Marine Permaculture and Deep-Water Upwelling Systems

Why Upwelling Is the Ocean's Productivity Engine

The ocean surface receives abundant solar energy but is depleted of nutrients in most of its area. Nitrogen, phosphorus, and silicate consumed by phytoplankton sink with dead biomass toward the deep ocean and are not returned to the surface by natural mixing in most of the tropics and subtropics. The result is a biological desert of warm, clear, nutrient-poor water that covers roughly 60% of the ocean's surface. These oligotrophic zones have low phytoplankton density, low fish biomass, and minimal carbon drawdown relative to their area.

Natural upwelling zones are the exception. Where prevailing winds drive surface water offshore (as in eastern boundary currents along California, Peru, Portugal, and Namibia), deep, cold, nutrient-rich water rises to replace it. Upwelling zones account for less than 1% of global ocean area but produce approximately 20% of the global fish catch. The California Current system alone, driven by consistent northerly winds in summer, supports sardine, anchovy, salmon, tuna, and a full pelagic food web that could not exist in its absence. The fundamental constraint on ocean productivity outside these zones is not sunlight, not temperature, and not CO2. It is nutrient supply from depth.

The marine permaculture concept, developed by Brian von Herzen and articulated in the Climate Foundation's programme since 2015, proposes to replicate the upwelling mechanism artificially. A wave-powered pump system anchored at depth raises water from 200-600 metres to the surface continuously, using the kinetic energy of wave motion rather than electricity or fuel. The pump design draws approximately 1-2 watts per unit from wave action, with no external energy input required after installation. At the surface, the cold, nutrient-rich water disperses through a kelp-supporting lattice of floating lines and mesh, driving primary productivity that coastal areas with similar sun exposure and temperature could not sustain without the nutrient supply.

The scale difference between coastal kelp aquaculture and marine permaculture is several orders of magnitude. A well-sited coastal kelp farm covers 5-50 hectares. The theoretical area of open ocean suitable for marine permaculture structures, defined by depth greater than 200 metres, tropical or subtropical location, and wave energy sufficient to power the pumps, measures in the tens of millions of hectares. This is not coastal farming scaled up. It is a different category of intervention.

The Climate Foundation Model: Structure, Mechanism, and Pilot Results

Brian von Herzen founded the Climate Foundation in 2007 with the explicit goal of developing marine permaculture as a scalable ocean restoration and climate intervention technology. The first pilot structures were deployed in the Philippines in 2016, in collaboration with Philippine government agencies and local fishing communities, using wave-powered pumps to bring deep water to the surface over a 1-hectare test plot supporting a kelp and seagrass canopy.

The Philippines pilots documented several results across 2016-2020. Kelp growth rates on marine permaculture structures exceeded the growth rates of the same species in adjacent unassisted ocean by factors of 2-4 times, consistent with the hypothesis that nutrient limitation was the primary constraint on local productivity. Fish aggregation around the structures was documented within 3-6 months of deployment: the artificial upwelling created a localised productive zone that attracted a food web. The structure function as a form of artificial reef in the habitat sense while simultaneously driving primary production through upwelling. This reef-plus-productivity combination was not anticipated in the original design; it emerged from the biology. Local fishing communities reported measurable increases in catch within 500 metres of the structures after 18 months of operation (vault_atom_TBD; Climate Foundation Philippines pilot report 2020).

The limit of the Philippines pilot as evidence for the marine permaculture hypothesis is scale. A 1-hectare structure in moderate wave conditions with a relatively calm typhoon season is not representative of the engineering conditions required for a 10,000-hectare deployment in the open Pacific. The pump and mooring system that survives a Category 2 typhoon in the Philippines requires substantially different engineering for the North Atlantic westerlies or the Southern Ocean. The Climate Foundation acknowledges this, with the current programme focus on optimising pump design and mooring systems for higher-energy ocean environments before larger-scale deployment.

The biology of kelp growth is well understood in coastal conditions. The question the Climate Foundation's work is answering is whether that biology transfers to open ocean conditions with artificial nutrient supply. The Philippines data suggests it does at the 1-hectare scale, with productivity gains consistent with theory. What the data does not yet address is what happens to productivity and ecology at 100 or 10,000 hectares, where the upwelling flux itself begins to interact with regional ocean circulation.

Tim Flannery and the Large-Scale Upwelling Argument

Australian scientist and author Tim Flannery has been the most prominent public advocate for large-scale marine upwelling as a climate intervention since his 2017 book Atmosphere of Hope articulated the case. Flannery's argument is not specifically about kelp or seaweed farming as a production system. It is about using the ocean's own nutrient cycling to drive the carbon capture and fishery restoration at scales that coastal aquaculture, regardless of how well it is developed, cannot reach.

The core of Flannery's position is a straightforward scaling argument. Global CO2 emissions in 2023 were approximately 37.4 billion tonnes (IEA, 2024). Coastal seaweed farming, even at optimistic growth projections, addresses a fraction of a percent of this. The ocean covers 71% of Earth's surface. If large-scale upwelling could replicate the productivity conditions of natural upwelling zones across even 10% of the oligotrophic ocean, the primary production increase would be orders of magnitude larger than anything coastal farming can achieve. The argument is not that upwelling will definitely sequester carbon at the required scale, but that it is the only ocean-based intervention with the geometric potential to matter at the scale of the climate problem.

The scientific response to Flannery's large-scale argument has been measured rather than dismissive. The oceanographic community broadly accepts that artificial upwelling would increase primary production in oligotrophic zones. The debate is about two consequences that Flannery's optimistic framing does not fully engage: first, large-scale upwelling in tropical zones would also bring CO2-rich deep water to the surface (deep water is supersaturated with CO2 from decomposed organic matter), potentially releasing substantial amounts of CO2 even as the primary production it drives captures some. The net carbon balance of large-scale artificial upwelling is not settled and may not be positive in all cases. Second, large-scale modification of ocean nutrient distribution could alter existing marine ecosystems in ways that are difficult to predict or reverse, including changes to established commercial fisheries that depend on current circulation patterns.

Flannery acknowledges both concerns in later writing, arguing that pilot programmes should be designed specifically to measure these effects before any large-scale deployment. This is also the Climate Foundation's position. The disagreement is not about whether to pilot, but about the pace and ambition of scaling from pilot to deployment-level programmes.

Carbon Sequestration: What the Evidence Actually Shows

The carbon sequestration potential of marine permaculture depends on a chain of physical and biological events, each with its own uncertainty. Kelp grows using dissolved CO2 and bicarbonate from surface seawater. Surface seawater is in equilibrium with atmospheric CO2 through gas exchange, so as kelp removes dissolved inorganic carbon, additional CO2 diffuses from the atmosphere to re-equilibrate the surface layer. This is additive atmospheric carbon capture: new kelp biomass growth pulls CO2 from the atmosphere indirectly through this exchange process.

Whether that carbon stays out of the atmosphere depends entirely on what happens to the biomass. If harvested and used as animal feed, bioplastic, or food, the carbon cycles back to the atmosphere quickly through digestion, combustion, or decomposition. If left to sink to the deep ocean (below the permanent thermocline at roughly 1,000 metres), the carbon can remain sequestered for timescales measured in hundreds to thousands of years. Krause-Jensen and Duarte (2016) in Nature Geoscience estimated that macroalgae naturally export approximately 173 TgC per year to the deep ocean via this sinking pathway, making macroalgae a significant but underrecognised component of the biological carbon pump.

Blue carbon science has grappled with the additionality and measurement problem for over a decade. Hurd et al. (2022) in ICES Journal of Marine Science identified two core problems with claiming carbon credits for seaweed: most seaweed biomass decomposition happens near the surface rather than in the deep ocean, and measuring the fraction that actually sinks is analytically difficult at the scale required for carbon accounting. These concerns apply to both natural and farmed seaweed. For marine permaculture specifically, the challenge is that the additional productivity driven by upwelling creates additional biomass, but whether that biomass sinks at higher rates than background, and how the upwelled CO2-rich water affects the net surface balance, requires site-specific measurement that has not yet been done at meaningful scale.

The most defensible near-term value proposition for marine permaculture is not carbon but fishery enhancement. The documented fish aggregation around pilot structures, the local catch increases reported by fishing communities, and the general principle that nutrient enrichment of oligotrophic zones would drive food web productivity all point toward a system that could substantially increase marine protein production per unit ocean area. For coastal and island communities in the Indo-Pacific where marine protein is a primary food source and where fish populations have declined with ocean warming, this is a tangible near-term benefit that does not depend on resolving the carbon accounting questions. The carbon potential is real but speculative at scale. The fishery enhancement is real and observed at pilot scale.

The Engineering and Economic Constraints: What Has to Work

Three engineering problems stand between current marine permaculture pilots and deployment at the scale that would matter for climate or food systems: storm survival, biofouling, and cost-per-hectare at scale. Each is solvable in principle. None is solved in practice.

Storm survival is the most immediately constraining. The Climate Foundation's Philippines pilots experienced partial structure loss in typhoon events above Category 2. The mooring and line systems developed for nearshore conditions are not adequate for the open Pacific, where wave heights during major storm events regularly exceed 15 metres and current forces on moored structures are substantially higher than in sheltered tropical waters. Engineering solutions exist in the offshore energy sector (deepwater oil platforms and offshore wind foundations withstand comparable forces) but translate to marine permaculture at prohibitive cost per unit. The Climate Foundation is developing neutrally buoyant submerging structures that descend below storm-impacted surface layers during high-wave events and re-surface afterwards. This approach has been tested in benign conditions; performance in major storm events remains to be validated.

Biofouling is a secondary constraint that becomes primary at operating scale. Any surface structure in productive tropical ocean accumulates fouling organisms: barnacles, mussels, tunicates, and algal mats. Fouling increases the drag and weight on structures, degrades pump function, and can competitively outgrow intended kelp cultures on the support lattice. Coastal aquaculture manages biofouling through regular manual cleaning, which is feasible at 5-50 hectare farm scale with a small boat and crew. At 1,000-hectare marine permaculture deployment, the cleaning labour alone becomes a substantial fraction of operating cost. Antifouling coatings effective enough to matter at scale are either toxic (prohibited near biological systems) or degradable (requiring reapplication). This is an unsolved operational problem for any open-ocean structure programme.

Cost-per-hectare is the economic constraint that determines whether marine permaculture can access capital at the scale needed for meaningful deployment. Current estimates for a deployable marine permaculture array, based on Climate Foundation engineering specifications, run at approximately 50,000-150,000 USD per hectare for structure, mooring, and installation at pilot scale. At commercial ocean wind farm scale (with the cost reductions that come from series production and specialised installation vessels), the target cost is 15,000-40,000 USD per hectare. For comparison, coastal kelp farm infrastructure in the US Atlantic costs roughly 8,000-20,000 USD per hectare at current small-scale build-out (vault_atom_TBD; Greenwave infrastructure disclosures). Open-ocean marine permaculture is categorically more expensive per hectare than coastal farming, even at optimistic engineering cost projections.

The counterargument on economics is addressable area. Coastal farming is constrained by coastline length, permit zones, and community access. Marine permaculture operates in open ocean where no comparable constraint exists. The total addressable area for marine permaculture at suitable depth and wave conditions is hundreds of millions of hectares. If cost-per-hectare can be brought to a level where fishery value and carbon payments together make deployment economically viable, the scalable area is essentially unconstrained by geography. The regulatory question for offshore marine permaculture is different from coastal farming: it falls under international maritime law for structures in international waters, or under national jurisdiction for EEZ deployment, with no equivalent of the coastal permitting process. This is both a regulatory advantage (no 2-5 year coastal permit process) and a governance gap (no framework yet exists for large-scale open-ocean biological intervention).

The full picture of the seaweed farming frontier is that coastal production and open-ocean marine permaculture are not competing approaches. Kelp-shellfish finfish stacks in coastal IMTA systems address food production, nitrogen remediation, and local fishery integration at 5-100 hectare scales. Salmon-kelp coastal integration uses kelp to process the nitrogen load from salmon farming. Marine permaculture addresses a different question: what is possible when the constraint of coastal proximity is removed and the scale is set by oceanographic potential rather than permitting and community access. Both are needed. The former is deployable now with existing technology and regulatory frameworks. The latter requires another decade of engineering, biology, and economic validation before it is ready for serious capital deployment. Methane reduction from livestock feed, described in Asparagopsis trials at grazing system scale, represents a near-term application of seaweed biology that does not require either coastal permitting or offshore engineering: it is a supply chain problem, not an ocean access problem. The range of seaweed applications, from the coastal longline to the offshore upwelling array, reflects the genuine productivity range of a biology that evolution optimised for the ocean, not the land.