A Multivariate Analysis of the Recovery of Calcareous Nannoplankton and Foraminifera from the Cretaceous-Paleogene Mass Extinction

While the extinction of microplankton related to the Cretaceous-Paleogene (K-P) boundary has been studied in great detail, the subsequent recovery has not been intensely investigated. To understand how the ecosystem and microplankton recovered from the K-P extinction, multivariate analyses were run on foraminifera and calcareous nannoplankton. Non metric multi-dimensional scaling (NMS) was used on datasets from three sites around the world. The results of the NMS were compared to species abundance, diversity, and carbon isotope data to determine what ecological parameters were being described by the analysis. Four main recovery intervals were discovered that relate to changes in species dominance, NMS values, and the carbon isotopic gradient. These four intervals are found in both foraminifera and calcareous nannoplankton indicating there is close relationship to the recovery of these organisms. While there are minor differences in the recovery based on location, the overall patterns appear in all sites studied. This implies that these patterns are not local phenomenon, but rather are showing the global reestablishment of the biological pump and ocean function.