Found almost 70 miles off Virginia’s coast, the Norfolk Canyon is a unique habitat with a vast array of exciting, potentially undiscovered marine life.
What & Where is Norfolk Canyon?
Norfolk Canyon is the southernmost of the large submarine canyons located along the edge of the continental shelf from Canada to Cape Hatteras.
The head of the canyon is approximately 69 miles east of the Chesapeake Bay mouth and Virginia’s coastline.
The largest underwater feature off Virginia’s coast, the canyon is 35 miles long, and its deepest point is 6,562 feet, or more than 1 mile, below the surface of the water.
Like many canyons on land, Norfolk Canyon has deep, V-shaped valleys with rocky outcrops and flat terraces.
How did Norfolk Canyon form?
At the peak of the last Ice Age 20,000 years ago, sea level was as much as 400 feet lower than today because much of the water was locked up in glaciers.
At that time, the shoreline was more than 60 miles east of its current location, and the Susquehanna River cut across the continental shelf to the shelf edge.
The river eroded a valley that would gradually be submerged as the climate warmed and sea level rose.
The valley at the shelf edge enlarged as avalanches of sediment called turbidity currents periodically flowed downslope, scouring away rock and sediment to create the Norfolk Canyon.
The river valley to the west also flooded, forming the Chesapeake Bay.
Four reasons why Norfolk Canyon is valuable:
1) It’s a hot spot for ocean life, both within the canyon and in the waters above.
- The warm Gulf Stream and the cool Labrador Current meet near the canyon, bringing together species from different ecosystems.
- In addition, this gouge in the continental shelf and slope guides bottom currents loaded with nutrients to the surface, a process called upwelling that creates a productive feeding area for marine animals including billfish, marine mammals, sea turtles, and ocean birds.
- Wherever there are fish, fishermen are sure to be close by, and the Norfolk Canyon is a popular destination for charter boats in search of tuna and marlin.
2) The canyon is home to the southernmost community of deep-sea giant tree corals.
- These spectacular tree corals can reach heights of 10 feet and provide habitat for many invertebrates and fishes.
- They may live for hundreds or even thousands of years, and their “skeletons” provide scientists with information about what ocean conditions were like in the past.
- Deep-sea corals and sponges also have chemical compounds that have proved valuable to human medicine, including in treating cancer and synthesizing artificial bone.
3) A methane seep near the canyon mouth is possibly the largest in the North Atlantic.
- The methane gas bubbling up through the bottom creates special conditions in the water around the seep.
- An unusual community of organisms that can use methane as an energy source thrives here, including chemosynthetic bacteria and mussels.
- The bacteria and animals living in the seep community can survive only where methane is available, making them sensitive to anything that disturbs their habitat.
4) Shipwrecks near the canyon helped lay the foundations for the U.S. Air Force.
- In the summer of 1921, captured German naval vessels, including the battleship Ostfriesland, were bombed by Billy Mitchell’s U.S. Army Air Service to demonstrate that aerial attacks could sink ships.
- The so-called “Billy Mitchell Fleet” rests near the Norfolk Canyon, and helped usher in the age of air power. These bombed ships laid the foundations for the independent U.S. Air Force and shaped the future of U.S. Naval Aviation.