The Late Palaeozoic phytoplankton blackout - Artefact or evidence of global change?

The remarkable temporal coincidence of the Phytoplankton Blackout with plate tectonic processes during the assembly and breakup of Pangaea and the concomitant rise of land plants towards the end of the Devonian provide arguments that nutrient depletion in the ocean may have played a decisive role in controlling the phytoplankton blackout. Contrary arguments in favour of oceanic eutrophication, changes in life cycles of dominant phytoplankton groups or selective preservation are discussed and weighed against the scenario presented here. Metazoan evolution seems only loosely linked with the phytoplankton blackout. However, there is good agreement between phytoplankton and reef evolution throughout the Phanerozoic.