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The EPA has moved the MPRSA research permit for our MACS process to a public comment period. If this permit is approved, we will proceed with a 20-tonne test in the Orca Basin.
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MACS testing stages
1. We have collected seawater and sediment samples from the basin to provide a baseline, and are continuing to expand on that work. These will act as a control to detect environmental change.
2. We will lower 20 one-tonne biomass packages into the brine pool. Once they reach the seafloor, we release them from the ship’s winch line using an acoustic release.
3. Samplers will be recovered 8 and 14 months after placement using a second acoustic release, and will return brine, biomass, and sediment samples to the surface for chemical analysis.
4. We will monitor the site after deployment and recovery to understand the longer-term response of the environment.
Over the last three years, we’ve conducted rigorous laboratory and in-basin experiments showing the effectiveness of our approach. Research led by our collaborators at the UCSB NOISE Lab confirms that anoxic brine pools — that is, extremely salty basins of water that are oxygen-free — can be exceptional sites for safe, long-term organic carbon preservation.
Next, we plan to scale our testing with a 20-tonne field experiment, which will increase our understanding of how brine pools might contribute to climate mitigation. Our research goals are to: 1) study how biomass breaks down in brine at larger scales under realistic conditions; and 2) test and optimize our proposed Measurement, Reporting, and Verification (MRV) systems.
In 2024, we applied for an EPA Marine Protection, Research and Sanctuaries Act (MPRSA) research permit to place 20 one-tonne bales of compressed sugarcane bagasse in the Orca Basin, south of Louisiana. The EPA has now reviewed our application and approved advancing it to the public comment period, where it will be open to comments until July 14, 2025.
Should this permit be approved, we will embark on the Orca Basin project and pursue this research over the course of 2.5 years. Conducting this in-field testing will provide us with crucial information on how isolated, anoxic environments respond to the addition of enhanced quantities of organic material. It will address questions related to feasibility, potential risks, and MRV technologies that must be understood before consideration of commercial-scale activities.
The results of this work will be the first direct evaluation of our MACS approach at this scale.
The Orca Basin is a deep, hypersaline, oxygen-free (anoxic) basin located 186 miles (270 km) off the coast of Louisiana, on the U.S. continental shelf.
This depression in the seafloor is filled with an extremely salty brine containing roughly 10x the saline level of normal seawater. The permanently anoxic waters of the Orca Basin sit below ~7,200 ft (~2200 m) of seawater, isolated from the overlying ocean for thousands of years by a natural interface that prevents mixing between the two water bodies.
Although brine pools are common across the continental shelf, the Orca Basin is particularly large and more than 650 ft (200 m) deep. The proposed research will occur within a 3-square-mile (8 km2) region in the middle portion of the basin.
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The biomass for this experiment will consist of 20 one-tonne bales of sugarcane bagasse that has been dried and densified into briquettes. Sugarcane bagasse is a woody material left over after sugarcane processing. It's not needed for food or other uses, and is produced at a rate that exceeds storage and management capacity.
Before placement, we will verify that our biomass is free of harmful chemicals or contaminants, and compress it so that it sinks quickly and consistently to the seafloor. The briquettes will be packaged into 20 one-tonne bales using burlap bags and manila rope. Bagasse, burlap, and manila rope all chemically resemble the naturally occurring organic matter already dissolved in the brine.
Learn how Marine Anoxic Carbon Storage (MACS) uses natural systems to rocesses carbon in ocean brine pools.
Download the MACS One-SheetExplore the goals, methods, and importance of our upcoming 20-tonne field test in the Orca Basin, off the coast of Louisiana.
Download the Project Explainer
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