Ocean health and climate solutions startup Gigablue announced that it has raised $20 million at the first close of its Series A financing, with proceeds aimed at scaling its solution to capture and remove carbon from the atmosphere, and store it deep in the ocean.

Founded in 2022, Gigablue designs and deploys a marine-based carbon dioxide removal method to capture and store CO₂ at large scale through natural marine processes, a methodology known as Microalgae Carbon Fixation Sinking (MCFS). The company’s solution utilizes substrates comprised of naturally occurring compounds, on which photosynthetic phytoplankton absorb CO2 and convert it into biomass and, subsequently sink to the depths.

The company said that its technology uses the ocean’s natural biological carbon pump, while improving the natural sequestration ratio by two orders of magnitude.

According to Gigablue, its technology is designed to be measurable, scalable and environmentally responsible, with each deployment is supported by a robust Measurement, Monitoring, Reporting and Verification (MMRV) framework integrating in-situ oceanographic data, environmental DNA sampling, water chemistry analysis and custom deep-sea monitoring tools.

The funding was led by ocean-climate-technology venture capital fund Planet Ocean Capital.

Gigablue leadership said:

“High-integrity carbon removal is increasingly recognized as essential alongside emissions reductions. This first close reflects growing confidence that marine carbon removal — when governed by science, transparency, and environmental safeguards — can play a critical role in achieving global net-zero targets while strengthening ocean health.”

Gigablue is currently working on the second close of the Series A round, the company said.