Revealing the Shifting Sands of Time
Florida’s famous springs share many characteristics: refreshing, clear water, serene settings and plentiful wildlife. But a recent study by Stetson University revealed that no two springs are alike.
Thanks to a $17,667 grant from the Foundation, researchers used core samples at five springs to reveal secrets hiding in the geologic record. For instance, Wekiwa and Gilchrist Blue Springs date to the last Glacial Period over 15,000 years ago, acting as watering holes for mastodons, mammoths, giant ground sloths, and huge land tortoises. Many scientists had assumed that Florida’s springs emerged as sea levels approached their modern position about 8,000 years ago. These findings challenge that assumption and suggest that many Florida springs may be significantly older than once thought. However, Otter Spring is young by contrast; the oldest core samples dated to 4,500 years ago, around the time the Egyptian pyramids were being constructed
In addition to variations in age, the study demonstrated that each spring had a unique environmental history. For instance, some have supported abundant snail populations through time while others nearby have not. Some springs have been resilient to current environmental changes while neighboring springs suffered significantly. Particularly relevant for current conservation efforts, many sampled springs show increased algal abundance and sedimentation as the result of human activity, leading to a loss of biodiversity. However, this observation was not universal among all five springs, pointing to the need for individual conservation strategies to manage each spring.
“Many thought that springs would scour out their channels along the spring run, leaving a lack of sediment in the channel,” said Benjamin Tanner, lead researcher and associate professor of environmental science and studies at Stetson University. “Instead, we have found that spring runs provide a wonderful sediment history that can be used to study how they change through time. Knowing how a spring has functioned in the past outside of the effects of significant human impacts can help us to put modern changes into perspective.”
The team next plans to examine the cores for ancient evidence of water lettuce, currently considered an invasive plant in Florida, but suspected by some to be native. If spotted, it could result in changes in how the plant is managed.
Funds for the grant came from the Foundation’s Protect Florida Springs license plate, which contains the image of a scuba diver. Twenty-five dollars from each purchased plate supports the conservation of Florida’s unique springs.
“We were fascinated by the team’s findings,” said Foundation President and CEO Andrew Walker. “Florida’s springs are a unique treasure, and this study offers invaluable insight into how best manage their conservation.”