Does Gigablue’s $20 Million In Fundraising Signal A New Dawn For Ocean-Based Carbon Removals?

On January 27, 2026, New York based Gigablue announced it had raised $20 million – its first close of a Series A funding round – to scale its ocean-based carbon removal operations. Gigablue uses microalgae carbon fixation sinking (MCFS) to sequester carbon; in essence, plankton is grown on natural substrate, and then sunk to the ocean depths, capturing the carbon. But Gigablue is not the first carbon removal developer to dip its toes in these waters – can it succeed where others have failed?

There is one cautionary tale that stands out above the rest when it comes to ocean-based carbon removals: the decline and fall of Running Tide. Founded in 2017, Running Tide raised $50 million, promising to use MCFS for carbon removals (see Verdantix Buyer’s Guide: Carbon Dioxide Removal Technology (2024)). It rapidly garnered an impressive roster of enterprise clients – with Microsoft and Shopify signing offtake agreements – and scaled to some 140 employees. To counter critics, who doubted the scientific validity of the removal technology, Running Tide partnered with Deloitte to conduct environmental assessments. Running Tide holds the honour of being the first organization to ever actually retire ocean-based removal credits. Yet, what could have been a significant growth story ended in dismal failure – by June 2024, Running Tide had shut down its operations, citing a lack of market demand.

Why did Running Tide fail? The problem mostly lies in the approach itself. The essential bedrock of ocean-based sequestration involves moving biological decay – and therefore CO₂ release – from ‘short’ to ‘long’ term cycles, in Running Tide’s parlance. According to one climate economist, this is a "vast oversimplification that substantially overstates the net climate benefits when you apply that to ocean-based processes". What about the effect on the ocean environment? Significant studies argue that ‘ocean-based interventions’ are likely to have major consequences for entire ecosystems. Essentially, ocean-based removals are an entirely new frontier: no-one really knows how much carbon is sequestered, or the impact it will have. Buyers also can’t see the technology in action or monitor long-term impacts on the ocean floor – a serious blow in a fragile, reputation-based market.

Since the demise of Running Tide, ocean-based removals have been considered a dead pathway – one of the many wayward branches that has been pruned as technologies refine, and the chaff is separated from the wheat. Gigablue’s fundraising round may inspire some hope in ocean carbon removal believers. The firm seemingly promises to do things differently, acting in concert with environmental authorities, such as the New Zealand Environmental Protection Authority (EPA), and headlining an intention to create positive impact by “Acting responsibly: every tonne, every time”. As yet, Gigablue had announced no significant offtake agreements with the removal titans; perhaps the major buyers are too wary to be stung again. And will the scientific community support ocean-based interventions this time round? It seems unlikely.