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Promising Areas for Ocean Exploration Ocean exploration is a vast field and the variety of specific discovery plans seems endless. Biological, chemical, geological, physical, and archaeo- logical investigations, and interdisciplinary combinations thereof, are within the purview of an ocean exploration program. Programs also might seek to discover new information about specific regions or ecosystems. Some areas, both geographic and topical, are particularly timely and could return excep- tionally valuable discoveries. Certainly there are important aspects of ocean research that have advanced well beyond the exploratory phase. Important geophysical observations on the shape of ocean basins, the locations of earthquakes, and the variations in seafloor magnetization that were collected during and after World War 11 were elegantly assembled into the theory of plate tectonics. This powerful theory provides researchers with an excellent first-order understanding of the age and history of Earth's ocean basins and it is the starting point for ~ I investigating earthquakes and volcanoes. Few surprises would be likely to emerge from an ocean exploration program that focused on measuring the geologic age or the tectonic history of the seafloor. As a result of coordi- nated international programs, such as the World Ocean Circulation Experi- ment, similar arguments likely could be made about our understanding of the general circulation of the ocean. Just as for experiments designed to test a specific hypothesis, the design of an exploration program must be based on solid scientific (or archaeologi- cal) information that allows an assessment of the amount of observation or measurement that is necessary to answer the question being asked or to observe new phenomena. For example, before the Mid-Ocean Dynamics Experiment, which was designed to investigate the nature of mesoscale variability in the sea, a series of preliminary experiments was done to define the time-and-space resolution necessary to elucidate the Mid-Ocean Dynamics Experiment measurements. ~2

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PROMISING AREAS FOR OCEAN EXPLORATION Recommendation: To achieve the recommended goals (as outlined in Chapter 2), early efforts in ocean exploration should be selected using the following criteria: Research is conducted in areas of international interest. Particularly salient are themes that are amenable to international cooperation and those suggested by International Global Ocean Exploration Workshop participants. Questions advance the current state of knowledge. Characteristics of the habitat, region, or discipline suggest a poten- tial for bold, new discoveries. . The results have a potential to benefit humanity. Recommendation: Several promising areas were identified as having broad international interest and are recommended as potential initial exploration themes: marine biodiversity; the Arctic Ocean; the Southern Ocean and Antarctic ice shelves; deep water and its influence on climate change; exploring the ocean through time; and marine archaeology. Studies in those areas will reveal additional insights into living and nonliving resources (fisheries, bioproducts, energy resources, mineral deposits); human history; and how changes in physical, chemical, and biological properties of the ocean and seafloor affect our environment and climate. The list clearly is not exhaustive, but it identifies some areas in which international interest has been demonstrated, and for which major dis- coveries are likely. Two of these exploration themes, marine biodiversity and the Arctic Ocean, are used later in this report as examples for the project selection process for ocean exploration Programs. MARINE BIODIVERSITY Exploitation of the genetic diversity of ocean life and long-term manage- ment of commercial fisheries will require a thorough knowledge and cata- loging of resources. To date, just a fraction of the world's marine species have been scientifical ly named or taxonomical ly identified (Wi nston, 1992; World Resources Institute, 20011. New species, including corals, fishes, ~3

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EXPLORATION OF THE SEAS and plants, are discovered on virtually every expedition that seeks to uncover them. Even microorganisms, such as Archaea, a primitive form of life, have been discovered by happenstance in places where conditions of tempera- ture and pressure are so extreme, no life would be expected (National Research Council, 19951. The recent realization of the abundance and distribution of deep, cold-water corals (Box 3.1, Figure 3.1) is another example. Ocean exploration offers the opportunity to make such discoveries in a coordinated and systematic way. If little is known about the biodiversity in the oceans, even less is known about the abundance of organisms, their ecological functions, how food webs are structured, and how vast areas of the oceans are interconnected through biological interactions. A reliable, well-organized, and accessible inventory of existing and newly discovered marine species will promote scientific and public understanding of marine ecosystems. The Census of Marine Life is an exciting program of international research for assessing and explaining the diversity, distribution, and abundance of marine organ- isms throughout the world's oceans (Consortium for Oceanographic Research and Education, 20021. Collaborative projects involving more than 60 institutions from 15 countries began the Census of Marine Life in 2000 with funding from the Alfred P. Sloan Foundation and the National Oceano- graphic Partnership Program member agencies. The Ocean Biogeographic Recent confirmation of the extensive distribution of deep, cold-water coral reefs (Lophelia and Madrepora spy surprised and alarmed the fisheries management community and conserva- tion organizations. Cold-water corals occur in the North Atlantic and North Pacific Oceans to depths of 2,000 m, and they are estimated to grow very slowly, between 6 and 25 mm per year. Without the photosynthetic symbionts that allow tropical coral to thrive, the metabolism of these organisms remains a mystery, but researchers believe they feed on carbon litter that falls to the ocean floor. Fishermen have been aware of these corals for some time, as they have harvested fish that live above these systems and pull in large pieces of the living coral (Figure 3.11. The distributions of these unique ecosystems are only now beginning to be con- firmed (Freiwald et al., 1999; Huvenne et al., 2002), mapped (De Mol et al., 2002), and explained (Hovland and Thomsen, 1997; Roberts et al., 2003) another example of the mysteries the oceans still hold for us.

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PROMISING AREAS FOR OCEAN EXPLORATION ~5 FIGURE 3.1 A cold-water coral from Alaska (Malakoff, 2003). Information System, the information component of the Census of Marine Life, will be a critical component of an integrated ocean observing system. Currently managed as a federation of database sources, the Ocean Bio- geographic Information System is expected to develop into a globally dis- tributed network of species-based, geographically referenced databases that will be available to a variety of users, including ecosystem managers, fisheries organizations, and coral-reef-monitoring programs. Because even remote areas of the ocean contain detectable amounts of contaminants (Group of Experts on the Scientific Aspects of Marine Environ- mental Protection, 2001 ), the extent to which humans directly and indi-

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~6 EXPLORATION OF THE SEAS rectly affect marine ecosystem health and productivity can be observed, if not yet quantified. Ultimately, a better understanding of marine systems and the effects of human activities on them will enable wiser stewardship of the oceans' vast resources. The marine biodiversity theme area highlights the interdisciplinary nature of the proposed ocean exploration program, the proposal and funding selection process, and the utility of such a program. A few particularly exciting areas for exploration of marine biodiversity include microbial life within the ocean, extreme environments such as hydrothermal vents, the subseafloor biosphere, coral reefs, seamounts, and continental shelves. Microbial Ocean Although thousands of organisms can be identified in a single drop of seawater, the vast majority of those organisms cannot be cultured in a laboratory. New genetic tools are allowing researchers to unlock the secrets of identity, taxonomy, spatial diversity, and function of microbes in the ecosystem. Chance discoveries from exploring the microbial genome have highlighted how important these organisms are to the cycling of chemicals and energy in the open ocean and between the ocean and the seafloor. Opportunities abound for fundamental discoveries with great societal ben- efit. Many drugs in use are derived from chemicals produced by terrestrial microbes. Recent research suggests chemicals produced by marine microbes could be developed into new formulations for treating diseases (Feling et al., 2003), and several are currently in development, primarily for treatment of cancer (Pompon), 20011. The advantage of exploring marine microbial diversity is that fermentation of microbes can provide a sustainable supply. At least three federal programs could form the basis for an integrated pro- gram of microbial ocean exploration and research. Through its Microbial Observatories program, the National Science Foundation (NSF) funds the study of novel microorganisms through time and environmental gradients. Drug discovery is the goal of two interagency programs that could, but do not currently, include exploration of the microbial ocean: the International Cooperative Biodiversity Groups (the National Institutes of Health, NSF, and the U.S. Agency for International Development) and the Centers for Oceans and H uman Health (the National I nstitute of Envi ronmental Health Sciences and NSF). An ocean exploration program would extend the reach of those programs more thoroughly into the oceans. Likewise, discoveries from the ocean exploration program would provide new resources for their drug discovery programs.

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PROMISING AREAS FOR OCEAN EXPLORATION Extreme Environments The ocean floor harbors some of Earth's most extreme environments, with high pressures, temperatures ranging from close to freezing to more than 400 C, and fluids with chemical compositions that support unique life forms. The public and marine scientists were surprised when Jacques Piccard and Donald Walsh found life in the deepest part of the ocean, at the bottom of the Mariana Trench in the Pacific Ocean. Until a quarter of a century ago the deep sea was viewed as a hostile environment with low biomass and a limited supply of food from surface waters above. The discovery in 1977 of luxuriant ecosystems associated with deep-sea hydro- thermal vents dramatically altered our views of life in the deep ocean (Figure 3.21. Those ecosystems are unlike any other on Earth, and they do ~7 FIGURE 3.2 The surprise discovery of complex marine ecosystems that exist independent of sunlight and photosynthesis revolutionized our understanding of the possibilities for ecosystem support. The tube worms, crab, and fish pictured here all depend on chemosynthetic bacteria expelled from the seafloor at the hydrothermal vents (Lutz et al., 2001; used with permission from Richard Lutz, Rutgers University; Stephen Low Productions; and the Woods Hole Oceanographic Institution).

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~8 EXPLORATION OF THE SEAS not depend on organic matter sinking from the sunlit surface ocean. Rather, microorganisms at the base of those ecosystems use chemosynthesis rather than photosynthesis to convert hydrogen, hydrogen sulfide, and methane from the high-temperature fluids at the vents into energy (Figure 3.31. The discovery of the vent ecosystems greatly increased the known range of environments suitable for life in the universe. More than 500 new species have been described from those vents in the past 25 years, and this probably represents less than one-tenth of one percent of the estimated biodiversity of vent communities worldwide. Because the vent organisms live in extreme FIGURE 3.3 Instead of photosynthesis, vent ecosystems derive their energy from chemicals in a process called chemosynthesis. Both methods involve an energy source, carbon dioxide, and water to produce sugars. Photosynthesis gives off oxygen gas as a byproduct, while chemosynthesis produces sulfide (used with permission from E. Paul Oberlander, Woods Hole Oceanographic Institution).

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PROMISING AREAS FOR OCEAN EXPLORATION environments, they produce substances unknown on land many of which are being studied for pharmaceutical, commercial, and biotechnological purposes. For example, the commercially available enzyme most widely used today to replicate DNA is derived from an enzyme found in microbes discovered near hydrothermal vents. It is likely that other chemicals with applications in extreme industrial processes will be discovered and com- mercialized. There are potential opportunities for synergy with existing programs that support research in extreme environments. NSF's Ridge Interdisciplinary Global Experiments (RIDGE), and the new RIDGE 2000 (Pennsylvania State University, 2003) programs are examples of integrated research that form the basis for development of an international organiza- tion (Inter-RIDGE) to coordinate national efforts for the study of midocean ridges. I nter-RI DO E provides support for the U n iversity-National Oceano- graphic Laboratory System assets to be deployed, primarily to known sites of interest. Coordination with an ocean exploration program would pro- mote the discovery and characterization of new and unstudied extreme envi ronments. Subseafloor Biosphere In 1991, scientists working in the submersible Alvin on the midocean ridge in the eastern Pacific witnessed a "blizzard" of microbes and micro- bial debris being spewed out of the seafloor (Haymon et al., 19931. The material rose more than 30 m above the ocean bottom and formed a white layer 10 cm thick on the seafloor. Since then, this phenomenon of rapid effusion of microbial material has been observed several times in the vicinity of seawater volcanic eruptions. Microbes also have been detected in cores recovered by the Ocean Dri 11 ing Program (ODP) several hundred meters below the bottom. This serendipitous discovery led to the hypothesis that a massive, deep subseafloor biosphere exists in the rocks and sediments that make up the seafloor. Volcanic, rather than solar, energy catalyzes chemical reactions that generate life-sustaining materials from rocks and seawater. This is an ecosystem the extent and character of which is almost completely unknown, and yet its biomass could be greater than the combined biomass present in the entire ocean above the seafloor. Continued exploration, in collaboration with ODP, could provide a better understanding of life on Earth, as well as the possibility of life on other planets, and might reveal microorganisms and new substances with pharmaceutical or other com- mercial applications. ~9

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50 EXPLORATION OF THE SEAS Coral Reefs Coral reefs are among the most productive, diverse, and economically important ecosystems on the planet. Although they cover only 0.2 percent of ocean area, they provide habitat for one-third of marine fishes. The systems provide ecological services including shoreline protection and habitat that support an estimated one million different species. Economi- cally, healthy coral reefs are essential to sustainable fisheries and income from tourism (e.g., Cesar, 20001. Tourism at coral reef sites contributes about $1.6 billion annually to Florida's economy alone, and globally coral reefs are especially critical to the economic well-being of developing nations, providing fisheries resources and social and cultural benefits. The declining health of coral reef ecosystems (Figure 3.~) has been widely reported for tropical oceans around the world likely the result of overfishing, eutrophi- cation, and pollution from land runoff; increased disease susceptibility; and harvesting of corals for international trade (World Resources Institute, 1998; National Oceanic and Atmospheric Administration, 2002a). Global warm- ing has been suggested as the largest long-term threat to coral reefs, as evidenced by the bleaching of vast tracts of coral coinciding with ocean warming during El Nino events. Although much is understood regionally about the declining health of coral reefs, it is clear that there is much to be investigated and learned. Seamounts The summits of seamounts volcanic, underwater mountains are rich and functionally important marine ecosystems. Seamounts are unusually productive; by the 1980s nearly 600 species of invertebrates had been described from those systems (Wilson and Kaufman, 19871. More recently, 850 macro- and mega-faunal species have been described 29 to 34 per- cent of them new to science and possibly endemic to seamount ecosystems (de Forges et al., 20001. They disrupt the deep currents and cause upwelling of nutrient-rich water. Although the major seamounts are known from ship and spacecraft topographic mapping, many small but ecologically critical seamounts have not yet been identified. A recent survey of fish aggregation and spawning areas in the western Pacific has revealed an extensive array of seamounts, providing a good foundation for future efforts to choose sites for marine protected areas that will serve to maintain fisheries production and safeguard biodiversity. Exploration and discovery of seamounts in other places also could lead to discovery of new fisheries and other living resources.

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PROMISING AREAS FOR OCEAN EXPLORATION FIGURE 3.4 (A) A diseased colony and (B) a coral (Dendrogyra cylindrical) infected with the coral disease white plague type 11 (used with permission from L. Richardson). The disease progression, caused by a bacterial pathogen (Aurantimonas coralicida), results in tissue loss exposing the coral skeleton. 51

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52 EXPLORATION OF THE SEAS Continental Shelves The organisms that live within the sediments on continental shelves, especially temperate banks and intertidal areas, include numbers of species rivaling those of tropical-forest insects. Sediment-dwelling organisms are thought to link the seafloor ecosystem with the water column above and ultimately to support the marine food web. NSF's Continental Margins Research program provides a focus for coordinated, interdisciplinary, hypothesis-based research on the physical, chemical, and biological pro- cesses critical for margin formation. The Coastal Ocean Processes research effort investigates processes that dominate the transport and fate of material within the continental margins. An ocean exploration program would complement such programs by examining new areas to determine how those systems function and to elucidate the effects of human activity. Dis- coveries of new habitats and processes could provide the basis for addi- tional investigations in Margins and the Coastal Ocean Processes. Unfortunately, the seafloor in many coastal areas has been degraded or destroyed by trawling, dredging, and coastal construction (National Research Council, 20021. International workshop participants emphasized that ocean exploration should not focus exclusively on offshore oceanic environments. Equally important is the exploration of the coastal ocean because this is where the consequences of human activity will be most severe. There are several U.S. programs for near-shore coastal mapping and monitoring. One is the Southeast Area Monitoring and Assessment Program, a combined state, federal, and university program for the collection, management, and dissemination of fishery-independent data and information in the south- eastern United States (Gulf States Marine Fisheries Commission, 20031. Federal funding is provided by the National Marine Fisheries Service and the data are used primarily by fisheries management councils in the respec- tive regions. Such programs generally are not exploratory, but they could benefit from exploration, particularly if new living resources were identified. Similar benefits of exploration could be seen in coastal waste management, marine minerals exploitation, and environmental matters associated with ocean energy. ARCTIC OCEAN The broad continental margins of the Arctic Ocean basin contain unknown quantities of living and nonliving resources. Those areas have been the target of numerous heroic, and in earlier times, often tragic visits

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PROMISING AREAS FOR OCEAN EXPLORATION by explorers. Variations in ice cover affect marine ecosystems and the physical oceanography of the North Atlantic, which directly influence the habitability of northern North America and Eurasia. Little is known about the seafloor or the fundamental processes that create new ocean crust there or about the deep-sea ecology of this isolated basin. Hence, the Arctic Ocean is high on the list for exploration, particularly for the waters beneath the ice (Box 3.21. Below-ice exploration will require new technology; including development of a new generation of specialized autonomous underwater vehicles or other probes that can be lowered through holes drilled through hundreds of meters of ice. The Arctic is the second theme area discussed in this report as particularly promising for an exploration program, and it is revisited in later chapters. New exploration efforts in the Arctic will build on earlier work by the SCICEX program. Beginning in 1 993, and continuing with annual cruises from 1 995-1 999, U.S. Naval submarines carried academic researchers into the Arctic Ocean (Edwards and Coakley, in press). Typical cruises lasted 30 or more days, and geophysical, cryospheric, and oceanographic data were collected. NSF provided support for the researchers and equipment. The program continues as of this publication, although researchers are no longer brought aboard the Naval vessels; crew members now collect data on behalf of the researchers. Among the important discoveries in the Arctic, SCICEX provided early observations of the increasing intrusion of warm Atlantic waters into the Arctic Ocean, and documented the decline of the thickness of the ice canopy. The International Arctic Science Committee (lASC), a nongovernmental consortium of national science programs, is one source of international coordination and funding for Arctic research. NSF's Office of Polar Programs will represent the United States on the committee. That office coordinates review and funding of Arctic research in other NSF programs, such as ODP. IASC member organizations identify scientific priorities for cooperative projects. As proposed in the structure for an international global ocean exploration program (Chapter 4), IASC could provide recommendations for coordinated programs in Arctic research to the international advisory com- mittee. Because programs supported by IASC are terrestrial (International Arctic Science Committee, 2003), an Arctic Ocean exploration program could provide complementary information regarding marine resources. The synergy possible between the ocean and terrestrial programs could catapult our understanding of this important ecosystem forward and improve our abi I ity to manage its resources wisely. 53

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54 EXPLORATION OF THE SEAS The year 2007-2008 will mark the 125th anniversary of the First Inter- national Polar Year (IPY; 1882-1883), the 75th anniversary of the Second Polar Year (1932-1933), and the 50th anniversary of the International Geophysical Year (IGY; 1957-19581. IPY and IGY were major initiatives resulting in step changes in our understanding of polar phenomena and the role of the polar regions in global processes. IGY in particular was momentous, triggering among other things the space age, the human exploration of the polar regions, and spawning the World Data Centres, the World Climate Research Programme, the Scientific Committee on Antarctic Research, and the Antarctic Treaty System. Although enormous progress has been made in the last 50 years, much funda- mental and globally relevant polar research remains to be completed. IPY is an initiative to intensify polar research on a global scale by assem- bling national scientific research programs into a cohesive, international entity. The first IPY (IPY-1; 1882-1883) was proposed in 1879, at which time it was determined that once eight international monitoring stations in the Arctic or Antarctic were secured the IPY-1 research program would begin the goal was realized in 1882 when the United States joined the enterprise. Through IPY-1, significant advances were realized, particularly in geophysics (e.g., iden- tification of the ionosphere), engineering (instrumentation in extreme envi- ronments), and analytical science (standardization of techniques). After this success, a subsequent polar year was initiated in 1932 (IPY-2), primarily as an effort to investigate the global implications of the newly discovered "Jet Stream." Although IPY-2 focused solely on the Arctic Region, the endeavor was an astounding success. The program was able to persevere through the Great Depression and provide significant advances in describing Earth system- atics. To reflect the expanding body of knowledge and the global implications of the polar data set compiled, the third IPY (IPY-3) was renamed IGY. The scientific achievements resulting from IGY include the theory of plate tectonics, identification of the ionosphere and ozone layer, the launch of satellites for Arctic Ice and Climate Change The first time the Arctic Ocean had a sea ice cover was in the middle Paleogene (40 million years ago). Properties of the Arctic Ocean before glaciation (in the "warm polar ocean") are unknown and can be posited only by applying new technology for sampling ocean sediments below the ice. Those sediments could reveal a history that could be studied to predict

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PROMISING AREAS FOR OCEAN EXPLORATION remote sensing observations, and mapping of Antarctic bedrock. The number of monitoring stations expanded from a total of 11 in the Arctic and Antarctic (1882) to over 8,000 global locations (19571. The international venture included over 67 nations, representing a landmark in international cooperation. Both the United States and the Soviet Union participated, despite the height of Cold War tensions, and territorial rivalries among national governments in Antarctica were suspended, leading to the eventual ratification of the Antarctic Treaty (1 9611. In spite of these substantial efforts, the relative inaccessibility and chal- lenging environment in the Arctic and Antarctic have hampered polar research; consequently, polar regions remain poorly understood, relative to other, more accessible areas. This need has been recognized, and in June 2002, at the international symposium "Perspectives of Modern Polar Research" in Bad Durkeim, Germany, a fourth IPY (IPY-4) was proposed for 2007. IPY-4 will attempt to continue the legacy of significant advances in science and tech- nology, international cooperation, and understanding of geophysical processes that have typified previous IPY and IGY initiatives. In addition, IPY-4 will cap- ture a broader and more integrative perspective than IGY, by incorporating interdisciplinary components from outside geosciences. Although the scien- tific objectives of IPY-4 will evolve, the overarching goal will be to collect synoptic measurements in the polar regions to address the specific scientific directives. A partial list of objectives include determining the causes and effects of climatic variability, monitoring lithosphere dynamics, coordinating in situ and remote sensing of oceanographic and terrestrial conditions, assess- ing the response of the polar environment to fluctuations in solar intensity, and evaluating the socioeconomic impact of environmental changes. Signifi- cant advances in technology and communication will facilitate the data collec- tion processes, and expand the educational opportunities and dissemination of information resulting from IPY-4. More information on IPY-4 is available through the National Research Council (2003a). what is likely in the near future as a result of global warming. Exploration of the Arctic Ocean is therefore a high priority particularly for nations in the far Northern Hemisphere. There is now evidence that the surface salinity in the high-latitude North Atlantic Ocean is decreasing. This could increase the speed of climate change by suppressing the formation of North Atlantic Deep Water 55

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56 EXPLORATION OF THE SEAS (NADW). Under normal conditions, the combination of low temperature and high salinity produces dense surface water that sinks into the deep ocean and spreads lateral Iy as part of global deep-ocean ci rcu ration. If the surface ocean freshens, the intensity of formation of NADW could result in less intense surface currents and less poleward transport of heat. The path of the Gulf Stream also could be altered, with serious implications for winter conditions in northern Europe. The formation of NADW has other effects on global climate. It carries greenhouse gases and heat to the ocean bottom, out of contact with the atmosphere for hundreds of years. Extraction of fresh water from the ocean via evaporation, which increases NADW salinity, provides water for the global hydrological cycle. A better understanding of the global climate system requires detailed information about ocean circulation, its vulnerabil- ity to change, and the processes that govern water mass formation rates (National Research Council, 1994, 20011. Retrospective exploration of deep ocean water temperatures over time could provide insights about bends in global climate change. Surface water temperatures can be measured from space with limited accuracy but high resolution. New systems, including the Array for Real-Time Geostrophic Oceanography, measure the temperature of the oceans to depths of 1,000 m with an average resolution of 300 km. New programs will extend the ability to sample ocean temperatures in shallow waters, but deep water variability is still unexplored. This is particularly unfortunate because the highly variable surface layers of the ocean could mask longer term trends associated with rapid climate change. Exploration of the deep ocean could be applied to explain the forces that have shaped abrupt climate changes in the past, as inferred from the paleoceanographic record, and extrapolated to predict what will shape them in the future (Figure 3.51. Arctic Seafloor The tectonic history of the western Arctic Ocean is basically unknown. The ultra-slow spreading of the Arctic midocean ridges gives rise to spec- taculartopographic relief and a complex crustal architecture. Volcanic activity is low, and major portions of the ridge are composed of rocks from the mantle. We know virtually nothing about this type of midocean ridge or the mechanism of building new crust there. Studies of Arctic midocean ridges will complete our picture of how the Earth is regularly repaved by submarine volcanic and tectonic activity.

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PROMISING AREAS FOR OCEAN EXPLORATION 1 600 0.3 1 Preboreal (PB) ct ~ 0.1 c' ._ ~ o.o- o ._ ct c' c' ct 0.3 - 0.1 57 1700 depth (m) 1800 Younger Dryas (YD) Bolling/Allerod (BA) Oldest Dryas (OD) 0.0 - 3-year change 11590 11690 12860 12960 14620 age (ybp) raw data 25-vear smoothed . . . 1 7nnn 25-year smoothed 1 4720 FIGURE 3.5 In Greenland the ice accumulation rate was low during the Younger Dryas; both the start and the end of that period show as abrupt changes (modified from Alley et al., 1993). The isolation of the Arctic Ocean and its separation from all other ridge systems raises fundamental questions about the evolution and ecology of Arctic vent fauna. The hydrographic barriers and geologic features that enclose the Arctic Ocean's spreading centers pose a significant directional barrier to dispersal of vent species. The recent recovery of a few specimens of vent fauna during dredging along the Gakkel Ridge (Figure 3.6) confirms the existence of vent ecosystems in the region and offers unique opportun

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58 :~f EXPLORATION OF THE SEAS . ~ ~ . . A.. 3 r FIGURE 3.6 Arctic Ocean map showing the Gakkel Ridge (used with permission from M. Jakobsson).

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PROMISING AREAS FOR OCEAN EXPLORATION ties to characterize Arctic vent systems. Indeed, those isolated ecosystems could contain life forms that hold keys to explaining the evolution of life in hydrothermal vents and to the discovery of processes and substances with industrial and pharmacologic appl ications. SOUTHERN OCEAN AND ANTARCTIC ICE SHELVES Oceanographic observations of the Southern Ocean are scarce, particu- larly during the austral winter, when ice formation doubles the size of Antarctica. Even during the austral summer some regions are inaccessible to ships (Box 3.31. Among them are the waters below the floating ice shelves, which are home to highly specialized organisms. Those waters are extremely cold and dense they cascade down the adjacent continental margin and contribute to the formation of the Antarctic bottom water with its unique physical and chemical properties. This is one of the most impor- tant oceanographic processes on Earth. It is a principal mechanism of deep water formation and transport. Vast areas of the Southern Ocean seafloor are unmapped, yet the basin's bathymetric and age patterns contain records of the disintegration of the Gondwana supercontinent and the opening of the Drake Passage. Many believe the latter to have been an important key event in the development of the current global climate. The Southern Ocean is highly productive biologically. It has large stocks of living resources, such as the krill population, that require understanding for effec- tive use, protection, and management. The Scientific Committee on Antarctic Research is an international, nongovernmental committee of the International Council for Science that provides advice on scientific research i n the region. Th is wel l-establ ished 59 Recent moderate resolution imaging spectroradiometer satellite imagery analyzed at the University of Colorado's National Snow and Ice Data Center revealed that the northern section of the Larsen B ice shelf, a large floating ice mass on the eastern side of the Antarctic Peninsula, has shattered and separated from the continent. The shattered ice formed a plume of thou- sands of icebergs adrift in the Weddell Sea. A total of about 3,250 km2 of shelf area disintegrated in a 35-day period beginning January 31, 2002. Over the past five years, the shelf has lost 5,700 km2, and it is now about 40 percent the size of its previous minimum stable extent.

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60 EXPLORATION OF THE SEAS group could provide recommendations for coordinated programs in Antarctic research to the international advisory committee. EXPLORING THE OCEAN THROUGH TIME Sustained, large-scale, long-term observations are indispensable to all ocean science disciplines, and they often lead to discoveries of the processes that link the physics, chemistry, biology, and geology of the ocean. The ocean exploration program should be a partner in the establishment and use of observation systems, particularly in unexplored areas. An exploration- based ocean-observing system can and should provide information that will be useful for basic and applied research and for real-world applications. Processes that influence global climate, the continued development of accurate regional and global model-based forecasting capabilities, and the tracking of migrations of marine life are all areas for study. The benefits of observation systems to various economic sectors (as among them ocean transport and fisheries) and to the world's nations would add substantially to the val ue of the program. The opportunity exists for a cooperative effort by all involved countries to work toward the placement and operation of multinational global and regional ocean observation systems. That goal wi 11 requ i re the creation of new partnerships among scientists, government agencies, industry, and other potential users; extend) ng fi nancial relationsh ips to i ncl ude shard ng of i ntel- lect, experience, data, instruments, facilities, and labor. Indeed, the multi- national effort involved in installing and operating observation systems for ocean exploration, at coastal or open-ocean priority sites, might prove essential in creating the required synergies among interested nations to get a viable international ocean exploration program started and fully opera- tional. Ocean-observing systems, shared within a multinational framework, should help provide answers to questions about regional priorities in fisheries, pollution, biodiversity, and ocean circulation to ocean exploration partici- pants worldwide. It is unlikely that the central features of importance for ocean exploration long-term sampl i ng and observation can be sustai ned by governments without such a broad range of supportive users. MARINE ARCHAEOLOGY One cannot imagine a history of our globe without watercraft. From the primitive floats and rafts that carried the first people to Australia 50,000

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PROMISING AREAS FOR OCEAN EXPLORATION years ago to the giant oil tankers and aircraft carriers of today, boats and ships have allowed the discovery, colonization, supply, and defense of entire continents. Human history owes much to the contributions of Greek triremes, Roman grain carriers, Chinese junks, birchbark canoes, and Viking longboats. Many of the most famous explorers chose the sea as their high- way: Columbus, da Gama, Magellan, and Cortes. Turning points in human history are associated with such names as Mayflower, Trafalgar, Beagle, Normandy, and Midway. And from earliest times until the advent of space vehicles, seagoing ships usually were the most technologically complex creations of their time. The study of the history of ships is therefore impor- tant in itself. But just as important is the study of objects made by humans. From tiny obsidian blades and bits of jewelry to huge marble elements of temples and churches, all have been transported at one time or another over water. Thus, the exploration of shipwrecks will write definitive histories of weapons, tools and other utensils, glass, ceramics, games, sculpture, weights and measures, metallurgy, and, especially in later times, instruments and machines of all kinds. Equally important is what shipwrecks can teach us about economic history. Then, too, there are inundated coastal habitation sites that can tell us about our early ancestors. Archaeological exploration of underwater sites will promote our understanding of global cultural heritage. The public is fascinated by marine archaeology. Nielsen ratings showed that an ABC-TV "20/20" program on the exploration of a classical Greek ship was the second-most-watched program in America the week it was televised, and National Geographic magazine has found shipwrecks a favorite subject among readers of its various international editions. Such interest can lead to direct and indirect economic benefits through tourism. The museum that houses the seventeenth-century warship Vasa is the greatest tourist attraction in Sweden; the Bodrum Museum of Underwater Archaeology is the most visited archaeology museum in all of Turkey; and, when restored, La Salle's ship Be//e will be the centerpiece of the new Bob Bullock State History Museum in Austin. Although there are national programs of marine archaeology in France, Greece, Portugal, Israel, Spain, and Australia, among others, federal support of global archaeology in the United States comes mainly from NSF, which no longer funds all aspects of marine archaeology, and from the National Endowment for the Humanities, which does not support essential explor- atory surveys. 61

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62 EXPLORATION OF THE SEAS SUMMARY To a large degree, the oceans remain one of the great mysteries of our world. So many discoveries likely remain that narrowing the possibilities to those highlighted here was the source of much discussion among the com- mittee members. In all, the areas highlighted are likely not only to attract partners from many nations, but to provide important discoveries relatively rapidly. Should an ocean exploration program be initiated for a lengthy period of time, these areas of promise could be greatly expanded.