You can fit a whole lot of life in a single jar.
Christianne McDonald peers into a glass vase full of water from the Sturgeon River on a sunny summer's day. The amber liquid teems with life. Red water mites bumble about the floating algae like drunken bees. A nematode worm wriggles sinuously through the jungle. A fearsome water tiger chases a massive baby dragonfly.
McDonald, a biologist and co-ordinator of the Big Lake Environment Support Society's (BLESS) summer nature centre, is one of many local residents who keep an eye on life in the Sturgeon. "Ever since I can remember, I've been something of a nature freak."
She scoops up scores of critters from the Sturgeon each summer to teach kids about life under the waves.
Water bugs are actually one of the most mysterious parts of the Sturgeon, according to researchers, as no one has ever done a formal, watershed-wide study of them. This summer, a team from the Northern Alberta Institute of Technology (NAIT) will dive into this mystery with the first-ever comprehensive study of benthic invertebrates in the Sturgeon River.
The Sturgeon has a bad rap for being a dead river, McDonald says, but it's actually full of living creatures. "It's a pretty healthy ecosystem."
Mysteries in the muck
Joel Gervais wades into that ecosystem later that afternoon. Net in hand and dressed in hip waders, the St. Albert resident and lead researcher on the NAIT team wades into the murky water up to his waist.
The NAIT team is doing an on-going study on the river, he says. This summer, they'll be taking water quality readings at 22 sites on the river from Entwistle to Fort Saskatchewan, testing everything from water chemistry to bug life.
There's actually quite a lot of interesting life in the river, Gervais says, including crayfish, clams and pike. To find them, he and his team will use a highly scientific technique known as the "boogie shuffle" — kick-sampling, in layman's terms. By kicking up mud and catching it downstream with your net, you can snag an arc's-worth of river bugs for study.
Once you've filled your net, you wade back to shore, screen out the mud, and start counting your critters — a process that can take hours. "It's fairly tedious," Gervais says, as some of the creatures are the size of sand.
Benthic invertebrates are spineless bugs that live in river and lake sediment, says Josh Haag, a biologist with Aquality Environmental Consulting who is working on the upcoming State of the Sturgeon report, and there are few formal studies on them anywhere in Alberta. "They're not a very sexy topic," he says, and you don't have hordes of amateurs taking an interest in them.
These studies are also very labour intensive, McDonald notes. "Each sweep, you're getting boatloads [of bugs] to identify," she says, and you need to do many sweeps at many sites. "It would take months of full-time work and multiple people."
But studying benthic invertebrates can give you a bug's-eye view of a watershed, Haag notes, as many of them are sensitive to poor water quality. "These are things that are very low down on the food chain," he adds, and any threats to them can affect the many fish and birds that eat them.
Benthic bestiary
The presence or absence of certain water bugs can tell you a lot about life under the waves. "Everything has a story to tell," McDonald says.
Take mayflies, for example. These bugs are super-sensitive to pollution and low oxygen levels and are part of the EPT Index — a measure of the number of kinds of ephemeroptera (mayfly), plecoptera (stonefly) and trichoptera (caddisfly) in a river. An unpolluted, fast, oxygenated river would have plenty of these bugs and a high EPT number; the Sturgeon has relatively few of these bugs and would have a low one. Any swings in this number can point to a change in the river's condition.
McDonald sweeps a net through the Sturgeon by St. Albert Place and drops her catch into a white water basin. She finds a surprise guest right away — a big brown black-masked vertebrate called a wood frog. This is the most common type of frog we have around here and its presence is a good sign. "Frogs need a lot of food in order to survive," she notes and their tadpoles need a fair amount of oxygen in the water. Fat, healthy frogs are signs of a relatively healthy river.
Most Sturgeon sweeps will pick up about a zillion shrimp — pinkie-nail-sized critters that gallop pell-mell through the water. Shrimp are a vital food source for other birds and bugs.
These creatures are very resilient, Gervais says, and are common even in very poor water conditions. "You jump in with your waders and jump out, and you've got like 20 just stuck on your waders quite often."
McDonald spots another food source making a break for it up the side of the basin — a tiny brown snail. These guys eat plants and algae, she says, and usually retreat into their shell when threatened. Watch carefully and you might see them sticking to the underside of the surface of the water.
McDonald scoops up a pair of damselfly nymphs. Each about two centimetres long, these predators undulate through the water by swishing their triple-tails, which also serve as gills. They can also shoot out their lower jaws to snag their prey — McDonald catches one nymph with a water flea in its mouth.
These damselflies are dwarfed by the dragonfly nymph she catches next. About four centimetres long with massive eyes and long legs, this proto-dragonfly is the Red October of the benthic world. It even has jet propulsion, she notes, as it squirts water into the air — these bugs have gills in their butts, and can shoot water from their rears for a quick escape.
Like damselflies, dragonflies spend several years living in the water eating everything in sight. "They're fantastic predators with marvellous sight," McDonald says. Their extensible jaws and brown camouflage let them sit under debris to ambush other creatures, such as mosquito larvae.
Canny searchers might get to see the dragonfly's remarkable metamorphosis. After about three years, McDonald says, these nymphs will crawl out of the water onto a plant, typically at dusk or dawn, split their skin open along the back and pull themselves out. Over the course of several hours, the dragonfly will inflate its wings with blood, wrench them perpendicular to its body, dry and take flight, ready to eat more mosquitoes.
Studying the Sturgeon
A small-scale invertebrate survey by St. Albert Catholic High School students found about four species of stonefly and caddisfly. That's not a lot, Haag says, and suggests that the water quality when the students took their samples was probably not that good.
But that doesn't necessarily mean that the river is in bad shape, he adds; stoneflies and caddisflies favour cold, fast-flowing rivers, which the Sturgeon is most certainly not. Prairie rivers are also runoff-fed, which means more nutrients and less oxygen and are prone to big spikes in flow — none of which are good for these bugs.
We could help life in the river by replanting riparian zones, Haag notes. Thicker shoreline vegetation would shade the water and keep more nutrients out of it, adding oxygen, reducing algae blooms and cooling the water.
The NAIT team's work with bugs in the Sturgeon could help researchers track the effects of water pollution throughout Alberta, Haag says. "It may be that we are surprised by the quality of water in the Sturgeon watershed."
