Macrozooplankton and Late Ordovician climate change

Researchers report that two communities of graptolites, a group of extinct macrozooplankton that lived before the onset of the Late Ordovician mass extinction, became less diverse and dominated by fewer species than earlier communities, likely through changes in low-oxygen habitat availability, suggesting that the aggregation of subtle shifts in community structure caused by environmental degradation may culminate in abrupt mass extinction events. - Read at PNAS.org

Article #16-02102: “Graptolite community responses to global climate change and the Late Ordovician mass extinction,” by H. David Sheets et al.