Evolution and paleoecology of the Late Ordovician North American epicontinental brachiopod fauna through diversification and environmental change

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During the Ordovician period (485-444 million years ago), the Great Ordovician Biodiversification Event marked the rise of the filter feeding Paleozoic Fauna during a sustained sea level rise and greenhouse climate regime. This was interrupted by a glaciation causing the Late Ordovician Mass Extinction that devastated the shallow marine ecosystem. Global biodiversification trends during this critical interval in the history of life are becoming clearer, but evolutionary innovations in individual lineages and the changes within benthic communities during these events are only beginning to be studied. We do not understand, for example, what characteristics made some lineages more successful while others became extinct. We do know, however, that brachiopods were among the most abundant and diverse elements of the marine ecosystem throughout these events making them an excellent proxy for changes in the shallow marine ecosystem as a whole. My research program will take a quantitative approach to studying evolutionary trends in time and space and understanding the community-level changes behind these major biodiversification and extinction events. Students will use a hands-on specimen-based approach to build morphometric (shell measurement) and ecological (species abundance, presence/absence) databases. These databases will be examined using multivariate statistical methods (e.g. principal component analysis, non-metric dimensional scaling) to search for overarching trends within individual brachiopod lineages and regional collections of ecological data. Initially, my research will focus on the pre-extinction Ordovician biodiversification as fossil brachiopods from that interval are best preserved and most abundant. Brachiopods from the Interlake of Manitoba and areas near Lake Simcoe and Manitoulin Island in Ontario will be used to compare trends in two different settings. During the Ordovician, southern Ontario was subject to regular intense tropical storms disrupting the shallow marine environment and rapidly rising sea level. At the same time Manitoba was located near the equator in a relatively stable intracratonic setting and quiescent environment, but the fauna may have had to adapt to a stagnant water column with periods of poor circulation in the water column. With a better understanding of how benthic organisms such as brachiopods adapted through these major evolutionary shifts during intervals of sea level change, we may be able to better predict how the modern shallow marine ecosystem will respond to climate change and sea level rise. While modern biological studies have documented the short-term effects of climate change and sea level rise, only the fossil record can show the effects of environmental change on the thousand- to million-year timescale. As Canada continues to plan for the effects of climate change in the future, this research will provide insight as to how the shallow marine ecosystem adapts to environmental shifts.