Hydroacoustic observations reveal drivers of mixing and salinization of a karst subterranean estuary during intense precipitation

Geophysical Research Letters
By: , and 

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Abstract

Karst subterranean estuaries within globally ubiquitous carbonate aquifers are coastal groundwater ecosystems that provide an essential water resource for human populations. To understand the drivers of salinization within a coastal aquifer in the Yucatan Peninsula (Mexico), we employed hydroacoustics in flooded caves to observe how oceanic and atmospheric events facilitate mixing between the meteoric lens (fresh-brackish groundwater) and the saline groundwater on tidal and episodic timescales. Precipitation during Tropical Storm Carlotta increased the flow and salinity of the meteoric lens without evidence for vertical mixing across the halocline. We postulate that vertical migration of haloclines in the conduit relative to those within the rock matrix during precipitation creates lateral density gradients that drive mixing, and ultimately creates a brackish layer within the meteoric lens. These results provide a mechanistic explanation for vertical and lateral exchange in a coastal carbonate aquifer, which has implications for groundwater response to future climatic change.

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Publication type Article
Publication Subtype Journal Article
Title Hydroacoustic observations reveal drivers of mixing and salinization of a karst subterranean estuary during intense precipitation
Series title Geophysical Research Letters
DOI 10.1029/2024GL109993
Volume 51
Issue 22
Publication Date November 16, 2024
Year Published 2024
Language English
Publisher American Geophysical Union
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description e2024GL109993, 10 p.
Country Mexico
Other Geospatial Ox Bel Ha cave system, Yucatan peninsula
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