Effect of nutrient availability on marine origination rates throughout the Phanerozoic eon

摘要

Throughout the Phanerozoic eon (542 Myr ago to the present), the diversity of marine organisms has varied. These changes are fairly well resolved, but the controls on origination and diversification are less well understood. Changes in origination rates are thought to arise from a complex interplay between biological forces such as competition and predation, phytoplankton stoichiometry and bioturbation and abiotic controls such as environmental setting, temperature, sea level and nutrient availability. Here we statistically assess relationships between records of environmental conditions and global marine origination rates during the Phanerozoic. We find significant positive correlations between changes in origination rates and variations in indicators of continental weathering (87 Sr/ 86 Sr) and phosphorus recycling (34 S), as well as a significant negative correlation between variability in origination rates and eustatic sea level. We suggest that continental weathering, phosphorus recycling and sea levelthrough the exposure of the continental shelf area to erosionare all controls on the availability of marine nutrients. We therefore propose that over secular timescales, nutrient availability, as controlled by continental weathering and phosphorus recycling, is an important regulator of genus-level origination in the marine realm, with periods of increased nutrient availability associated with higher origination rates.