RUI: From Greenhouse to Icehouse: Documenting evolutionary trends in freshwater siliceous organisms over 80 million years of environmental change

Connecticut College, New London CT

Investigators

Abstract

Over geologic time, shifts in global temperatures from warm to cold and vice versa have influenced the evolution and extinction of species, and caused large-scale reorganizations of ecosystems worldwide. The latest swing from Greenhouse to the current Icehouse began over 55 million years ago, concurrent with declines in atmospheric carbon dioxide. The objective of this project is to use the fossil record to examine the evolutionary trends of selected freshwater organisms during the shift from Greenhouse to Icehouse conditions. The project will build a foundation for understanding what freshwater ecosystems were like under globally warm conditions, especially in northern latitudes, and how they responded to cooling temperatures. This will provide a framework for understanding ecosystem responses under future climate warming scenarios. The project will advance evolutionary knowledge of the target lineages, uncover new species, examine the oldest localities harboring freshwater diatoms, provide time-specific markers for calibrating components of the Tree of Life to geologic time, and enhance the value of museum specimens. The project will provide undergraduate research internships, and educational opportunities for the general public through presentations at libraries and senior centers. The goal of this project is to expand knowledge of North American freshwater fossil synurophytes, chrysophytes, diatoms, euglyphids, heliozoans and sponges through documentation of species spanning 80 million years from the Late Cretaceous through the Miocene. Microfossils will be documented in several hundred samples from nine localities, and merged with historical information from the literature and museum records to assemble a database to test specific hypotheses on evolutionary history. The suite of fossil localities will yield an abundance of new species that, in turn, will advance an understanding of biodiversity, biogeography, and evolution of morphological traits for all of the organisms over a critical time period spanning the transition from a Greenhouse to Icehouse Earth. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.