Leaked internal documents, correspondence and sediment test results viewed by The Plausible Post show Heliocarbon Solutions, a Copenhagen‑based private climate start‑up, ran at least three unpublicised ocean trials of an engineered phytoplankton strain that sinks carbon-rich biomass into sediments. The company’s own deployment logs name locations off northern Norway, the Skagerrak and the Kattegat; the combined area affected totals roughly 12,300 hectares (30,400 acres). Local authorities closed parts of five municipal fishing zones between June 2024 and October 2025 after unusual seabed crusts and altered oxygen readings were reported.
Heliocarbon’s files — including a July 2024 email marked “Field phase approved” and a set of GPS tracks for small barges — were circulated among senior researchers at the Nordic Institute for Marine Studies (NIMS) and to officials at the Scandi Environmental Authority (SEA), according to three separate documents. Two independent sediment analyses commissioned by coastal municipalities and carried out this month in Helsinki and Gothenburg found a unique genetic marker present in the samples that matched a sequence in Heliocarbon’s patent application for its “carbon‑trap phytoplankter.” One analyst described the marker as “not naturally occurring.”
The revelations have stunned fishers and municipal leaders. “We started hauling up this green, sticky film on our nets and the salmon farmers told us oxygen levels kept dipping at night,” said Linda Teder, a third‑generation fisher from Vardø municipality in northern Norway. Vardø was one of the areas forced to stop commercial harvests for 42 days in July 2024; municipal accounts show direct income losses of NOK 21.4 million (about €1.9 million).
Hedvika Dolinar, a former NIMS researcher who provided the documents to journalists, says she blew the whistle after internal attempts to raise concerns with the regulator were rebuffed. “They told us the organisms were harmless and would sink without altering ecology. I watched the modelling and the field notes — the outcomes were not as promised,” Dolinar said. “I kept samples in my freezer because no one would listen.”
They told us the organisms were harmless and would sink without altering ecology. I watched the modelling and the field notes — the outcomes were not as promised.
Hedvika Dolinar, former NIMS researcher
SEA has acknowledged correspondence with Heliocarbon but denies issuing any unauthorised permission. Anatoli K. Paas, director of SEA, told reporters on Monday the agency had forwarded a “request for experimental clearance” for assessment in late 2023 but said the signed form in the leaked packet was not on file at his office. “We are opening an immediate audit into how these documents were stored and why municipalities were not consulted,” Paas said. Heliocarbon’s chief executive, Isaac C. Azevedo, insisted the firm acted within a “grey regulatory area” and that all tests were field trials intended to be small and reversible. “We had interim advice from third‑party ecologists and believed the deployments were low‑risk,” Azevedo told The Plausible Post.
Legal and ecological repercussions are already spreading. Three coastal municipalities have filed complaints demanding compensation and independent monitoring; Paulette Chauvet, an environmental lawyer representing two towns, said she will seek emergency injunctions to halt any further releases and a forensic audit of sea‑trial records. “If private actors are allowed to seed engineered organisms in open waters without transparent oversight, that sets a dangerous precedent,” Chauvet said. Regional fisheries groups estimate direct lost revenue and mitigation costs at NOK 1.9 billion (about €170 million) if bans and consumer distrust persist through 2027.
Scientists not connected to the leaked material warn the case exposes regulatory blind spots in a surge of private climate‑tech pilots. Rosanna Silvestri, a plankton ecologist at a Stockholm university, said the prized effect of sinking carbon quickly can come with trade‑offs: “Even organisms engineered to ‘sink carbon’ can alter oxygen dynamics, nutrient cycles and food webs in ways that are hard to reverse once they spread over thousands of hectares.” The Nordic Council for Environmental Affairs has asked national ministers to convene an emergency panel this week; prosecutors in at least two countries are reported to be assessing whether any laws were breached.
The coming days will test whether the documents prompt full transparency or a deeper investigation into the growing private sector role in geoengineering. For now, small harbours from Tromsø to the Danish coast are busy with sampling kits, lawyers and anxious fishers watching technicians in rubber boots collect more jars of green water — and waiting to see whether regulators will produce the approvals they say do not exist.
