Strangled Waters: First Wave

Abstract

On a balmy day in June 1955, George Anderson took his sailboat out on Lake Washington, the long stretch of fresh water that separates Seattle from its eastern suburbs. Anderson had recently finished his doctoral research on phytoplankton, and knew the lake well. The water that day looked odd; he noticed a strange brown tinge. So he collected a sample in an empty beer bottle and brought it back to the University of Washington lab where he worked with his mentor, W.T. Edmondson, the ranking authority on the lake. Under the microscope, Anderson and Edmondson found a life form they’d never seen before. It grew in long, narrow chains, striated with lines that separated one cell from the next. They thought this might be a species infamous among limnologists, the cyanobacterium Oscillatoria rubescens. (Cyanobacteria, popularly known as blue-green algae, are in fact distinct from and far more ancient than algae. They appeared more than 3 billion years ago, when the planet was inhabited only by microbes, and were the first organisms to evolve photosynthesis. Their proliferation and release of great volumes of oxygen profoundly changed the chemical makeup of Earth’s atmosphere, making the evolution of complex life possible.) The researchers needed to be sure, so they sent a sample off to an expert, who confirmed their suspicions. O. rubescens signaled deteriorating conditions in Lake Washington. To Edmondson, it also meant an unprecedented opportunity to track the impacts of nutrient overload. O. rubescens had been the harbinger of drastic change in a number of western European lakes. The best-known case was that of Lake Zurich in Switzerland. Fed by Alpine glaciers, Lake Zurich was, until the late 1800s, an expanse of blue known for its abundant populations of whitefish and lake trout, which thrive in deep water. The lake is made up of two basins separated by a narrow passage. In the late nineteenth century towns at the edge of the lower basin, the Untersee, abandoned privies for flush toilets, and began to release their raw sewage into the lake.