Ocean's Depths

Helen M. Rozwadowski

The category of “exploration” seems inextricably connected to the ocean.  Think of all the explorers who had to cross oceans to find new lands and islands.  Today’s ocean scientists eagerly point out – to bolster arguments for funding their work – that the depths are the most unexplored spaces on the globe.  As a cultural category, too, oceans seem to be exactly the kind of place where exploration happens – not an ordinary, accessible environment, and certainly not a place where people can live, but a remote and at times dangerous place.  This essay responds to a challenge to discuss the ocean’s depths as an extreme environment, akin to outer space or the polar regions.  The comparison is instructive.  The ocean does seem like space in that humans literally cannot breath in it without technological assistance.  On the other hand, all parts of the ocean host life, which is not true, as far as we currently know, of space.  Moving instruments and human bodies through all of these extreme environments poses technological challenges that inspire ingenuity.  Some themes emerge from considering exploration of extreme environments.  The most striking relates to the prospect of exploration without humans.  As the Mars rover Curiosity roams the red planet, the continued calls for sending people into space and into the ocean’s depths make clear that exploration, as a cultural category, seems to require human bodies.  The other constant is the role of imagination in driving continued exploration.  We explore remote places in part to find ourselves.


Those engaged with the ocean in various ways like to point out that our planet is covered mostly by water.  Working as I do at a coastal campus, where research and teaching focus on the ocean, more than one of my colleagues includes this Arthur C. Clarke quote in an email footer:  “How inappropriate to call this planet Earth, when it is quite clearly Ocean.”  While my colleagues and I, and others whose livelihoods are tied up with the sea, are hyper aware of oceans, and of the environmental and political issues related to them, most people in the world think of the ocean only occasionally, and then mainly in conjunction with recreation, some news item, dinner, or perhaps a pause for personal contemplation.


Historians mirror the general population in their overall benign neglect of the sea.  When I began trying to write a history of the deep sea, few historians had noticed the ocean.[1]  I discovered that some aspects of the ocean are amenable to study using existing methods and historiographies.  For example, the discovery of the deep sea in the mid nineteenth century is, in part, a story that reflects imperial reach and influence.  On the other hand, studying the ocean posed some challenges to what I had been taught about the practice of history.  Like environmental history, natural boundaries matter.  While national contexts inform ocean history, it proved critical to follow those people involved in the economic, intellectual, political and social discovery of the depths, regardless of their nationality.  The sum total of their individual and collective efforts transformed the depths into a relevant place. [2]

I like to challenge my students to think about whether the oceans are different enough from land to merit a different kind of history.  On the one hand, as historians of field science have learned, sometimes study of the field, which initially seemed like a distinctive locale for science, ended up illuminating the laboratory.[3]  Similarly, I would expect to find elements of extreme histories that will inform study of non-extreme environments.  On the other hand, there appear to be distinctive physical characteristics of the ocean, and especially the great depths, that demand special treatment. 


Tracklessness, opacity and vast scale are physical aspects of the ocean that are identified, to some degree, relative to human senses and scale.  Especially based on my recent research into undersea exploration of the 1950s and 1960s, I have begun to understand that – for historians at least – consideration of extreme environments requires the context of human bodies (including their absence).


One characteristic of the depths relative to land, which is also shared by the sea’s surface, is that voyagers leave no tracks in the water (although they can, and do, leave traces in the sea).  This quality strongly shapes perception of the ocean and presents a challenge to efforts to tell ocean history.  To a voyager gazing at the horizon, the sea appears the same at that moment as at all times in the past.  Sailors often feel an affinity with each other and with sailors of past times.  Storms likewise evoke universal reactions among mariners (and sometimes non-mariners):  terror, despair, and relief at their end.  The sense of constancy conveys an impression of the sea as an ahistoric place.  Literature contributes to the idea of the ocean as apart from history.  This perception is deeply and widely held, including by many historians, who treat the sea as a backdrop for human activities rather than as a place susceptible to, and involved in, historical change. 


Just as the ocean seems outside history, it also seems unimaginably enormous relative to human scale.  The sea’s opacity forces the use of indirect methods to gain knowledge of its depths, such as deploying sounding gear or fishing nets to find the bottom contour or sample marine life.  The vastness, in all three dimensions, impedes meaningful scientific knowledge based on direct, personal experience and demands, instead, systematic sampling using standardized instruments across large parts of the sea.  Both the ocean’s scale and its opacity mean that knowledge of the sea is mediated by technology and knowledge systems.  These include the gear and knowledge of fishermen, navigators and others who work at sea as well as the tools and understanding of modern science.  Indeed, our knowledge of the ocean is so dependent on technology and knowledge systems that these can be understood as, to some extent, constituting the ocean.[4]


As central as technology was, and remains, for knowing the ocean, motive is the critical precursor to technology.  Cultural notions and political and economic intentions for using the ocean spurred efforts to probe the depths.  In the mid nineteenth century, expectations for a transatlantic submarine telegraph cable exerted a powerful influence on the interpretation of soundings along the proposed track of the cable.  The resulting image of the sea floor as a plateau of moderate depths, perfectly suited for submarine telegraphy, diverged from previous understanding of the ocean bottom as rugged and forbidding and, within two decades, gave way to the discovery of a major mid-ocean mountain chain.[5]  In the 1960s, promoters of ocean exploration described the sea as a “frontier” to evoke the wealth of living and non-living resources they believed possible to extract.[6]  Perhaps the most striking evidence that culture – in the form of motive or desire – matters as much or more than technology comes with the recognition that the ability to reach great depths did not guarantee continued efforts to do so.  After the bathyscaphe Trieste reached the bottom of the Marianas Trench at the Challenger Deep, the deepest point of the ocean, in 1960, no further efforts were made to revisit the deepest sea floor areas for over three decades. [7]  The categories of imagination and desire are critical for the ocean. 


It may seem to some observers that actual human bodies were no longer relevant for the deep ocean by the mid to late twentieth century.  Strikingly unlike experimental rocket tests, for which unmanned shots preceded manned missions, the Trieste’s first and only dive to the Challenger Deep was manned.  When exploration of the spot resumed in 1995, it was by robot.  Despite the scientists and explorers who continue today to insist on the need for human presence underwater, the debate is largely over.[8]  Remotely operated vehicles and, increasingly, autonomous underwater vehicles, appear to be the technology of choice for today’s exploration of the great depths and much of the sea floor.  That does not, however, mean that historians should cease considering the ocean, even the depths, in terms of human physiology.


While scientists define the ocean by fixed categories such as shelf, slope, and abyss, historians must, I believe, define zones of the sea differently – more fluidly, less geographically and, most of all, in ways that reflect the activities and desires of historical actors.  In the mid nineteenth century, for example, the functional depth of the “deep ocean” changed over time and depending on who defined it.  Hydrographers at the start of the century considered any depth beyond their 200-fathom sounding lines (1200 feet) as deep, while dredgers defined the category in relation to the vessels and gear they used to collect samples.[9] 


People interested in the underwater realm in the 1950s and 1960s likewise defined “undersea” differently over time, always in reference to human ability to survive in an environment otherwise hostile to humans.  Generally speaking, the first thirty-three feet (to 1 atmosphere of pressure) underwater is the zone where ordinary people, both free divers and those using conventional scuba gear, are most comfortable, although beginning recreational diver training now extends to 120 feet.  But human limits in the sea can change with technology.  Adjustments to the mix of breathing gases can extend depth range, while the use of gear such as slides and lift assists can enable breath-holding free divers to achieve record depths of over 650 feet.  Properly trained and outfitted technical divers can operate to 180 feet; record dives with scuba gear have dipped below 980 feet.  Time spent at depth need not be short.  Experiments with saturation diving have demonstrated that humans can live at depths of 200 feet for 30 days, 328 feet for 22 days, and 980 feet for 14 days.[10]  In short, parts of the ocean (defined by the intersection of human physiology and technology) can be viewed as an accessible environment.


Even accessible parts of the ocean can share more in common with extreme (as opposed to “non-extreme”) environments.  For example, technology – whether snorkels, scuba or robots – plays a necessary mediating role.  While there are extreme environments such as outer space where exploration fits in the category of work, much ocean exploration is, instead, play. [11]  Our histories of ocean must, then, consider both robots and wreck divers, both official and personal exploration. 


The experience of going underwater has been understood as transformative.  "Everyone who goes underwater becomes an amateur scientist," declared science fiction author and scuba enthusiast Arthur C. Clark.[12]  This sentiment can be found in diving manuals, television shows, and novels.  Even physical transformation of people was at one time not considered out of the question, with experiments aimed at exploring the possibility of surgery to enable mammals to breath oxygen directly from seawater.[13]


The ocean’s scale presents a spatial challenge to historians, who are most comfortable with explicitly defined units of time and place.  Ocean currents and tides ensure that there is literally no place in the ocean that remains constant.  While ocean history can, following traditional history, focus on specific times and places (as sources allow), it may be that ocean history will benefit from attention to types of terrain or to sets of places with similar environmental characteristics.  My recent research suggests a robustness to the category of “undersea” for the postwar period that reminds me of the category of “deep ocean” for the mid nineteenth century.  Histories of beaches may share common elements with each other, for instance, while histories of gyres or trade wind belts or seamount areas or particular depth zones might likewise reveal things that a history of Long Island Sound or Georges Bank, to name examples of specific places, might not.


As we attempt to chronicle extreme environments, it may help to recognize the possibility of writing the history of a category within the ocean, such as “the deep ocean” or “tides,” which might have characteristics of both historical specificity and environmental universality (or something close to that) across the space of the globe.  To offer another example, the 1960s fascination for undersea exploration transcended even salt water.  The same motives that drew growing numbers of people into the ocean’s depths in the postwar period also sent people under the surface in lakes and even quarries.  For the project of writing the history of undersea exploration, then, it may be necessary to jump from California beaches to Lake Winnipesuakee to an Alabama quarry to tell this chapter of ocean history.[14]  The undersea habitat now known only to local diver-explorers in Wisconsin’s Lake Mendota stands as mute testimony to a period of intense cultural fascination with the underwater realm.[15]




Oceans have been perceived as ahistoric but, of course, they are susceptible to history.  Oceans have natural history, geological history, and evolutionary history.  Water masses are different ages, while bottom sediments are comprised of layers laid down over time.  Certainly it is possible to discern the history of the ocean scientifically and to use such information to inform environmental history.  Evidence is mounting that human impacts on marine populations can be traced back to the distant past.  To the question ‘can changes in the land apply to seamounts?’, the answer must be affirmative.  We know that people are changing the structure of marine ecosystems through overfishing.  It is very likely that human activities are even altering ocean chemistry.  Environmental history, then, applies to every corner of the ocean and extends to every drop of water. 


Yet some characteristics of the ocean defined by the present project as “extreme” seem not entirely accounted for by the methods, questions and assumptions of environmental history.  Not all historians would agree that parts of the ocean devoid of resources useful to people even deserve historical attention.[16]  The sea’s vastness, opacity and hostility to human life present challenges to prospective historians.  Ocean history will have to incorporate technology and the creation of knowledge as fundamental constituents.  On the other hand, human physiology itself may define ocean space as critically as technology.  Culture, including desire and imagination, may matter as much as practice or technology.  The scale of our histories may have to be global and local simultaneously, rendering zones, categories of places, or types of environments foundational for histories of extremes in ways that specific places and times are for traditional history.


[1] For a historigraphic review and proposal outlining a field of ocean history, see Helen M. Rozwadowski, “Oceans: Fusing the History of Science and Technology with Environmental History,” in Douglas Cazaux Sackman, ed., A Companion to American Environmental History (Malden, MA: Wiley-Blackwell, forthcoming).


[2] Two books about the mid nineteenth century ocean analyze the intersection of imperialism with the sea, its uses, and emerging ocean sciences in ways that owe debts to existing scholarly methods and yet also try to account for spatial characteristics of the ocean.  See Michael S. Reidy, Tides of History: Ocean Science and Her Majesty's Navy (Chicago: University of Chicago Press, 2008); and Helen M. Rozwadowski, Fathoming the Ocean: The Discovery and Exploration of the Deep Sea. Cambridge, MA: Harvard University Press, 2005.


[3] An example is the recognition of the field origins of laboratory animals such as rats or drosophila.  See Bonnie Tocher Clause, “The Wistar Rat as a Right Choice: Establishing Mammalian Standards and the Ideal of a Standardized Mammal,” Journal of the History of Biology 26 (2)(1993): 329-349.; Robert E. Kohler, Lords of the Fly: Drosophila Genetics and the Experimental Life (New York: Oxford University Press, 1994); and Henrika Kuklick and Robert E. Kohler, eds., Science in the Field, vol. 11, Osiris (1996).


[4] Rozwadowski, “Oceans.”  Keith R. Benson, Helen M. Rozwadowski, and David K. van Keuren, “Introduction,” in Rozwadowski and van Keuren, eds., The Machine in Neptune's Garden (Canton, MA: Science History Publications/USA,  2004), xiii-xxviii.


[5] Helen M. Rozwadowski, "Technology and Ocean-scape: Defining the Deep Sea in the Mid Nineteenth Century," History and Technology 17(2001): 217-247.


[6] See, for example, Robert C. Cowen, Frontiers of the Sea (New York: Bantam Books, 1960); Gardner Soule, Undersea Frontiers (Chicago: Rand McNally & Company, 1968); and Richard C. Vetter, Oceanography: The Last Frontier (New York: Basic Books, 1973).


[7] Similarly, of the numerous small, deep-diving research submersibles, such as Alvin and NR-1, most have been retired without replacement, while only one of the dozens of undersea habitats built and used in the 1960s and 1970s is still in operation (http://uncw.edu/aquarius/).


[8] For an example of a scientist who continues to advocate for the need to send people undersea, see Sylvia Earle, Sea Change: A Message of the Oceans (New York: G.P. Putnam’s Sons, 1995).


[9] Rozwadowski, Fathoming the Ocean, 32-35.


[10] James W. Miller and Ian G. Koblick, Living and Working in the Sea, 2nd ed. (Plymouth, VT: Five Corners Publications, Ltd., 1995), 384-395.

[11] Helen M. Rozwadowski, “Playing by – and on and under – the Sea: The Importance of Play for Knowing the Ocean,” in Jeremy Vetter, ed., Knowing Global Environments: New Historical Perspectives on the Field Sciences (Rutgers University Press, forthcoming).


[12] Arthur C. Clarke, The Challenge of the Sea (New York: Holt, Rinehart and Winston, 1960).


[13] “Gills for a Hamster,” Life 57 (19)(November 6, 1964): 55-56.


[14] See, for example, “Tucking in a Tadpole,” Life 51 (2)(July 14, 1961): 108; and “A Homemade Sub,” Life 34 (19)(May 11, 1953): 73-74, 76.


[15] The wiscuba.com site has a few references to the habitat, such as http://www.wiscuba.com/yabbse/index.php?topic=334.0.


[16] W. Jeffrey Bolster, “Opportunities in Marine Environmental History,” Environmental History 11(3)(2006): 567-597


Note: Essay first published in Extreme Environments and edited by Steve Pyne.

Helen M. Rozwadowski
Helen M. Rozwadowski

Helen Rozwadowski is an associate professor of history at the University of Connecticut and directs the Maritime Studies program at the Avery Point campus.  Her teaching includes environmental history and history of science as well as interdisciplinary maritime studies courses.  Her award-winning book, Fathoming the Ocean: The Discovery and Exploration of the Deep Sea, is a scientific and cultural history of 19th-century interest in the ocean, and her current research focuses on undersea exploration in the 1960s, a time when ocean boosters had optimistic dreams for working and living in the sea.  For more information, see http://history.uconn.edu/people/rozwadowski.php.