International Weddell Sea Oceanographic Expeditions
Encyclopedia
The International Weddell Sea Oceanographic Expeditions or IWSOE are a series of scientific research expeditions to the Weddell Sea
begun in 1967, involving cooperation among Norway
, Canada
, Chile
and the United States
.
The Weddell Sea, part of the Southern Ocean, is a unique scientific research environment. The outflow of Weddell Sea Bottom Water and Antarctic Bottom Water
formed in the Weddell and Ross Seas is a major source of oceanic deep water and changes affecting the formation of these water masses are liable to have an effect on the circulation of deep water globally. The water of the Weddell Sea is about 1400 m deep at its deepest point; it is exceptionally clear (the Secchi disk visibility reading at 80 metres recorded in the Weddell Sea on 13 October 1986 was the deepest ever, at the theoretical maximum in absolutely pure water). Much of the southern part of the sea is permanent ice, the Filchner-Ronne Ice Shelf
, which can be up to 600 m thick.
IWSOE research projects have involved a variety of institutions and covered a wide range of disciplines.
For example, in 1969 scientists from the Universities of Bergen (Norway) and Minnesota, Connecticut and California, Los Angeles, (USA), and the US Coast Guard Oceanographic Unit studied the formation of Antarctic Bottom Water, the population density and diversity of the deep sea benthos
of the Weddell Sea, the population dynamics of Antarctic seals and sedimentation processes in the Weddell Sea and carried out physical, chemical and photographic oceanographic surveys.
Other subjects of IWSOE research include the Weddell Sea currents and the biology of krill
, a species of zooplankton
abundant in the area.
The expeditions were initially led aboard the USCGC Glacier, an icebreaker
modified for oceanographic research which in 1968 was the first ship to cross the Weddell Sea from the edge of the ice pack to the continental landmass. At the time, the Glacier was the world's largest icebreaker.
Weddell Sea
The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha Coast, Queen Maud Land. To the east of Cape Norvegia is...
begun in 1967, involving cooperation among Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Antarctic Bottom Water
The 'Antarctic Bottom Water' is a type of water mass in the seas surrounding Antarctica with temperatures ranging from 0 to -0.8◦ C, salinities from 34.6 to 34.7 psu, and a density near 27.88...
formed in the Weddell and Ross Seas is a major source of oceanic deep water and changes affecting the formation of these water masses are liable to have an effect on the circulation of deep water globally. The water of the Weddell Sea is about 1400 m deep at its deepest point; it is exceptionally clear (the Secchi disk visibility reading at 80 metres recorded in the Weddell Sea on 13 October 1986 was the deepest ever, at the theoretical maximum in absolutely pure water). Much of the southern part of the sea is permanent ice, the Filchner-Ronne Ice Shelf
Filchner-Ronne Ice Shelf
The Filchner-Ronne Ice Shelf, also known as Ronne-Filchner Ice Shelf, is an Antarctic ice shelf bordering the Weddell Sea.-Description:...
, which can be up to 600 m thick.
IWSOE research projects have involved a variety of institutions and covered a wide range of disciplines.
For example, in 1969 scientists from the Universities of Bergen (Norway) and Minnesota, Connecticut and California, Los Angeles, (USA), and the US Coast Guard Oceanographic Unit studied the formation of Antarctic Bottom Water, the population density and diversity of the deep sea benthos
Benthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...
of the Weddell Sea, the population dynamics of Antarctic seals and sedimentation processes in the Weddell Sea and carried out physical, chemical and photographic oceanographic surveys.
Other subjects of IWSOE research include the Weddell Sea currents and the biology of krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
, a species of zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
abundant in the area.
Icebreaker
An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels .For a ship to be considered an icebreaker, it requires three traits most...
modified for oceanographic research which in 1968 was the first ship to cross the Weddell Sea from the edge of the ice pack to the continental landmass. At the time, the Glacier was the world's largest icebreaker.