SAVANNAH, Ga. -- The U.S. Army Corps of Engineers’ Savannah River basin lakes, J. Strom Thurmond, Richard B. Russell and Hartwell, have some strange inhabitants that are alien, globby-looking things, and sometimes mistaken for the eggs of some aquatic creature, but in-fact, they are filter-feeding, microscopic invertebrates known as Freshwater Bryozoan or zooids, and their presence indicates a healthy body of water.