COORDINATED DIVERSITY CHANGES IN CENOZOIC MARINE VERTEBRATE REFLECT CLIMATIC FLUCTUATIONS

Marine vertebrates are key elements of many oceanic ecosystems. Some (like many cetaceans and pinnipeds) represent top predators in their respective food webs. As such, they are at least potentially, quite sensitive to changing climatic conditions that affect these food webs. Here, the Paleobiology Database (paleobiodb.org) was used to collect, process, and refine data on marine vertebrates including: cetaceans, pinnipeds, sirenians, desmostylians, marine birds, pelagic fish, and reef fish to determine whether or not changes in diversity in these groups was coordinated over the Cenozoic, and whether or not these diversity fluctuations are related to changes in the paleoclimatic conditions. Coordinated diversity peaks are present among most of these groups in the Chattian, Burdigalian, and Tortonian. Coordinated diversity troughs are present in the Bartonian, Aquitanian, and Messinian. These changes may be due to changes in oceanic circulation, sea level, temperature, and/or ice volume. Interestingly enough, there is virtually no diversity change in any group across the Eocene-Oligocene (Priabonian-Rupelian) boundary, which is the initiation of the Oi1 glaciation in Antarctica, and one of the most profound changes in oceanic circulation and paleoclimate throughout the Cenozoic. In addition to diversity, taxonomic turnover will also be explored to see if paleoclimatic changes drive changes in the taxonomic makeup of these groups in addition to or instead of changes in overall diversity.