"Lake Tahoe is being invaded. But not by skiers or Bay Area residents seeking a relaxing weekend at the beach.
In a troubling trend, scientists have discovered the rapid spread of the Asian clam, an exotic bivalve roughly the size of a dime, in the mud and sediments around Tahoe's south shore.
Although it is too early to know what the clam's impact will be, in a worst-case scenario, its continued spread could litter beaches with sharp shells and consume plankton that fish rely on for food. Worse, the clam appears to be sparking the growth of stringy green algae that feeds on its waste, leading to concerns that some sections of the lake's azure blue waters eventually could turn a murky green."