Sarah Brisson PhD Defense
Analysis of palaeoecological and paleoenvironmental change during the Late Devonian mass extinction in the Appalachian Basin
When: July 14, 2023 at 10 am
Where: Beach Hall, University of Connecticut, Room 233
Webex Link: s.uconn.edu/gsci
Mass extinction events represent intervals of tremendous environmental and ecological disruption, often leaving lasting imprints on the content and structure of the biosphere. Results of these events are particularly evident in shallow marine environments, which have some of the longest and most persistent records of life. Studying the ecological response to mass extinction events in shallow marine systems is important to understanding ecosystem evolution through deep time and may yield predictions about future biotic responses to environmental change. In analyzing changes through these events, we can interpret factors framing landscapes, gaining a more nuanced understanding of the intersection of geological and biological systems. Here, I examine ecological and environmental gradients in the shallow marine Appalachian Basin through the first pulse, the Lower Kellwasser event (LKW), of the FrasnianFamennian (F-F) Extinction, which I use to establish methods for quantitative comparison of ecological gradient analyses through time. Using brachiopod abundance data and stable isotope records from across a transect of the Appalachian Basin, I characterize changes in the ecological and environmental gradients through the LKW interval. Specifically, I (1) evaluate changes in regional brachiopod community structure resulting from the extinction using nonmetric multidimensional scaling (nMDS), (2) create a method for quantitative comparison between pre- and post-extinction nMDS ecological gradient analyses, and (3) document and examine regional shifts in marine nitrogen cycling associated with the extinction interval
For more information, contact: Christin Donnelly at christin.donnelly@uconn.edu