Karst Rock Landscapes
(Fig 1.) Karst Springs and Aquifer Formations
Florida Karst Rock Formations
Karst rock is found in Florida from Tallahassee to Miami, but not always near the surface. When karst rock is found near the surface, a unique hydrogeologic phenomenon can occur. Water contained in the porous rock can flow like a sub-surface river. West Central Florida is one great example of hydrogeologic movement embedded in karst rock. In fact, Florida is virtually unique in all the world based on the number of natural karst springs and aquifers at or near the surface. It is easy to visualize an aquifer when one sees a crystal clear surface spring. The springs are spectacular examples of gravity driven water flow.
How Is Karst Rock Beneficial?
We know that natural clean, fresh rainwater is slightly acidic, and karst rock is soluble in water. Each time rain water is absorbed in karst, some of the karst dissolves, eventually creating underground caverns filled with clear, clean freshwater. These earthen hydrogeologic structures are called, “aquifers”. Aquifers near or at the surface sometimes form natural freshwater springs. Aquifers and springs are beneficial for drinking water, agriculture, feeding livestock and the like.
Natural springs form where large cracks within the karst rock aquifer earthen structures. The structures are made of limestone, clay, and sand and lie at or near the surface. Florida has thousands of these types of springs. In fact, the deepest natural spring in the world found thus far is near Tallahassee, Florida. Karst rock springs and caves, and caverns are numerous and can be found from Tallahassee, south along the Gulf of Mexico to Tampa, Florida.
The Floridan Aquifer
The largest aquifer system in Florida is called the “Floridan” aquifer system. In west central Florida, the Floridan aquifer is located directly in a karst rock landscape. The Floridan aquifer system encompasses thousands of square miles of multiple layered aquifer systems, buried under layers of karst rock. All the various layered aquifer systems float upon the Floridan aquifer system. This makes the Floridan aquifer system a unique ecosystem, possibly one of the most important karst rock ecosystems on the planet. The Floridan aquifer is in danger of surface pollutants and severe environmental impacts due directly to Florida’s phosphate industry practices. Historically, Florida's phosphate industry are poor stewards of the environment in and around phosphate plants in general.
Karst Landscapes are Vulnerable to Surface Pollutants
We can see west central Florida karst rock formations at or near the surface benefits local residents in many ways. The karst rock helps residents in the form of aquifers by absorbing rainwater from the surface. This type of landscape also absorbs natural and man-made pollutants as well. The pollutants are absorbed into the aquifers, and can cause severe environmental damage to the aquifer system. Some pollutants, such as phosphorus-based nutrients cause unwanted algae growth. The algae growth has a negative impact on the health of Florida’s springs and aquifers. Algae deplete the dissolved oxygen concentrations in water causing plant life in the area to suffocate and die. This, in turn, causes more plant life to die and so on until the fish, mollusks, and other fauna begins to disappear. This is known as an aquatic “dead zone” and is void of life. All of the above mentioned is causing severe drinking water issues including quality and quantity in west central Florida.
Algae Impacts On Humans
Algae in Florida’s springs and aquifers have also shown to be dangerous to humans. The Florida park service keeps records of any issues related to algae growth and has determined algae can cause respiratory issues, rashes, and other skin irritations. The Florida park service reported over 140 incidents from algae related health complaints to humans in 2002.
Aquifer and Spring Degradation
Florida’s aquifers and springs are in imminent danger from surface pollutants, such as the phosphate industries toxic waste being dumped directly into the local aquifers daily. Unfortunately, Florida’s politicians side with the phosphate industry and will until held accountable for their discretions.