Strange AnimalsDive Depth
The ocean averages about 3,700 metres deep, and every ten metres adds another atmosphere of pressure. Drag down through the water column to see the light disappear, the pressure climb, and which animals can still follow you.
Collapse the lungs, store the oxygen
Whales, seals and penguins don't fight the pressure: their lungs collapse on the way down, pushing air out of the places where nitrogen would dissolve into the blood. Oxygen is carried instead in muscle, bound to so much myoglobin that sperm whale meat is almost black. A Cuvier's beaked whale holds its breath for over two hours.
Why no fish lives below about 8,200 m
Fish protect their proteins from pressure with a molecule called TMAO, and its concentration rises with depth. Around 8,200 metres the fish's body fluids would become so concentrated that seawater would flood in. The deepest fish ever filmed, a snailfish at 8,336 m, sits right on that line.
Life at 10,900 metres
At the floor of the Challenger Deep the pressure is over 1,000 atmospheres. Amphipods, shrimp-like scavengers a few centimetres long, live there in numbers, digesting sunken wood and plant matter with enzymes no shallow-water relative has.
- Schorr, G. S., et al. (2014). First long-term behavioral records from Cuvier's beaked whales reveal record-breaking dives. PLOS ONE, 9(3), e92633.
- Tyminski, J. P., et al. (2015). Vertical movements and patterns in diving behavior of whale sharks as revealed by pop-up satellite tags in the eastern Gulf of Mexico. PLOS ONE, 10(11), e0142156.
- Doyle, T. K., et al. (2008). Leatherback turtles satellite-tagged in European waters. Endangered Species Research, 4, 23-31.
- Wienecke, B., Robertson, G., Kirkwood, R., & Lawton, K. (2007). Extreme dives by free-ranging emperor penguins. Polar Biology, 30, 133-142.
- Yancey, P. H., et al. (2014). Marine fish may be biochemically constrained from inhabiting the deepest ocean depths. PNAS, 111(12), 4461-4465.
- Kobayashi, H., et al. (2012). The hadal amphipod Hirondellea gigas possessing a unique cellulase for digesting wooden debris buried in the deepest seafloor. PLOS ONE, 7(8), e42727.
Keep exploring
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