Language selection


Taking a deep dive into Canada’s oceans

Rare tube worms, glass sponge reefs, pingos — some of the fascinating features found in our oceans

June 2022

An autonomous underwater vehicle, a smoking sea vent, life on the ocean floor, dinoflagellates, bathymetric maps.

Canada's coastline is the world's longest, at 243,042 kilometres. Photos top left and bottom right: National Oceanic and Atmospheric Administration (NOAA) photo library.

Oceans are full of unique and wonderful geological formations and aquatic creatures. And since Canada has the world’s longest coastline, there’s plenty to study here.

While scientists have been exploring our deep waters for centuries, there’s still so much more to discover — in fact, more than 80 percent of our oceans worldwide still remain unmapped. And today, using technologies like autonomous underwater vehicles and high-resolution digital imagery, researchers are getting a more detailed understanding of our oceans than ever before. For example, they’re now able to use highly accurate echo sounders to measure the depth of water down to the seafloor and to create bathymetrical maps. These maps use various colours to clearly distinguish different depths, running from red (closest to the surface) to yellow, green and, finally, to blue (the deepest portions).

A crater and microbial and macrofaunal communities on the sea floor.

Craters, or irregular depressions, indicate areas where vents in the sea floor, called cold seeps, are releasing methane, hydrogen sulphide and other hydrocarbon fluids. Deep-sea microbial and macrofaunal communities often colonize these sites. Location: deep waters off the Nova Scotia coast. Images: Pierre-Arnaud Desiage (GSC) and NSDRR.

Research of this kind is especially vital now, as our oceans are constantly changing and adapting to increased environmental pressures as temperatures rise, shorelines shift, and permafrost melts, among other trends. And Geological Survey of Canada (GSC) scientists are leading the way in this research by exploring, documenting and sharing some of the fascinating stories our oceans have to tell.

Curious? Let’s just dive in!

A black smoker.

Black smoker in the Endeavour Hydrothermal Vent fields. Photo: NOAA photo library, University of Washington; NOAA/OAR/OER, licensed

Black smokers

“Black smokers” are tall underwater sulphide chimneys that expel hot black fluid at temperatures reaching over 300°C. They can grow up to 45 metres high before toppling over — that’s comparable to an eight-storey office building!

In the Pacific Ocean off the coast of Vancouver Island, British Columbia, a group of nearly 600 of them are found in an area called the Endeavour Hydrothermal Vent Fields. They stand in a deep underwater valley where the seafloor is ripping apart — gradually pushing the Pacific Plate west toward Japan. Designated as the first Marine Protected Area under Canada’s Oceans Act in 2003, the Endeavour Fields is home to many diverse and abundant ecological communities, including several aquatic plant and animal species not found anywhere else on Earth.

Tube worms and bathymetrical map of a mud volcano.

Images: Scott Dallimore/ GSC

Mud volcanoes

Since it’s covered with ice most of the year, the Arctic Ocean might not be the first place that comes to mind as a hotbed of volcanic activity. But surprise! Mud volcanoes are seafloor mounds found near the upper slope of the Beaufort Sea in the Canadian Arctic. Occuring both underwater and on land, they come in a wide variety of shapes and sizes. They expel massive quantities of different kinds of fluids and sediments, depending on the source, and their eruptions can be discrete or go on over the course of hours or even centuries!

Because of their distinct geology, mud volcanoes can create unique biological environments. A recent GSC study of mud volcanoes in the Beaufort Sea revealed the existence of tube worms — a rare species recorded at only one other location on Earth.

Four dinoflagellates

Images: Manuel Bringué


Dinoflagellates — microscopic, single-celled aquatic organisms with characteristics of both plants and animals — provide scientists with clues to what the marine environment was like throughout history. Their resting cysts are fossilized in sedimentary rocks dating as far back as approximately 240 million years. These fossils serve as markers both for the age of the rocks where the dinoflagellates lived and for the particular environmental conditions at that time.

GSC scientists are currently studying dinoflagellate cysts in the Smoking Hills area in the Northwest Territories to determine the age of the rocks and to help reconstruct environmental conditions over the last 11,000 years in the Kitimat Fiord System along British Columbia’s North Coast.

Glass sponge reefs

Photo: Fisheries and Oceans Canada

Glass sponge reefs

In the deep waters off the coast of British Columbia, scientists have discovered glass sponge reefs — a unique organism once thought to be extinct. Unlike other sponges that form their structures from protein, glass sponges form their structures using silica, a mineral that is the primary constituent of glass and the electronic semiconductors that drive our computer age. The reefs they form can grow up to 25 metres high and develop slowly over centuries as three species of glass sponges progressively attach themselves to earlier generations of sponges. Like all sponges, glass sponges not only take in water but also release it, and they do so with great efficiency: a single small reef of them can filter enough water to fill an Olympic-sized swimming pool in less than 60 seconds!


Images: Scott Dallimore/ GSC


Pingos are distinct ice-filled hills found in some coastal areas where there is permafrost. While pingo means “small hill” in Inuvialuit, some of these iconic features are massive. Above ground, pingos can reach more than 50 metres in height and 1,000 metres in diameter at the base. The Ibyuk Pingo — one of the world's largest — is located in the Tuktoyaktuk Peninsula region of the Northwest Territories, along with more than 2,350 other pingos. Scientists only recently identified about 1,000 of them by using high-resolution digital imagery. Pingos also occur underwater, but there they are typically smaller — less than 30 metres high and 300 metres in diameter. They can be found on the seafloor of the Beaufort Shelf and other areas of the Arctic Ocean. Recent seabed maps from the GSC reveal that underwater pingos can occur as isolated mounds or clustered close together.

An underwater avalanche

Pangnirtung Fiord, Nunavut image: Alexandre Normandeau

Underwater avalanches

An underwater avalanche, also called a turbidity current, is a rapid flow of water and sediment particles down a sea slope below the surface. Just like an avalanche above ground, these underwater events can be triggered when mud and sand on the continental shelf are loosened by earthquakes, collapsing slopes or other geological disturbances. Underwater avalanches can change the physical shape of the seafloor by eroding large areas and creating underwater canyons.

The largest underwater avalanche ever recorded in Canada occurred off the shore of Newfoundland in 1929. It travelled for more than 100 km and carried enough sand and mud to fill 80 million Olympic-sized swimming pools!

Everything is connected

So we can see that, indeed, there’s a lot of commotion in the ocean! And these fascinating marine features and creatures, while interesting in themselves, don’t exist in isolation. Marine ecosystems are complex so there’s still much more to learn about their unique geological formations. Identifying their features and appreciating how they interconnect will help us understand patterns and trends from the past and into the future.


Geoscience: Marine & coastal
Hope for climate change from Canada's Arctic Ocean
Learning from tragedy: the 1929 tsunami (podcast)
Icebergs can cause landslides, new discovery (video)
The dangers of underwater landslides (podcast)

Page details

Report a problem on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: