A study finds that the dispersion and coalescence of continental plates influence marine biodiversity. The breakup of continents is thought to increase biodiversity, whereas aggregation into supercontinents is thought to reduce biodiversity. Using a global database of marine animal fossils and a paleogeographic reconstruction model, Andrew Zaffos and colleagues tested how plate tectonics regulates genus-level richness—a proxy for the number of species in an ecosystem—of marine invertebrates. The model indicates a positive association between richness and continental fragmentation during coalescence-breakup cycles from the Cambrian Period to modern times. In particular, the assembly and disassembly of the supercontinent Pangaea appears to have influenced the trajectory of marine biodiversity over the past 443 million years. The model suggests that the state of continental fragmentation at any given time influences the state of global biodiversity for tens of millions of years. The study found that the strength of the positive correlation between marine richness and continental fragmentation was greater than that of the negative correlation between marine richness and continental coalescence. The latter had a small negative or stabilizing effect on marine richness. According to the authors, coalescence-breakup cycles of continental landmasses, together with other macroevolutionary processes, likely drives long-term global biodiversity patterns. - Read at PNAS
Article #17-02297: “Plate tectonic regulation of global marine animal diversity,” by Andrew Zaffos, Seth Finnegan, and Shanan E. Peters.