SUPPLEMENTAL INFORMATION...IN GREATER DEPTH

16-20 October 2017

OCEANOGRAPHIC EXPEDITIONS THAT MADE AN IMPACT


Oceanographic expeditions began with the three voyages of Captain James Cook of the British Royal Navy over the period 1768-80. These voyages were made aboard, at various times, the HMS Endeavour, Resolution, Adventure and Discovery. While the chief objective was not science, but to establish a British presence in the South Seas, some scientific information was sought and obtained. The science included astronomy, and exploration of New Zealand, Australia's Great Barrier Reef, Tonga, and the Easter Islands. Cook and his crew took samples of fauna and floral, marine life, the ocean bottom and geological formations. He was the first to circumnavigate the Earth at high latitudes and sail as far south as about 70 degrees S; however, he did not sight Antarctica. He was commissioned to find a Northwest Passage. He charted the West Coast of North America and "discovered" Hawaii, although he was killed on the Big Island in a confrontation with the native people.

Again, while the main objective was not science, the British explorers, Sirs John and James Clark Ross addressed deep-sampling problems. In 1818, Sir John Ross obtained a bottom sample from greater than 1900 m depth off Greenland. Sir James Clark Ross, who discovered the Ross Sea and Victoria Land in Antarctica, achieved depth soundings of greater than 4400 m and almost 4900 m in the South Atlantic.

From 1831 to 1836, the HMS Beagle undertook a voyage to study natural science; Charles Darwin sailed as a naturalist. Again, while not a voyage of oceanographic discovery, Darwin's first major work was Structure and Distribution of Coral Reefs (1842). In this work, he correctly argued that the form and structure of reefs and atolls develop because they are living organisms growing upward in an effort to remain in the photic zone as compensation for the sinking seafloor. Darwin also wrote on several marine subjects including barnacle biology and fossils, all of which was overshadowed by his On the Origin of Species.

While the first genuine for-science-only oceanographic voyage was probably the British Challenger Expedition of 1872-76, the United States launched the U.S. Exploring Expedition in 1838-42. The latter was a two-pronged expedition in that it was primarily a naval expedition but had more scientific latitude than the Challenger Expedition. Had it not been for the difficult and contentious personality of its leader, Lt. Charles Wilkes, USN, this expedition might have been as famous as the Cook or Challenger Voyages. The flagship was the Vincennes, but included five other vessels. Their goals and achievements included showing the flag, charting, whale observing, geological gathering, and general scientific observing. The voyages explored and charted large parts of the east Antarctic coasts, confirming that Antarctica was a continent. The most unusual goal certainly must have been to test the hypothesis that Earth was hollow with two large holes to enter through either the North or South Poles. The many specimens and artifacts, scientific and otherwise, formed the nucleus of the then recently established Smithsonian Institution in Washington D.C. Wilkes and his scientific staff produced a 19-volume final report.

The Challenger Expedition of 1872-76 was the first expedition dedicated entirely to marine science, as conceived by Charles Wyville Thompson, and funded and supported by the Royal Society. The British government provided the ship, the HMS Challenger, as well as a captain and crew. In a forerunner of today's operations, the Captain ran the ship, but a board of six chief scientists was in charge of the scientific enterprise. Thompson and his colleague John Murray even coined the word oceanography. HMS Challenger sailed on 21 December 1872 for a 4-year voyage around the world to cover 127,000 km (79,300 mi)--a distance more than three times the diameter of the Earth.

An important hypothesis to test was that because of extreme pressure and no light, no life could exist below a depth of 550 m. The Challenger was able to sample to a depth of 8,185 m (~5 mi). The Challenger made 492 deep soundings, with samples and nets at 362 stations. The hypothesis was proven false when 4717 new animals and plants were discovered at stations to all depths. The Challenger also took physical oceanographic and meteorological data of air and sea temperatures, salinities, densities, including 77 stored samples, currents, and winds. As many as 151 open ocean trawls were made and coral reefs were charted. Sediment samples were collected along with thousands of pounds of various specimens brought back for museum study. Manganese nodules were discovered on the ocean bottom spurring interest in sea bottom mining. Probably the most important result of the voyage was the 50-volume Challenger Report. The Report was written and published between 18 80 and 1895 by Sir John Murray and provided the foundation for the science of oceanography. This magnificent account is still used today and can be found in the libraries of many major universities.

Two American expeditions inspired by the Challenger results were directed by the American naturalist Alexander Agassiz on the U.S. Coast and Geodetic Survey Ship Blake (1877), and later on the survey ship the Albatross (ca. 1900). Both voyages made important contributions to the new science of oceanography. The Blake collected data at 355 deep-sea stations that validated the Challenger observations, especially concerning manganese nodules.

In the period between these two American contributions, the Russians under S.O. Makarov, made a 3-year cruise (1886-1889) aboard the corvette Vitiaz analyzing the physical characteristics of the North Pacific waters.

In the late 1800s, a wooden ship, the Jennette, was crushed in the Arctic polar ice off Siberia in the western Arctic. Some three years later, pieces of the Jennette had transited the Arctic Ocean in the ice and were found emerging from the Arctic ice cover through the strait in the eastern Arctic between Greenland and Spitzbergen (now called the Fram Strait). In a truly remarkable testing of an idea, Fridtjof Nansen (a Norwegian polar explorer, humanitarian, statesman, marine zoologist, pioneer oceanographer and Nobel Peace Prize winner) hypothesized that the Arctic Ocean and ice circulation was predictable enough that he also could transit the Arctic Ocean in a proper ship. He built a ship with a round bottom that would pop up out of crushing ice and thereby sail or drift across the Arctic Ocean in three years. He left Norway on the ship Fram on 24 June 1893 and entered the Arctic Ocean and sailed with the Arctic ice for two years. He then left the ship while on the ice cap to try to sled dog to the North Pole. He did not attain his goal, but he reached Franz Josef Land, where he boarded a ship in 1896 to sail back to Norway. He arrived within a day or so of the Fram that had indeed transited the Arctic ice cap in three years. Nansen continued to sail for almost two decades into the 20th century in the Fram primarily in the polar regions. The Fram is now in a maritime museum in Oslo, Norway.

In 1925, the Germans mounted a 2-year expedition in the open South Atlantic in the Meteor. They used more modern optical, acoustic and electronic equipment applied to oceanography. Probably the most important innovation was the acoustic echo sounder to nearly instantly measure and record the depth and profile of the bottom of the sea. These observations drastically changed the view of the bottom of the sea from being monotonously flat to a rugged sea bottom with mountain ranges in the middle of the ocean basin. In addition, these data provided important clues to sea floor spreading and plate tectonics.

In 1931, the Atlantis was the first ship built specifically for oceanographic research, and did seminal work on confirming the existence of the Mid-Atlantic Ridge. Establishment of the Scripps Institution of Oceanography in 1902, more than a century ago, helped advance oceanographic research. In 1937, the institution's schooner E.W. Scripps began a broad program on physical, biological, chemical and physical oceanography off Southern California. The results of the program on the E.W. Scripps and others led to the publication of the well-known book on the ocean sciences, The Oceans, in 1942.

In 1951, the HMS Challenger II undertook a 2-year survey of precise deep-sea measurements of the world ocean. The deepest depth measured was in the Mariannas Trench. This depth, called the Challenger Deep, is 11,020 m (36,000 ft or nearly 7 mi) below the ocean's surface and was reached in 1960 by U.S. Navy Lieutenant Don Walsh and Jacques Piccard in the Swiss designed deep-sea bathyscaphe Trieste. It has not been reached by humans since.

Finally, in 1968, the deep sea drilling ship the Glomar Challenger began a 15-year odyssey, drilling in water depths to 6000 m and then into the sea floor and crust to depths of more than 1700 m (> 1 mi). She traveled more than 600,000 km (375,000 mi) and recovered 96 km (~58 mi) of deep-sea cores. A primary goal of these expeditions was to test the hypothesis of sea floor spreading and plate tectonics. The answer was a resounding confirmation of this hypothesis. Another major finding was that the oceanic crust is no older than 180 million years, compared with the oldest dated continental crust of more than 3.8 billion years old. This discovery was supported when deep sea drilling was taken over by the much larger and advanced JOIDES Resolution (Joint Oceanographic Institutions for Deep Earth Sampling). JOIDES Resolution is capable of drilling in water 8100 m (27,000 ft) deep and into the sea floor and upper crust to depths greater than 2000 m. While sea floor spreading and plate tectonics are fully supported by the deep-sea drill cores, the cores are also used to study Earth history. At present, the Ocean Drilling Program has drilled into the bottom of the ocean, uncovering a record that extends as far back as 227 million years ago.


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Prepared by H.J. Niebauer and Edward J. Hopkins, Ph.D., email hopkins@aos.wisc.edu
© Copyright, 2017, The American Meteorological Society.