OPUS: Documenting and Preserving the Evolutionary and Environmental History of Silica-Bearing Freshwater Protists

Fossils reveal life forms on Earth during ancient time periods. Tracing fossil remains over time helps us understand evolutionary processes, extinction events, and shifts in geographic patterns of organisms, especially in response to environmental changes such as warming events, ice ages, and shifts between wet and arid climates. Linking past shifts with alterations in the types, abundances and distributions of species can provide clues of the potential impacts of future changes.

The majority of fossil discoveries are of plants and animals, which represent a small slice of life forms on Earth. The vast majority of species and genetic diversity are found in microscopic forms, including organisms called protists. Despite the importance of these tiny organisms, their use in understanding the impacts of environmental change is severely limited because very few fossil records exist.

Over the past three decades, the PI has uncovered numerous fossil deposits rich in these microscopic organisms that span millions of years of geologic time, and significant periods of environmental change. The objective of this work is to synthesize the extensive body of information on past microscopic life, with the goals of improving the ability of scientists to model future impacts of environmental changes on Earth’s ecosystems, and to better understand evolutionary patterns of these microbes.

A broader impact of this work will include securing and archiving the extensive fossil collection, and associated data, in an established museum to benefit future exploration of these important organisms.

Being an OPUS award, this project is synthesis driven, using an extensive fossil database of freshwater microfossil species established using scanning electron microscopy (SEM) analyses of hundreds of rock samples from numerous North American sites. Samples and specimens were derived from rocks taken from deep drilled cores, numerous outcrops, and subsamples of rock matrices from plant and animal macrofossils archived at multiple museums.

The sites span 82 million years of geologic history dating from the Cretaceous. Documentation of new species, morphological traits, and estimates of environmental conditions will be determined for each protist group represented in the fossil collection. Next, a comparative synthesis of the diversity, distribution, ecology and morphological form across all groups will be made.

The synthesis will also evaluate the potential of each protist group to migrate under different climate scenarios, their use as bioindicators, the extent of evolutionary change, and provide estimates of minimum age constraints for use in molecular phylogenetic studies. All field and laboratory results will be digitized and organized into catalogs by group and site, and made available to the scientific community.

Original notes and data will be deposited in the Lear Archive Collection at Connecticut College, and all rock samples, processed slurries, SEM mounts and prepared slides archived at established museums.

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.