The Challenger Oceanographic Expedition

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Sir Charles Wyville Thomson, Sir John Murray and John Buchanan:
Chief naturalist, assistant naturalist and chemist aboard the HMS Challenger

The Challenger Expedition claims the title of the world's first totally scientific oceanographic expedition By the time the HMS Challenger left the dock on December 21, 1872 (why do these British voyages always start around Christmas time?), the world was experiencing an intellectual and technological revolution of sorts. Except for the poles, few places remained to be conquered by man. And in a time when knowledge began to be equated with power, the British government was amenable to schemes for acquiring knowledge.

With a rising tide of intellectual fervor behind him, Sir Charles Wyville Thomson, a natural history professor at the University of Edinburgh in Scotland, and his Canadian-born student, John Murray (later, Sir John Murray) hatched a scheme to explore the oceans in the grandest oceanographic mission ever conceived. They called their proposal "oceanography" and pleaded their case before the Royal Navy and the Royal Society to send a ship around the world for one purpose: to study the oceans.

With the agreement that a portion of any profits from the trip would go to the government, Thomson and Murray secured a ship from the Royal Navy. The Challenger Society for Marine Science provides this best description of the HMS Challenger:

The vessel was a three-masted square-rigged wooden ship of 2300 tons displacement and some 200 feet [226 feet] overall. She was essentially a sailing ship though possessing an engine of 1200 horsepower. It was planned that the ship would be under sail for most of the cruise, using the engine primarily for maneuvering when conducting scientific observations and deploying heavy gear. All but two of the ship's 17 guns had been removed to make way for purpose-built scientific laboratories and workrooms designed specifically for biological, chemical and physical work. Storage space for all the trawls and dredges was also necessary, together with space for the anticipated sample collection.

challengermap.gif (20545 bytes)I've found nothing of the previous history of this ship, which is too bad, because all ships have interesting histories (Cousteau's Calypso was a converted mine sweeper). Nonetheless, she was well outfitted for a grand three and a half-year voyage that would take her across 68, 890 nautical miles of ocean (as the crow flies but I bet it was longer than that in terms of water under her bow) from the drift ice of the North Atlantic to south of the Antarctic Circle and around the world.

The expedition's mission, by and large, was quite simple: to gather detailed and consistent observations of various oceanographic phenomena across as much of the ocean as possible. The sampling plan devised by Thomson and Murray resembles the sampling plan of modern day oceanographic expeditions; an assortment of physical, chemical, geological and biological measurements stretched over the day(s) at regular intervals across the sea. Samples that weren't analyzed on board were stored for laboratory analysis at the end of the expedition, a task that required the labors of more than 100 scientists.

Over the course of their voyage, the ship "stopped" and collected data and samples at 362 stations "at intervals as nearly uniform as possible". This systematic sampling plan belies one of the fundamental limitations of oceanographic research: gathering data over huge expanses that is representative of the ocean as a whole. Apparently, Thomson and Murray felt that an orderly sampling regime was best suited for their purposes. Whether they appreciated the complexity of the ocean environment and the difficulty of obtaining representative samples, I don't know. Their journals may shed light on this.

Nonetheless, here is the regimen they performed as best as possible at each of the 362 stations they visited:

buchananwatersamplert.jpg (1667 bytes)The equipment available to them for performing these measurements was typical for the times (but not state-of-the-art, according to the historian at Scripps Institution of Oceanography) and, in some cases, not much different than what modern day oceanographers use. (Are you getting the perception that oceanography hasn't changed much in 125+ years?) Water samples were procured using a device called a Buchanan water sampler, invented (apparently) by the chemist on the expedition, John Buchanan, a rather disagreeable fellow (according to reports). Like modern day water sampling devices, the Buchanan sampler was attached to a line in an open position and triggered with a metal (usually brass) messenger that tripped the sampling bottle closed. The sampler could then be hauled on board where portions of the water could be analyzed for temperature (and perhaps other shipboard analyses) or preserved for laboratory analyses.

chglassspnget.jpg (1322 bytes)Biological samples were obtained in a similar fashion: tying a device to a wire and towing it through the water or along the bottom. One of the many remarkable achievements of the Challenger Expedition was their discovery of marine organisms at the bottom of the deepest parts of the ocean. Until that time, many oceanographers felt that there could not possibly be enough food for anything to live in the far reaches of the sea bottom. The data collected aboard Challenger proved otherwise. One of the more interesting finds was a deep-sea glass sponge, a beautiful animal, as shown in the figure at right. Nowadays, oceanographers realize that a rain of organic particles from the surface nourishes such animals, as well as the occasional large carcass, such as a dead whale or lost sailor, which provide food to bottom-dwelling scavengers.

challdinost.jpg (1981 bytes)Plankton samples also proved to be a rich source of new discoveries. Many of the microscopic forms had not been seen previously and the extent of their habitat, from the surface of the sea to the deepest depths, was unexpected. The illustrations of these organisms are still widely used today and are of such detail and artistic quality that even non-planktologists marvel at their beauty. The dinoflagellates shown at left are just one of the hundreds of examples. In total, Challenger scientists catalogued 4,717 new species, a staggering achievement. The next closest achievement in terms of finding new species has to be the late 1970s discovery of hundreds of new species of animals living on deep-sea hydrothermal vents and possibly, more recent explorations of the abyssopelagic environments with ROVs and submersibles. But even combined, these accomplishments don't nearly match the sheer numbers of new organisms brought to our attention by the Challenger.

challnger1t.jpg (6005 bytes)One of the more intriguing methods used by Challenger that thankfully is not necessary today was their method for determining the depth of the bottom. To accomplish the many tasks of towing nets, dredging the bottom, collecting water samples and determining depth, the ship need a substantial amount of cable and lines. One report I saw mentioned 144 miles of hemp rope for sounding and 12.5 miles of piano wire on board  for sampling (Duxbury reports this figure also). To determine the depth of the bottom (a process called sounding), a weight (over 100 pounds worth) was attached to the rope and lowered over the bottom. The line was marked in intervals and the depth of the bottom determined. The deepest depth recorded by the Expedition was located in the Marianas Trench, a place now known as the Challenger Deep. At this location, the scientists measured a depth of 26, 850 feet!

William Broad in his recent publication, The Universe Below (1997), recalls the words of another naturalist on board, Henry Mosely, who describes the evolution of feeling about this type of work.

At first, when the dredge came up, every man and boy who could possibly slip away, crowded 'round it, to see what had been fished up...Gradually, as the novelty of the thing wore off, the crowd became smaller and smaller, until at last only the scientific staff, and perhaps one or two other officers besides the one on duty, awaited the arrival of the net on the dredging bridge.

Such is the glamour of shipboard work! Indeed, many times the dredge or sounding rope would be lowered at 9 in the morning and not retrieved until 5 in the afternoon. Imagine being on watch making sure nothing happens to it. The hours do get long and tedious sometimes. But it's the possibility of discovering something that no one has seen before or no one has known before that makes you want to get up in the morning and do it all over again.

Listing the highlights and accomplishments of the Challenger Expedition are sort of like trying to list Michael Jordan's achievements in one sentence. Where do you start? The work of the 100+ scientists involved in the project occupied 50 volumes--29,500 pages--each volume as "thick as a family Bible", an accomplishment that took 23 years to complete.

That volume of knowledge notwithstanding, there are key discoveries reported by the expedition that deserve our attention. As reported by the Environmental News Network Daily News web site (I guess they're just catching up!), the major findings of the Challenger Expedition include:

The Challenger Society provides these accolades:

At its completion, The Report discussed with full detail of text and illustrations the currents, temperatures, depths and constituents of the oceans, the topography of the sea bottom, the geology and biology of its covering and the animal life of the abyssal waters. The Challenger cruise had lain the cornerstone of scientific oceanography and begun its introduction to the wider scientific and lay community...The findings of the cruise were correctly described by John Murray in 1895 as "the greatest advance in the knowledge of our planet since the celebrated discoveries of the fifteenth and sixteenth centuries".

A prodigious number of observations laid the foundations for much of the oceanography to come. In one sense, the Challenger Expedition marked the arrival of oceanography as a science. Exploration and map-making would no longer take the primary role in ocean science. A new ocean science, encompassing physical, chemical, geological and biological studies was born.

Obviously, there's lots more to tell. A few of these web sites provide interesting stories, images and details of the expedition, though none of them are very complete. Most oceanography textbooks (like Garrison and Duxbury) devote a page or two of text and figures to the Challenger expedition, although the best stories are found elsewhere (i.e. Broad's The Universe Below and Idyll's Abyss). A couple other accounts of the Expedition are available through online bookstores, though I have not read them. If you see something interesting about the Challenger Expedition and think it should be included here (like the story of Huxley's Bathybius), send it along. There's always room for more in The Remarkable Ocean World!

Environmental News Network

Fame and Fortune: The pay of scientists and sailors on the Challenger

The Voyage of the Challenger, great summary, awesome images

Cyberhiker: The birth of oceanography

Challenger Society for Marine Science, nice description of HMS Challenger

Notable Oceanographic Expeditions, Summaries of Notable Oceanographers

Maritime History

Exploration of the Pacific Ocean (nicely done)

Zegraham Deep-Sea Voyages: Visit the Titanic in a submersible, serious!

Historical Oceanography, Timelines

History of Marine Biology

Adventures of Fritdjof Nansen

NOVA Chronology of Deep Sea Exploration

NOVA: Into the Abyss