Dark Waters: The Incredible Oceanic “Twilight Zone”

Most of the ocean’s looks nothing like what we typically associate it with. Deep beneath the ocean’s surface, between 200m and 1000m below, lies another watery world – dark, frigid and rarely explored. This is the area known to scientists as the Mesopelagic or “Twilight Zone’. It gets almost no sunset and hovers around 4°C. The bottom dwellers that live there are just as alien as the name of their home implies. They have bioluminescent bodies, tentacles galore, singular ways of moving and mating, and all kinds of other unique characteristics to enable them to survive in such extreme conditions. These critters are not just cool looking; they also play an important role in keeping CO2 out of our atmosphere. “The animals feed near the surface,” says ocean scientist Heidi Sosik of Woods Hole Oceanographic Institute. “They bring carbon in their food into the deep waters, where some of that carbon can stay behind and remain isolate from our atmosphere for hundreds or even thousands of years.

Watch Heidi’s TED talk on how she’s leading the effort to explore these unchartered waters and their inhabitants to preserve their ability to protect the Earth’s climate.


Watch Steinhart Aquarium, director of the California Academy of Sciences and his team explore the mesopelagic or twilight zone in the Philippines.

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