One of nature’s biggest secrets is hidden beneath the chilly waters of the Bering Sea. Lying roughly halfway between Siberia and Alaska, Zhemchug Canyon is 2,600 metres deep, making it almost one and a half times deeper than the Grand Canyon.
What’s more, the waters filling this massive canyon are brimming with ocean wildlife. Dolphins, whales, seals, squid and seabirds are among the animals that flock here to feed.
Key to this teeming biological hotpot is the unique shape and dimensions of Zhemchug. The steep, Y-shaped escarpment creates strong upwelling currents that sweep nutrient-rich waters from the deep seafloor of the Aleutian Basin towards the surface.
Once those nutrients reach the sunlit shallows they trigger a flourishing soup of phytoplankton, which in turn stirs the rest of the marine ecosystem into life. Huge shoals of filter-feeding fish, such as walleye pollock, gorge on the plankton. Then the superabundant fish fall prey to masses of other predators.
Together with the slightly smaller neighbouring canyon, Pribilof, Zhemchug provides important foraging habitat for rare and protected species such as northern fur seals, short-tailed albatross and Steller sea lions. Endangered bowhead whales and northern right whales migrate through the region.
The submarine canyons also provide habitat for a profuse mix of bottom-dwelling creatures. Snow crabs, king crabs and tanner crabs all live in great abundance on the seabed. Colourful gardens of deep-sea corals and sponges grow on the rocky canyons.
There are thickets of bamboo corals, bubblegum corals and glass sponges all filtering the clouds of food particles that sweep up the canyon walls.
Deep-sea scientists have discovered higher densities of corals and sponges growing in these canyons than most other places surveyed across the entire North Pacific, and they’ve revealed how important they are as nursery habitats for many fish and invertebrates.
Species new to science have been found here. Aaptos kanuux is a sponge that was named after the Aleut word for heart, signifying the place of Zhemchug and Pribilof in the beating biological heart of the Bering Sea.
Worldwide, canyons are rare habitats in the ocean, covering only around four per cent of the seafloor. They often form near to the mouths of great rivers on land, such as the Amazon, Congo and Ganges. It isn’t the water pouring from the rivers that carves canyons, rather they’re sculpted when sediments build up on continental shelves and then slump in great underwater landslides.
There’s so much life thriving in Zhemchug Canyon that it’s long been a major focus for major industrial fisheries. Back when it was discovered by Russian fishermen in the 1960s, they knew immediately how special this place was from their bountiful catches. That’s why they named it Zhemchug, the “pearl”.
