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The Challenger Expedition: The Birth of Oceanography

1.1. The Challenger cruise (1872-1876)

It is to Great Britain's credit that the first major oceanographic expeditions were organized, thus confirming its undeniable supremacy over the oceans (Rule, Britannia!).

One name came to be highly recognized at the end of the 19th Century, the English naturalist Charles Wyville Thomson (see Box 1.1). For many (Deacon 2001), the circumnavigation of the HMS Challenger he commanded between 1872 and 1876 marked "Year 1" of offshore oceanography. This multidisciplinary expedition sponsored by the Royal Society of London is the most expensive ever undertaken, at a cost of about 10 million pounds today.

It is true that Great Britain was at the height of its maritime domination and could not bear the idea of the United States, Germany or Sweden taking the lead. Let us examine the contributions of this circumnavigation of 68,916 miles across all oceans to the far reaches of the Southern Ocean using sails for transit and the steam engine at stations, especially for dredging.

This expedition with precise objectives (Corfield 2003) was out of the ordinary due to the meticulous preparation of the ship. Eighteen months were needed to select the old, 70-m, three-masted warship, set up laboratories and housing, winches and oceanographic equipment to study the distribution of pelagic fauna, collect organisms living at depth, multiply bathymetric measurements and take water samples at all depths.

Box 1.1. Charles Wyville Thomson and John Murray

The two major players in the Challenger cruise

The English naturalist Charles Wyville Thomson (1830-1882, Linlithgow), fascinated by crinoids, true living fossils, confirmed that life is abundant and diversified up to a depth of at least 4,500 m and that there is a deep ocean circulation. He published his results in The Depths of the Sea (1873), the first book dealing with the great depths, which made him the true founder of modern oceanography. He was entrusted by the British navy with the direction of the Challenger cruise and was knighted upon his return in 1876.

Figure 1.1. Sir John Murray (©NOAA Ocean exploration and research)

John Murray (1841, Cobourg-1914, Kirkliston) (see Figure 1.1), a man capable of all during this cruise, was responsible for the publication, at the British government's expense, of the 50 volumes published between 1880 and 1895. With quite a bit of humor, Murray wrote in the introduction: "Our knowledge of the ocean was, in the strict sense, superficial." In 1912, he published with the Norwegian Johan Hjort The Depths of the Ocean (1912), whose first chapter summarizes the history of oceanography from its origins. He was also knighted in 1898.

This mission was considered exceptional due to its significant number of staff. When the Challenger left Portsmouth on December 21, 1872, it had 243 officers, crew and scientists on board.

The head of the mission, Scotsman Wyville Thomson, was not in good health and returned exhausted from this journey. John Murray, another Scot, in charge of studying deep sediments, was a skillful and vigorous man. The Scot John Buchanan, a chemist, irascible and pretentious, was the genius of DIY and invention. Henry Moseley, a true naturalist, also an astronomer, was assisted by the German Rudolph von Willemoes-Suhm, who died during one of the first stops. John Wild was the expedition's secretary and artist.

The monotony of the soundings and dredgings (see Figure 1.2) during the Challenger's journey (see Figure 1.3) led to a number of defections by the crew: about 60 abandoned the voyage and about 10 died.

Figure 1.2. Dredging and sounding on board the HMS Challenger (©NOAA Ocean exploration and research)

Figure 1.3. "Around the world" trip of the Challenger between December 21, 1872 and May 24, 1876

Still out of the ordinary, the 713 days at sea allowed 362 "stations": determination of depth, meteorological conditions, direction and speed of the surface current, sampling of the surface layer of the sediment, sampling of bottom water and measurement of its temperature. In addition to most stations, plankton sampling by hauls of net and bottom dredging and trawling with beam trawls were carried out.

This expedition marked the beginning of oceanography because of its major contributions to ocean knowledge:

1. 1) It definitively put an end to the theory of the British naturalist Edward Forbes (1843) who had stated that there could be no life beyond 400 m. Certainly, as early as 1861, the rise of a telegraph cable immersed 1,800 m at the bottom of the Mediterranean on which solitary corals had settled had already eroded this hypothesis (not to mention the forgotten work of the pharmacist and naturalist from Nice Antoine Risso in Histoire naturelle des crustacés des environs de Nice, published in 1816);
2. 2) Of the 7,000 species harvested, about 1,500 were new; showing the richness and diversity of the deep environment, which Thomson (1873) translated into these terms:

   It is inhabited by a fauna more rich and varied on account of the enormous extent of the area, and with organisms in many cases apparently even more elaborately and delicately formed and more exquisitely beautiful, in their soft shades of coloring and the rainbow tints of their wonderful phosphorescence, than the fauna of the well- known belt of shallow water.

3. 3) It specified the topography of the seabed showing a depth of more than 8,183 m in the Mariana trench (the Challenger did not have a longer cable!) and highlighted the mid-Atlantic ridge, thus preparing the way for Alfred Wegener's (1912) continental drift theory;
4. 4) It showed that sediments were formed from pelagic organisms: globigerin, diatomaceous earth, pteropod and red mud from the deep sea;
5. 5) It brilliantly confirmed the constancy of the relative proportions of the various salts contained in seawater, having been previously observed in 1819 by the Swiss Alexandre Marcet and, in 1855, by the American Matthew Fontaine Maury. We will elaborate on this at the beginning of Chapter 3.

Carpenter's hope to discover the mechanisms of ocean circulation was not materializing, despite valuable information gathered on vertical profiles of temperature, salinity and density, including confirmation that cold waters (2°C) found near the bottom in the vicinity of Fernando de Noronha formed on the surface and in winter in the North Atlantic. This partial success was due to the absence of a real physicist, the poor quality of the thermometers (maximum-minimum temperature produced by Mille-Casella, then Negretti and Zambra, and Richter and Wiese reversing thermometers), the inadequacy of British meteorology and the lack of knowledge of fluid mechanics at that time.

The return to Great Britain did not mark the end of the adventure. Thomson set up a study in Edinburgh to collate the data, distribute the specimens and supervise the publication of the results, which lasted 23 years for 50 volumes and 30,000 pages written by many scholars under the supervision of John Murray (Thomson and Murray 1885-1895). This period was marked by quarrels between the British Museum, which wanted to coordinate this synthesis, English researchers, who wanted exclusivity, and the Treasury, who was reluctant to pay an ever-increasing bill.

1.2. From the Challenger to the "golden age" of oceanography

As our book shows the development of concepts essentially between 1960 and today, we would not want to abandon the Challenger by suggesting that there was nothing between this expedition and the "golden age" of oceanography. On the contrary, many cruises enabled the development of concepts and methods. Georg

Wüst (1964) listed about 20 oceanographic cruises between 1873 and 1960 and, with less strict criteria, François Carré (2001) counted between 110 and 115 between 1900 and 1956 with increasing frequency after the Second World War when Germany disappeared into the background and the United States and the USSR moved to the foreground. These cruises remained national for political or economic reasons (northern shipping route, fishing, whaling). Twelve countries participated in this expansion, with only eight being present throughout the period: Argentina, Belgium, Canada, Denmark, France (including Monaco), the Netherlands, Sweden and the United Kingdom. The practice of oceanography by enlightened and wealthy individuals on board their yachts (Alexandre Agassiz, John Buchanan, Albert I of Monaco [see Figure 1.4], King Don Carlos of Portugal, the Duke of Orléans and Jean Charcot) disappeared due to financial requirements and the institutionalization of research.

Figure 1.4. Prince Albert I of Monaco aboard Princess Alice (©Coll. Institut océanographique, Fondation Albert Ier, Prince of Monaco)

The first cruises, centered on hydrography, were carried out on national marine vessels (Challenger, Gazelle, the first Vitiaz) before oceanographers had their own...