About This Project
This proposal addresses scalable CO₂ removal by enhancing mineral dissolution and precipitation with photosynthetic organisms in mine waters. By transforming abandoned mine pit lakes into carbon sinks, we combine bioweathering with industrial waste reuse as sustainable feedstocks. Success of this project will unlock a novel, low-cost, eco-friendly pathway for mega- to gigaton-scale carbon removal, with simplified monitoring, reduced land-use conflicts, and long-term carbon stability.
Ask the Scientists
Join The DiscussionMotivating Factor
Enhanced rock weathering (ERW) and ocean alkalinity enhancement (OAE) are emerging technologies to sequester CO2 to combat global warming. However, they are constrained by the difficulty of measurement and monitoring in open systems, as well as potential ecosystem disturbances [1, 2, 3]. Repurposing abandoned mine pit lakes for rock weathering and alkalinity enhancement can address these issues. Pit lakes are degraded, nominally contained aquatic systems that frequently lack robust ecosystems and can be easily monitored. Additionally, former mine sites often have finely ground alkaline mineral feedstocks available on or near the site, which can be dissolved into the water to promote absorption of atmospheric CO2, leading to carbonate mineralization. A major challenge of this approach is accelerating the dissolution of these types of alkaline minerals in an energy- and cost-efficient manner.
Specific Bottleneck
To accelerate feedstock dissolution, we may be able to use photosynthetic bioweathering (PBW). Algae and cyanobacteria are promising candidates, as they are tested for carbon capture and utilization (CCU) [4,5], known to increase silicate weathering and carbonate precipitation rates in nature [6, 7], and can grow on alkaline feedstock [8]. While photosynthetic microbe use in climate tech has been demonstrated, its large-scale application for CO₂ removal (CDR) via bioweathering remains unexplored. Key gaps include understanding microbe-feedstock interactions and their effects on dissolution rates and subsequent CO₂ sequestration and storage efficiency in aquatic settings. Photosynthetic growth in low nutrient mine drainages is also poorly understood, complicating baseline CO₂ uptake quantification. Investigating PBW’s impact on mine water chemistry is crucial to assessing the potential of mine pits as energy- and cost-effective CDR reactors.
Actionable Goals
To address challenges in PBW in mine pit lakes, research should:
- Characterize the alkaline feedstock and mine water
- Select multiple pure algal/cyanobacterial strains for simplicity and to minimize culture-specific limitations
- Assess the baseline growth and CO₂ uptake efficiency of selected organisms in optimal conditions vs. simulated/real mine water in the lab (targeting neutral to mildly basic initial conditions for higher growth and CDR rates)
- Investigate how photosynthetic growth affects the dissolution rates of alkaline industrial feedstocks and CDR, as compared to abiotic weathering in mine water
- Monitor changes in chlorophyll, alkalinity, DIC, EC, DO, pH, major ion and metal concentrations
- Model ionic speciation and carbonate saturation
- Determine dissolution rates of metals from the feedstock
- Determine CO2 sequestration and carbonate precipitation rates
- Evaluate the changes in feedstock chemistry and carbonate mineralogy
Budget
N/A
Meet the Team
Team Bio
Aquarry, founded in 2023 by Kate Murphy and Spencer Whitman, is a four-person team, including three PhDs. Our 760 sqft lab and office in Golden, CO, hosts all experimental work. With a hands-on, collaborative approach, we meet weekly to discuss progress, troubleshoot, and generate ideas. Our expertise in geochemistry, hydrogeology, microbiology, materials science, and physics drives innovative R&D, bridging fundamental science with real-world scalable carbon dioxide removal (CDR) solutions.
Cansu Floyd
Dr. Cansu Demirel-Floyd is a geochemist and geomicrobiologist specializing in biomining, mineral weathering, carbonate biomineralization, and carbon dioxide removal (CDR). She holds a Ph.D. in Geology with a focus on geomicrobiology and planetary science, where she investigated microbe-mineral interactions, biological weathering by cyanobacteria, and carbon cycling in extreme environments. Additionally, she has authored multiple peer-reviewed publications on mineral weathering, biomining, carbonate biomineralization, and carbonate system geochemistry. Her expertise in geochemical modeling, geochemistry, and geomicrobiology lab methods and carbonate chemistry informs her work in developing scalable CO₂ sequestration solutions using alkaline feedstocks in mine pit lakes.
As a Laboratory Scientist & Manager at Aquarry, Inc., Dr. Demirel-Floyd leads abiotic laboratory studies on alkaline feedstocks and mine water characterization for CDR applications. Her work focuses on:
- Chemical & mineralogical feedstock screening to evaluate CO₂ sequestration potential
- Baseline abiotic dissolution experiments to quantify feedstock dissolution rates
- Post-leach cleanup strategies to mitigate metal release from alkaline feedstocks
- Investigating the carbonation efficiency of feedstocks to enhance CO₂ mineralization and stability
Previously, at Endolith Mining, a former subsidiary of Cemvita Inc., Dr. Demirel-Floyd led Ni and Co bioextraction research while also contributing to Li and Co bioextraction projects. She applied biogeochemical and biomining techniques to enhance metal recovery from ores, integrating microbial-assisted leaching strategies for sustainable resource extraction.
These green biotechnology efforts with her extensive background support leading the efforts for integrating bio-enhanced rock weathering (PBW) for scalable CO₂ removal in mine pit lakes, advancing biotechnical solutions for climate mitigation.
Spencer Whitman
Dr. Spencer Whitman is a hydrogeologist and geochemist specializing in fluid flow, metals transport, and the integration of field and laboratory measurements with numerical simulation of hydrologic and geochemical processes. He holds a PhD in Hydrogeology from the University of Nevada Reno, where he studied potential groundwater contamination due to transport of metals from acid mine drainage in joint project between private industry, the Nevada Department of Environmental Protection, and the University. Prior to, during, and after his graduate studies, Dr. Whitman worked as a consulting geoscientist for the mining industry, working on projects ranging from baseline studies to support permitting for a copper mine, to closure scenario evaluations for uranium mines. Throughout his work, Dr. Whitman has maintained strong relationships with consultants, industry partners, regulators, and researchers across the mining ecosystem. At Aquarry, Dr. Whitman sets broad research directions and goals for the company, works with the technical team to solve challenges, and works closely with the CEO to align technical goals with company objectives. Dr. Whitman also works with the CEO to foster collaboration with mining industry partners. Dr. Whitman is currently a fellow of the West Gate program at the National Renewable Energy Laboratory and will be leading joint research efforts between Aquarry and the National Renewable Energy Laboratory.
Audrey Grimes
Audrey completed her undergraduate degree in physics at Middlebury College. She has previous research experience investigating offshore wind measurements using LiDAR sensing at Woods Hole Oceanographic Institute, where she was also introduced to topics in ocean alkalinity enhancement. Additionally, she has worked as a failure analysis engineer at FUJIFILM Dimatix, where she gained laboratory experience in materials science and data analysis. She was introduced to enhanced rock weathering through a geochemistry course project at Middlebury, where she modeled rock weathering in soils and contributed to a peer-reviewed article on basalt weathering in tropical soils. At Aquarry, Audrey uses her physics background to engineer prototype reactors for conducting experiments, as well as researching and implementing sensors and innovative MRV practices. She also assists with data analysis, modeling, and running laboratory experiments.
Kate Murphy
Dr. Murphy holds a PhD in Materials Science & Engineering from the University of Pennsylvania. Following her doctorate she worked within the corporate research organization of the Swiss technologies firm ABB before joining Xerox PARC, the groundbreaking research center which invented the personal computer and had a significant portfolio in climate tech. At PARC she led or contributed to a wide array of projects, from producing structured lithium-ion battery cathodes to business development for roof-cooling paint to solar geoengineering. After spending some time as the first employee of electrification startup Elmworks, Dr. Murphy joined the venture builder Deep Science Ventures in March 2022 to explore abiotic carbon capture. She spent several months surveying the landscape of technologies and startups in carbon mineralization and ocean alkalinity enhancement, identifying problems, and coming up with solutions, ultimately leading to the formation of Aquarry.
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