Arctic Bacterium Eats Acetone, Fixes Carbon
A newly identified marine bacterium uses light and acetone to grow in Arctic surface waters, a finding published in Nature Communications.
Updated on Nov. 4, 2026 in Life Sciences
Researchers have identified Porticoccus arcticus, a marine bacterium that consumes acetone, harvests light for energy, and fixes carbon dioxide. The organism was consistently found in Arctic surface waters across samples collected from 2017 to 2023.
Why it matters
The bacterium's ability to fix carbon using acetone adds a previously unrecognized process to Arctic carbon cycling. Its compact genome and light-driven metabolism suggest it is well adapted to nutrient-poor surface waters.
Porticoccus arcticus has a genome of 1.29 million base pairs, compared with 2.47 million base pairs for its closest relative, and reached up to 9% of 16S rRNA gene sequences at some Canada Basin surface sites at 5 and 20 meters depth. Its total role in Arctic carbon fixation has not been quantified.
The players
Concordia University
A university in Montreal whose researchers led the study identifying the bacterium.
Heriot-Watt University
A university in Edinburgh whose researchers co-authored the study.
The details
The bacterium carries a complete acetone carboxylation pathway and two proteorhodopsin genes acquired through lateral gene transfer, with the blue-light version expressed at roughly 64 times the level of the green-light version. It also carries a cytoplasmic carbonic anhydrase that converts dissolved CO2 into bicarbonate, the substrate its acetone carboxylase requires.
Timeline
Microbial samples were collected across the Arctic Ocean from 2017 to 2023.
Big Picture
The discovery adds to ongoing research into how microbial communities in the Arctic Ocean process carbon as sea ice retreats. It points to a light-driven carbon pathway that may be relevant to other marine photoheterotrophs.
The findings could eventually inform how scientists model carbon uptake in Arctic waters. Any practical application would depend on further study of how widely the acetone pathway occurs in marine environments.
The takeaway
Light-driven microbes may play a larger role in ocean carbon cycling than previously assumed. Tracking these organisms as Arctic conditions change could help clarify how the region's carbon balance shifts over time.
Further reading
Explore more research in our Life Sciences section.
Source note: This article includes information reported by Earth.
