Prof. Burke Hales Ocean Alkalinity Enhancement

Accelerating anthropogenic CO2 releases have driven rising atmospheric CO2, ocean acidification (OA) and climate disruption at rates not seen in earth’s history. While the only viable quantitative remediation on global scales remains the reduction of anthropogenic CO2 emissions, the current-day impacts are already affecting sensitive ecosystems and motivating local mitigation efforts. While so called blue carbon efforts come with short-term CO2-reduction and other ecosystem benefits, the net CO2 removal is short-term. Manipulating ocean alkalinity, alternatively, alleviates ocean acidification locally and intensifies the ocean CO2 sink on timescales of ~10ka, modulated by calcite compensation processes. This approach has proven indispensable in restoring the shellfish aquaculture industry in the Pacific Northwest to historic levels following an OA-driven crash in the late 2000s. However, minerals that are seawater soluble and sufficiently alkaline do not exist in sufficient quantities for viable application of Ocean Acidification Enhancement (OAE). Inducing dissolution of alkaline minerals requires manipulation of seawater chemistry that demands energetic input to overcome thermodynamic limitations. Further, the efficacy of any alkalinity addition is dependent on limitation of spontaneous nucleation and secondary re-precipitation of basic minerals. I present 1) historical efforts at Oregon State to monitor high-amplitude coastal carbonate-system variability and to support the shellfish aquaculture industry by developing seawater monitoring and buffering strategies for ocean acidification mitigation in hatchery culture; 2) pilot study of a wave-powered combined electrolyzer and mineral-dissolution seawater alkalizing system; and 3) preliminary results from a seawater heterogeneous-phase reactor examining the modes of abiotic nucleation of carbonate minerals and the kinetics of the resulting precipitation.