The fate of urban springs: Pumping-induced seawater intrusion in a phreatic cave

Scharping, Robert J.; Garman, K. Michael; Henry, Ryan P.; Eswara, Prahathees J.; Garey, James R.

doi:10.1016/j.jhydrol.2018.07.016

Cited by 10 publications

(15 citation statements)

References 43 publications

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“…Near these fracture-fed saltwater vents, vertically intruding saline water and slightly brackish cave water remain density stratified, and this phenomenon produces a karst subterranean estuary in Sulphur Springs Cave. The salinity of Sulphur Springs water has increased from fresh to ~5,000 µS/cm between 1946 and 2017 as a result of seawater intrusion through these fractures, which has been exacerbated by spring water extraction from Sulphur Springs Pool (Scharping et al, 2018). Groundwater flow in the Sulphur Springs area is generally from north to south and is ac- Sink with sediment and debris, which reduced the connectivity between these sinks and the confined aquifer, and reduced the efficiency with which these sinks drain Curiosity Creek (MWH, 2009;SWFWMD, 2009).…”

Section: Sulphur Springs Urban Karst Hydrogeologymentioning

confidence: 99%

“…Two conspicuous biofilm types inhabit Sulphur Springs Cave (Scharping et al, 2018). Brown-coloured biofilm grows in thick mats on every solid surface in the cave except for areas near fracture-fed saltwater vents, where delicate, filamentous, white biofilm grows instead (Scharping et al, 2018).…”

Section: Using Microbial Indicators In Sulphur Springsmentioning

confidence: 99%

“…These biofilms also differ from one another in their microscopic structure, and it is hypothesized that the white biofilm is dominated by sulphur-oxidizing bacteria (Scharping et al, 2018).…”

Section: Using Microbial Indicators In Sulphur Springsmentioning

confidence: 99%

“…The Hillsborough River is dammed upstream of Sulphur Springs to store public water supply in the Hillsborough River Reservoir (SWFWMD, 2015). During dry seasons, local resource managers frequently extract spring water from Sulphur Springs Pool (Scharping et al., 2018), and the extracted water is pumped to the base of the Hillsborough River Dam to maintain flows and low‐salinity habitat in estuarine portions of the river when releases from the reservoir are insufficient to do so (SWFWMD, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Jasmine Sink and Orchid Sink;Figure 1a). Positive values measured at either site indicated the potential for surficial aquifer water and/or surface water to flow into the confined aquifer.Water levels in Sulphur Springs Pool drop rapidly when spring water is being extracted and pumped to the Hillsborough River(Scharping et al, 2018), so Sulphur Springs Pool levels were used as a measureof pumping activity and of confined aquifer potentiometric surface levels in the immediate area. Lower Sulphur Springs Pool levels indicated the increased potential for groundwater in the surficial aquifer water to leak into the underlying confined aquifer and ultimately into Sulphur Springs Cave.…”

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confidence: 99%

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Relationship between aquifer biofilms and unattached microbial indicators of urban groundwater contamination

Scharping

Garey

2020

Molecular Ecology

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Aquifers, springs and other groundwater-dependent ecosystems are threatened by urban land use, which causes water quality deterioration through nutrient loading, sewage infiltration, groundwater extraction and, along coasts, seawater intrusion. The presence of certain microbes in groundwater can indicate that an aquifer is anthropogenically contaminated. Interpretations made from observations of indicator microbes in groundwater are limited because the relationship between the presumably allochthonous indicator microbes and relevant autochthonous microbial communities has not been characterized. This study addressed whether autochthonous aquifer biofilms can influence the presence of presumed microbial indicators in groundwater, and simultaneously used microbial indicators to trace sources of urban contamination at a karst spring of conservation concern. These questions were approached using a 17-month time series analysis of attached biofilm and adjacent unattached bacteria in the submerged karst aquifer conduit associated with this spring. Environmental 16S rRNA gene sequencing was performed to characterize these communities, and community structure data were contextualized with groundwater geochemical and hydrogeological measurements. Linear regression models were developed to explain the relative abundance patterns of indicator microbes and other unattached microbes at this site. The results of this study suggest that dominant aquifer biofilms do not influence the presence of unattached microbial taxa that are presumed to be indicators of groundwater contamination, and generated new information about the origin of coliform bacteria at the study site. These results build confidence in the use of microbial indicators in groundwater-dependent ecosystem conservation strategies and inform future management plans for urban aquifers and springs worldwide. K E Y W O R D S conservation, groundwater-dependent ecosystems, indicator species, land use, microbial biodiversity, urbanization | 325 SCHARPING ANd GAREY 1 | INTRODUC TI ON 1.1 | Conserving groundwater-dependent ecosystems in a changing world Ecosystems that rely on a supply of groundwater to maintain their structure and function, termed groundwater-dependent ecosystems, are both ecologically important and sensitive to environmental changes. This ecosystem type, which includes aquifers, springs, wetlands and many surface water bodies, makes important contributions to the biodiversity of a region by providing habitats for endemic, relict and specialized obligate species (Humphreys, 2006; Kløve, Ala-aho, et al., 2011). Groundwater-dependent ecosystems also provide useful services to people. For example, they support globally significant sources of potable and irrigation water, act as filters for nutrient and toxin loads, generate nursery habitats for economically important game species and are at the core of many recreational activities and cultural sites (Kløve, Allan, et al., 2011; Stinnesbeck et al., 2018). However, because groundwater-dependent ecosystems tend ...

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Section: Sulphur Springs Urban Karst Hydrogeologymentioning

confidence: 99%

Section: Using Microbial Indicators In Sulphur Springsmentioning

confidence: 99%

Section: Using Microbial Indicators In Sulphur Springsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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