Future Directions for Southern Ocean and Antarctic Nearshore and Coastal Research (2024)
Chapter: 1 Introduction
1
Introduction
The Southern Ocean and the coast of Antarctica are some of the harshest and most remote places on Earth, distant from all major population centers, and yet a region of global importance. Floating sea ice and ice shelves dominate more than 1.5 million square kilometers in the region and hinder coastal access to about 75 percent of Antarctica’s coastline (Rignot et al., 2013). Whereas sea ice is formed by saltwater freezing, floating ice shelves are fed by glaciers and large, inland ice sheets (see Figure S-1 in the Summary). This grounded ice plays a crucial role in the delicate hydrological equilibrium between land and ocean. The net balance of ice and snow is controlled by extreme wind and precipitation patterns, as well as the warming waters of the adjacent Southern Ocean.
The Southern Ocean, in turn, connects Earth’s major oceans and supports a global circulation (see Figure S-2 in the Summary). The northern boundary of the Southern Ocean is loosely defined and ranges from 60°S, per the Antarctic Treaty of 1961, to 38°S or even 30°S (in the Pacific region) when considered as the northernmost edge of the Antarctic Circumpolar Current (ACC) and all associated water mass characteristics (Talley et al., 2011). The Southern Ocean is unique in that its eastern-flowing ACC is uninterrupted by landmasses. It therefore serves as a connection between the Atlantic, Indian, and Pacific Ocean basins and as a transport pathway between all the major oceans. The ACC’s unimpeded, wind-driven, west-to-east flow influences the global transport of heat, nutrients, and dissolved gases. A lack of continental boundaries also permits exchange between lower-latitude basins, as well as a meridional overturning circulation that allows deep water access to the surface within the Southern Ocean (Olbers et al., 2004).
This extreme and dynamic physical world is inhabited by a diversity of life, much of which likely remains undiscovered. Biota in the Southern Ocean ranges from primary producers (e.g., plankton and algae) to megafauna (e.g., penguins and other seabirds, seals, whales). Krill are a key species in this ecosystem because of their role in the food web for higher trophic levels and as the target species of the largest fishery in the Southern Ocean (Nicol et al., 2012).
Although diverse and complex, the Southern Ocean and nearshore Antarctic ecosystems and environments are fragile, and currently facing increasing stresses from human-induced factors, especially climate change. Ocean temperatures are rising (Schmidtko et al., 2014), sea ice extent is changing (Maksym, 2019; Raphael and Handcock, 2022), ice shelves are retreating (Dutrieux et al., 2014a; Paolo et al., 2015; Pritchard et al., 2012), and the underlying structure and food webs of ecosystems are evolving (e.g., Fuentes et al., 2016; Sahade et al., 2015). Many of these processes have important feedbacks that can in turn affect global processes. For example, reduced sea ice leads to lower surface albedo and further warming (Stammerjohn et al., 2012). Additionally, the loss of krill leads
to weakening the biological carbon pump, which can sequester carbon into the deep ocean (Belcher et al., 2019; Cavan et al., 2019a). A robust understanding of the past and present physical, chemical, biological, and geological processes that occur in nearshore Antarctica and the Southern Ocean is essential for predicting how the evolving local environment might impact the globe.
COMMITTEE’S TASK AND APPROACH
In 2022, the National Science Foundation (NSF) requested that the National Academies of Sciences, Engineering, and Medicine complete a study that identifies (1) the science drivers in Southern Ocean and Antarctic nearshore and coastal research, (2) the capabilities essential to support these science drivers, and (3) gaps between the science drivers and the portfolio of capabilities. The full statement of task is found in Box 1-1. The committee interpreted the statement of task as referring to the entire Southern Ocean, including areas slightly north of 60°S through which a U.S. Antarctic Program (USAP) vessel might regularly transit. The committee also interpreted the wording of “nearshore and coastal” in the statement of task to include regions of Antarctica that are near to, or influence, the coastal region. NSF supported these interpretations.1 Given the focus in the statement of task on observational capabilities (e.g., Antarctic Research Vessel [ARV], remotely operated vehicles, autonomous underwater vehicles, drilling), the committee did not consider necessary advances in modeling or theoretical work in detail—although continued investment in these areas will be required to advance all the science drivers identified in this report.
During this study, an ARV was in the Preliminary Design Stage of the Major Research Equipment and Facilities Construction process (Chapter 2). The statement of task specifically requests that the committee consider
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1 Presentation to the committee by NSF, December 2022.
the capabilities needed for the ARV. Because of the advanced stage of the design, only minor adjustments to the ARV design may be practical to keep the design process on schedule and budget. However, this study is not solely focused on the ARV. The statement of task also calls out other “tools, technologies, and approaches,” which the committee interpreted broadly to include capabilities that might be deployed from the ARV, as well as those that might not necessarily be supported by vessels, such as satellite and fixed-wing supported remote sensing.
The committee used numerous resources, including several previous National Academies consensus reports, in its information-gathering. As part of its deliberation of the highest-priority science drivers, the committee compiled and considered the science questions identified in these reports:
- Next Generation Earth Systems Science at the National Science Foundation (NASEM, 2022b),
- Mid-Term Assessment of Progress on the 2015 Strategic Vision for Antarctic and Southern Ocean Research (NASEM, 2021b),
- A Vision for NSF Earth Sciences 2020-2030: Earth in Time (NASEM, 2020),
- A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research (NASEM, 2015),
- Sea Change: 2015-2025 Decadal Survey of Ocean Sciences (NRC, 2015), and
- Future Science Opportunities in Antarctica and the Southern Ocean (NRC, 2011).
The committee also referenced several prior workshops:
- Antarctic Sea Ice Variability in the Southern Ocean-Climate System: Proceedings of a Workshop (NASEM, 2017b),
- Technology Developments to Advance Antarctic Research: Proceedings of a Workshop (NASEM, 2022c), and
- Identifying New Community-Driven Science Themes for NSF’s Support of Paleoclimate Research: Proceedings of a Workshop (NASEM, 2021a).
It also used the booklet Antarctic Science: Why U.S. Leadership and Investments Matter (NASEM, 2022a).
As part of its deliberation of the highest-priority science drivers and capabilities, the committee held a community workshop on February 9–10, 2023. The workshop had 69 registered in-person attendees and 194 registered virtual attendees, including 28 invited experts, most of whom gave presentations. The workshop agenda included three sessions modeled after the science drivers identified in this report, as well as other sessions that were more discipline specific. The invited experts were asked to present on what they considered to be the highest-priority science drivers and the capabilities necessary to enable that research. The workshop included several breakout sessions, in which participants discussed the prioritization of science drivers and capabilities, as well as a final breakout room where participants were invited to share thoughts on these topics.
The committee assessed the information gathered at the community workshop and the compiled science priorities from previous reports to define the final high-priority science drivers and capabilities presented in this report. These priorities do not represent the full breadth of science that USAP supports, but rather the most compelling science that is poised for near-term progress, including research with a high potential for societal impact.
The committee notes that Antarctica remains poorly explored because of past access limitations. As such, it is likely that new discoveries will be made and the science drivers will evolve over time. The science drivers that were identified in this report are similar, but not identical, to the science priorities identified in A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research (NASEM, 2015), which laid out a decadal vision for NSF’s Office of Polar Programs (OPP). Indeed, the reader will identify that two priorities in NASEM (2015) map well on to the science drivers presented in this report: sea level rise (see Priority I in NASEM [2015]) and changing ecosystems (see Priority II in NASEM [2015]). Priority III of NASEM (2015) focused on cosmic microwave background research that occurs at the South Pole, which does not fit within this study’s scope of nearshore and coastal Antarctic research and is therefore not represented in this report. NASEM (2021b) assessed progress on the 2015 plan and noted the urgent need for improved access to the marine realm around Antarctica, along with more focus on coordinated interdisciplinary programs and interagency and international partnerships, themes that are revisited here.
While the committee benefited greatly from prior reports, it did not confine itself to only considering priorities called out in NASEM (2015), but instead considered a more holistic review of reports and community input to develop a forward-looking view of emerging scientific opportunities and the infrastructure needed to enable progress. Nevertheless, because of their similarities, continued advancements of science Priorities I and II in NASEM (2015) will also advance the science drivers identified in this report.
The committee held three additional open sessions. The first, in December 2022, was focused on gathering information from the study sponsor (the NSF OPP) and the authors of prior reports on the Southern Ocean and Antarctica. The second, in March 2023, was focused on the capabilities of potential national and international partners (see Appendix B for partner capabilities). The final open session, in May of 2023, included updates from the study sponsor as well as from the ARV Science Advisory Subcommittee.
OUTLINE OF REPORT
Following the compilation and consideration of priority science questions identified in past reports and the information gathered at the various open sessions, the committee identified the following as the three most compelling science drivers, based on their immediate relevance to society and the global ecosystem:
- the impact of Antarctica and the Southern Ocean on global sea level,
- the impact of Southern Ocean circulation and air–sea exchange on global heat and carbon budgets, and
- the impact of environmental change on Antarctic and Southern Ocean biota and their ecosystem services.
Shorthand, the drivers will be referred to as sea level rise, global heat and carbon budgets, and changing ecosystems. These prioritized science drivers are interdisciplinary, with disciplines and subdisciplines such as geosciences (e.g., paleoceanography), biological sciences (e.g., biogeochemistry, genomics), chemical sciences (e.g., thermodynamics), oceanographic sciences (e.g., physical, chemical, biological oceanography), physical sciences (e.g., marine geophysics), and engineering, among others, playing an important role in each.
Following an overview of the National Antarctic Program in Chapter 2, Chapters 3, 4, and 5 expand on each of these interdisciplinary science drivers by identifying the near- and long-term science priorities within each and the required observations to complete these science priorities. The conclusions at the end of Chapters 3, 4, and 5 summarize the needed observations and actions to advance science priorities. Chapter 6 then summarizes the tools, technologies, and approaches called out in previous chapters and identifies whether these capabilities are currently supported by the United States or potential partners. Conclusions at the end of Chapter 6 identify the gaps between the science drivers and the portfolio of capabilities. Specific, actionable recommendations are provided at the end of Chapter 6 for NSF to address those gaps.
