Using Phytoplankton To Sequester Carbon

Using phytoplankton to help sequester carbon. (Image: Marek)

This week, I had the opportunity to chat with Philip Kithil, CEO, and Salvador Garcia, CRO, from Ocean-Based Climate Solutions to chat about how their Autonomous Upwelling Pump systems are pumping deep-ocean nutrient-rich seawater to fertilize phytoplankton on the ocean surface to sequester carbon.

Why did you start OBCS?

Philip: “The climate was front and center from day one. What sparked the idea of upwelling cold water to the surface was Hurricane Katrina in August 2005, one of the strongest hurricanes to hit the US Coast. Colder ocean waters slow down hurricane intensity. So our team ran some tests in the Gulf of Mexico in October 2005 to see if we can bring up cold water to the surface, and it worked! That same month, I had a phone call with Rod Johnson and Tony Knap at Bermuda Institute of Ocean Sciences about upwelling nutrients. They invited our team in December 2005 on a cruise to test the pump. And it worked! Since then, our technology has evolved into what I think is a silver bullet for climate change to get us back to 300 parts per million CO2 by 2100. And I’m firmly convinced we can do that. I’m a serial entrepreneur; this is startup number six since 1972. Previously worked in and sold my automotive safety smart airbag technology and started the predecessor to OBCS, Atmocean, in 2006. 

What are phytoplankton/marine snow, and how do they impact the ocean system in terms of conventional life and carbon capture?

Salvador: Marine snow is dead, eaten, or excreted phytoplankton and fish. It’s chunks of that organic biological matter that gently falls to the seafloor. It also serves as nutrients for deep-ocean creatures that ultimately start piling up on the seafloor, turning to what we know today as limestone. For example, The White Cliffs of Dover is an example of limestone peeking out of the ocean, shelled organisms that fed on phytoplankton over millions of years, billions of years.

Philip: And so look out the window you see a leaf on a tree. That’s a photo synthesizer. It takes in CO2 from the atmosphere, takes energy from the sun, takes water from the tree’s roots from the ground, and does photosynthesis and gives off oxygen. Phytoplankton is the very same thing, but they’re in the ocean, and they’re microscopic; they’re not the size of a leaf on a tree. So it’s the same process. It’s just out in the ocean, and it’s huge because of the scale of the oceans and the doubling time of phytoplankton. They double in mass every 24 hours. And so our solution is a much faster process out in the sea, which is 70% of Earth’s surface, absorbing CO2 through photosynthesis converted into solid carbon, which becomes marine snow. It then sinks to the seafloor while feeding the fish and the ocean’s mid-level and deep-level life forms.

Salvador: 99.9% of all CO2 is held in limestone deposited on the seafloor. It got there from phytoplankton and fish over millions of years. Our climate solution is to trigger phytoplankton blooms year-round in the ocean gyres, far offshore. There’s little to no phytoplankton in the center of the ocean gyres – because the sunlit upper ocean is starved of nutrients – it’s a low nutrient, low chlorophyll zone. Due to the warming of our oceans caused by excess atmospheric CO2 absorbing heat from the sun, about 40% of the world’s phytoplankton has disappeared since 1950. So the lack of phytoplankton contributes to more atmospheric CO2. Because our technology is just a one-time upfront cost yet lasts 80 to 100 years and is powered by free renewable wave energy, the cost per ton of CO2 removed decreases by half every year.

Why does Autonomous Upwelling Pump (AUP) technology make sense?

Philip: An AUP is designed to trigger year-round phytoplankton blooms, extending more than 500 meters (1,640 feet) into the nutrient-rich layer of our oceans to pump up, or upwell, cold nutrient-rich seawater to stimulate phytoplankton growth; powered entirely by 100% renewable ocean wave energy. An AUP is a buoy tethered to a 500-meter long tube with a one-way valve at the bottom, weighted by a two-ton weight, to keep it vertical. As the buoy rises on a passing wave, the entire tube also rises, closing the valve at the bottom and moving the water upward by the height of the wave. On the wave downslope, the whole tube sinks, opening a valve at the bottom filling the tube with that nutrient-rich seawater, and releasing the topwater into the sunlit zone, where it quickly triggers photosynthesis and phytoplankton growth.

Where in the world do you plan to start, and who do you have onboard thus far?

Salvador: The North Pacific and the subtropical South Pacific are the best starting locations for our application. Due to its vast size and slow-moving circulation patterns, the Pacific Ocean contains the oldest ocean water, giving us 1,000 plus years of storage at depth. Furthermore, the North Pacific is a low nutrient, low chlorophyll zone – perfect for our application. The subtropical South Pacific is a high nutrient, but low chlorophyll zone, meaning the sunlit surface is ready to go once critical trace minerals (such as iron) are upwelled. So the same application will work there. Our AUPs can be deployed in the center of any ocean gyre where there is low phytoplankton. However, it makes the most sense to start with where there is the most potential for long-term storage.

How does your technology compare to the last generation of Ocean Technology and what are you doing differently?

Phil: What we have done is engineer the Autonomous Upwelling Pump for extreme durability. The ocean is the harshest environment on Earth. Huge waves, bad weather, wind, you name it. Now you have to realize that 99% of our device is underwater, so it’s not going to see those winds and most of those extreme events. The weather makes no difference. AUPs are very rugged, durable, long-lasting, and autonomous, meaning they are free-drifting with the ocean currents. That reduces the stress compared to if each AUP was anchored to the seafloor. So by letting it drift with the currents, you’re eliminating more than 50% of the harshness of the ocean environment.

Salvador: Fisheries also benefit from the AUPs being free-drifting, with localized phytoplankton blooms traveling with the currents of the ocean gyres. Fisheries will emerge, develop or translocate within the arrays of AUPs. This benefits fish, tuna, sharks, dolphins, and whales. Think of drifting oases of vibrant sea life in the middle of ocean deserts! Other co-benefits are jobs at port cities where AUPs are deployed – our technology will spur a new industry. Another benefit is its low cost per ton of CO2 removed. AUPs are designed to operate for 80-100 years and remove approximately 257 tons of CO2 every year, making the long-term cost under $10 per ton of CO2 removed.

What are the challenges for Ocean-based Climate Solutions?

Phil: So our number one challenge at the moment is gaining the confidence of investors. The second is to sign up corporations to become net-zero CO2 footprint within 10 to 15 years. But this will happen on its own as there is such a high level of public and shareholder interest in solving the climate crisis. To help these corporations, we have a funding methodology called Stock for Carbon. Public companies can purchase AUPs at no cash expense by paying using their publicly traded stock. Because our solution is nature-based, we are taking advantage of biological effects in the open ocean, which are currently untapped, meeting the criteria of “additionality” – the CO2 removal would not have happened without our involvement. Also, we can measure and verify the CO2 absorbed by the phytoplankton using biogeochemical ARGO sensors. These are the robotic floats that can measure ocean chemistry and carbon sequestration from 2,000m deep up to the surface. And then, we have the business model that makes it fundamentally doable with many corporations who are now very much wanting to become carbon neutral.

Salvador: Another challenge is governance. It’s in the open seas; it’s not near the coast. So we do follow all the laws that we’re aware of in terms of executing what we do in international waters. Still, perceptions and arguments do arise about our method. Another challenge is or will be public acceptance of our practice on our implementation. We want to be close with all stakeholders, the world, and the public. One of our fundamental values is transparency. The data that the ARGO’s provide is publicly available online. Anyone who desires to review the data our AUPs produce can access it – so independent scientists or organizations can verify our work.

Why do you believe your technology is a silver bullet?

Philip: Because we partner with phytoplankton, and our technology is modular. AUPs are not big devices. The ocean is vast. It’s possible to produce and deploy a large number of AUPs and space them in the open ocean so they are invisible from an airplane, not hazardous to shipping, and sequester CO2 in the deep ocean and help feed fish! Also, they oxygenate and cool the upper ocean and provide jobs at port cities! The oceans hold 50x more CO2 than our atmosphere and 20x more than on land. The ocean is the place to solve climate change, and this is the technology that can do it at the lowest cost with the least risk.  


The ocean is a body for change, using its lifeforms to mitigate the climate crisis. Utilizing this seemingly terrestrial process in “soil” rotation of phytoplankton to create marine snow in bulk, there is significant potential to not only remove carbon from the atmosphere via photosynthesis but also create a healthier ocean as a result.

As for whether or not this technology is a silver bullet…well let’s wait and see. Combating climate change is a multilateral approach across all industries in all sectors in all walks of life. No one is immune to it. No one is excused from it. If this technology is a silver bullet, it will certainly help speed up the rate at which we can remove CO2 from the atmosphere.

About The Author

Matthew Morris Impact

Matthew Morris

Impact Investment Fellow

Matt is an Impact Investment Fellow with Vectors Angels as a part of the organization’s sustainability team. While most disciplined in power generation and energy storage, Matt takes on a wide array of technologies in the sector.

Leveraging these skills, Matt works with early-stage startups on fundraising and go-to-market strategies, understanding their market, and competitor due diligence.

Matt holds a BS in Finance and Economics from Boston College and an MEng from Boston University in Materials Science & Engineering. Matt’s graduate research and passion focused on the impact fundraising mechanisms and financial institutions have on the success of startups in the renewable energy and cleantech industries. His current interests involve developing new financial instruments to fund demo and pilot “tough tech” projects and closing the commercialization gap.

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