The Late Devonian extinction, which is one of the five largest mass extinction events in the history of life on Earth, consisted of several extinction events in the Late Devonian Epoch. The causes of these extinctions are unclear, but leading hypotheses include changes in sea level and ocean anoxia, possibly triggered by global cooling or oceanic. The Late Devonian extinction occurred over a long time, making it difficult to assign a single cause and separate cause from effect.
The end-Frasnian extinction, which happened about 375 million years ago, is the only one of the three important extinctions in the latter half of the Devonian Period that is normally considered large enough to be one of the “Big Five” . The extinction was most pronounced in tropical environments, particularly in the reefs of the shallow seas. Reef-building sponges called stromatoporoids and corals suffered losses, and stromatoporoids finally disappeared in the third extinction near the end of the Devonian. Brachiopods associated with reefs also became extinct.
While there are several hypotheses about the causes of the Late Devonian extinction, including meteor impact, volcanism, changes in ocean chemistry, oxygen depletion, and glaciation, plant-caused weathering and cooling is arguably the most compelling cause for the end-Devonian extinction. However, scientists are still quite uncertain about what initially caused the Late Devonian extinction.
