Dave Borlace delivers a startling pivot in the deep-sea mining debate, suggesting that the very ecosystem companies claim to barely disturb may be the planet's most critical, yet misunderstood, carbon sink. While industry proponents point to localized plume data to justify extraction, Borlace highlights a conflicting December 2025 study revealing that deep-ocean microbes are fixing carbon in ways science previously deemed impossible. This isn't just a technical correction; it implies that vacuuming the ocean floor could sever a vital, ancient link in the global climate control system.
The Illusion of Localized Impact
Borlace begins by dissecting a November 2025 paper funded by Naru Ocean Resources, a subsidiary of The Metals Company. The study utilized thorium-234, a radioactive tracer, to track sediment plumes from a mining test in the Clarion Clipperton zone. The company's interpretation was optimistic: "The sheer scale of the ocean means sediment concentrations in commercial scale midwater plumes dilute rapidly within a few kilometers." Borlace notes that this finding was used to argue that mining impacts are negligible and strictly local.
However, Borlace immediately contextualizes this with a counter-narrative from independent researchers. He points out that the industry's confidence relies on a narrow view of ocean dynamics, ignoring the complex, long-term biological consequences. "Even if the deep sea collection machine is precise, the ocean isn't obliged to keep the mess neatly inside the lines," he observes. This framing is effective because it exposes the flaw in assuming that physical dispersion equals biological safety. Critics might argue that industrial modeling is improving, but Borlace's citation of 26-year-old disturbance tests showing lingering microbial disruption suggests that the ocean's recovery time is measured in generations, not seasons.
The restoration of these natural processes is not fully understood, yet the industry is rushing to exploit them.
Rewriting the Deep Ocean Carbon Cycle
The commentary shifts to a groundbreaking study from the University of California, Santa Barbara, led by Allison Santoro. Borlace explains that the scientific community long believed ammonia-oxidizing archaea were the primary drivers of carbon fixation in the dark ocean. The new research challenges this by inhibiting these archaea and finding that carbon fixation rates barely dropped. "Carbon fixation rates hardly dropped at all," Borlace notes, indicating that these organisms account for only a fraction of the process.
Instead, the study points to heterotrophs—microbes previously thought to be mere consumers of organic matter—as significant players in fixing inorganic carbon. Borlace describes this as a paradigm shift: "Now, that established wisdom appears to be turned on its head." This is the piece's intellectual core. By revealing that the base of the deep-sea food web is more complex and active than assumed, Borlace argues that the stakes of mining are exponentially higher. The implication is that trampling the seabed with industrial vacuum cleaners could disrupt a carbon cycle that has operated for millions of years, potentially releasing stored carbon or halting future absorption.
The Precautionary Principle vs. Commercial Urgency
Borlace contrasts the scientific uncertainty with the regulatory stalemate. He notes that nations like France, Germany, and Canada have called for a moratorium, while the International Seabed Authority (ISA) continues to negotiate frameworks without issuing licenses. He highlights the disconnect between the pace of scientific discovery and the pressure to mine: "Should we really be rushing down to the deep ocean floor to scoop up what could very well be a multi-billion dollar bonanza for deep sea mining companies?"
The author's argument gains weight by citing independent fluid dynamics modeling which suggests that while single events are localized, sustained operations create persistent dispersion. "Spread the plume and you spread the disturbance footprint," Borlace writes, emphasizing that microbial processes are spatially structured and easily disrupted. This section effectively dismantles the industry's "dilution" argument by showing that the cumulative effect of multiple mining sites could alter biogeochemical functions across vast areas. The missing context here is the specific economic timeline; while the science demands decades of study, the market for cobalt and nickel demands immediate supply.
Bottom Line
Borlace's strongest move is connecting two seemingly unrelated studies to reveal a hidden vulnerability in the deep-sea mining business case: the ecosystem's role in carbon storage is far more active and fragile than the industry admits. The argument's biggest vulnerability is that it relies on emerging science that, while compelling, has not yet been fully integrated into regulatory risk assessments. Readers should watch for how the International Seabed Authority responds to these new findings regarding heterotrophic carbon fixation, as this could be the tipping point for a global mining pause.