and eating prey may be a secret weapon in the battle against climate change.

A new species of fish has the potential to sequester carbon even as oceans warm and become more acidic.

The microbe, abundant around the world, is able to make and release carbon-rich exopolymer that attracts and sucks in other microbes. It abandons its exopolymer after eating some of the prey. The exopolymer is made heavier and sinks when it is trapped by other microbes.

The study is the first to show this behavior, according to Dr. Michaela Larsson.

The vertical export and sequestering of carbon by marine microbes is one of the processes that affect global climate.

While the contribution of phytoplankton to the carbon pump is well established, the roles of other microbes are less understood and rarely quantified. She says this is true for mixotrophic protists, which can consume other organisms.

Some plants, like the Venus flytrap, gain additional nutrition by catching and consuming insects, which use the soil as a source of nutrition. Similarly, marine microbes that grow in the ocean use the dissolved in the surrounding water to grow.

The study organisms, Prorocentrum balticum, is a mixotroph and can eat other microbes for a concentrated hit of vitamins. This microbe can occupy parts of the ocean devoid of dissolved nutrients and therefore unsuitable for most phytoplankton, because it has the capacity to acquire different types of nutrients.

Professor Doblin says the findings have global significance for how we see the ocean balancing carbon dioxide in the atmosphere.

The researchers estimate that this species has the potential to sink up to 15% of the world's carbon dioxide annually. According to a report by the National Academies of Sciences, Engineering, and Medicine, CO 2 removal technologies and strategies will need to remove 10 gigatons of CO 2 from the atmosphere every year until 2050 to meet climate goals.

This is an entirely new species, never before described in this amount of detail. The implication is that there is 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.

She says there is an intriguing question about whether this process could be used to enhance carbon capture in the ocean.

The natural production of extra-cellular carbon-rich polymers by ocean microbes, which we will 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 tobacteria breakdown.

This could be a game-changing change in the way we think about carbon and how it moves in the marine environment.

The paper "Mucospheres produced by a mixotrophic protist impact ocean carbon cycling" is in Nature Communications.

More information: Oxidative metabolisms catalyzed Earth's oxygenation, Nature Communications (2022). DOI: 10.1038/s41467-022-28867-8 Journal information: Nature Communications Citation: Microscopic ocean predator with a taste for carbon capture (2022, March 14) retrieved 14 March 2022 from https://phys.org/news/2022-03-microscopic-ocean-predator-carbon-capture.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.