Sea Change: 2015-2025 Decadal Survey of Ocean Sciences (2015)

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21st-Century Achievements in Ocean Science

The remarkable thing is that although basic research does not begin with a particular practical goal, when you look at the results over the years, it ends up being one of the most practical things government does.

—President Ronald Reagan, Radio Address to the Nation on the Federal Role in Scientific Research, April 2, 1988

The 15 years since the turn of the millennium have brought dramatic changes in the collection, analysis, and distribution of information across many sectors of society, creating tremendous new opportunities in the sciences. In the ocean sciences, advances in observational and computational capabilities have led to rapid increases in understanding—from the minutest organisms to the vast expanse of the ocean basins. Ocean biologists and biogeochemists applied molecular biology techniques to understand the diversity and function of marine life, while satellites and autonomous sensor systems have revealed a dynamic global ocean on unprecedented temporal and spatial scales. Precise measurements of ocean chemistry have shown a decline in ocean pH, prompting studies on its potential impact on marine organisms and ecosystems. Advances in seafloor exploration have documented eruptions on the deep seafloor, discovered new morphologic features, and uncovered active subseafloor microbial communities. Predictability of the dynamic variability of ocean and climate systems at all scales has been enhanced by new observing technologies and analytical strategies, including improved models.

The accomplishments summarized below represent significant advancements in ocean research and reflect support and innovations from federal agencies, some foundations, and many nations. They were selected from government, international, National Research Council, and academic reports from roughly the past 15 years; from Division of Ocean Science (OCE) highlights provided by National Science Foundation (NSF) program officers; from the primary literature; and from discussions within the committee. While no such list can be truly comprehensive, this chapter captures some of the most exciting developments in ocean science that have yielded rapid increases in knowledge and major advances in understanding of the ocean over the past decade.

THE OCEAN COMPONENT OF CLIMATE VARIABILITY AND CHANGE

Sea level rise varies greatly across geographic regions. If the ocean were simply a giant bathtub, sea level rise from increasing ocean temperature and additional water from melting land ice would occur uniformly. However, a variety of physical and geological processes cause water levels to increase dramatically in some regions while others see little to no change or even declines. Sea level along the U.S. eastern seaboard is a striking example—sea level is rising faster between Cape Hatteras, North Carolina, and Cape Cod, Massachusetts, than anywhere else along the East Coast (Figure 1-1). This is vital information for coastal engineers, planners, and communities.

Arctic summer sea ice volume over the past decade has decreased on a trajectory that is steeper than other indicators of global change. Unlike many climate change signals, the loss of Arctic sea ice has been remarkably persistent—its volume has decreased by a factor of 5 in the September minimum between 1979 and 2014 (Figure 1-2). This ice loss has geopolitical and ecological consequences. Increased opportunities for shipping, cruise ship tourism, hydrocarbon resource exploitation, and fishing heighten the potential for large-scale search-and-rescue missions, oil spill response, and international disputes that can increase national security concerns. The effect of an ice-free Arctic on the global climate system, and in particular mid-latitude weather patterns, is still unclear. However, the decreased reflectivity of sunlight (albedo) in an ice-free Arctic points

FIGURE 1-1 Sea-level rise rate differences for a 60-year time series at tide gauge locations across the East Coast of North America.
SOURCE: Sallenger et al., 2012.

to further amplification of regional warming, suggesting that loss of sea ice could be irreversible.

The first seafloor drilling in the perennially icebound central Arctic showed a transition from a warmer “greenhouse” climate ~55 million years ago to a colder environment ~45 million years ago that continues to the present. Seafloor sediment cores indicated that surface temperatures ~55 million years ago were significantly warmer, supporting the hypothesis that the earliest Arctic cooling occurred at the same time as cooling in Antarctica and that climate change was symmetric at the poles. Additionally, the cores documented a transition from poorly to fully oxygenated sediments in the Arctic, attributed to the opening of the Fram Strait, which permitted deep-water exchange between the Arctic and North Atlantic Oceans. The effects of albedo, temperature, and oxygen variations determined from these cores helped illuminate the history of the Arctic circulation regime, which is key to successfully modeling global thermohaline circulation and the global climate system.

FIGURE 1-2 Yearly minimums of Arctic ice volume from 1980 to 2014 calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (Zhang and Rothrock, 2003). The red line shows the linear trend. Data from the Polar Science Center, Applied Physics Laboratory, University of Washington.

Reconstruction of climate patterns from the geologic past reveals causes and effects of climate change that are relevant for interpreting modern climate patterns. Methodological improvements have increased the chronological precision for accelerator mass spectrometry measurements and radiocarbon calibration; uranium-series dating of corals, speleothems, and lake carbonates; layer counting in sediments and ice cores; trace gas, O₂/N₂, and isotopic measurements in ice cores; and zircon U/Pb and ⁴⁰Ar/³⁹Ar dating. This new information reveals event sequences and helps to diagnose causes and effects of the dynamically changing Earth system and resolves an apparent paradox in climate patterns and elevated atmospheric CO₂ in the Northern and Southern Hemispheres.

Based on more accurate chronologies, the global-scale paleotemperature compilation shows that increases in global and Northern Hemisphere temperature lag behind the rise in

FIGURE 1-3 Global proxy temperature (blue) and Antarctic ice-core composite temperature (red) during the last deglacial transition, compared to atmospheric CO₂ concentration (yellow circles). Abbreviations are as follows: LGM, Last Glacial Maximum; OD, Oldest Dryas; B/A, Bølling-Allerød; and YD, Younger Dryas. SOURCE: Shakun et al., 2012.

atmospheric CO₂ by an amount consistent with the thermal inertia of the global ocean-ice system (Figure 1-3). Paradoxically, high-latitude Southern Hemisphere climate records show warming prior to the increase in CO₂. New findings indicate that natural sources and sinks of carbon and dynamic controls of regional warming are linked to ocean circulation, providing an explanation for the apparent paradox from Southern Hemisphere ice core data. This synthesis of information provides compelling evidence from the geologic record that greenhouse gases are a powerful force for global climate change.

The ocean’s overturning circulation varies in both space and time, with significant variability on time scales less than a year and with spatially non-uniform upwelling. Recent observations and modeling results have challenged the “great ocean conveyor belt” paradigm. For decades oceanographers assumed that the overturning circulation changed gradually, that its strength was coherent across the entire Atlantic, and that the deep currents were concentrated along the western boundaries of the basins. Instead, it is now understood that the overturning circulation is marked by strong temporal and spatial variability and that the deep waters’ equatorward pathways include the ocean interior. The Southern Ocean plays a key role in returning deep waters to the surface via wind-driven upwelling. This more sophisticated view of ocean circulation, which is the result of the international observational programs as well as the novel use of Lagrangian floats, opens new avenues for understanding ocean heat, freshwater, and carbon transport.

More comprehensive data from the Argo array augments 50 years of historical data to measure with high certainty the multi-decadal warming of the global oceans and changes in ocean salinity patterns. Heating rates have been estimated at 0.45 ± 0.15 W/m², averaged over the surface area of the Earth. The increase in ocean heat content represents about 90% of the net energy imbalance in the total climate system. Most of the present ocean heat content increase is in the extratropical Southern Hemisphere. Compared with the relatively steady and continuing increase in ocean heat content (or vertically averaged temperature), the mean surface temperature of the ocean and of the base of the marine atmosphere is more variable. For example, data [significantly augmented by the Argo program (Box 1-1)] show that the recent much-discussed “pause” in warming is confined to surface temperature data and that upper ocean heat content (to 2,000 m depth) has increased unabated. Multi-decadal trends in upper ocean salinity indicate that the relatively fresh regions of the oceans have become fresher and the salty regions saltier, consistent with enhancement of the mean patterns of evaporation minus precipitation. Argo is a case study of how transformational discoveries result from a good alignment of infrastructure with science priorities.

BIOGEOCHEMICAL AND ECOLOGICAL DIMENSIONS OF A CHANGING OCEAN

About one-third of the CO₂ released to the atmosphere by human activities has been absorbed by the ocean, causing a decline in the pH of upper ocean waters (often called “ocean acidification”). Changing ocean pH can affect the physiology, behavior, growth, and reproduction of marine organisms. The deleterious effect of this altered chemistry on the success of organisms that make calcium carbonate skeletal material or shells (e.g., corals, mollusks) has already been documented. This can have lethal impacts; for example, molluscan larvae that fail to produce a sufficiently calcified first shell that is needed to attach to hard substrate for maturation. In some regions, this is causing massive hatchery failures for coastal oyster aquaculture. Planktonic mollusks that have delicate shells, such as pteropods, are important components of oceanic food webs, and significant changes in their abundance could impact valuable fisheries (e.g., the Pacific Northwest salmon).

The prevalence of oxygen-depleted waters is increasing in many coastal and deeper ocean areas. Rivers carrying nitrogen and phosphorus from urban waste systems and from agricultural application of fertilizers have fundamentally altered many coastal ecosystems, stimulating phytoplankton blooms (Figure 1-4). When phytoplankton growth exceeds the capacity of zooplankton grazers, the excess production sinks and is biodegraded by bacteria that consume oxygen. In extreme cases, the bottom waters become hypoxic or even anoxic, often referred to as “dead zones” because most fish and other marine life cannot survive there. Excess algal growth also reduces the clarity of water in shallow coastal areas, blocking sunlight that is necessary for maintaining sea grasses and coral reefs, which provide essential habitat for fish and invertebrates. In some areas on the U.S. Pacific Coast, influxes of low-oxygen water have been

FIGURE 1-4 Incidences of dead zones from hypoxic systems in coastal regions, as well as the “human footprint” on land. The human footprint is a measure of potential human influence on the land surface, determined by population density, land transformation, access, and electrical power infrastructure (Sanderson et al., 2002). SOURCE: Diaz and Rosenberg, 2008.

associated with shoaling of deeper water rather than runoff of nutrients from land-based sources. The North Pacific has experienced oxygen declines for the past 50 years, possibly due to changes in ventilation from increased freshening of surface waters and atmospheric warming. Because the hypoxic zone in the North Pacific is the most extensive and the shallowest of the major oceans, relatively small oxygen decreases in deep water will impact the essential habitat of many species in the food web. A decline in the oxygenation of the deeper waters may be a result of a warmer, more strati-

FIGURE 1-5 Shifts in the distribution of marine taxa. Black arrows show the mean shift of surveyed taxa in each region. Inset graphs show the mean (black), maximum (blue), and minimum (red) latitude of detection for Pacific cod (Gadus macrocephalus) in the Gulf of Alaska, big skate (Raja binoculata) on the U.S. West Coast, and American lobster (Homarus americanus) in the Northeast as examples. Gray dashed lines in insets indicate the range of surveyed latitudes. SOURCE: Pinsky et al., 2013.

FIGURE 1-6 Monthly ratio of a warm-water copepod species (Calanus helgolandicus) to a cold-water species (Calanus finmarchicus) from 1958 to 2012 as averaged over the North Atlantic. Red values indicate dominance of the warm-water species and blue values indicate dominance of the cold-water species (0, total C. finmarchicus dominance; 1, total C. helgolandicus dominance). SOURCE: Used with permission from David Johns, Sir Alister Hardy Foundation for Ocean Science.

fied surface layer and, therefore, could be an early manifestation of climate change. A multiple-stressors approach will be needed to tackle the effect of concurrent stressors such as lower pH and oxygen.

The geographic distribution of ocean life—including phytoplankton, zooplankton, fish, and marine mammals—is shifting, affecting the structure of marine food webs. The ecological effects of global warming include poleward shifts in some species distributions (Figures 1-5 and 1-6) and/or changes in the timing of species migrations. These shifts did not occur as a linear effect of ocean warming; rather they are due to complex interactions of the biota with physical oceanographic properties such as currents, fronts, and eddies (e.g., some species seek greater depths instead of poleward migration to maintain optimal temperature conditions, especially in semi-enclosed seas). The shift of species distributions occurs at different rates, suggesting that large-scale population shifts may create new ecosystem associations over time. These changes are expected to have profound impacts on marine ecosystem productivity, with consequences for human communities that depend upon them.

BIODIVERSITY, COMPLEXITY, AND DYNAMICS OF OCEAN ECOSYSTEMS

Direct sequencing of DNA from the environment revealed the vast complexity, physiological capabilities, novel biogeochemical pathways, and species interactions of the microbial ocean. Analysis of DNA in seawater samples has revealed that the great majority of the microorganisms in the ocean have yet to be cultured or characterized. Viruses have been shown to influence marine microbial populations, from triggering the end of an algal phytoplankton bloom to changing the composition of bacterial communities. DNA sequencing technology has also contributed to efforts to catalog the diversity of larger, multicellular marine life through an international program known as the Census of Marine Life (Box 1-2).

Overfishing has had profound effects on marine species and ecosystems. Marine species are dynamically connected, directly and indirectly, such that human interventions—from extractive activities such as fishing to conservation efforts such as habitat restoration—have the potential to affect the ocean’s trophic structure. Research and management actions have revealed the deep interdependencies among ecological, economic, and social systems. Data from long-term monitoring programs in large marine ecosystems have documented the profound effects of overfishing and sequential depletion on the productivity and species compositions of marine ecosystems, including cascading impacts throughout the ecosystem due to the removal of top predators. Regionally based ecosystem monitoring, such as the international program Global Ocean Ecosystem Dynamics (GLOBEC) and the California Cooperative Oceanic Fisheries Investigations (CalCOFI), clearly demonstrated the impacts of overfishing, including the functional replacement of high-value stocks with less valuable fish species (Figure 1-7). Increased public awareness of the vulnerability of marine

ecosystems to human activities has led to new national and international management policies and some successes with ecosystem recovery.

THE SEAFLOOR IS GEOLOGICALLY, PHYSICALLY, AND BIOLOGICALLY DYNAMIC

The Hawaiian hotspot is created by mantle upwelling beginning more than 1,000 km beneath Earth’s surface. The largest ocean bottom seismometer deployment of the past decade, the Plume-Lithosphere Undersea Mantle Experiment (PLUME), demonstrated that upwelling beneath Hawaii begins in the lower mantle, refuting a hypothesis that all volcanic hotspots originate within the upper mantle. Combined with petrological studies and geodynamical modeling, experiments like PLUME reveal the pattern of mantle convection beneath the plates. Paleomagnetic and age-dating studies using samples from the Louisville and Hawaiian seamount chains (obtained by scientific ocean drilling) have shown that mantle convection has caused the two hotspots to migrate independently.

FIGURE 1-7 Illustrative examples of fishing down the food web characterized by (a) sequential collapse followed by replacement mode and (b) sequential addition mode. Total yearly catch for each 0.1 trophic-level increment is indicated by the color bar on the right (104 kg/year). The mean trophic level (white line) was created by using a locally weighted regression smoother. (a) The Scotian Shelf ecosystem exhibited a sharp decline in mean trophic level from 1990 to 2001 owing to the collapse of the cod fishery followed by a decline in the herring fishery and then the growth of the northern prawn fishery. (b) The mean trophic level of the Patagonian Shelf declined from 1980 to 2001, during which time catches for upper-trophic-level species (Argentinean hake) grew substantially while new fisheries for shortfin squid developed. SOURCE: Essington et al., 2006.

Anomalous ridge features and hydrothermal activity reveal the flow of fluids and magma through the ocean floor. Seafloor mapping demonstrated the existence of hydrothermal activity and pyroclastic volcanic materials at super-slow-spreading mid-ocean ridges, while other parts of these ridges appear to be completely lacking in volcanic activity (Figure 1-8). These observations challenge the existing plate tectonic paradigm and indicate that mantle melting is not

FIGURE 1-8 Bathymetry of the Gakkel Ridge overlaid with a range of lithologies recovered by dredge (basalt [red], peridotite [green], gabbro [orange], diabase [blue]). The western volcanic zone terminates at the eastern end of panel a. The sparsely magmatic zone continues to the eastern end of panel b. The eastern volcanic zone includes the eastern end of panel b as well as panels c and d. SOURCE: Michael et al., 2003.

simply a function of spreading rate but rather has a complex, poorly understood relationship. Hydrothermal processes in the ridge system influence ocean chemistry, contribute to mineral deposits, and provide habitats that support novel biological communities.

Surprising slip behavior is observed in fault zones. In some subduction zones, slow magnitude 7 earthquakes regularly occur at depths just beyond the zone that produces great earthquakes. These events last approximately 2 weeks, rather than slipping in a few seconds like typical earthquakes, and may be involved in triggering the occasional shallower earthquakes. In the great Tōhoku earthquake seaward of Japan in 2011, the huge tsunami was generated in part by as much as 50 m of slip on the fault at the trench axis in a portion of the subduction zone that was previously expected to slip gradually and quietly rather than suddenly. Using the Chikyu drillship, an Integrated Ocean Drilling Program expedition drilled into the toe of the Tōhoku fault zone and demonstrated that the unusual amount of slip was facilitated by a thin, very weak layer of clay. Understanding the controls on the nature of the slip along subduction zones could lead to better earthquake and tsunami forecasting and reduce the lag between event detection and response to major earthquake events.

A widespread and diverse microbial biosphere has been encountered beneath the ocean floor, and each new discovery produces new implications for global energy and carbon cycles. This subseafloor biosphere derives energy, in part, from the weathering products of oceanic crust and the availability of oxidants through subsurface circulation. The deep biosphere may represent a significant fraction of the total living biosphere on Earth, but it remains the least explored. Research on the subseafloor biosphere may have the potential for identifying new species, metabolic properties, and unique biochemical pathways that could be of value for biotechnology applications.

NEW TECHNOLOGIES ENABLE EFFICIENT COLLECTION OF GLOBAL OCEAN DATA

New sensor, vehicle, and laboratory technologies have revolutionized ocean observing by decreasing the cost of many observations; increasing resolution and accuracy in support of discovery, quantitative studies, and modeling; and enabling physical, chemical, and biological observations that were previously impossible. Great progress has been made with sensors to characterize acidification, the carbon and nutrient cycles, and the planktonic food web.

Miniaturized satellite-tracking tags on a variety of marine animals have disclosed migration paths, such as the trans-Pacific trek of leatherback turtles and the white shark aggregations midway between Baja California and Hawaii. Migratory paths and aggregations indicate behavioral strategies and the degree of interconnectivity of populations—vital information for fisheries management and conservation.

Genomics, the study of an organism’s DNA, has expanded over the past decade into “omics,” a collection of technologies to explore the relationships and actions of genes, proteins, and small metabolites. This is one example of how transformational discoveries in another discipline—biomedical science—have been applied to significant questions in ocean science. Two key advances made this possible: rapid high-throughput sequencing and mass spectrometric analysis of macromolecules, and bioinformatics to manage and analyze the vast data volumes generated. As speed, versatility, and affordability have increased, “omics” has moved from national facilities to individual laboratories and research ships, fostering discovery and experimentation. Metagenomics can be used to assess and quantify microbial diversity and functions, while metatranscriptomics and metabolomics can provide information on metabolic activities and may even lead to the discovery of novel biogeochemical pathways.

Robotic sensing is also revolutionizing physical measurements in the ocean. A collaboration of many nations established the Argo array of more than 3,000 profiling floats to measure changes of temperature and salinity in the ocean’s upper 2,000 m (Box 1-1). These variables directly address the global heat budget, the water cycle, and the ocean dynamics affecting them. Argo data accurately determine upper ocean heat content and have shown that subsurface ocean warming has been relentless, even as surface temperature increases slowed over the past 15 years. Expanding the global float array to full ocean depth and adding chemical and biological sensors is under way.

The widespread use of unmanned research vehicles is transforming oceanographic infrastructure. Large, powerful, and fast autonomous underwater vehicles (AUVs) are increasingly used in research and exploration. High stored energy and payload enable large sensor suites, water sampling, operations under ice, and high-resolution mapping to reveal geological features and processes (in addition to high-resolution mapping from ships [Box 1-3]). Easier handling and long ranges free some AUVs and buoyancy-driven gliders from ship support, enabling operations under ice or in remote locations and making sustained sampling feasible, particularly near coasts. Small, low-power sensors are now regularly monitoring physical, chemical, and biological indicators of dynamical variability and ecosystem variations in coastal and island settings.

Sustaining very long-term observations at low cost by harvesting energy from the environment is also a theme of recent, compelling technological advances. Particularly at the ocean surface, where wind, solar radiation, and surface waves are high-intensity energy sources, vehicles and moored sensor suites are becoming environmentally powered. Small surface vehicles and moored wire-walking profilers harvest wave energy for propulsion, increasingly affordable solar panels and improved methods of keeping them clean make solar power ever more useful, and modernized

forms of the sailboat and windmill abound. Energy has also been harvested from the ocean’s thermal stratification by vertically profiling vehicles, but the small ocean temperature difference from surface to depth has hindered their efficiency.

COLLABORATIONS ADVANCE OCEANOGRAPHY ACHIEVEMENTS

Federal Partnerships

In addition to the accomplishments highlighted above, there have been many contributions arising from cooperatively funded programs and partnerships, both federal and international. A few examples to illustrate how these joint activities can foster advances in scientific knowledge and support the missions of the federal ocean agencies are provided.

ONR’s major collaborations with NSF have been in the provision of ships, tools, and sensors. NSF has greatly benefited from ONR’s sustained investments in infrastructure and sensors such as Alvin, moorings, current meters, conductivity-temperature-depth and microstructure sensors, bioacoustics, autonomous underwater vehicles, Argo development, and gliders.

NSF, NOAA, the Environmental Protection Agency, ONR, and the National Aeronautics and Space Administration have cooperatively funded programs on the ecology of harmful algal blooms for over a decade. These projects have led to breakthroughs in understanding the mechanisms that underlie development of harmful algal blooms and their impacts on ecosystems, fisheries, and local economies, as well as potential management strategies.

NOAA and NSF cooperated on international GLOBEC studies in the Northwest Atlantic, the Northeast Pacific and Gulf of Alaska, and the Southern Ocean over the course of a decade. The studies were a successful interdisciplinary effort to assess the impact of global change on physical and biological oceanographic processes with a focus on economically valuable fisheries.

The National Institute of Environmental Health Sciences worked with NSF and NOAA on an interagency effort on oceans and human health, which established new centers and forged new research directions on marine toxins and disease and led to discoveries of natural products with potential pharmacologic value.

International Partnerships

The United States (through NSF and ONR), has often played a major role in large, international ocean science programs. Although internationally planned and coordinated oceanography involves some upfront costs in terms of efficiency and management, these programs have often demonstrated that significant achievements can be gained that otherwise would not have occurred. Some examples of past successes in international ocean science research are described below. These examples are illustrative and not exhaustive, chosen to demonstrate the scope and high value of activities.

The World Ocean Circulation Experiment Hydrographic Survey was the first attempt to measure and map the global ocean’s physical properties, using a common measurement protocol. Many nations contributed their research vessels to the multiple legs that comprised the survey. The ongoing international Argo program (Box 1-1) can be viewed as a continuation of the survey.

The Integrated Ocean Drilling Program (IODP [2003-2013]) and the current International Ocean Discovery Program (IODP [2013-2018]) have the objective to advance the understanding of the subseafloor environment by utilizing specialized drilling platforms to sample, install instrumentation, and monitor conditions. IODP (2013-2018) involves partnerships among 26 nations.

The Joint Global Ocean Flux Study international program pooled oceanographic resources of several nations to mount a major study of biogeochemical processes contributing to the fluxes of organic matter at several locations. It brought together not only scientists of many nations but also a wide range of disciplines to work together, often for the first time. Iron fertilization experiments were conducted to test the role of iron in stimulating biological productivity in the open ocean. The results not only contributed to the scientific understanding of ocean productivity, but also informed debates on proposals to use iron fertilization for carbon capture and sequestration.

The ongoing International Study of Marine Biogeochemical Cycles of Trace Elements and their Isotopes (GEOTRACES) surveys are measuring trace chemical, isotopic, and biogeochemical properties of the global ocean to increase understanding of biogeochemical cycles. GEOTRACES is designed to provide a globally consistent view of tracer distributions to develop a more accurate understanding of their behavior. These tracers are often invoked as regulators of key biogeochemical processes, for their utility in decoding past environmental changes, and as a measure of the human impact on the global environment.

ANALYSIS OF THE SCIENTIFIC ACCOMPLISHMENTS

In the late 1990s, OCE undertook a community-based assessment of research opportunities that would define the next decade of ocean science (Ocean Sciences at the New Millennium [NSF, 2001]). Each ocean science discipline prepared a report on what it saw as the major research opportunities, which were used to identify seven interdisciplinary topics that were ripe for advancement. In addition, the summary highlighted key findings, new science trends, and interdisciplinary fields of interest to the ocean sciences.

There is good concordance between those seven topics identified in 2001 and the major advances identified above, demonstrating that forward planning was indeed successful

in fostering meaningful scientific accomplishment. However, not every research theme was anticipated. For example, the New Millennium report did not highlight sea level rise or ocean acidification as major research topics. The subsequent shift to research on these themes argues for providing flexibility to the research program to allow for changes in direction as new issues or priorities emerge.

In addition, the rapid rate of new discoveries and increases in understanding of fundamental ocean properties indicates that during the first decade of the millennium there was a productive balance of investment in core research, major research infrastructure assets, technology development, and multidisciplinary and internationally coordinated research programs. The success of the past decade and a half also demonstrates the invaluable contributions of long-term monitoring programs (Box 1-4).

OCE has an enviable track record of past success, based on strategic basic research investments and partnering with other organizations to enhance research opportunities for the scientific community. In many cases, these accomplishments have led to practical applications with direct societal benefits. Basic research in the ocean sciences provides a strong foundation for mission agencies to build upon, for international collaborations, and for public welfare.

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