Macroevolutionary coupling of marine biomass and biodiversity across the Phanerozoic

Ecosystem function and its evolution depend on the number of taxa and the amount of biomass. For the oceans, spatial and temporal trends in diversity are well known, and spatial variation in biomass within the modern ocean is increasingly documented. Temporal variation in biomass, by contrast, remains undocumented, leaving a crucial gap in our understanding of how the marine biosphere evolved over geologic time. Here, we compiled compositional data from 7,749 marine limestone samples spanning the past 541 million years that document the proportion of sediment comprising the shells of animals, algae, and protists. The data capture temporal variation in skeletal content that is consistent across geologic settings, water depths, and latitudes. The variation largely parallels long-term trends in taxonomic diversity during intervals of diversification and across the three major mass extinctions with high-resolution compositional data, pointing toward a macroevolutionary coupling between marine biodiversity and biomass.