Chukchi Sea

• 1. Introduction

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  The Chukchi Sea sits at the top of the world, wedged between Russia and Alaska, where the Pacific Ocean finally meets the Arctic. Its southernmost boundary is the Bering Strait, one of the most consequential stretches of water on earth. The International Date Line crosses the Chukchi Sea from northwest to southeast, bending eastward specifically to avoid Wrangel Island and the Russian mainland of the Chukotka Autonomous Okrug. That small cartographic detour hints at something larger: this sea is a place where geography, history, and survival have always been intimately tangled. Its principal port is the Russian settlement of Uelen. What drew polar explorers, Soviet heroes, and oil companies to these frigid waters? What lives beneath its ice? And what dangers are quietly waking up in its sediments?

• 2. A Sea Takes Its Name

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  Harald Sverdrup, a Norwegian polar explorer, was conducting hydrographic observations in 1928 when he made a key distinction. The sea between Point Barrow and Wrangel Island, he concluded, behaved differently enough from the sea between the New Siberian Islands and Wrangel Island that the two should be treated separately. That observation triggered a formal separation from the East Siberian Sea. The newly defined body of water was named after the people who had lived on its shores for generations: the Chukchi. The name was officially approved in 1935. The Chukchi people of the Chukotka Peninsula had long fished, hunted walrus, and pursued whales in these waters before any European cartographer drew a boundary around the sea.

• 3. Shape and Scale

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  The Chukchi Sea covers approximately 595,000 square kilometers. For most of the year it is unreachable by ship; open water exists for only about four months annually. Beneath the surface, the dominant geological feature is the Hope Basin, stretching some 700 kilometers, bounded to the northeast by the Herald Arch. Shallow water defines much of the seafloor: depths under 50 meters account for 56 percent of the total area. The sea's island count is thin compared to other Arctic seas. Wrangel Island anchors the northwest corner, while Herald Island sits off Wrangel Island's Waring Point near the northern limit. The Chukchi Sea Shelf forms the westernmost reach of the United States continental shelf and simultaneously the easternmost reach of Russia's. A 50-mile passage within that shelf, called the Chukchi Corridor, channels one of the largest marine mammal migrations on the planet, with bowhead whales, beluga whales, Pacific walrus, and bearded seals documented moving through it.

• 4. Ice, Ships, and Calamity

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  Semyon Dezhnyov sailed from the Kolyma River to the Anadyr River in 1648, tracing a path through what would later be called the Chukchi Sea, but his route proved so impractical that no one repeated it for the next two centuries. Vitus Bering entered from the Pacific in 1728, followed by Captain James Cook in 1779. The sea's most dramatic chapter in exploration came on the 28th of September 1878, when Adolf Erik Nordenskiöld's steamship Vega became locked in fast ice while attempting the first full transit of the Northeast Passage. The crew could see that open water lay only a few miles ahead, yet they could not reach it. They secured the ship for winter and waited. Two days after the ice finally released Vega the following year, she passed through the Bering Strait and continued toward the Pacific. The 1913 voyage of Karluk ended far worse. Expedition leader Vilhjalmur Stefansson abandoned the ship, which then drifted north and was crushed by ice near Herald Island. Captain Robert Bartlett and an Inuk man named Kataktovik walked hundreds of kilometers across the sea ice to reach Cape Vankarem on the Chukotka coast, arriving on the 15th of April 1914. Twelve survivors were eventually found on Wrangel Island by the schooner King & Winge, nine months after the disaster began.

• 5. The Chelyuskin Saga

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  The steamer Chelyuskin left Murmansk in 1933 with an ambitious goal: to prove that the Northern Sea Route from the Atlantic to the Pacific could be completed in a single season. The vessel became trapped in heavy Chukchi Sea ice and drifted for more than two months before being crushed and sinking on the 13th of February 1934, near Kolyuchin Island. One person died. The remaining 104 people managed to establish a camp on the sea ice. The Soviet government mounted a celebrated aerial rescue, and all survivors were brought to safety. Captain Vladimir Voronin and expedition leader Otto Schmidt became national heroes. The wreck rested on the seafloor for decades until a Russian expedition called Chelyuskin-70 located it in mid-September 2006. Divers recovered two small pieces of the ship's superstructure and sent them to the vessel's builders, Burmeister & Wain of Copenhagen, for identification.

• 6. Life Under the Ice

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  Polar bears living on the Chukchi Sea's pack ice belong to one of five genetically distinct Eurasian populations of the species. The sea's biology also holds a quieter and more dangerous surprise in its sediments. Research published by Anderson et al. in 2021 identified two cyst beds of the dinoflagellate Alexandrium catenella in Ledyard Bay and Barrow Canyon. Together these beds cover 145,600 square kilometers, an area comparable to the state of Iowa, and their cyst concentrations rank among the highest measured anywhere on earth. When dormant, these cysts sit harmlessly in the seafloor. When conditions are right, they germinate, rise into the water column, and produce saxitoxin, a neurotoxin that causes paralytic shellfish poisoning in people who eat contaminated seafood. At bottom water temperatures of around 3 degrees Celsius, germination takes approximately 28 days; at 8 degrees, the process accelerates to 10 days. Blooms attributed to these beds occurred in July and August of 2018 and 2019. Over the past two decades, bloom initiation has moved three weeks earlier in the season, and the window during which harmful surface blooms can form has grown longer.

• 7. Oil, Drilling, and Retreat

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  The Chukchi Shelf is estimated to hold oil and gas reserves as high as 30 billion barrels. On the 6th of February 2008, the U.S. government announced the results of an auction in which winning bidders agreed to pay a combined 2.6 billion dollars for extraction rights. Environmentalists criticized the auction sharply. In May 2015, the Obama administration's Bureau of Ocean Energy Management gave Shell Oil conditional approval to drill in Chukchi Sea waters as shallow as 140 feet. By September of that year, Shell reversed course entirely, citing both the tremendous cost of operating in the region and falling oil prices. The company initially said it would return, but eventually surrendered all but one of its Arctic leases. Meanwhile, in October 2010, Russian scientists opened a floating polar research station called Severny Polyus-38 in the Chukchi Sea, housing 15 researchers for a year to conduct polar studies and to build the scientific record supporting Russia's territorial claims in the Arctic.