Lower Danian bivalves, Stevns Klint, Denmark: continuity across the K/T boundary

The paleoenvironmental change at the K/T boundary at Stevns Klint is a change from an upper Maastrichtian bryozoan bioherm environment, with different faunas from the bioherms and from the interbiohermal basins, to an early Danian environment comparable to the biohermal basins, except for a nearly complete lack of bryozoans in the lowermost Danian. The bivalves exhibit a drastic reduction in species number when the complete faunas are compared. However, a within-habitat comparison between the Maastrichtian interbiohermal basins and the Danian shows an increase in the number of infaunal species across the boundary. A decline in the number of epifaunal species is related to the lack of bryozoans, acting as substrates for epibyssate bivalves. Comparison with other K/T boundary sections rich in marine mesobenthos, does not support the presence of general patterns in the faunal change at the boundary.