One of the more hopeful ideas in ocean carbon removal is that kelp, grown quickly and in huge volumes, could be sunk into the deep ocean to lock its captured carbon away for centuries. A 2026 study from the University of Victoria, led by Kohen Bauer, is some of the most direct evidence yet on whether that idea actually holds up.
The team lowered a camera-equipped lander to the seafloor of the Cascadia Basin, an oxygen-poor stretch of ocean off Vancouver Island, and left it running for a full year, from September 2023 to September 2024, with bins of kelp biomass placed both on the sediment and suspended in the water column above, alongside kelp-free controls. Time-lapse imaging tracked exactly how the kelp broke down and how the surrounding seafloor community responded, logging more than 5,000 individual observations across the 13 animal species that showed up to feed on it.
The results were not encouraging for the sink-it-and-forget-it version of the idea: more than 90% of the kelp biomass had decomposed and vanished within roughly 100 days, and it was essentially gone by 210 days, with amphipods and grooved tanner crabs moving in to feed on it along the way. That pace suggests kelp dropped into deep water in places like this doesn’t stay locked away nearly as long as carbon-removal proposals often assume. The researchers are careful to note real limits to the experiment: they tracked visible biomass disappearing, not the exact chemical fate of the carbon itself, and they’re now calling for standardized studies across different deep-sea environments, along with chemical tracer work, before anyone scales up kelp-based carbon burial as a climate solution.