DID PHYTOPLANKTON EVOLUTION FUEL THE DIVERSIFICATION OF THE MARINE BIOSPHERE? NEW EVIDENCE
Marine generic diversity is paralleled by strontium isotope ratios, phosphorus and selenium data (3) indicating continental weathering, and δ13C indicating primary productivity (4). The relatively subdued marine biodiversity of the Paleozoic corresponds to a time of relatively low phosphorus availability and poor food quality of green phytoplankton lineages dominated by acritarchs, whereas diversification of the Modern Fauna through the Meso-Cenozoic occurred during the diversification of phosphorus-rich phytoplankton: coccolithophorids, dinoflagellates, and diatoms.
We assess our suppositions against recently-published biogeochemical models for geologic time scales (5). Major peaks of marine diversity often occur near rising or peak fluxes of silica, phosphorus and dissolved reactive oceanic phosphorus; either major or minor 87Sr/86Sr peaks; and frequently in the vicinity of major (e.g., the Circum-Atlantic Magmatic Province) and minor volcanic events, some of which are associated with Oceanic Anoxic Events.
References: (1) Fischer, A.G. & Arthur, M.A. 1977. Secular variations in the pelagic realm. In Cook, H.E. & Enos, P. (eds.): Deep-Water Carbonate Environments, 19. SEPM (Society for Sedimentary Geology) Spec. Publ. 25.; (2) Sterner, R.W. & Elser, J.J. 2002. Ecological Stoichiometry. Princeton U. Press, Princeton, 439 p.; (3) Large, R.R. et al. 2015. Gond. Res. 28: 1282; (4) Martin, R. E., & Servais, T. 2019. Did phytoplankton evolution fuel the diversification of the marine biosphere? Lethaia. DOI:10.1111/let.12343; (5) Arvidson, R.S. et al. 2013. Geologic history of seawater: A MAGic approach to carbon chemistry and ocean ventilation. Chem. Geol. 362: 287.