Improved understanding of climate-change consequences in the ocean will come from technological advances and new interdisciplinary efforts. We plan to combine connectivity ecology, metal isotope geochemistry, and paleoclimatology to identify new proxies for ocean acidification. These will be used to assess pH exposures in living organisms (e.g., squid and mussels) and, potentially to interpret the geologic record. The approach is based on the hypothesis that the isotopic composition of larval calcium carbonates reflects changes in seawater chemistry driven by ocean acidification and, in some instances, with associated decline in oxygen levels. The integration of pH and oxygen in proxy development should provide important insights about climate-induced stress on the early life stages of marine organisms.