Wednesday, February 20, 2013

Another Voyage of Discovery ~ A Review of Richard Corfield's The Silent Landscape

In which the blogger reviews a very good book and ultimately wanders off to join the American Miscellaneous Society.

On February 21, 1873, the HMS Challenger could have been found dredging and taking soundings at 24º 20′ N, 24º 28′ W, about 538 miles southwest of the Canary Islands and some 604 miles from the west coast of Africa.  From the bottom, some 2,740 fathoms (3.1 miles) below the ship, the dredge brought up red clay.  The recorded water temperature on the seafloor was 2º C.

The Challenger was a small vessel, about 2,300 tons displacement and 200 feet long.

The illustration above is from Sir Charles Wyville Thomson’s published account of the ship’s time in the Atlantic Ocean during the voyage.  Wyville Thomson was the lead scientist aboard the ship, heading a staff of five other scientists.  (This and all other images in this blog post are taken from The Voyage of the “Challenger”:  The Atlantic, A Preliminary Account of the General Results of the Exploring Voyage of H.M.S. “Challenger” During the Year 1873 and the Early Part of the Year 1876, Volume I,  1878.)

On that day, 140 years ago tomorrow, the Challenger was in the first months of what scientist and writer Richard Corfield has described as
. . . the first great voyage of scientific exploration, sent out with no other purpose than the acquisition of knowledge.  It was a milestone in the history of humanity, when the importance of learning for its own sake was perceived, not just by a small intellectual elite, but by ordinary people as well.”  (The Silent Landscape:  The Scientific Voyage of HMS Challenger, 2003, p. 252 – 253.)

The voyage would take about three and a half years and, by the time it ended, on May 24, 1876, the vessel and (most of) its crew would have covered 68,900 miles circumnavigating the globe.  The results of that voyage of scientific discovery have echoed down these many years, helping to make and remake fundamental concepts in biology, geology, and oceanography.  Corfield avers that "its importance can hardly be exaggerated."

The Silent Landscape is Corfield’s fascinating, well told account of the voyage, but it is much more than that.  It’s also an accessible exploration of the scientific meaning of the voyage, covering an expansive range of scientific topics of fundamental importance for us today, including climate change, plate tectonics, and evolution.  (Though the book was published a decade ago, I've only just discovered it.)

The Challenger voyage, the product of a collaboration between the Royal Society (with Thomas Huxley at the helm) and the British Admiralty, was undertaken to explore the deep oceans worldwide.  To that end, the scientists on board systematically and regularly gathered such information as depth and temperature, analyzed the chemical composition of sea water at varying depths, determined the makeup of deep seafloor deposits, and examined the organic life found at different depths, including the ocean floor.  (The Silent Landscape, p. 4-5.)

Thus, dredging, such as that undertaken on February 21, 1873, was a crucial activity on the mission, and it occurred often.  The map below shows where and how often the bottom was dredged and soundings taken (perhaps some trawling as well) during the Atlantic crossing in 1873.

Each time muck from the bottom was brought to the surface, it was pounced upon by the Scientifics (as the team of scientists was called by the crew).  Each "catch" from the dredge was analyzed in the labs and work areas that had replaced nearly all of the Challenger's guns (testament to the scientific focus of the voyage).  Depicted below is the ship’s natural history workroom.

As the ship moved across the Atlantic in early 1873, the Scientifics noticed dramatic changes in the material coming from the ocean floor.

Corfield’s discussion of this phenomenon follows his overall approach to the Challenger’s scientific discoveries throughout the book.  First, he sets the scene – where the vessel is located, what events might have punctuated the life of the men on board, and what the scientists were up to and finding.  Then he explores the understanding today of the science behind the discoveries, and often describes how that understanding was achieved.  It’s an eminently workable and successful framework for his book.

Immediately after departing the Canary Islands, the dredges had brought up the expected white mud from the seafloor, identified by the Scientifics as Pteropod and Globigerina ooze.  The former consisted largely of small mollusk shells; the latter was made up of tiny foraminifera shells.  Two views of a shell from the foraminifera Pulvinulina menardii are shown in the illustration below.  Wyville Thomson noted that this specimen was found at 1,900 fathoms.

But as the water’s depth increased, the nature of what came to the surface in the dredges changed, from white ooze, to gray, until a red clay appeared.  According to Corfield, the Scientifics observed that, during this crossing, Pteropod ooze marked shallow bottoms down to some 400 fathoms, and was succeeded by Globigerina ooze to a depth of about 1,500 fathoms.  At that depth, grey mud showed up, which was ultimately replaced by red clay when the depth reached 2,200 fathoms or more.

Corfield recounts that the Scientifics took a large step toward explaining this red clay phenomenon when they added a weak acid to the Globigerina ooze, revealing the presence of red clay as the shells dissolved.  As a result, they knew that the red clay marked the absence of the mollusk and foraminifera shells, not a new precipitation of red clay.  That was as far as they got.

At this point in his account, Corfield explains what we now know to be behind this phenomenon.  As ocean depth increases, the acidity of the water also increases until it reaches a point where the water is sufficiently acidic to dissolve the calcium carbonate shells of mollusks and foraminifera.  This is the calcite compensation depth “where the rate of calcium carbonate supply from the surface is balanced by the rate of dissolution so that there is no net accumulation of carbonate.”  (p. 63)  Corfield then describes the process accounting for the increase in acidity with greater depth.  [Later edit:  As the climate changes, this relationship between calcium carbonate shells and ocean acidity is playing out in a threatening way.  The increasing levels of carbon dioxide in the atmosphere contribute to greater acidification of the oceans which, in turn, directly affects shell-producing organisms such as foraminifera.  A recent study found foraminifera shells to be a third thinner than they were in the immediate past.  (Sean B. Carroll, "Nature's Masons" Do Double Duty as Storytellers, New York Times, June 25, 2012.)]

As he moves back and forth between the Challenger voyage to an explication of our current scientific knowledge, Corfield provides vignettes of the efforts of later scientists to whom we owe our contemporary understanding.  As a result, we readers learn of many “voyages” of discovery, from the work of Bruce Heezen and Marie Tharp whose creation of detailed maps of the ocean floor were crucial to showing that the seafloor was spreading outward from mid-ocean rifts, to the creation of the bathysphere by William Beebee and Otis Barton which took humans to ocean depths never before achieved and which sparked invention of mobile, powered deep sea exploration vehicles such as the bathyscaphe of August and Jacques Piccard.  Even when the Challenger bypassed the Mediterranean, it’s an occasion for Corfield to comment on a missed opportunity and explain what the Scientifics might have learned (in this case, that the Mediterranean floor reveals that some 5 to 6 million years ago, the Mediterranean, drained of all its water, was a salt encrusted desert).

The voyage was a dangerous experience.  Lives were lost, including one of the Scientifics.  But, it was also mind numbingly tedious.  Much of the time at sea was marked by days of boredom for the crew as the ship sailed a short distance and then engaged in the time consuming process of dredging, trawling, and taking sounds.  Over and over this process was repeated as the vessel circled the globe.

To get a flavor of what it was like to serve on the Challenger, I am currently reading the collected letters of one of the Challenger seamen, Joseph Matkin, the ship's steward's assistant.  (At Sea with the Scientifics:  The Challenger Letters of Joseph Matkin, edited by Philip R. Rehbock, 1992.).  It's a rare glimpse below decks.  Matkin makes clear the impact that the scientific nature of the voyage had on life at sea.  In a letter dated March 16, 1873, describing the crossing of the Atlantic, Matkin wrote, "We are 17 days from Teneriffe [Tenerife in the Canary Islands] today & expect to be there [St. Thomas in the Virgin Islands] in about 12 more days for we furl sails every day for 8 or 9 hours, & dredge, & take soundings &c which of course makes the journey much longer, & tedious."

Small ship, years at sea, not sailing to reach port, little sense of the big picture, no wonder fully a fourth of the crew deserted the Challenger during this voyage.  No one said doing science had to be comfortable or endlessly exciting.

Finally, I have to thank Corfield for introducing me to the wonderful, though short-lived, American Miscellaneous Society (AMSOC).  In his discussion of deep sea drilling efforts (the Deep Sea Drilling Project and its successor the Ocean Drilling Program) and their contribution to our understanding of plate tectonics and climate change, Corfield notes the crucial role played by AMSOC.  It organized Project Mohole (to explore the boundary between the earth’s crust and mantle) which was funded by the National Science Foundation, helping to foster subsequent deep sea drilling.

Although it has a clear connection to scientific work prompted by the Challenger exploration, AMSOC is a definite diversion for this review.  In some ways, it's a counterpoint to the dreary nature of much of the back breaking work that went on during that scientific voyage of discovery.  AMSOC is clever men of science having serious fun.  I love it.

AMSOC was the brainchild, in 1952, of Gordon Lill and Carl Alexis, two geologists working in the Geophysics Branch of the Office of Naval Research (ONR).  They founded AMSOC to deal with the many “miscellaneous” proposals coming to the ONR, proposals that didn’t seem to fit in any general category.  One author has described AMSOC as follows:
Any scientist who has business with ONR’s Geophysics Branch is likely to claim membership in the American Miscellaneous Society since there are no official membership rolls.  In fact, there are no bylaws, officers, publications or formal meetings.  Nor are there any dues, for funds are a source of controversy.  The membership is largely composed of university professors or scientific researchers but the rumor that only persons can be admitted whose research proposals to ONR have been turned down because they are too far-fetched is completely false – it is merely a coincidence.  (Willard Bascom, as quoted in Albatross Award of the American Miscellaneous Society, Scripps Institution Of Oceanography Archives.)
Indeed, it was summed up by one of its intimates as having been created "to see the lighter side of heavier problems."  (John Knauss, Gordon Lill, and Arthur Maxwell, Recounting the History of the Albatross Award, Eos, January 20, 1998.)  Its “members” took a non-bureaucratic, cut-the-crap approach to ONR proposals.  Corfield notes, AMSOC “existed solely to get things done.”  (p. 238).  That AMSOC created a “Committee for Co-operation with Visitors from Outer Space” and the “Society for Informing Animals of their Taxonomic Positions,” should certainly be viewed in its favor.

[Later edit:  Rereading the few sources out there about AMSOC and the confused passages I've written about it, I realize that I really don't know what it was - a joke that, for a moment (Project Mohole), became serious; an effort by a group of research scientists to actually "get things done" that was able to fly under the bureaucratic radar because of its cover of humor; or something else entirely.]

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