Ichnological, geochemical and sedimentological data show evidence of widespread low oxygen conditions. Normally oxygenated waters return in the late Griesbachian and there is a moderate increase in tiering above and below the surface. Macrofaunal and ichnofossil diversity decrease markedly during the Smithian, with the appearance of more terrigenous strata possibly reflecting an increased run-off and more brackish conditions. Complete recovery begins in the basal Spathian with an increase in tiering above and below the substrate. Crinoids and ammonoids appear for the first time in the Werfen Formation, and the ichnogenus Rhizocorallium re-appears.
Global correlation is hindered by poor biostratigraphy in the Dolomites region.
However, on a broad scale it appears as though many of the palaeoenvironmental changes are repeated worldwide. The two events resulted in significant ecological disruption and, in both cases, the biotic responses were very similar. Taxa inhabiting the upper water column were unaffected by anoxia and included ammonites and, in the eTo, belemnites. As conditions ameliorated, the biota became more diverse and gradually began to resemble pre-extinction biotas. However, recovery of the early Danian community is initially retarded.