The Weddell Sea is considered to be a southern extension of the Atlantic Ocean and marks the northernmost part of mainland Antarctica. In the west, it is surrounded by the Antarctic Peninsula of Western Antarctica and in the east, it faces the Coats Land of Eastern Antarctica.
On its southern side, it is covered with thick ice shelves. The eastern end of the sea is defined by Cape Norvegia, situated on the Princess Martha coast which also separates the Weddell sea and the King Haakon VII Sea. The South Scotia ridge distinguishes its waters from the northern Scotia Sea while the Antarctic Peninsula separates it from the Bellingshausen Sea.
The southern part of the Weddell sea is covered with huge icebergs throughout the year, thus navigation is dependent on weather and ice conditions. Hence, cargo ships and carriers are restricted to the northernmost part of the Weddell sea.
Covered with thick ice sheets, possessing a polar climate and beautiful panoramas, the Weddell sea is one of the most important water bodies on our planet that also plays a significant role in global climate regulation. Let us explore a few interesting facts about this Sea of the South pole.
1. Weddell sea is the largest Sea of the Southern Ocean
A major sea of the Southern Ocean, it covers about 2.8 million square kilometres. It is about 2000 km or 1200 miles wide at its broadest point. Located at the edge of the continent, the Weddell sea has a depth of 1600 feet or 500 m due to a break between the shelf and the continental slope. For a continental margin, this is a great depth resulting from the massive ice load imposed on the Antarctic landmass. Its waters are claimed by the Antarctic territories of Britain, Argentina and Chile.
The Weddell Sea is said to possess the cleanest water among all the world’s seas and in the 1980s scientists concluded that it had the transparency of distilled water. Objects lying at a depth of 80 m or 260 feet can be clearly seen from the surface, making it one of the clearest water bodies on earth.
The Southern Ocean, also called the Antarctic Ocean comprises the southernmost waters of the world’s oceans. Interestingly, the Five Deeps Expedition was undertaken in 2018-19 to find the deepest point of the world’s 5 biggest oceans by Victor Lance Vescovo, an explorer, ex-naval officer and founder of Insight Equity Holdings. His team measured the deepest point of the Southern Ocean using multibeam sonar and named it Factorian deep as it lies at an underwater depth of 24,390 feet or 7,434 m.
After the Weddell Sea, the second-largest sea of the Southern Ocean is the Somov sea which stretches to 1,150,000 square kilometres and is roughly 3000 m deep. Situated north of Greater Antarctica, it is surrounded by the D’Urville sea in the west and the Ross Sea in the east. It was named in honour of a Russian explorer named Mikhail Somav who led the first Soviet expedition to Antarctica in 1955.
2. Formed during the Jurassic period some 145 million years ago
The Weddell Sea shares its geological history with the rest of Antarctica and also South America. It was formed by the breakup of the Gondwana landmass accompanied by massive volcanic eruptions during the wet and temperate conditions of the Jurassic era. The Weddell sea emerged as the southern extension of the Rocas Verdes Basin, a seismically active zone during those times. In the Cretaceous period, this basin transformed into a foreland basin called the Magallanes. While these geological processes unfolded in South America, the Weddell sea escaped these changes and retained the character of an ocean basin.
It expanded during the Cretaceous and Eocene geological periods. Around 35 million years ago, the Drake passage opened up making the sea seismically inactive. Formations of ice sheets and their continuous drifting in the eastern and western Antarctic region led to the erosion of enormous amounts of rock and sediment from the continent. These were deposited on the margins of the Weddell Sea 30 million years ago and some of it is still trapped in the age-old ice caps.
3. Discovered by Scottish explorer James Weddell in 1823
The Weddell Sea was discovered by the seal hunter and famous English explorer James Weddell who first sailed through its waters in 1823. He named it the sea of King George IV but subsequently it was renamed after James Weddell in 1900.
Weddell sea was not navigable during the 19th century. Otto Nordenskiold, Finnish geologist and leader of the Antarctic Expedition of Sweden spent almost a year on Snow Hill Island when his ship was crushed by icebergs floating in the Weddell Sea. The expedition which began in 1901 was unsuccessful and all the crew members were rescued from Hope bay after being stranded on Paulet Island. However, only one member survived.
Weddell Sea is also the site where Ernest Shackleton’s ship, The Endurance capsized in 1915. He led three British expeditions to the Antarctic in the 1900s and was determined to cross the Antarctic and the South Pole. However, his ship was trapped in thick polar ice for ten months. All the men escaped and spent five months trekking over ice sheets till they reached Elephant Island through a lifeboat. They were rescued and luckily all crew members survived. In March 2022, the wreck of the Endurance was found by the Endurance 22 Expedition, four miles from its estimated location at a water depth of 9,869 feet.
4. World’s second-largest Antarctic ice shelf, the Ronne-Filchner Ice Shelf borders the Weddell Sea
The Ronne-Filchner ice shelf is divided into the eastern or the Filchner shelf and the Western or the Ronne ice shelf by the Berkner island. As a whole, it covers around 430,000 square kilometres and is the second-largest ice shelf on earth. It is becoming bigger due to the inward flow of massive ice sheets, however, regular calving also results in the separation of ice sheets and the formation of gigantic floating icebergs.
Between the two, the Ronne ice shelf is bigger and is surrounded by the Antarctic peninsula on the west. It was first discovered by Finn Ronne, the supervisor of the Ronne Antarctic Research Expedition undertaken in 1957. The Filchner ice shelf is bound by the Coats Land on the east and was discovered by a German expedition to Antarctica headed by the explorer Wilhelm Filchner in 1912. It is fed by the Slessor glacier, Recovery and Support force glaciers situated near the Berkner island.
The Ronne-Filcher ice shelf is 600 m thick with a water depth of 1400 m at the deepest point. It has been a subject of immense interest for biologists and scientists who believe it could reveal secrets of the paleo marine environment and extinct flora and fauna. An international programme was also initiated in 1973 to study the ice shelf.
However, the harms of global warming on the ice shelf are visible as outlined in recent research published in Nature. The Alfred Wegener Institute in Germany conducted a study and predicted that around 455,000 km2 of the Antarctic ice shelf would melt by the end of this century resulting in a 4.5 mm rise in sea level every year.
In 2020, sponges and unidentified marine growth were reported to have been growing on an ice boulder under the western end of the Filchner ice shelf, at a water depth of 1234 m.
5. Weddell Sea is part of many ancient myths and legends
The Weddell Sea region has been described as one of the harshest and desolate, yet most breathtaking places on the planet by the historian and explorer Thomas. R Henry, the first person to write about the Weddell Sea and the continent of Antarctica.
His book called the White Continent was published in 1950 and was the first work to describe in detail the climate, weather, flora and fauna of Antarctica, which was largely unexplored during that period. He had accompanied Admiral Byrd on his expedition to the Antarctic in 1946-47 which prompted him to write about his extraordinary experience.
He mentioned that the Weddell sea is filled with icebergs and impossible to navigate especially during winters. He devoted an entire chapter to the myths of the green-haired merman and mermaids living in the Weddell sea waters, sighted by many sailors passing through the treacherous water body. He also highlighted the navigational difficulties faced by him and his crew members while crossing the sea.
6. Weddell Sea is one of the few sites of deep water mass formation contributing to global thermohaline circulation
Weddell sea has an extremely harsh and cold climate accompanied by strong winds and ice-packed waters. However, the sea is of utmost importance as it regulates global weather and the circulation of world ocean currents through the process of thermohaline circulation. Thermo means heat and haline refers to the levels of salinity.
Hence, these variations in water temperature and salinity resulting from interactions between surface forcing due to various geological processes lead to the flow of the ocean and sea waters across our planet. Hence, the Weddell sea is an important component of this global water cycle, pushing cold water northwards. It also contributes to the formation of deep water masses through cabbeling, brine exclusion and the phenomenon of wind cooling.
7. One of the two gyres of the Southern Ocean is found in the Weddell Sea
The western Weddell Sea has a northward flowing ocean current which is a part of the wind-driven cyclonic current system known as the Weddell gyre. This northward current is the main reason for the outflow of water from the Weddell sea, a place of deep ocean water modification. It comprises cold and low salinity surface water separated by a narrow pycnocline from the thick layer of comparatively warm and highly saline water known as the Wendell deep water.
Weddell Gyre is one of the two major gyres or ocean currents of the Southern Ocean rotating clockwise in the Weddell Sea and formed by the intersection of the Antarctic Circumpolar Current and the Antarctic continental ice shelf.
8. Weddell Sea is home to large populations of seals, penguins and whales
The ice-cold waters of the Weddell sea support a rich marine life comprising seals, penguins and different species of whales. Weddell seal is a common species that are mostly found in inshore regions. Though named after the sea, they are found all over Antarctica. Smaller than the Weddell seal, and measuring up to 2 metres, the crabeater seal is another species that can be seen on the icebergs. It is preyed upon by the leopard seal which ranks among the top predators of the Antarctic. Not only do they kill other seals, but they are also known to be aggressive and have even attacked humans.
Adelie Penguins can be easily spotted amidst the thick ice of the Antarctic region. They are small in size but can be easily distinguished due to the white circular patterns around their eyes. A few years back, scientists found a colony of Emperor Penguins, the biggest penguin species on Snow Hill Island.
The enormous amounts of Antarctic krill attract huge baleen whales to the Weddell Sea. The Southern Minke whale and humpback whales are also commonly found whale species in the Weddell Sea waters. Many other whale species such as the Blue whale, fin whale, sei whale, and sperm whale migrate to the Antarctic region. Seals and penguin populations attract groups of Orca whales, known for their strategic hunting skills, such as creating high waves to push seals off from the ice sheets into the water.
9. Offers many thrilling adventures to intrepid explorers
With advancements in shipping technologies and the invention of icebreaker ships, much of the Antarctic region can be explored. Enthusiastic adventurers can reach the northwestern parts of the sea since the rest is covered with thick, impenetrable ice sheets.
Many routes can be taken to Antarctica however Weddell Sea is close to Argentina and cruises for the sea ply from the resort town of Ushuaia, the southernmost city of Argentina. It is a famous tourist destination that provides skiing opportunities, a tour to the Tierra del Fuego national park or a visit to the Martial Glacier.
The journey from the resort town to the sea can take about four to five days depending on the weather conditions. Travellers can explore the region through land excursions, helicopter flights and cruise voyages. Whaling stations, old research facilities, penguin colonies etc can be seen on a trip to the Weddell Sea.
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Disclaimer: The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendations on any course of action to be followed by the reader.
Shilavadra Bhattacharjee is a shipbroker with a background in commercial operations after having sailed onboard as a Third Officer. His interests primarily lie in the energy sector, books and travelling.