Who knew that fish had ears? Or that those ears could hold subtle hints about the state of the environment?

It’s certainly no surprise to Dr. Brian Fryer at the University of Windsor. Dr. Fryer is a specialist in the analysis of otolith—the bony material in the ear of a fish.

“The basic analogy is to tree rings,” explains Dr. Fryer. “As a tree grows, it lays down rings. The ear bones in fish do the same thing. The composition of each ring reflects the environment the fish was in at the time.”

Using a precision laser, Dr. Fryer can vapourize a sample from a single layer of otolith as thin as three millionths of a metre—the equivalent of one day’s growth in a young fish. It’s no more than a whisper of material, but analyzed in a mass spectrometer, it can reveal tell-tale traces of the chemical environment surrounding the fish on that particular day. Analyze a series of samples from a range of otolith layers, and you get a chemical chronicle of a fish’s entire life.

From there, a little scientific detective work can lead to important environmental insights. By combining information from a fish’s daily otolith “diary” with knowledge of a species’ migration patterns, Dr. Fryer can deduce chemical conditions at various points along the route a fish has followed—and pick up the first faint hints of contamination.

Dr. Fryer pursues his research in the remarkable context of the Great Lakes Institute for Environmental Research—GLIER— where he is also Director. The institute takes a determinedly cross-disciplinary approach to understanding the Great Lakes environment. “There’s a recognition now that environmental issues aren’t one-dimensional,” says Dr. Fryer. As a result, all kinds of scientists work together under one roof at the facility. Using a suite of tools funded in part by the Ontario Innovation Trust, they bring a wide range of disciplines to bear on the Great Lakes environment, from micro-chemistry—Dr. Fryer’s field—to genetic analysis, and earth sciences like seismology.

“We’ve got physicists playing with lasers right next to gene jocks doing DNA analysis,” Dr. Fryer laughs. “It’s the kind of environment that exposes you to things you’ve never studied, and you start recognizing what kinds of skills you need to move forward.”

Asked about the ultimate importance of the research going on at GLIER, his tone becomes a little more sombre. “Globally, fresh water is probably the most important resource we have. And when decisions have to be made about that resource, we’ll need a body of scientific knowledge and understanding to make sure those decisions are good ones.”