Constraining Uncertainties in Marine Calcifier Oxygen Isotope Values (δ18O ${\boldsymbol{\delta }}^{\mathbf{18}}\mathbf{O}$) Across Latitudes and Kingdoms Using a Proxy System Modeling Framework

Abstract 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 () 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 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 captured the measured well at some locations, local environmental variability derived from a reanalysis product and chronological uncertainties limit the ability to effectively model at other locations. Using the PSM approach we highlight the complexity of interpreting as seawater temperature and oxygen isotope composition in these remote locations.