2021 Summer Undergraduate Research Program (SURP) Symposium

Location

Ballroom, Maucker Student Union, University of Northern Iowa

Presentation Type

Open Access Poster Presentation

Document Type

poster

Keywords

Organic compounds--South Dakota--Wind Cave; Crystal growth--South Dakota--Wind Cave; Speleothems--South Dakota--Wind Cave;

Abstract

In Wind Cave, organic molecules from the surface dissolved in water will slowly filter down into the cave through the porous limestone. While the water slowly proceeds down through the limestone, the water dissolves the limestone along the way. This dissolving of the limestone causes a quasi-equilibrium that deposits the organic molecules into the calcite structures found in Wind Cave. These large trapped organic molecules, mainly humic and fulvic acid, can be tracked by using UV light. The UV light causes these molecules to fluoresce blue, while the calcite structures generally do not have a strong blue fluorescence. The water from the cave shows a similar but stronger signal to that of the organic laced calcite. This water was used to replicate the fluorescence of the crystals in the cave by using the cave water to dissolve calcium chloride and reacted with ammonium carbonate. The fluorescence of the water after being reacted showed that the organic molecules were precipitated out with the calcite. This reaction resulted in the synthesized crystals having a shifted λmax and a different crystal morphology when compared to the cave crystals.

Start Date

30-7-2021 11:30 AM

End Date

30-7-2021 1:15 PM

Event Host

Summer Undergraduate Research Program, University of Northern Iowa

Faculty Advisor

Joshua Sebree

Department

Department of Chemistry and Biochemistry

File Format

application/pdf

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Jul 30th, 11:30 AM Jul 30th, 1:15 PM

Analog Studies of Organic Pathways in Wind Cave through Cave Water and Crystals

Ballroom, Maucker Student Union, University of Northern Iowa

In Wind Cave, organic molecules from the surface dissolved in water will slowly filter down into the cave through the porous limestone. While the water slowly proceeds down through the limestone, the water dissolves the limestone along the way. This dissolving of the limestone causes a quasi-equilibrium that deposits the organic molecules into the calcite structures found in Wind Cave. These large trapped organic molecules, mainly humic and fulvic acid, can be tracked by using UV light. The UV light causes these molecules to fluoresce blue, while the calcite structures generally do not have a strong blue fluorescence. The water from the cave shows a similar but stronger signal to that of the organic laced calcite. This water was used to replicate the fluorescence of the crystals in the cave by using the cave water to dissolve calcium chloride and reacted with ammonium carbonate. The fluorescence of the water after being reacted showed that the organic molecules were precipitated out with the calcite. This reaction resulted in the synthesized crystals having a shifted λmax and a different crystal morphology when compared to the cave crystals.