Lake 223 and The Man Who Made Acid Rain

Schindler in arm cast (from a float plane accident) 

David Schindler grew up in a small town in Minnesota, in the Red River Valley. His father farmed potatoes and sunflowers. His mother taught music. It was the kind of upbringing where you fixed things yourself, or they stayed broken, and Schindler later credited that farm logic with allowing him confidence in tinkering, in taking things apart to understand how they worked.

Minnesota is on the edge of the Canadian Shield, ancient Precambrian rock that is the core of North America. Lakes are everywhere up here. In High School, he took a month-long fishing trip into northwestern Ontario, into the boreal lakes cut from the Precambrian rock. Something about the place must have resonated with him.

In college, Professor Gabriel Comita gave him his first real research opportunity, studying lake food web energetics, and that was enough. He was off. In 1962, he won a Rhodes Scholarship and went to Oxford. He began working under Nikolaas Tinbergen, the famous ethologist who would later share the Nobel Prize, the only Nobel ever given for behavioral work. He later shifted to Charles Elton. 

Charles Elton was one of the founders of modern ecology. Elton had almost single-handedly established the concept of ecological communities as structured, quantifiable systems. He wrote the book Animal Ecology in 1927, when he was 26. In the book, he formalized the idea of the food chain, showing that energy and matter move through ecosystems in structured sequences from plants to herbivores to predators, expounding on the concept of an energy pyramid. He introduced the ecological niche as what an animal did, its functional role in the community. This was a different, and more correct, idea of what a niche was thought of previously. The concepts of Elton’s still adorn ecology and basic biology textbooks today. 

Wait, let’s go back. 

Elton wrote a book called Animal Ecology in 1927, when he was 26. The concepts presented in the book are the ones in today’s ecology textbooks. Mostly without alterations. When he was 26! 

Studying under him in the 1960s must have been an astounding experience. 

Schindler completed his doctorate in ecology in 1966, with his research focused on zooplankton energetics in Minnesota lakes. 

In 1968, Schindler helped co-found the Experimental Lakes Area (ELA) in northwestern Ontario, a cluster of 58 small lakes set aside for whole-ecosystem research. The idea was straightforward and unprecedented. If you want to understand how lakes work, don't study them in a jar. Use the actual lakes.

The first experiment that made Schindler famous was about algae. Some lakes across North America were turning green. Eutrophication: Runaway algal growth that choked out other life. Everyone agreed it was a problem. Nobody agreed on what was causing it. Industry had a strong preference for the answer being carbon or nitrogen, both of which were expensive to regulate. Phosphorus, which came largely from agricultural runoff and the phosphates in laundry detergent, was the leading scientific candidate.

Schindler settled it with a curtain. He took ELA Lake 226, strung a vinyl barrier across the middle to divide it into two basins, and added phosphorus to one half. The other half got nitrogen and carbon. Within weeks, the phosphorus half turned green. The other stayed clear. He photographed it from the air, and that image, a lake divided perfectly between green and blue, went around the world. It is still described as one of the most powerful single images in the history of limnology. 

Lake 226 divided by a curtain

Phosphorus was the culprit. Detergent manufacturers lost their preferred argument, and phosphate bans followed across North America.

Then came acid rain.

In the 1970s, industry was making another argument: that sulfur dioxide emissions from coal plants and smelters probably weren't really acidifying lakes, and even if they were, you couldn't prove it was causing harm. 

Schindler's answer was to make acid rain himself. He chose a small, clear, unremarkable lake in the ELA, Lake 223, and began adding a mixture of sulfuric and nitric acids, slowly dropping the pH. He wanted to reproduce what industrial emissions were doing to lakes downwind of the Ohio Valley and the Ontario Smelting Belt, but slowly enough that he could watch each ecological change as it happened.

The seventeen-year experiment was one of the longest ecological manipulations ever conducted. What Schindler found was that the lake's food web didn't collapse all at once. It unraveled, step by step, in a specific order. The freshwater shrimp, Mysis relicta, went first. Then the cisco, a deep-water fish that depended on the shrimp. Then the lake trout, which had eaten the cisco for twenty thousand years, disappeared entirely. The lake became clearer as the pH dropped, because the phytoplankton that normally cloud healthy water were dying too. 

The lake looked pristine because it was nearly empty.

The data from Lake 223 was central to the negotiations that produced the 1991 Canada-United States Air Quality Agreement, which required the two countries to reduce sulfur dioxide emissions. It was also cited in the 1990 amendments to the U.S. Clean Air Act. 

A section of the ELA region; the closest lakes are 223, 224, and 222.

The recovery, when Canada and the U.S. finally began cutting emissions, was slow. The lake's pH began to rise, but the ecosystem did not simply reassemble itself. Mysis shrimp had been regionally extirpated. By the late 1990s, the lake was still largely barren. The acidification had lasted long enough to break something that the end of acidification could not simply fix.

Schindler spent his final years working on the Athabasca River. The oil sands operations in northern Alberta were discharging contaminants into the watershed, and the government was saying the evidence was inconclusive. In 2010, he published a study showing that the watershed was receiving polycyclic aromatic compounds and other toxins from the industry.

David Schindler and a deformed whitefish from Lake Athabasca

The experiment he started in 1976 was still running when he died in 2021, he was 80. He did not lived long enough to see Lake 223 recover. The trout never came back during his lifetime. Eight months after his death, researchers confirmed that the Mysis shrimp reintroduced into Lake 223 in 2019 had established a breeding population.  

His story, his research, is apropos to one of today’s greatest threats, ocean acidification, and indeed, the drop in pH of all the waters of the planet. We are in trouble; we need David Schlinder again.