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Prehistoric isopod offers insights to Virginia's drinking water
By Dana Whitney
Photo Credit: USFWS
Millions of years ago, a tiny marine creature thrived alongside the dinosaurs.
After ocean waters receded from its habitat, these blind and colorless crustaceans evolved into freshwater swimmers call isopods. One of those isopods, the Madison Cave isopod (Antrolana lira), survived millions of years and now resides in only a few underground caves and aquifers in parts of Virginia and West Virginia. But it offers biologists much broader insights. Protecting this diminutive species means protecting a prehistoric organism, as well as safeguarding a clean water supply.
The Madison Cave isopod, a crustacean that only grows to the size of a paperclip, was listed as threatened under the Endangered Species Act in 1982. Since this isopod's family is more typically found in marine waters, biologists believe these crustaceans were left behind millions of years ago. Sumalee Hoskin, a biologist in the U.S. Fish and Wildlife Service's Virginia Field Office in Gloucester, considers these organisms to be living fossils in this ever-changing world.
In addition to their unique status in biological history, the habitat of these isopods is of top importance. This is why Hoskin and others are working with to craft management guidelines for landowners and land managers within the Madison Cave isopod's range.
The species is only found in and around the Shenandoah Valley, from Lexington, Virginia to Harpers Ferry, West Virginia. Though this crustacean lives in a dark, underground habitat, it is part of a broader ecosystem that starts on the surface above their home. Actions on the landscape can greatly affect their subterranean lives and in turn affect safe and clean drinking water.
Photo Credit: USFWS
Contamination of the underground water and habitat loss are the primary threats the Madison Cave isopod faces today. To address the issue, the Service worked with Dominion Virginia Power and Warren County to place an easement on a known Madison Cave isopod site, and the Service is also working with a private landowner on establishing an easement on a second site.
Biologists are also working with communities in these areas to minimize impacts to the species and its habitat. People should maintain a natural buffer around sinkholes (natural depressions in the land surface) and fissures (narrow cracks in the earth's surface). This helps reduce the number and frequency of contaminants entering the ground water as well as sedimentation (erosion of the surface). Additionally, everyone should properly dispose of household wastes and regularly maintain septic systems. Efforts to protect this species also benefit people by ensuring safe and clean drinking water.
While you may never see a Madison Cave isopod, and perhaps did not even know there are freshwater crustaceans swimming freely in underground caves, their minute presence offers big insights for biologists in Virginia and West Virginia and all over the country.
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