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At a conference in 1963, oceanographer Carleton Ray observed that we kind of biffed it when we named our planet. “We call this planet Earth,” he said, “yet this is the only planet that has a sea. I think we should have called it ‘Sea.’” Ray Radbury and others said something similar, and they have a point. While we know that water can be found elsewhere in the solar system, such as on some of Jupiter’s moons, it’s tough to overstate the importance of water on Earth.

In a 2021 Science Talks webinar from the Faculty of Science, researcher explained, “more than 70 per cent of our planet’s surface is covered by seawater and our oceans contain more than half of our world’s biodiversity.” Ocean organisms generate the oxygen that goes into “more than one of every two breaths you take.” Earth’s oceans are also a major storage sink for the planet’s carbon dioxide, and currents carry heat from the equator to the poles — making agriculture possible in mid-latitude places like ºÚÁϲ»´òìÈ.

says that our bodies are up to 60 per cent water. Over 3.5 billion of us rely on marine animals for food. Global fisheries are valued at $240 billion annually. Water shapes us in ways large and small, from the vapour you’re exhaling as you read this to the shallow sea that covered what’s now ºÚÁϲ»´òìÈ during the Devonian period 380 million years ago.

But the converse is true, too. As temperatures rise, coral reefs die and hurricanes intensify, and our ability to affect life below water on a global scale becomes undeniable. So does our need to understand it. Here is how Green and other U of A researchers are illuminating life below water at different levels.

Reef Restoration

Half of all living coral reefs have died since the 1950s, due to the warming ocean, pollution, coastal developments and overfishing. Reefs are stores of biodiversity — at least 25 per cent of known marine species live on them. Coral reefs also protect coastal communities from storms. Reversing their decline would be a win for life on Earth.

How to do it is a focus of Green’s research in the Department of Biological Sciences. One branch of her research looks at ways to improve transplanting live corals onto reefs where they’ve died.

“This is like reforestation underwater,” says Green in the webinar. “We’re doing this, in particular, with corals that are resistant to heat stress and other effects of climate change. So we can grow back coral reefs better, with corals more likely to survive ongoing climate change.” Reef restoration is labour intensive. To understand where it makes the most difference, researchers in Green’s lab have built “replicate” corals with 3D printing and detailed digital models of reefs.

“In areas of already high complexity, where lots of that reef framework is left, we see a lesser response among fish to adding live coral back,” says Green. But in low-complexity reefs, already flattened by erosion, she reports a strong positive response among fish to adding a live coral cover.

It feels like a kind of hope for our oceans.

Water, the Sculptor

The oceans themselves are fed by a vast network of freshwater systems. “I tell my students they can stand in any stream, take a water sample and use it to think about the ecosystem upstream, the land they’re standing on and what’s happening downstream,” says U of A researcher , ’02 MSc. “Freshwater systems integrate the landscape.”

Tank’s work examines how water changes landscapes as it moves from the land to the ocean.

“I work a lot in a region that’s right at the N.W.T.-Yukon border — the edge of the last glaciation,” she says. As the ice sheets retreated about 10,000 years ago, they left huge chunks of ice buried in the permafrost. As permafrost thaws due to climate change, those gigantic underground ice cubes thaw too.

“The net effect kind of looks like a landslide,” Tank says. “These are huge topographical features. When they collapse, it’s a fundamental reorganization of the landscape.”

Tank also tracks the changing chemistry of rivers that drain into the Arctic Ocean, including the Peel watershed in the Yukon. “Things are changing in the Peel at an alarming rate,” she says. She describes a nearly pristine region, with minimal settlement, no agriculture, minimal extractive water use and no direct water pollution. “But we’re still seeing really striking trends in water chemistry.”

While she charts the impact of climate change and trends like nitrogen deposition on ecosystems, Tank remains hopeful about our ability to use water responsibly.

“I think we’re past the point of needing to show that we should clean up our act. People are really concerned. And I think this will lead to change,” she says. “When that happens, switches flip quickly.”

From vast oceans to the waterways that feed them, you can zoom in further still.

Just Keep Swimming

“I have stuck with studying fish because they do weird things in terms of evolution,” says , another U of A biological sciences researcher. “There is a lamprey that loses its entire digestive tract before it reproduces. How can that be supported by evolution?”

Exploring questions like these has led Venney to study DNA methylation, an epigenetic process through which gene expression changes are maintained across generations of, in this case, fish. It’s one of the main ways that environmental factors can influence gene expression.

“I mostly look at trout, salmon, whitefish — the salmonids,” she says. “They’re economically and culturally important.”

They are also almost all in decline in Canada.

“Urbanization and anthropogenic change are factors — road salt and contaminants can be a big deal. But climate change is the big one, since salmonids are sensitive to temperature,” Venney says. In response to this decline, conservation programs aim to spawn these fish in protected habitats and release them into the wild.

“Some of my research looks at harnessing epigenetics to improve those practices,” Venney says. “In brook trout, for example, we heated up some of the parent fish a little bit during sexual maturation.” Venney found that the spawn of these warmed-up fish were better acclimated to warmer waters than trout whose parents stayed cool. Hatchery programs can use such insights to release fish with a better chance of completing their life cycle — or growing to an appreciable size before winding up on a plate.

Warming trout to prepare their offspring for life might seem like a small change in the grand scheme of things. But, as Venney points out, small changes have a way of adding up.

“Gradual change is something we can all invest in, even for one species in one place,” Venney says. “I find it motivating that a lot of people want to make small changes.”