Margaret Fraiser

Assistant Professor

356 Lapham Hall
(414) 229-3827
mfraiser@uwm.edu

PhD: University of Southern California
MS: University of Southern California
BS: University of Georgia

Specializations: Evolutionary Paleoecology and Paleobiology

Research:

1. Paleoecology of the aftermath of the end-Permian mass extinction

The end-Permian mass extinction was the most devastating mass extinction of the Phanerozoic and was followed by 5-6 million years of oceanic and atmospheric perturbations during the Early Triassic.  I conduct field work on Lower Triassic strata exposed around the world to determine the short- and long-term effects of these deleterious environmental conditions on marine skeletonized organisms, microbes, and the sedimentary rock record. 

2. Role of elevated atmospheric CO₂ on shallow marine invertebrates in Earth’s history

In Modern times, the atmospheric CO₂ concentration has risen continuously since the Industrial Era.  Passive diffusion of atmospheric CO₂ into ocean-surface waters decreases the pH and CaCO₃ saturation state of seawater, causing a physiological and biocalcification crisis for many marine invertebrates. Understanding the effects of elevated atmospheric CO₂ on shallow marine invertebrates in Earth’s past is important for understanding the biotic crisis that is predicted to occur in Earth’s oceans due to increased anthropogenic atmospheric CO₂ input. 

3. Microbial structures

It is a microbial world and it always has been: microbes were the first life and are the progenitors of all subsequent forms of life on Earth; they populate nearly every environment; they dominate energy flow in the world’s ecosystems today and have throughout the geologic past; and they have shaped the chemistry and physical properties of the planet via their metabolic activities.   I have studied the formation and preservation of microbial structures in a cap carbonate following a Snowball Earth event and in environments deposited after the end-Permian mass extinction.

4. Broad evolutionary patterns

Large-scale evolutionary patterns are recognized throughout the fossil record in taxonomic and paleoenvironmental contexts.  One renowned taxonomic pattern, comprised of three “great evolutionary faunas”, identifies large-scale variations in faunal dominance throughout the Phanerozoic marine record.  Each evolutionary fauna is composed of higher taxonomic groups that share similar histories of diversification and these taxa together dominate the marine biota for a particular extended interval of geologic time.  The expansion of each evolutionary fauna is associated with the decline of the previously dominant evolutionary fauna.  I am interested in deciphering the ecology of the great evolutionary faunas. 

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