Bering Sea

• 1. Introduction

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  The Bering Sea sits at the edge of two worlds. It is the body of water that divides the two largest landmasses on Earth: Eurasia and the Americas. On the 18th of December 2018, a meteor the size of a small building exploded above it at an altitude of 25.6 kilometers, releasing 49 kilotons of energy into the sky. Almost no one saw it. That is the Bering Sea: enormous, remote, and violent in ways that rarely make the news.

  This is a sea that has shaped human history more than most people realize. During the last glacial period, sea levels dropped far enough that people could walk east from Asia to North America across what is now open ocean. Scientists call that path the Bering land bridge. The questions that follow from this place run deep. How did life take hold in waters this cold and dark? Why do the largest seafood companies on Earth depend on it? And what happens to the rest of the world when the Bering Sea begins to change?

• 2. The Navigator's Sea

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  Vitus Bering, a Danish-born navigator sailing in service of Russia, became the first European to systematically explore these waters in 1728. He sailed northward from the Pacific Ocean, passing through the strait that now bears his name, pushing into the Arctic Ocean beyond. The sea he mapped would eventually carry his name too, and Bering Island in the Komandorski Islands group stands as a further marker of that legacy.

  The Bering Strait itself is more than a geographic feature. It is the far north boundary of the sea and the passage connecting the Bering Sea to the Arctic Ocean's Chukchi Sea. To the south, the Alaska Peninsula and the Aleutian Islands form a sweeping arc that separates the Bering Sea from the Gulf of Alaska. The International Hydrographic Organization defines the sea's southern limit as a line running from Kabuch Point on the Alaskan Peninsula, threading through the Aleutian Islands to the south extremes of the Komandorski Islands, and then on to Cape Kamchatka. Every narrow waterway between Alaska and Kamchatka falls inside that boundary.

• 3. Scale and Structure

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  Over 2,000,000 square kilometers of water make up the Bering Sea, bordered on the east and northeast by Alaska, on the west by the Russian Far East and the Kamchatka Peninsula, and on the south by the long Aleutian chain. Its floor is not flat. A deep water basin drops away at its center, then rises through a narrow slope onto shallower continental shelves near the coasts.

  Bristol Bay carves its own identity within this larger body, sitting between the Alaska Peninsula and Cape Newenham on mainland Southwest Alaska. Beneath the surface, the sea holds 16 submarine canyons. One of them, Zhemchug Canyon, is the largest submarine canyon in the world. The Pribilof Islands, St. Lawrence Island, the Diomede Islands, Nunivak Island, and the other islands scattered across the sea each create their own local conditions for the life that depends on them. There is also a small remnant of the ancient Kula tectonic plate resting beneath the Bering Sea, a piece of ocean floor that once subducted under Alaska before the plate itself largely disappeared.

• 4. The Engine of Productivity

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  Where the shallow continental shelf drops away into the North Aleutians Basin, something remarkable happens. Cold, nutrient-rich water from the deep basin rises up the slope and mixes with the warmer, shallower shelf water above. This zone, known as the Greenbelt, is the dominant engine of biological production in the entire sea. The steady upwelling drives constant blooms of phytoplankton, the microscopic plants that anchor the food web.

  Seasonal sea ice plays a second role. When winter ice melts each spring, it releases lower-salinity meltwater into the middle shelf areas. That meltwater creates layers of water that do not easily mix, a condition called stratification, and those layered conditions help trigger the spring phytoplankton bloom. The ice is not only a hydrological tool; it also provides a surface for algae to colonize and an interstitial habitat for ice algae growing within the ice itself. The interaction of ocean currents, sea ice, and weather creates what scientists describe as a vigorous and productive ecosystem, one complex enough that its full workings remain little understood.

• 5. Life in the Cold

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  At least 419 species of fish have been recorded in the Bering Sea. Among them are Pacific cod, sablefish, Pacific salmon, Pacific herring, and several species of flatfish, all of which support commercial fisheries. Red king crab and snow crab round out the shellfish harvest. The sea also shelters blue whales, humpback whales, bowhead whales, gray whales, beluga whales, and the vulnerable sperm whale. The North Pacific right whale, described as the rarest whale in the world, lives here too, alongside fin whales and sei whales, both of which are endangered.

  Over 30 species of seabirds breed in the Bering Sea region, totaling approximately 20 million individual birds. Tufted puffins, red-legged kittiwakes, spectacled eiders, and the endangered short-tailed albatross all depend on its waters. Colonies of crested auklets number upwards of a million individuals. Walrus, Steller sea lions, northern fur seals, orcas, and polar bears complete the roster of marine mammals. Two species are gone entirely: the Steller's sea cow and the spectacled cormorant were both driven to extinction by human overexploitation. A small subspecies of Canada goose, the Bering Canada goose, also disappeared, lost to overhunting and the introduction of rats to its breeding islands.

• 6. The Billion-Dollar Harvest

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  Commercial fishing on the U.S. side of the Bering Sea generates approximately one billion dollars in seafood annually. Russian Bering Sea fisheries add approximately 600 million dollars more. Landings from Alaskan waters alone represent half the U.S. catch of fish and shellfish, a share that makes the Bering Sea the backbone of the American seafood industry.

  King crab, opilio crab, tanner crab, Bristol Bay salmon, and pollock are the flagship catches. The crab seasons in particular have earned a public profile through the Discovery Channel television program Deadliest Catch, which chronicles the dangerous work of harvesting king crab and snow crab. In the middle of the sea, beyond national jurisdictions, lies a stretch of international water known as the Donut Hole, a gap between the U.S. and Russian exclusive zones where governance over resources is more complicated. The food web that supports all of this fishing remains, in the words of scientists who study it, complicated and little understood.

• 7. A Sea Under Pressure

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  A long record of carbon isotopes preserved in samples of bowhead whale baleen tells a sobering story. Those isotopes reflect trends in primary production across the Bering Sea over time. The data suggest that average seasonal primary productivity has declined by 30-40% over the last 50 years. Fewer plants at the base of the food web means the sea can support less life overall.

  In the summer of 1997, unusually warm water triggered a massive bloom of coccolithophorid phytoplankton. These single-celled algae are low in energy compared to the phytoplankton species that normally dominate the bloom, which means the same volume of plant life delivered less nutrition to the animals feeding on it. Between 1979 and 2012, the Bering Sea region saw a small growth in sea ice extent, a pattern that ran counter to the dramatic summer ice losses occurring in the Arctic Ocean to the north. Scientists describe the future of the Bering Sea's climate and ecosystem as uncertain. What is certain is that the Pribilof, Zhemchug, and Pervenets canyons, those nutrient-rich upwelling zones that seabirds and marine mammals depend on, are among the features most likely to determine what survives the coming changes.