Personal Perspectives

What We DON'T Know About the Deep Sea

Dive through the zones of the ocean to the deep ocean bottom where many strange species live, and there are many yet to be discovered. Explore them in the Deep Ocean Exploration section.
Dive through the zones of the ocean to the deep ocean bottom where many strange species live, and there are many yet to be discovered. Explore them in the Deep Ocean Exploration section. (Karen Carr / Smithsonian National Museum of Natural History Sant Ocean Hall)


The deep sea—that part of the ocean that is perpetually dark—is 103 million square miles in area. However, despite a dramatic increase in exploration in recent decades, we still know very little about this “inner space.” We urgently need to know a lot more. Why? Well…

  1. With its great currents slowly moving enormous quantities of water around our planet, the deep sea is the engine that controls the overall climate—but we don’t yet understand enough about how this engine works. In light of climate change, the rapid melting of ice at the poles is increasing the flow of cold water into the deep sea. We must be able to monitor great deep-sea changes so we can better predict future crises, such as rising sea-level, for heavily populated coastal areas.
  2. Fisheries are beginning to explore the deep. As species that live closer to the surface are depleted, commercial fisheries are seeking other species at even greater depths. But we know little about the biology of these delicious deep-sea denizens. Without much basic information, how can we manage potentially destructive fisheries, so that seafood will be abundantly available to future generations?
  3. In the vicinity of hydrothermal vents, there are very valuable mineral deposits, including silver and gold. Covering thousands of square miles of the deep-sea floor are billions of tons of so-called “manganese nodules” that are rich in cobalt, nickel, and manganese. Serious mining has yet to begin, even though the technology is here, but be assured that international consortia are pressing to get started! What effects will mining have on fragile deep-sea habitats?
  4. Some years ago, the serious suggestion was made that our estimated 70,000 tons of radioactive waste could be stored in stainless steel cylinders buried in the deep sea, in holes drilled one-half mile deep in the mud in stable areas of the ocean—nowhere near sites of volcanic activity. Is this a good idea? Recently, we learned that there is microscopic life deep in this mud. Knowing this, is the waste disposal idea still a good one? Can we afford to have possible high-radioactivity leakage in the vicinity of this deep-mud life?
  5. There are almost four thousand offshore oil wells in the Gulf of Mexico.  When will we have another gigantic oil spill like the Deepwater Horizon accident of 2010, and how much short-term and long-term damage will it do? Do we have enough baseline information now, so we can accurately judge the extent of possible future damage and recovery times? Short answer: no.

So, there are a lot of unanswered questions.  Many great scientific institutions around the world are addressing some, and the recently-completed 10-year Census of Marine Life has provided a great stimulus. We must continue to explore the deep sea, for it is no longer remote, no longer inaccessible, and it will inevitably become more important to us in the future as a vital source of food and minerals.

Editors' Note: NMNH's Dave Pawson, the author of this blog post, interviewed Penn State deep sea biologist Charles Fisher about the deep sea on July 19, 2012 from 3-4 PM EST in the museum's Baird Auditorium in Washington, DC. 

July 2012