The fossil record holds clues that allow scientists to use the past to predict the future and understand how modern ecosystems will respond to anthropogenic climate change. The Mid-Pliocene Warm Period (3.3-3.0 Ma) was an interval of continuous global warming with surface temperatures around 2-3 °C warmer than today. Mid-Pliocene marine invertebrates are well preserved in Yorktown Formation deposits in the Virginia Coastal Plain. Using bulk samples of fossils from before, during, and after the Mid-Pliocene Warm Period, this study developed a dataset of species abundance values and used statistical methods to contribute to the understanding of how climate conditions impact marine invertebrate species richness. Rarefaction analysis results show that species richness declined across the Mid-Pliocene Warm Period. When the Mid-Pliocene Warm Period ended, species richness did not recover to richness levels prior to the temperature increase. Marine invertebrate species abundant during the Mid-Pliocene were able to tolerate warm conditions, while species that are not present during or after Mid-Pliocene warming were not able to tolerate increased temperature conditions. Although marine invertebrates possess strategies to cope with temperature change, the Mid-Pliocene Warm Period was a rapid and geologically short interval (300,000 yrs), and species unable to tolerate warm conditions likely did not survive. These results provide insights into how global warming will impact modern marine invertebrate communities and how large-scale biodiversity patterns could shift.
Topness, Emily, "Decline in marine invertebrate species richness across the Mid-Pliocene Warm Period in the Virginia Coastal Plain" (2022). Geology Senior Theses. William & Mary. Paper 30.