Water/Hycean Worlds & Oceanography

Offworld Away Team Analog: New Opportunities and Untapped Scientific Potential in Earth’s Abyssal Ocean

By Keith Cowing
Status Report
Frontiers In Marine Science
May 23, 2024
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Offworld Away Team Analog: New Opportunities and Untapped Scientific Potential in Earth’s Abyssal Ocean
2016: Alvin working on the East Pacific Rise, as viewed from a camera on an elevator (Woods Hole Oceanographic Institution)

The abyssal ocean covers more than half of the Earth’s surface, yet remains understudied and underappreciated. In this Perspectives article, we mark the occasion of the Deep Submergence Vehicle Alvin’s increased depth range (from 4500 to 6500 m) to highlight the scientific potential of the abyssal seafloor.

From a geologic perspective, ultra-slow spreading mid-ocean ridges, Petit Spot volcanism, transform faults, and subduction zones put the full life cycle of oceanic crust on display in the abyss, revealing constructive and destructive forces over wide ranges in time and space.

Geochemically, the abyssal pressure regime influences the solubility of constituents such as silica and carbonate, and extremely high-temperature fluid-rock reactions in the shallow subsurface lead to distinctive and potentially unique geochemical profiles.

Microbial residents range from low-abundance, low-energy communities on the abyssal plains to fast growing thermophiles at hydrothermal vents. Given its spatial extent and position as an intermediate zone between coastal and deep hadal settings, the abyss represents a lynchpin in global-scale processes such as nutrient and energy flux, population structure, and biogeographic diversity.

Taken together, the abyssal ocean contributes critical ecosystem services while facing acute and diffuse anthropogenic threats from deep-sea mining, pollution, and climate change.

Abyssal seafloor features in the context of open ocean environments. (A) A schematic outline of the diverse habitats and features on the abyssal seafloor, some of which extend above and/or below the abyssal zone. (B) Pillow basalt at a Petit Spot seafloor volcano, providing a window into the earth’s upper mantle through (C) peridotite xenoliths (image 2 mm across). (D) Abyssal seafloor nodules at the Clarion-Clipperton zone; insets show (E) Benthodytes, (F) Grimpoteuthis, and (G) Actiniaria; all scale bars 5 cm. (H) Hydrothermal chimneys with vent shrimp at the Piccard hydrothermal field. [Image credits: (B) Tohoku University; (C) Morishita et al. (2020); (D) GEOMAR; (E) Simon-Lledó et al. (2019); (F) Simon-Lledó et al. (2020); (G) Simon-Lledó et al. (2019); (H) Chris German, WHOI/NASA].

New Opportunities and Untapped Scientific Potential in the Abyssal Ocean, Frontiers In Marine Science (open access)

Astrobiology, oceanography,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻