Nearly all of the continental shelf waters would have had to become severely hypoxic to account for the magnitude of the extinction, but such a catastrophe would make it difficult to explain the very selective pattern of the extinction.
Case todas as augas das plataformas continentais se deberon facer moi hipóxicas para que se poida explicar a magnitude da extinción, pero cunha catástrofe así sería difícil de explicar o patrón moi selectivo da extinción.