GSA Connects 2021 in Portland, Oregon

Paper No. 225-16
Presentation Time: 9:00 AM-1:00 PM


GFATTER, Christian and OWENS, Jeremy, Department of Earth, Ocean and Atmospheric Science, Florida State University, 1011 Academic Way, Tallahassee, FL 32306; National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310

Organisms, such as foraminifera, have long been utilized in culturing experiments to study the exposure effects to one or more elements at varying concentrations. Trace elements like copper can pose a challenge to researchers because adsorption by components of the culturing apparatus may interfere with the objectives of the experiment. Similarly, growth experiments with redox‑sensitive trace metals such as molybdenum (Mo) to explore their potential as proxies require uncompromising techniques that ensure reliable data. Products manufactured from polytetrafluoroethylene (PTFE) and perfluoroalkoxy alkanes (PFA) are adhesion resistant and commonly used to handle samples intended for trace metal analyses. Incorporating these fluoropolymer products into an apparatus designed to culture organisms reduces adhesive surfaces, thereby providing trustworthy results. Accordingly, the prospect of using data from ancient foraminiferal tests as a proxy to reconstruct the marine inventory of redox‑sensitive elements can be better evaluated.

We demonstrate that our flow through culturing system design does not incorporate Mo into the components of the system. Ensuing experiments will evaluate whether higher seawater concentrations of Mo are therefore reliably recorded in the calcitic tests of living benthic foraminifera. We hypothesize that fluctuations in Mo concentrations are reflected in the tests, and so changes in Mo values chronicled from fossil foraminiferal tests would thus record shifts in the ancient seawater inventory of redox‑sensitive elements. The goal of this research is to expand the sedimentary archives beyond those of black shales for more robust long term paleo-redox reconstructions through supporting details elucidated from foraminiferal calcite.

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