[Eoas-seminar] Gfatter Dissertation

Tue Oct 20 15:00:00 EDT 2026

Good afternoon,

Please join us for Christian Gfatter's Dissertation on October 26, 2026 at 11 am in EOAS 6067.

Title: REDOX-SENSITIVE TRACE METAL ANALYSES OF FORAMINIFERAL CALCITE TO BETTER CONSTRAIN ANCIENT HYPOXIC MARINE ENVIRONMENTS

Name: Christian Helmut Gfatter

Date: 10/26/2026

Time: 11:00 a.m.

Location: EOA 6067

If Zoom: https://fsu.zoom.us/j/97357212030<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Ffsu.zoom.us%2Fj%2F97357212030&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7C9b693c640a784694824208df2edc5d67%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C639281196132349183%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2BkWww%2F9ZFRqua7ZZkoB4%2FlPWTHJN2tUmXRSG222Iaow%3D&reserved=0>

Major Professor: Jeremy D. Owens

Abstract:

Analyses of elemental composition of foraminiferal calcite have been used as proxies to quantify contemporaneous oceanic conditions such as the circulation of deep‑water masses using cadmium‑to‑calcium (Cd/Ca) and barium‑to‑calcium (Ba/Ca) ratios, but few foraminiferal calcite studies have investigated bioessential redox‑sensitive trace elements. Molybdenum (Mo) and vanadium (V) affect enzymatic processes for primary producers, dominantly via nitrogen fixation, and paleo-ocean studies suggest low concentrations of these elements during globally extensive reducing marine conditions associated with climate events as they are sequestered in sediments more readily than the oxic conditions of the modern ocean. Therefore, tracking these redox‑sensitive elements is of broad interest to better track and understand the effect of climate perturbation feedbacks. Currently, the only archive is through black shale deposition but the spatiotemporal resolution through the Cenozoic is limited. Thus, the application of elemental concentrations in foraminiferal calcite could be a useful archive to track seawater trace metal concentrations that are related to the global marine redox state.
The foremost purpose of this research is to quantify the incorporation of Mo and V by a cultured modern benthic foraminifera, Ammonia tepida, and advance foraminiferal culturing techniques. The first project emphasizes the effect of materials implemented in experiments on these and other living benthic foraminiferal species, such as Elphidium spp., collected and studied for their response to changes in seawater trace metal concentrations. The chosen setup and components were then used to investigate the incorporation of molybdenum into the foraminiferal tests of A. tepida.
The subsequent propagule experiments were performed to examine the yield from fine sediments of A. tepida over prolonged time periods. Adequate quantities of benthic foraminifera for given periods would indicate the length of effectiveness for stored sediments to be a mechanism to provide specimens for future use in foraminiferal culturing experiments. In addition, these experiments could boost the study of dormancy in benthic foraminifera and provide an initial benchmark of the duration threshold.
Finally, ambient seawater concentrations of multiple redox‑sensitive trace elements—molybdenum, vanadium, nickel, zinc, and uranium—were tested to determine if those elemental concentrations become recorded in the calcitic tests of benthic foraminifera. Elemental relationships that may be learned from modern foraminifera may subsequently be used to determine if there is a correlation to fossil foraminiferal tests. For instance, these data and future results from modern foraminiferal calcite could be compared to that of calcitic fossils of an oceanic anoxic event (OAE) such as the OAE 2. Thus, laboratory controlled experiments could provide a framework to understand ancient variability by observing the effects on a range of redox‑sensitive trace elements concentrations, which may offer a method for more robust paleo-redox reconstructions with better temporal and spatial resolution by including analyses of microfossils from a range of lithological deposition. In this way, interpreting foraminiferal tests has the potential to harness carbonate records for use in recording the integrated global signature.

Best,
Adea

Adea Arrison

Sr. Academic Program Specialist

Department of Earth, Ocean & Atmospheric Science

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