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78-7 Surface water and groundwater interface controls on microbial N2O cycling in karst aquifers

Session: New Frontiers in Cave and Karst Science

Presenting Author:

Seonkyoo Yoon

Authors:

Yoon, Seonkyoo¹, Oh, Chamteut², Martin, Jonathan B.³

(1) Geological Sciences, University of Florida, Gainesville, FL, USA, (2) Environmental Engineering Sciences, University of Florida, Gainesville, FL, USA, (3) Geological Sciences, University of Florida, Geological Sciences, Gainesville, FL, USA,

Abstract:

Karst landscapes and aquifers have recently been identified as significant sources of nitrous oxide (N₂O), the third most abundant greenhouse gas, with a global warming potential approximately 300 times greater than that of carbon dioxide. Despite this, the exact processes driving N₂O production in karst systems remain poorly understood. In this research, we integrate field studies with microfluidic experiments to investigate how surface water–groundwater (SW-GW) interactions influence N₂O cycling in karst aquifers. At SW-GW interfaces within a karst aquifer, we collected groundwater samples to measure N₂O concentrations under different mixing conditions. In parallel, we used microfluidic devices that replicate karst environments to simulate SW-GW mixing and observe microbial N₂O cycling. By connecting the outcomes of these laboratory experiments with field measurements, we demonstrate that inputs of dissolved oxygen from surface water into anoxic groundwater inhibit the completion of denitrification, consequently leading to the accumulation and atmospheric release of N₂O from karst aquatic systems.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10825

Surface water and groundwater interface controls on microbial N2O cycling in karst aquifers

Description

Session Format: Oral

Presentation Date: 10/20/2025

Presentation Start Time: 09:50 AM

Presentation Room: HBGCC, 211

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