Limnologists study the biological and chemical features of lakes. Queen’s University professor, John Smol, has built his career in the sub-discipline of paleolimnology, examining lakebed sediments for a glimpse into the Earth’s past. Within the sediment layers, paleolimnologists are able to track the effects of climate change, human impacts, and natural processes long before historic recordkeeping began – all of which may hold the secrets to our environmental future.

On August 20, 2018, Dr. Smol was recognized by the International Society of Limnology (SIL) with a Naumann-Thienemann Medal – the highest honor awarded for outstanding contributions to limnology – adding another layer to a storied career that has seen him win more than 60 national and international awards for scientific and teaching excellence.

“Being awarded the Naumann-Thienemann Medal is very special to me,” says Dr. Smol, who was also recently named a Fellow of the Royal Society. “I have been a member of SIL since I was 21 years old and have watched many of my heroes receive this honour in the decades since, so I am humbled to be recognized at this level among my peers.”

During the early years of his career, Dr. Smol often felt that many limnologists thought the developing sub-discipline of paleolimnology was some odd offshoot of the field, and that its sediment predictions were more akin to alchemy than proven science. Over time, however, major scientific breakthroughs saw the discipline move from a largely descriptive discipline into a quantitative and precise science, and a vital part of environmental studies.

“Acid rain was one of the first environmental problems that made headlines, and we believed we had methods that could provide policymakers with information they needed to curb it,” says Dr. Smol. “By analyzing lakebed sediments we were able to look back in time to the 1800s, before acid rain, to show how pollution had harmed inland aquatic ecosystems and that lakes acidified because of acid rain and not because they were naturally acidic.” His collaborative work on acid rain went on to influence the implementation of environmental regulations, which are now showing positive results, with lake water acidity levels returning to background conditions.

Over time, environmental issues have only become more numerous and complex.

“Early limnologists, including the medal’s namesakes Einar Naumann and August Thienemann, often focused on issues separately,” says Dr. Smol. “They would examine things like the over-fertilization (eutrophication) of lakes and rivers within its own bubble, whereas today we are forced to address multiple environmental stressors simultaneously – not least of which is climate change. We have opened Pandora’s Box of evils on our planet, and now have to deal with these issues in increasingly innovative ways.”

Currently, Dr. Smol and colleagues are examining how they can help answer questions posed by conservation biologists, like those focused on vulnerable fish and seabird populations, amongst many other applications.

“The missing information with almost every environmental problem is a careful understanding of how we got to where we are,” says Dr. Smol. “Using lake sediments as a history book, we’re helping to track how ecosystems have changed over time, and why. Ultimately, we hope to shed light on how best to deal with multiple environmental stressors, as our climate continues to change.”

Much like examining sediments from time past for clues about the future, Dr. Smol attributes much of his career successes to younger limnologists and students who have added to his work.

“The real credit for this medal goes to an amazing group of current and past students, post-doctoral fellows, and staff” says Dr. Smol. “Over 100 graduates have passed through my lab thus far, and I hope many more still will. I have benefitted greatly from their hard work and ideas, and their successes remain my proudest achievement. It convinces me daily that the future for limnology is very bright.”

Dr. Smol was presented with the Naumann-Thienemann Medal at a SIL ceremony in Nanjing, China.