The massive number of seabirds (penguins and procellariiformes) and marine mammals (cetaceans and pinnipeds) -referred to here as top predators -is one of the most iconic components of the Antarctic and Southern Ocean. They play an important role as highly mobile consumers, structuring and connecting pelagic marine food webs and are widely studied relative to other taxa. Many birds and mammals establish dense breeding colonies or use haul-out sites, making them relatively easy to study. Cetaceans, however, spend their lives at sea and thus aspects of their life cycle are more complicated to monitor and study. Nevertheless, they all feed at sea and their reproductive success depends on the food availability in the marine environment, hence they are considered useful indicators of the state of the marine resources. In general, top predators have large body sizes that allow for instrumentation with miniature datarecording or transmitting devices to monitor their activities at sea. Development of scientific techniques to study reproduction and foraging of top predators has led to substantial scientific literature on their population trends, key biological parameters, migratory patterns, foraging and feeding ecology, and linkages with atmospheric or oceanographic dynamics, for a number of species and regions. We briefly summarize

In October 2016, the international community made history by adopting the world's largest marine protected area in the Ross Sea, Antarctica—by consensus. Achieving this feat required trade‐offs and compromise among the 24‐Member States (plus the European Union) comprising the Commission for the Conservation of Antarctic Marine Living Resources. The process took 5 years of intense international negotiations and more than 10 years of scientific planning. Based on interviews with national delegations and other stakeholders, 5 years of participatory observation of Commission meetings (2012–2016), and analysis of hundreds of documents, we present unique insights that explain the conditions that stalled or facilitated the adoption of the Ross Sea MPA. These included economic interests, geopolitics, an erosion of trust, high‐level diplomacy, and the compromises that were ultimately necessary. We reflect on lessons learned as the world considers how to achieve future large‐scale conservation successes in the global commons.

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popular beliefs that Antarctica is pristine, stable, isolated, and reliably frozen. An aspirational roadmap for Antarctic science has facilitated research since 2014. A renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond. Progress is already evident, such as addressing uncertainties in the causes and pace of ice loss and global sea-level rise. However, much remains to be learned. As an iconic global ''commons,'' the rapidity of Antarctic change will provoke further political action. Antarctic research is more vital than ever to a sustainable future for this One Earth.

Antarctica and the Southern Ocean comprise a critical part of the Earth System. Their environments are better understood than ever before, yet the region remains poorly considered among international agreements to improve the state of the global environment. In part the situation owes to isolated regional regulation within the Antarctic Treaty System, and in part to the dated notion that Antarctica and the Southern Ocean are well conserved and relatively free from human impact. Here we review growth in knowledge of Antarctic environments and anthropogenic pressures on them. We show that the region's unusual diversity is facing substantial local and globally mediated anthropogenic pressure, on a par with environments globally. Antarctic environmental management and regulation is being challenged to keep pace with the change. Much benefit can be derived from consideration of Antarctic environmental and resource management in the context of global agreements.

Although scholars have thoroughly explored theories and practices of formal and informal governance for oceans, most of the research has concentrated on interactions among individuals, or organizations within a sector. The emerging literature from management science argues that meta-organizations, organizations which members are themselves organizations, and especially cross-sectoral meta-organizations, may be a critical concept for scientists, public decision makers, managers, local communities and other actors in ocean governance. A meta-organization's main attributes (i.e., bringing together different formal organizations, consensus-based decision making process, little to no hierarchy, diversity of membership, information-production and collective capacity building and self-regulation mechanisms) can foster critically necessary collaborative behaviors among competitors and across sectors. Here we review key concepts regarding meta-organizations, study six examples of meta-organizations in marine systems, and outline how these advances in management and policy could foster cooperation rather than competition within and among sectors in ocean governance. Meta-organization thinking therefore can help us understand, but also frame and encourage, cross-sectoral collective actions that are solutions-oriented.

Global threats to ocean biodiversity have generated a worldwide movement to take actions to improve conservation and management. Several international initiatives have recommended the adoption of marine protected areas (MPAs) in national and international waters. National governments and the Commission for the Conservation of Antarctic Marine Living Resources have successfully adopted multiple MPAs in the Southern Ocean despite the challenging nature of establishing MPAs in international waters. But are these MPAs representative of Southern Ocean biodiversity? Here we answer this question for both existing and proposed Antarctic MPAs, using benthic and pelagic regionalizations as a proxy for biodiversity. Currently about 11.98% of the Southern Ocean is protected in MPAs, with 4.61% being encompassed by no-take areas. While this is a relatively large proportion of protection when compared to other international waters, current Antarctic MPAs are not representative of the full range of benthic and pelagic ecoregions. Implementing additional protected areas, including those currently under negotiation, would encompass almost 22% of the Southern Ocean. It would also substantially improve representation with 17 benthic and pelagic ecoregions (out of 23 and 19, respectively) achieving at least 10% representation.

Coral reefs are widely regarded as one of the top science and conservation priorities globally, as previous research has demonstrated that these ecosystems harbor an extraordinary biodiversity, myriad ecosystem services, and are highly vulnerable to human stressors. However, most of this knowledge is derived from studies on nearshore and shallow-water reefs, with coral reef ecosystems remaining virtually unstudied in marine areas beyond national jurisdiction (ABNJ), commonly known as the high seas. We reviewed information on the spatial distribution of reef-building corals throughout their depth range, and compiled a total of 537,782 records, including 116 unique records from ABNJ at depths between 218-5,647 m. The majority of reef-building coral records in ABNJ were in association with geomorphological features that have steep topographies. These habitats, which include escarpments, seamounts, and submarine ridges accounted for >74% of the records in international waters. Such geomorphological features, particularly those that occur within close proximity to the sea surface, should be prioritized for future scientific exploration. The majority of the reef-building coral records in ABNJ (>77%) were recorded in unprotected waters, and this study discusses the challenges and opportunities for protecting marine biodiversity in ABNJ. Finally, this study offers a definition of high seas coral reefs, and provides a framework to better understand and conserve these fragile ecosystems.

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