UC Riverside

Capitalizing on the diverse pool of students and early geoscience exposure in Riverside County, the NSF Geopaths Geoscientist Development (GEODE) Program at UCR is designed to remove barriers, recruit, and retain underrepresented students into the geosciences, the least diverse of the STEM fields. We report the results from the GEODE Internship Program that offered 10-week paid student internships, providing the opportunity for students to be exposed to the geosciences through research experiences. The students agreed that participating in research increased their interest in conducting scientific research in the future, reporting benefits of new research skills, career preparation, and networking. The studies herein were conducted with the assistance of undergraduate interns, highlighting the potential for rigorous research while strengthening geoscience educational pathways and increase diversity in STEM. The analysis of sclerobionts is a powerful tool for understanding ecological relationships and their trace fossils provide opportunities to study organisms not well-preserved. We examined sclerobionts on Hyotissa hyotis oysters from the Miocene Latrania Formation near Ocotillo, California, an ancient shoreline of the proto-Gulf of California. We analyzed occurrences and abundance of sponges, polychaetes, bivalves, phoronids, and corals. Combining taxonomic diversity with encrusting intensity yielded a more accurate representation of the dynamics of a hard substrate community than diversity alone. An Entobia ichnofacies, this assemblage supports a model of sediment starvation in the fan-delta deposits of the Latrania Formation.

We examined sclerobionts on modern Mercenaria mercenaria bivalves from Shelter Island, New York, in the Peconic Bay, an estuary with a history of pollution and hypoxia. We analyzed occurrences and abundance of sponges, polychaetes, bryozoans, barnacles, and molluscan attachment scars. Encrustation occurred with similar intensities on both surfaces of the valves and the co-occurrence of both deep- and shallow-tiered borings indicated the shells were exposed predominantly to a low energy environment, with periodic reworking events. For community studies involving encrusters, we found no added benefit from including heavily fragmented shells with complete shells. If complete valves are unavailable, we suggest examining valves >50% complete will yield robust results.

We present the preliminary data on a sclerochronological and isotopic analysis of the Miocene oyster Hyotissa hyotis.