David Schindler

Evolution and Ecology

Schindler identified detergent phosphates as a pollutant killing lakes in the 1960s, and pinpointed acid rain as a widespread cause of fish deaths in the 1970s & '80s. Schindler now warns that rapid exploitation of Alberta's oil sands is polluting the Athabaska River, and recommends that oil sands extraction be monitored more effectively.

"The days when we can afford to sit in our ivory towers and put our bound volumes on the shelves of our libraries, and then expect them to have any impact on how ecosystems are managed, are long gone."

 Not many students can list a prestigious journal as the publication where their first academic research paper appeared, but such is the case for Schindler. Co-authored with his supervisor Gabriel Comita, his research using the calorimeter to determine the energy content of small aquatic organisms including copepods, algae, and crayfish, was published in Science in 1963. Publishing for the very first time in one of the world’s premier science journals was perhaps to foreshadow the prominent role of the science Schindler has researched and published throughout his continuing career.

Schindler's PhD studies focused on lakes from an ecosystem perspective, studying initially with Nikko Tinbergen and then Charles Elton. Following completion of his PhD at Oxford, Schindler headed to Trent University in the small town of Peterborough, Ontario, a setting that appealed to Schindler because of its geological diversity and the many surrounding lakes. During his first year at Trent, Schindler learned about a new laboratory being opened by the Fisheries Research Board of Canada, a development that piqued his interest because of their intended focus on eutrophication studies–the study of how excess nutrients affected freshwater systems. So after only two years at Trent, Schindler interviewed for a position in the Eutrophication Section of what was to become known as the Experimental Lakes Area (ELA). Schindler accepted a job at the station, and was to remain part of the team for 21 years, a period during which his research had a profound impact on public policy.

Focusing on eutrophication, a phenomenon that resulted in lakes becoming starved of oxygen due to overgrowth of algae, Schindler and his colleagues identified phosphorus as one of the main culprits within a few years of initiating their whole-lake experimental research.  The approach of manipulating entire lakes was a revolutionary one, but one which provided more convincing evidence than smaller or lab-based studies.

When lakes contained excess phosphorus and nitrogen, it stimulated algal communities to grow.  Using experimental manipulation in some of the 46 lakes that comprised the Experimental Lakes Area, Schindler and his colleagues determined that the biological communities in lakes were capable of capturing nitrogen from the atmosphere if nitrogen in the water was in short supply. However they discovered that the same was not true for phosphorus.  As a result, eutrophication could be controlled by controlling inputs of a single element, phosphorus. This was easily done by removing it from sewage, and reformulating laundry detergents to be phosphate free.

In the late 1970s, Schindler's interest turned to freshwater acidification, addressing the problem of acid rain. Again Schindler and his team set up groundbreaking experiments that used both sulfuric and nitric acid on lake systems, demonstrating that acidification could knock out species within aquatic food chains, sometimes with dramatic and cascading effects. They discovered that two important species, opossum shrimp (Mysis relicta) and fathead minnow (Pimephales promelas), stopped reproducing at pH values below 6, when water has become slightly acidified (note: neutral pH is 7.0). Their results were important because they showed that fish were vulnerable to more subtle levels of acidity than had previously been recognized. Photographs of starving fish from some of Schindler's acidification research assisted in gaining the attention of the public, and persuading policymakers to enact legislation aimed at more rigorous air-quality standards to reduce the pollutants that contributed to acid rain.

Schindler later studied pesticides and other chlorinated compounds and their impacts on subarctic and alpine environments. He was concerned that the widespread use of chemicals  like DDT and PCBs in the 1950s and 60s would come back to haunt ecosystems as these chemicals, initially trapped in glaciers, began melting out as a result of a warming climate, contaminating high elevation lakes and rivers. Over the years, Schindler has also investigated the impacts of radio nuclides, forest fires, climate change,  mercury and invasive species on aquatic ecosystems. More recently, Schindler has come full circle, back to studies of eutrophication, but this time focusing on the inputs of phosphorus from agriculture. 

After accepting a position at the University of Alberta in 1989, Schindler and his wife, wetland ecologist Suzanne Bayley, were able to take advantage of the nearby Rocky Mountains, and an opportunity to study alpine lakes and wetlands. One of his topics of study was the earlier stocking of alpine lakes with non-native fish for recreational purposes, a practice that Schindler discovered had profound negative impacts on these delicate ecosystems.

From early on in his career, Schindler has made sure his science doesn't get lost on the shelves of libraries in academic institutions, and is well known for his feisty interactions with policymakers. His advocacy for seeing policy changes for reduced phosphorus pollution and acid rain has seen important legislative changes that have drastically improved water quality across Canada and in the US and Europe. 

His recent attention has turned to development of the oil sands, and the resulting environmental impacts of this massive project: a landscape transformation so large it is visible from space. Schindler and colleagues brought attention to the biologically significant levels of pollutants including polycyclic aromatic hydrocarbons that find their way into water systems downstream of oil sands developments (Kelly et al. 2009 and 2010 Proc. Nat. Acad. Sci. USA). Schindler has harshly criticized the lack of stringent monitoring of water quality in the oil sands region, and his studies of the Athabasca River indicated that current monitoring schemes are poorly designed to detect the impacts of these carcinogenic and physiologically damaging compounds on animal health and biodiversity. His papers on this topic, including a 2010 comment paper in Nature, resulted in both federal and provincial governments appointing panels of eminent scientists to review monitoring standards. Both panels came to the conclusion that Schindler's concerns were valid.  As Schindler explains, “monitoring programs were never intended or capable of detecting the impact of the oil sands industry on the river.”  

Although some changes have subsequently occurred, including the design of a new monitoring plan by Environment Canada, Schindler is concerned that improved monitoring schemes may not be adequately funded. Recently presenting his concerns to the Canadian Senate, Schindler remains concerned that monitoring has not improved sufficiently.

Asked what has maintained his enthusiasm and motivation for the study of freshwater ecosystems throughout his career, Schindler says, “more and more over the years - it’s been the urgency that I feel when I see how badly society treats ecosystems. If anything, I’ve seen a degradation in the amount of care that we take to protect these systems - our natural support systems - in order to make money. I really fear that down the road it’s going to be a major stumbling block for human society. It is already in some countries.”



One of Schindler's most important results was strikingly demonstrated in a photograph that is now an iconic representation of the dangers of phosphorus pollution. In an experiment where Schindler and colleagues separated a lake into two parts, essentially with a giant shower curtain, they treated one side with carbon, nitrogen, and phosphorus; and the other side with carbon and nitrogen alone. Aerial photographs captured the bright green and cloudy algal blooms of the phosphorus–treated side, while the other side remained clear. Lake 226, from an aerial view, was to become a picture that spoke a thousand words. Schindler, who in 1973 took over the task of communicating ELA’s results in national and international science policy meeings from Jack Vallentyne, as the project came under the direction of Fisheries and Environment Canada, was to use that powerful photograph when he testified in hearings that eventually helped pass laws in the US and Canada limiting the use of phosphorus in detergents and its removal in large sewage treatment plants.


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When asked what he feels is the most urgent issue of the upcoming decade, Schindler thinks the abundance of freshwater of suitable quality for human consumption is a problem that is already acute in many countries. “There is widespread impairment of water across southern Canada already–with respect to drinking water. The tip of the iceberg is Aboriginal communities, a high proportion of which have unsafe drinking water right now.” And it's not just drinking water that's affected, worries Schindler. Water quality is also important for other human activities that we enjoy in Canada, including recreation such as fishing and swimming. 

Schindler wrote about his concerns about water supply in a co-authored paper in the Proceedings of the National Academy of Sciences in 2006. In that paper, he and co-author William Donahue examined historical flow records for rivers in the Prairie Provinces and the impacts of climate change on northern regions. Schindler says he was shocked by how much river flows had changed, in some cases reduced in summer by as much as 85%. He predicts these declines in river flows will have direct impacts on cities that depend upon their water supply, such as Calgary, and the coldwater trout species of the Bow RIver.

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(Dr. Schindler’s recent publications can be viewed at the University of Alberta website.)

Schindler, D.W. 2009. A personal history of the Experimental Lakes Project. Can. J. Fish. Aquat. Sci. Vol. 66.

Comita, G.W. and Schindler, D.W. 1963. Calorific values of microcrustacea. Science 140: 1394-1396.

Schindler, D.W.  1977.  Evolution of phosphorus limitation in lakes:  Natural mechanisms compensate for deficiencies of nitrogen and carbon in eutrophied lakes.  Science 195: 260-262.

Schindler, D.W.  1974.  Eutrophication and recovery in experimental lakes:  Implications for lake management.  Science 184: 897-899.

DW Schindler and WF Donahue. 2006. "An impending water crisis in Canada's western prairie provinces." Proceedings of the National Academy of Sciences USA 103: 7210-7216.

EN Kelly, JW Short, DW Schindler, PV Hodson, M Ma, AK Kwan and BL Fortin. 2009. "Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries." Proceedings of the National Academy of Sciences USA 106: 22346-22351.

EN Kelly, DW Schindler, PV Hodson, JW Short, R Radmanovich and CC Nielsen. 2010. “Oil sands development contributes elements toxic at low concentrations to the Athabasca River and its tributaries.” Proceedings of the National Academy of Sciences USA 107: 16178–16183.

DW Schindler 2010. Tar sands need solid science. Nature 468: 499-501.




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