It’s hard to believe that any part of our planet remains undiscovered. But even today a vast part of Earth has almost entirely escaped human eyes. The Hadal Zone—those parts of the global ocean more than 6,000 meters deep—is still largely unexplored. That is where we are going to learn how life can exist at extreme depths.
After initial discoveries in the mid-1800s, much of what we know about life in the deep ocean, and in the ocean trenches that form much of the Hadal Zone, comes from a handful of scientific expeditions and a few opportunistic samples of animals, sediment, and rock brought to the surface. Over the next 40 days, a team of scientists and engineers will use Nereus, a deep-diving remotely operated vehicle, to explore part of the Kermedec Trench, one of the deepest in world, in a systematic effort to achieve ambitious research goals:
- Examine the composition, abundance, diversity, and community structure of life along the trench and up its flank onto the adjacent abyssal plain.
- Investigate how organic carbon and bacterial biomass is distributed in trench and abyssal environments and how it might serve as food for larger hadal organisms.
- Relate this distribution of carbon and bacterial biomass to the distribution and composition of communities and ecosystems at different depths and in different topographical regions.
- Explore the roles that different topographical features, such trenches and plains, and various ocean depths play in the nature and diversity of life in the trench.
- Examine correlations between ocean depths and food availability and trench organisms’ metabolic and respiration rates.
- Learn how different species have evolved to survive at different depths.
The Kermadec Trench runs northeast from the North Island of New Zealand (shown in red in this animation) to the Louisville Seamount Chain. It is the fifth deepest oceanic trench in the world and formed by subduction, a geophysical process in which the Pacific tectonic plate is pushed beneath the Indo-Australian Plate. (Jack Cook, Woods Hole Oceanographic Institution)