The Legend Of A Lake


During the late nineteenth century, in every spring and fall downpour, the silt became an enveloping submarine blizzard that rolled out into Lake Erie from every river and stream. In the original balance of the lake, the spring blooming of plankton came just when trillions of fish eggs were hatching, and the young fish fed on the plankton. But the sun could not penetrate these murky waters. Great spring crops of diatoms, single-celled globular plants, once a mainstay fish food in the western basin, were obliterated. Plankton-loving ciscoes were driven east. Whitefish eggs smothered in the reef refuges. Yellow walleyes, which used to rush upriver as soon as the ice had gone, were checked and driven back into the lake without spawning.

Gradually the silt storms smothered most of the shoreline aquatic vegetation that had been a refuge for all kinds of wildlife—waterfowl, aquatic insects, amphibians, and spawning fish. The lake’s western basin held between three hundred and five hundred thousand tons of silt in suspension at almost any time. The eggs of some yellow walleyes that spawned on gravel bottoms were smothered by the silt. Others, which still sought spawning grounds up rivers, were stopped by chemicals or by sawdust that compacted in their gills, and they were driven back into the lake to wander in search of new places to spawn.

But even in the lake there was little chance to escape the rush of displaced earth into the water. The yellow walleyes had spent generations habituating themselves to dim light. They would eat only at sunrise and sunset when the light was soft enough for them to hunt. Then they went after perch, minnows, and suckers. But the gathering silt, some of it so fine it was suspended in the water for months, clouded the lake. The yellow walleyes could not see well enough to hunt and left their traditional spawning grounds.

Hit by the sun, the particles of silt absorbed and retained heat, turning large areas of the lake into a kind of vast heat sponge. Some particles, decaying, actually produced heat. At the same time, heavily wooded streams lost their shade, and aquatic meadows everywhere were stripped away. The sun poured down on unshaded water everywhere. In the 1920’s an extremely hot summer drove the ciscoes into the deepest part of the central basin, and there they concentrated in immense numbers. There, also, the fishermen found them, and their eager nets caught ciscoes by the billions.

The fish and their wrecked spawning beds and the rivers of silt and chemicals were set pieces in a gradually enlarging drama. In the primeval days of the lake, about one million algae lived in every quart of water in the western basin. These tiny plants were the genesis, the starting point, for all the lake’s life systems. They had undergone delays and diversions in their life cycles during the silt blizzards, but the surface water always clarified enough to allow them to reproduce. In the 1930’s they began to proliferate in areas beyond the drifting silt.

They responded to the amount of phosphorus from fertilizers, detergents, and organic sewage flushed into the lake from men’s sewers and washed from their artificially managed fields. Within twenty-five years the algae had grown until there were almost four million of them in every quart of water. A special kind of algae, the bluegreen, came into dominance. They did not photosynthesize as much oxygen as did the others, but they demanded a greater share of the oxygen at night. The bluegreen algae reproduced at high speed, died in enormous numbers, and thus stimulated the omnipresent bacteria waiting for their deaths at the bottom of the lake. The bacteria, themselves now boosted in population, also demanded their share of the oxygen.

The blue-green algae were so well stimulated in their artificially ideal world that they displaced other plants that could not capitalize on the sewer bounty so well. Everywhere they encroached into the territories of the diatoms, suppressed their growth, and so set up a chain reaction that ended with young fish starving to death.

This was a preamble to looming catastrophe. The great submarine meadows of mayfly larvae, which in places consisted of several thousand creatures for every square yard of the lake bottom, were able to thrive through these changing conditions. They remained the great storehouse of food for all bottom-prowling fish. They could live on muddy bottoms. But gradually, oxygen became scarcer and scarcer during summers. The blue-green algae used it, the bacteria needed it; when the lake stratified into layers of different temperatures during hot, calm weather, oxygen at the surface was prevented from circulating to the bottom dwellers. In this stratification the poisonous chemicals from men’s works on shore sank to the oxygen-deprived bottom to create a kind of suffocating witch’s brew.

In the early suffocations fish fled, and the mayflies and midges died in large numbers; but there were always enough survivors to quickly build up populations again. However, in 1953, with the winds light and the abovewater temperatures in the 8o’s, the depletion of oxygen in the western basin became complete. The loss spread over hundreds of square miles, then thousands. The lake choked, then strangled. Every living creature on the bottom that needed oxygen was killed. The midges were gone. The mayflies, those ancient successes of evolution, were wiped out.