A Synthesis of Eastern Oyster (Crassostrea virginica) Growth and Calcification Responses Under Changing Environmental Conditions

Abstract Eastern oysters ( Crassostrea virginica ) are foundational reef builders and ecosystem engineers that provide habitat complexity, enhance biodiversity, and influence biogeochemical cycles by shifting local carbonate chemistry in estuaries along the U.S. Atlantic coast and Gulf of Mexico. However, the environmental ranges governing oyster shell growth and calcification rates remain poorly constrained because available studies vary in the metrics quantified, experimental settings, and spatial coverage. We synthesized existing literature on C. virginica growth and calcification, assessing directional responses to changing environmental conditions. Variability in ecological, spatial, and temporal scales among studies and disparities between laboratory and field-based measurements complicate direct comparisons. Despite heterogeneity in the synthesized data, consistent patterns emerged; shell growth limitations were common at salinities below ~ 12 in U.S. Gulf of Mexico populations, and calcification declines were frequently observed under acidified conditions (pH < 7.7) in U.S. Atlantic populations. By summarizing patterns across life stages, regions, and study types, we highlight environmental stressors likely to impair oyster reef resilience and function. A more integrative research approach, incorporating both individual- and reef-scale processes across experimental and natural settings, is critical for refining predictions of oyster reef resilience. Standardized methodologies and interdisciplinary frameworks will enhance our ability to quantify the role of oyster reefs in carbon cycling and assess their response to future environmental stressors.