Abstract
The deep ocean below 200 m water depth is the least observed, but largest habitat on our planet by volume and area. Over 150 years of exploration has revealed that this dynamic system provides critical climate regulation, houses a wealth of energy, mineral, and biological resources, and represents a vast repository of biological diversity. A long history of deep-ocean exploration and observation led to the initial concept for the Deep-Ocean Observing Strategy (DOOS), under the auspices of the Global Ocean Observing System (GOOS). Here we discuss the scientific need for globally integrated deep-ocean observing, its status, and the key scientific questions and societal mandates driving observing requirements over the next decade. We consider the Essential Ocean Variables (EOVs) needed to address deep-ocean challenges within the physical, biogeochemical, and biological/ecosystem sciences according to the Framework for Ocean Observing (FOO), and map these onto scientific questions. Opportunities for new and expanded synergies among deep-ocean stakeholders are discussed, including academic-industry partnerships with the oil and gas, mining, cable and fishing industries, the ocean exploration and mapping community, and biodiversity conservation initiatives. Future deep-ocean observing will benefit from the greater integration across traditional disciplines and sectors, achieved through demonstration projects and facilitated reuse and repurposing of existing deep-sea data efforts. We highlight examples of existing and emerging deep-sea methods and technologies, noting key challenges associated with data volume, preservation, standardization, and accessibility. Emerging technologies relevant to deep-ocean sustainability and the blue economy include novel genomics approaches, imaging technologies, and ultra-deep hydrographic measurements. Capacity building will be necessary to integrate capabilities into programs and projects at a global scale. Progress can be facilitated by Open Science and Findable, Accessible, Interoperable, Reusable (FAIR) data principles and converge on agreed to data standards, practices, vocabularies, and registries. We envision expansion of the deep-ocean observing community to embrace the participation of academia, industry, NGOs, national governments, international governmental organizations, and the public at large in order to unlock critical knowledge contained in the deep ocean over coming decades, and to realize the mutual benefits of thoughtful deep-ocean observing for all elements of a sustainable ocean.
Highlights
The deep sea as an analog for the origin of life and its extraterrestrial potential Extreme conditions found in deep-sea waters, at the seafloor, and in the deep biosphere offer insight into the processes enabling the origin of life and the potential for life on other planets and their moons
There are combinations of temperature, pressure, Eh, and pH found in the deep ocean that are conducive to abiotic processes that may generate primordial life (Cavanaugh et al, 2006; Schulte et al, 2006)
Hydrothermal vents offer confirmation that life can thrive in the dark depths of the ocean, utilizing chemosynthesis as the base of the food chain; analogous geologically active seafloors may occur in the oceans of the moons of Jupiter (Europa) and Saturn (Enceladus), based on ejected plumes with mixtures of compounds characteristic of hydrothermal venting (Deamer and Damer, 2017)
Summary
Edited by: Frank Edgar Muller-Karger, University of South Florida, United States. Reviewed by: Toste Tanhua, GEOMAR Helmholtz Center for Ocean Research Kiel, Germany Fabien Roquet, University of Gothenburg, Sweden. The contamination of the global ocean by these compounds has proved useful in oceanographic science, for example in the use of organohalogens (chlorofluorocarbons and sulfur hexafluoride) as tracers of water masses and their movement (Fine, 2011) These forms of widespread contamination of the environment and fauna of the deep ocean are little reported, in marked contrast to major point-source contaminations of the ocean such as the 2010 Macondo oil spill in the Gulf of Mexico. Accumulations of marine debris, plastic material, occur commonly in the deep sea, along with microplastics in a wide range of ecosystem compartments (e.g., Bergmann et al, 2017) Large objects such as shipping containers and fishing gear (derelict nets and trawls) can alter habitats by providing hard substrate, toxicological impacts associated with coatings or contents (Taylor et al, 2014), or entangling organisms (Humborstad et al, 2003). We introduce a subset of these questions that underpin observational requirements for the deep ocean (Box 2), largely derived from the DOOS Science Implementation Guide
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