The Cretaceous/Paleogene (K/Pg) mass extinction was the youngest of the five largest known extinction events. Because it occurred only 65 million years ago, records of this event are much more common and generally much less altered than records of the other four great mass extinctions. Consequently, the K/Pg event provides an unparalleled opportunity for documenting how global ecosystems recovered from one of the most biologically devastating catastrophes ever identified. We propose to take advantage of that opportunity by using K/Pg geochemical and paleontologic records to test fundamental hypotheses of marine biological recovery from mass extinctions. In particular, we propose to test (1) whether the geologic record supports the hypothesis that planktic evolution was a necessary precondition for the recovery of organic fluxes to deep water (or vice versa), and (2) whether post-extinction records of marine plankton are consistent with a low-productivity Strangelove-ocean model or an altered-ecosystem normal-productivity model of ecologic recovery from the K/Pg mass extinction.
