Archaeological Oceanography, Graduate Followed by a Random Sampling Effort Ocean That Permit Deepwater Circulation

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F o r t h o u sands of y e a r s , waters because compressed air becomes highly maneuverable submersibles in ancient mariners traversed our planet’s a deadly gas at less than 90-m depth. the 1960s, but there was still a lack of waters; unfortunately for them, many Recent advances in exotic gas mixtures precision manipulation and inabil- of their ships have been lost along the and the development of saturation div- ity to carry out mapping efforts to any opyright 2007 by The Oceanography Society. All rights reserved. P Society.Oceanography opyrightAll rights 2007 by The reserved. way, carrying their precious cargo and ing extend and lengthen a diver’s capa- degree of sophistication. Though George the history it represents to the bot- bility. But, these advances have been Bass (1975) pioneered the use of this tom of the sea. For hundreds of years, primarily limited to use by the military class of small submersibles to photo- attempts have been made to recover and the professional diving communi- mosaic a Roman Byzantine shipwreck their contents. In Architettura Militare ties. Although in the last few years some off Yassi Ada, Turkey, his idea did not by Francesco de Marchi (1490–1574), archaeologists have begun using exotic catch on within the marine archaeol- for example, a device best described gas mixtures, even then they are limited ogy community, which preferred the as a diving bell was used in a series of to less than 100 m of water, which repre- dexterity of human hands to excavate attempts to raise a fleet of “pleasure gal- sents less than 5% of the seafloor. ancient shipwrecks. leys” from the floor of Lake Nemi, Italy, The oceanographic community, While marine archaeologists contin- in 1531. In Treatise on Artillery by Diego however, has perfected the technology ued to rely upon divers to carry out their ermission is granted to in teaching copy this and research. for use article R Ufano in the mid-1600s, a diver wearing needed to work in world ocean depths work, marine geologists were perfecting a roughly fashioned hood and air hose of that average 4,000 m (Ballard, 2001a). the use of manned submersibles. At first, cowhide is shown lifting a cannon from In the middle of the last century, ocean- they, like marine archaeologists, con- the ocean floor. But, these early efforts ographers developed one-atmosphere, centrated on the shallow depths of the to recover lost cargo from sunken ship- manned vehicles that were initially crude continental shelf. Francis Shepard (1964) wrecks were crude and highly destructive and had only the simplest manipulative and his students at Scripps Institution of salvage operations. capabilities. The bathyscaphe, for exam- Oceanography began exploring nearby Only relatively recently have archae- ple, conquered the deepest ocean depth submarine canyons using SCUBA diving ologists taken an interest in such ship- in 1960 when it descended 11,000 m techniques but later turned to Jacques wrecks. Marine archaeology is a young into Challenger Deep off the Marianas Cousteau’s Souscoup to explore their 1931, R O Box research field with its roots deeply Islands. But bathyscaphes had limited deeper depths. Like the bathyscaphe embedded in the technology of SCUBA horizontal mobility and poor visibility. before it, Souscoup was used primar- ockville, MD 20849-1931, U ockville, epublication, systemmatic reproduction, (self-contained underwater breathing They were basically elevators to the bot- ily as an observational platform and apparatus) diving that emerged in the tom, capable only of returning shortly had limited manipulation and crude early 1950s (Ballard, 2001a). However, after they arrived. mapping capabilities. SCUBA is limited to relatively shallow Bathyscaphes were followed by small, A major breakthrough program SA.

62 Oceanography Vol. 20, No. 4 in marine geology—one that would of a diver’s hands. precision, measured in centimeters every also ultimately have a major impact In the late 1980s, it became appar- few seconds, which made it possible to on marine archaeology—was Project ent to some oceanographers that much place the vehicle in automated “closed- FAMOUS, the 1974 French-American manned submersible work could be con- loop” control, driven by a computer Mid-Ocean Undersea Study (Ballard, ducted by more efficient, cost-effective instead of a human operator. A few years 2001a). FAMOUS marked the first research platforms. To reach 4,000 m, later, SHARPS was replaced by a wireless manned exploration of the mid-ocean scientists spend two and half hours in system called EXACT, which now makes ridge and the first use of manned sub- the morning to make their descent to the it possible to precisely control an ROV mersibles for comprehensive mapping bottom, followed at the end of the day in any water depth, including down to of complex geologic terrain. Prior to this with a similar ascent to the surface. Thus, 6,000 m, now a common ROV operat- program, submersibles had been used they have only three or so hours to work ing depth—a depth that encompasses as exploratory tools, but due to the lack on the bottom, typically covering one 98% of the world’s ocean floor. Equally of precise knowledge about the terrain nautical mile of underwater terrain. important, scientists not only know in which they were operating as well as The advent of fiber-optic cables, also where the ROV is every few seconds, they the lack of accurate navigation, their use in the 1980s, made it possible to develop know the position of its various sensors, had been ineffectual, diminishing their a remotely operated vehicle (ROV) that sonars, and cameras. value in mainstream oceanographic could transmit high-quality imagery to programs. During Project FAMOUS, the surface and create “tele-presence” Hamilton and Scourge manned submersibles were used in a on the ship’s deck. With this technologi- Project more surgical fashion. cal leap forward, scientists were able to The first major application of this inte- Before the three FAMOUS submers- deploy an ROV for long periods on the grated technology for marine archaeo- ibles began their dives, the region to bottom while controlling its operation logical purposes was the 1990 survey be studied—the rift valley of the Mid- onboard ship. Critical to the success of of the Hamilton and Scourge in Lake Atlantic Ridge—was intensely surveyed this technology, however, was the abil- Ontario. These two American ships using a broad array of mapping devices, ity to precisely control both the surface sank in a violent storm during the War including multi-narrowbeam sonar ship and the ROV thousands of meters of 1812. They were identified in 1975 systems, side-scan sonars, and a vari- below. Control of the ship was made and later given to the Canadian city of ety of imaging systems. By the time the possible through the development of Hamilton by President Carter; the city submersibles were deployed, the scien- dynamic positioning systems coupled wanted to know their precise condition tists had acquired detailed topographic with the use of GPS navigation. Precise and whether these ships should be raised maps of the rift valley and developed control of the ROV was more difficult or left where they were. significant understanding of its geol- because, unlike GPS that had a broad Answering these questions required ogy. The submersibles were able to work user base, there was little interest in such a detailed survey of the ships to a preci- within this accurate database, examin- precise vehicle control. sion not previously possible. Installed ing specific targets of importance to the In the early 1990s, major new technol- on a barge anchored over the wreck site, scientific team. Even so, their mapping ogy closed the gap between the marine the SHARPS system tracked ROV Jason technology and acoustic navigation sys- geologist and the marine archaeologist operating in “closed-loop” control to tem limited their resolving power to a when engineers interested in precision record data from which detailed opti- few meters at best, clearly short of the control of ROVs developed the SHARPS cal and acoustical mosaics and three- mapping precision of marine archae- tracking system (Ballard, 2001a). The dimensional images were constructed. ologists, who were accustomed to cen- fact that this system was wired severely About the same time that this coop- timeter accuracy. And, once again, the limited its initial use to test tanks or shal- erative program between marine archae- manned submersible manipulators were low water. What was important about ologists and oceanographers accom- crude when compared to the dexterity the SHARPS system was its tracking plished these advances in precision

Oceanography December 2007 63 Over the next nine years, nine Roman trading ships (Figure 1) dating from the first century BCE to the fourth century CE were found within this corridor of ancient debris as well as two long lines of amphorae that were obviously thrown overboard by ships hoping to save them- selves in storms by jettisoning their cargo (Ballard, 1998; Ballard et al., 2000). Figure 1. Hercules ROV grasping amphora from first century CE shipwreck at Skerki Bank. Following this success, additional expeditions were conducted in search of more deepwater trade routes. In 1999, an expedition working off the Middle shallow-water mapping, new deep-water from shore, few modern scholars East located two Phoenician ships, each discoveries occurred that would have a believed these accounts. Those doubts, carrying a large cargo of wine on their profound impact on the field of marine however, began to be revisited when way from the Levant to either Egypt or archaeology. The discovery of RMS exploratory programs in the central Carthage (Figure 2) (Ballard, 2001b; Titanic marked the beginning. Prior to Mediterranean revealed ancient ship- Ballard et al., 2002). its discovery, little thought was given to wrecks far from shore. In both the Straits of Sicily and off the the fate of shipwrecks in the deep sea, Middle East, wood-boring organisms other than recent lost Russian and US Skerki Bank Project had attacked the ancient shipwrecks, submarines. What Titanic and its thou- The first such major program was removing any exposed wood. For hun- sands of artifacts revealed was that total conducted in 1988 along a proposed dreds of millions of years, trees and darkness, freezing temperatures, and deepwater trade route between ancient other wooden debris have been carried extreme pressures result in a preserv- Carthage and the Roman seaport of down rivers in storms and transported ing environment. That environment, Ostia. Called the Tyrenennian Sea, this out to sea where they sank to the bot- coupled with slow sedimentation rates body of water reaches depths of 4,000 m. tom. Given this source of nutrients to and the absence of human intrusion, The expedition team looked first along the nutrient-starved deep seafloor, mol- meant the deep sea was an ideal place to the shorter trade routes connecting lusks evolved into wood-boring organ- look for human history. Marine archae- Sardinia to Tunisia, Tunisia to Sicily, isms. Because the deep sea is provided ologists quickly conceded that the deep Sardinia to Sicily, and Sicily to Italy, with a constant source of dissolved ocean was a better preserving environ- but with no success. They then began oxygen due to the planet’s polar circula- ment than shallow water, but they ques- to explore the less-probable and longer tion patterns, wood-boring organisms tioned whether it contained a significant trade route connecting Tunisia to Rome. are found throughout the world’s ocean number of notable shipwrecks. Traveling along an east-west line in the anywhere there has been a constant Although ancient literature spoke Straits of Sicily north of Skerki Bank, source of wood. of the ancient mariners’ bravery and they began to spot isolated amphorae willingness to travel great distance lying on the soft sediment surface at Black Sea Project a depth of 1,000 m. After an extensive Wood-boring organisms are present in Robert D. Ballard ([email protected]. mapping effort, a seven-kilometer-long marginal seas, like the Mediterranean, edu) is Professor and Director, Institute for corridor of amphorae was delineated, that have connections to the world’s Archaeological Oceanography, Graduate followed by a random sampling effort ocean that permit deepwater circulation. School of Oceanography, University of that revealed their ages to span six centu- In the case of the Black Sea, however, no Rhode Island, Narragansett, RI, USA. ries of history. such deepwater connection exists. The

64 Oceanography Vol. 20, No. 4 Black Sea’s deep saline waters are iso- et al., 2001). Three of those ships were rae. Unlike the deeper shipwreck that lated from the deep oxygenated waters located above the anoxic layer (Figure 3) had come to rest in soft ooze, penetrat- of the Mediterranean by a shallow-water in water depths of 90 to 100 m, while the ing the bottom until the deck was at the sill connecting the Aegean Sea with the fourth was situated within the anoxic mud line, the shallower shipwrecks had Bosporus. This isolation has lead to the layer at a depth of 320 m. landed on a much harder, eroded surface depletion of dissolved oxygen at the bot- Wood was present in large quanti- and barely penetrated the bottom. tom of the Black Sea and the creation of ties throughout a broad depth range, anoxic conditions, causing scientists to even above the anoxic layer to as shal- Future Considerations predict that the Black Sea would be an low as 80 m. The most well-preserved Despite this proof of potential, there ideal place to look for highly preserved ship, however, was the deeper one was a need for sophisticated deepwater ancient wooden ships (Bascom, 1976). within the anoxic layer. The first sign excavation technology that would meet During the Cold War, western research- of the ship was when the ROV came in archaeological standards. Though sal- ers could not work freely within the on its wooden mast standing upright, vagers have developed varying levels of Black Sea. Beginning in 2000, however, 11-m high. Exposed frames, stanchions, recovery and mapping technologies— scientists were able to explore its deeper and what appeared to be a rudder sup- with the best example centered on the waters for the first time in search of port and sternpost were clearly visible. gold rush-era wreck of Central America highly preserved wrecks. As a result of The shipwrecks lying above the anoxic off Charleston, SC—they are not consid- that effort, four ancient wooden ship- layer had numerous exposed wooden ered archaeologically sound. wrecks have been discovered, all from the members, although the ships had splayed Marine archaeologists have made Byzantine period (Ballard, 2001b; Ballard open, forming a large mound of ampho- some limited efforts to conduct experi-

Figure 2. Mosaic of Phoenician shipwreck off Ashkelon.

Oceanography December 2007 65 To the world of marine archaeology, this sum is prohibitively expensive and even more prohibitive when compared to archaeological programs carried out on land. The traditional archaeological community and its traditional fund- ing sources are unlikely to allocate scare resources to study deep-sea shipwrecks. But, there is no reason why archaeo- logical oceanography could not be sup- ported by the same sources that fund other oceanographic research. It is important to point out that oceanography is not a separate disci- pline, as are physics, chemistry, or geol- ogy; rather, it is an arena in which these disciplines are bonded by common needs, such as for unique facilities that are required to carry out these separate Figure 3. Shipboard control van during the recovery of ancient artifacts from Byzantine shipwreck off lines of research. It is common for the Sinop, Turkey. Photo credit: David McLain various disciplines to work together on oceanographic field programs, similar to the way multidisciplinary programs mental excavations in the deep sea carry out the first deep-water excavation are carried out on land or in outer space. (Ballard et al., 2000). During the Skerki effort in the Black Sea during the sum- Oceanographers come from all fields Bank project, for example, the US Navy mer of 2007 (Figure 5). This project was of science and engineering, and the list nuclear submarine NR-1 was outfitted highly successful. could easily be expanded to include with a mud-pumping system, but the It is clear from these preliminary field the social sciences of maritime history, submarine’s large mechanical arm lacked programs that archaeological oceanog- archaeology, and anthropology. precision control and further excava- raphy holds great promise for the fields More importantly, oceanography is tion efforts were terminated. ROV Jason of maritime history, archaeology, and a young enough science to be inclusive, used a much smaller excavating device, anthropology. What holds it back is lack and its practitioners are accustomed but the deep-sea mud proved chal- of acceptance within the oceanographic to accepting new disciplines into the lenging, and only a limited amount of community. Oceanography, like marine fold. The history of marine geology is mud was removed before the ROV was archaeology, is a relatively new field of an excellent example. Initiated in the diverted to survey several additional research, a child of the twentieth century. 1930s, it was dominated for some time Roman shipwrecks discovered near the Unlike marine archaeology, oceanogra- by sedimentologists concentrating on end of the expedition. phy relies upon expensive resources such the continental margins of the world. Based upon these early efforts at as large research ships, submersibles, and But, the evolving theory of plate tecton- excavating ancient shipwrecks in the advanced undersea vehicles, including ics in the 1960s took the earth sciences deep sea, the Institute for Exploration ROVs. It is not uncommon for an ocean- into the deeper ocean basins, bring- in collaboration with the Institute for ographic expedition to cost $30,000 to ing in petrologists, volcanologists, and Archaeological Oceanography developed $40,000 per day. As a result, one month structural geologists. The discovery of a new ROV called Hercules (Figure 4) to at sea can cost $1M. hydrothermal vents on the mid-ocean

66 Oceanography Vol. 20, No. 4 Figure 4. Hercules remotely operated vehicle developed by the Institute for Exploration for excavating ancient shipwrecks in the deep sea.

Figure 5. Highly preserved wooden beam and amphora of Byzantine shipwreck located in anoxic bottom waters of the Black Sea.

ridge in 1977 was followed by an influx of chemists, geochemists, and a broad range of biologists, placing increasing demands on access to the expensive tools of oceanography. When we first began to discover deep, ancient shipwrecks in the central Mediterranean Sea in 1988, they were thought to be rare. However, in sub- sequent years, more and more ancient shipwrecks were found in other deepwa- ter locations. More recently, professional oceanography to accept a new discipline Ballard, R.D. 2001a. Maritime archaeology. Pp. 1675– 1681 in Encyclopedia of Ocean Sciences, Vol. 3, salvage companies have obtained the into the fold. J.H. Steele, K. Turekian, and S.A. Thorpe, eds, necessary technology to carry out com- It is encouraging to see recent will- Academic Press. mercial recovery programs. ingness on the part of the leadership of Ballard, R.D. 2001b. Ancient Ashkelon. National Geographic 199(1):91–93. It is increasingly clear that the deep the National Oceanic and Atmospheric Ballard, R.D., F.T. Hiebert, D.F. Coleman, C. Ward, J. sea could be of great importance to the Administration’s Ocean Exploration Smith, K. Willis, B. Foley, K. Croff, C. Major, and F. Torre. 2001, Deepwater Archaeology of the Black social fields of archaeology, anthropol- Program to support the budding field Sea: The 2000 Season at Sinop, Turkey. American ogy, history, and art, to name a few. of archaeological oceanography. We Journal of Archeology 105(4):607–623. But how can this interest turn into a hope that other federal funding agencies Ballard, R.D., L.E. Stager, D. Master, D. Yoerger, D. Mindell, L. Whitcomb, H. Singh, and D. Piechota. meaningful and viable research pro- follow suit. 2002. Iron Age shipwrecks in deep water off gram? Though the term archaeological Ashkelon, Israel. American Institute of Archaeology 106(1):151–168. oceanography may sound like the for- References Bascom, W. 1976. Deep Water, Ancient Ships: The mer is subordinate to the latter, that is Ballard, R.D. 1998. High-tech search for Roman ship- Treasure Vault of the Mediterranean. Doubleday wrecks. National Geographic 193(4):32–41. Books, 226 pp. not the case: just as a geological ocean- Ballard, R.D., A.M. McCann, D. Yoerger, L. Whitcomb, Bass, G. F. 1975. Archaeology Beneath the Sea. Walker ographer is a geologist working in the D. Mindell, J. Oleson, H. Singh, B. Foley, J. Adams, and Co., New York, 238 pp. ocean, an archaeological oceanogra- D. Piechota, and C. Giangrande. 2000. The dis- Shepard, F.P., J.R. Curray, D.L. Inman, E.A. Murray, covery of ancient history in the deep sea using E.L. Winterer, and R.F. Dill. 1964. Submarine geol- pher is an archaeologist working in the advanced deep submergence technology. Deep-Sea ogy by diving saucer. Science 145:1,042–1,046. ocean. Perhaps the time has come for Research Part I 47:1,591–1,620.

Oceanography December 2007 67