Date of Project

4-27-2018

Document Type

Honors Thesis

School Name

School of Environmental Studies

Department

Environmental Science

Major Advisor

Dr. Bulinski

Second Advisor

Dr. Carlson Mazur

Third Advisor

Dr. Challener

Abstract

Stromatoporoids are calcitic sponges that occurred in the fossil record from the Early Ordovician to Late Devonian period. These sponges interacted with other organisms, especially rugose and tabulate corals. Some corals appear to benefit from the rigidity of stromatoporoids in response to turbulent waters. Stromatoporoids and many corals went extinct during the Frasnian-Famennian crisis when paleoenvironmental parameters were shifting. Studying the relationships between these taxa may provide insight to their vulnerability during the extinction.

This research was performed at the Falls of the Ohio in Clarksville, Indiana. Organisms in the Coral Zone were studied using transect sampling. Each fossil along the 81 meters of transect line was identified, measured, and compass bearing was recorded. Stromatoporoid-coral interactions were also documented. The data were then analyzed and tables were created to summarize fossil occurrences and interactions.

Stromatoporoids accounted for 72.9% of the biomass of fossils identified, demonstrating their dominance in the biostrome. They most commonly interacted with small rugose corals. A meta-analysis using scientific literature compared results from the Falls of the Ohio to other Devonian systems across the world. Tabulate corals were the most common interaction, followed by rugose corals. Delicate corals were likely protected by the rigid stromatoporoid skeleton, but endobionts also competed with their host for food and slowed its growth. For this reason, both commensal and parasitic relationships between stromatoporoids and corals are possible. By studying interactions between these organisms, their life processes, paleoecology, and vulnerability to the Frasnian-Famennian extinction can be better understood.

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