Constraining Uncertainties in Marine Calcifier Oxygen Isotope Values (δ18O) Across Latitudes and Kingdoms Using a Proxy System Modeling Framework

Paleoceanographic proxy archives encode information about the marine environment, which can yield key insights into past climate variability. In particular, marine calcifiers' stable oxygen isotopic composition ((Formula presented.)) tells us about seawater temperature and oxygen isotope composition. Here, we use a proxy system model (PSM) framework to systematically evaluate the drivers of skeletal/shell (Formula presented.) in three taxa of fast-growing marine calcifiers (crustose coralline algae, bivalves, and sclerosponges) from disparate locations, including high latitudes and deeper waters. We evaluate the impact of the quality of environmental data, the recording season in which the calcifier might document the environmental variability, and the importance of uncertainties on the PSM. Whereas the overall PSM-modeled (Formula presented.) captured the measured (Formula presented.) well at some locations, local environmental variability derived from a reanalysis product and chronological uncertainties limit the ability to effectively model (Formula presented.) at other locations. Using the PSM approach we highlight the complexity of interpreting (Formula presented.) as seawater temperature and oxygen isotope composition in these remote locations.