Aquifer Discharge Drives Microbial Community Change in Karst Estuaries

• Published in: Estuaries and coasts Vol. 41; no. 2; pp. 430 - 443
• Main Authors: Menning, Damian M., Carraher-Stross, William A., Graham, Elaina D., Thomas, Devon N., Phillips, Annie R., Scharping, Robert J., Garey, James R.
• Format: Journal Article
• Language: English
• Published: New York Springer Science+Business Media 01.03.2018; Springer US; Springer Nature B.V
• Subjects: Aquifers; Bacteria; Climate change; Coastal Sciences; Communities; Discharge; DNA; Earth and Environmental Science; Ecology; Environment; Environmental Management; Estuaries; Estuarine dynamics; Estuarine environments; Freshwater; Freshwater & Marine Ecology; Geochemistry; Gradients; Heterogeneity; Hydrology; Inland water environment; Interactions; Karst; Marine environment; Microbial activity; Microbiomes; Microorganisms; Nucleotide sequence; Order parameters; PCR; Sea level; Sediment; Sediment samplers; Sediment samples; Spring; Water and Health; Water column; Environmental DNA; Biogeochemistry; Karst; Ecology; Microbial; Molecular; Estuary; Community
• ISSN: 1559-2723; 1559-2731
• DOI: 10.1007/s12237-017-0281-7

Karst estuaries are unique systems governed by fieshwater inputs that flow directly to the sea through karst conduits and/or matrices. Because they are found at the interface between terrestrial and marine environments, they can act as sentinels to climate change and as indicators of aquifer health. The physical and geochemical gradients formed in karst estuaries are a direct result of the interactions between inland hydrological conditions and sea level. To examine the influence these gradients have on microbial communities in the water column and sediment of a karst estuary, we studied the spring-fed Double Keyhole Karst Estuary in west central Florida for a 2-year period. Four sites were monitored within this system starting at the Double Keyhole Spring Conduit extending 2 km west through the estuary toward the Gulf of Mexico. Water column and sediment samples were collected quarterly at all sites from September 2011 through September 2013. Archaeal, bacterial, and microbial eukaryote communities were analyzed using quantitative PCR and lengthheterogeneity PCR. The biological communities were analyzed in the context of hydrological, physical, and geochemical parameters in order to determine which factor(s) governed the observed changes of microbial abundance and richness. The major finding of this study was that microbial community change in this karst estuary was primarily driven by the volume of aquifer discharge and associated physical gradients, and less by the geochemical fluctuations within the system.