Canada is one of the most urbanized countries in the world: most of us live in cities. Even if we venture out of those highly constructed places to spy on plants and animals in more natural environments, our immersion is usually around the edges. We follow trails in parks and wildlife areas, we take a canoe or kayak across the lake or down the river, we go camping… but that is as far as we usually get from our city lives.

I have the good fortune to work with people who regularly step off the edges to go deep into the world of natural history in their quest for species discovery. One of the ways to do that is to literally immerse themselves using scuba.

A scuba diver's head emerges from the water.
Mark Graham on a recent dive. Image: Jacqueline Madill © Canadian Museum of Nature

Scuba diving is a sport where the romance of it is greatly disconnected from how it really works. Most people who pass the training course will never dive again. It has something to do with claustrophobia, tight neoprene suits that makes it hard to move and loading up with lead and other heavy gear. If you are amongst the few who can get past those bits, then you will likely get completely hooked with what goes on below the surface.

Scientific diving adds other elements to the experience. Like other science operations, the objective is to use this method of investigation to challenge a question. Your objective isn’t to dive in the usual places to see how much cool stuff you can spot. Instead, you might team up with Dr. André Martel, who has deep insights into the natural history of freshwater clams, especially the rare ones.

Two people wading in the river near a boat and the shore.
Researcher André Martel and research assistant Jacqueline Madill on the Ottawa River, where they are studying freshwater-mussel populations. Image: Mark Graham © Canadian Museum of Nature

André creates a research scenario that considers bottom substrate (sand, rocks, etc.), water current, depth, previous records, and local knowledge. Then he pours over charts and like a prospector looking for treasure, points his finger and says, “I believe the clams will be there.” That’s when the fun begins for the divers. How do we get a boat there, are there any natural or man-made hazards, can we get permission, and so on?

A man's hands indicate a site on a chart.
Selecting a dive site on a chart of the Ottawa River. Image: Mark Graham © Canadian Museum of Nature

In his recent exploits on the Ottawa River, André wanted to dive in remote areas over sand, down to five metres, in fast current. To a diver, that means gearing up with extra lead to make sure you stay on the bottom, swimming through a bunch of weeds until you find the sand, turning on your light because it is dark below three metres, and knuckling along the bottom to make way into the current.

Because this is a science dive, it also means carrying bags for the collections, note pads to write observations, and a one-metre-square frame of rigid tubing to measure the density of animals living on the bottom (density is the number of clams counted per metre squared). Awesome.

A group of mussels at the bottom of a river.
Eastern elliptios (Elliptio complanata). This freshwater mussel species is native to Canada. Image: André Martel © Canadian Museum of Nature

What does a diver see out there in the dark, sandy reaches of the Ottawa River in the circle of light made by the flashlight on the bottom? Some clams, like the eastern elliptio, are common. These bulldozers of the river plough slowly along the bottom with their muscular foot, thereby mixing the nutrients through the top few centimetres of the bottom.

Every once in a while, a bass or a sturgeon will drift past and cause moments of muted excitement as the divers shout into their breathing apparatus, “Did you see that?” Then there are moments of discovery, like the recent find of rare hickory-nut clams. Finding things where no one else has looked, based on sound logic and a bit of luck, is about as good as it gets for a science diver.

The real hard work follows the euphoria of the discovery. How extensive are the populations? How does this new knowledge become conservation action? And like most of our research, we conserve a few good examples of what was found within the national collection so that others can study them.

On shore, two people hold mussels in both hands.
Each specimen is identified and samples are taken back to the lab for DNA analysis and for inclusion in the national collection. Image: Mark Graham © Canadian Museum of Nature

There are amazing things just beyond our urban existence, and natural history museums make it their business to help connect people to them. For example, the coming exhibition Arctic Voices (opening in December at the museum) will help immerse us into the natural history of the North.

Stay curious, you may spot our diver’s bubbles in a lake or river near you.