In 1963 Lake Tahoe was stocked with kokanee salmon to encourage outdoor tourism.
Also added to the lake were the opossum shrimp, meant to be food for the salmon. The shrimp all but destroyed the lakes zooplankton populations, which controlled organic particulate material, keeping the lake clear and clean.
In an effort to give the zooplankton a place to regroup itself, ceramic and glass blocks were sunk into the lake. The zooplankton didn’t much care for the surfaces, but these fungi like benthic communities found their homes in droves. Pyrite and silver have stuck to their gills.