Life Without Sunlight: The Secret World of Black Smokers
What happens when the ocean has no sunrise? At the bottom of the sea, black smokers release dark clouds of minerals. Nearby, remarkable communities of animals can survive around vents powered by geological heat and chemical energy. Our new Fact Book documentary follows the evidence through genuine expedition footage, scientific photography and original explanatory motion graphics.
These are real underwater environments filmed by remotely operated vehicles during NOAA and Ifremer research expeditions. Modern expedition footage is never described as film from the original 1977 discovery. Science diagrams are clearly marked editorial illustrations rather than underwater recordings.
Watch the full 8-minute Fact Book documentary
Watch the full documentary on YouTube. The film runs 8 minutes and 36 seconds and features the original Brian and Emma English narration.
What makes a black smoker black?
Cold seawater travels into fractures in the ocean crust and interacts with rock heated by geological activity. The returning fluid can reach hundreds of degrees Celsius under intense pressure. When this hot, mineral-rich water meets cold seawater, some dissolved metals form fine mineral particles. Those particles create the dark plume we see around active black smokers.
Black smokers are not burning or releasing soot from a fire. Their dark color often reflects deposits including iron sulfide. Other hydrothermal vents are called white smokers because their minerals form a pale plume. The color is a clue to the chemistry, not a direct measure of whether a vent supports life.
How life begins a food chain without sunlight
At the surface of the sea, most familiar food webs rely ultimately on photosynthesis. At some hydrothermal vents, microorganisms use energy from chemical reactions, a process known as chemosynthesis. These microbes can support living communities when sunlight cannot reach the ocean floor.
Some organisms graze on microbial material. Others live with microorganisms inside or on their bodies. Giant tubeworms can depend on internal bacterial partners; certain vent shrimp and mussels have other extraordinary adaptations. The animals do not all live at one temperature or in one kind of water. Many gather along narrow environmental boundaries where conditions are suitable.
What is in the real footage?
The documentary brings together real imagery from NOAA exploration in the Marianas, the Mid-Cayman Rise and the Moytirra vent field, alongside Ifremer ROV footage. Different camera angles show active and inactive mineral structures, shrimp swarms, benthic animals and instruments used to investigate the ocean floor. Scenes from different locations are explicitly treated as different expeditions.
The scientific images and original graphics explain the movement of water underground, the formation of mineral deposits, how microbes form the foundation of a food web, and the challenges faced by ocean exploration vehicles. The visual explanation is not substituted for genuine footage where suitable real imagery is available.
What does this tell us about other ocean worlds?
Researchers are interested in icy moons that may have oceans beneath their surfaces, including Europa and Enceladus. The possibility of chemical energy in a dark ocean provides a useful comparison to Earth’s vent environments. But no life has been confirmed on either moon, and black smokers do not prove a particular origin-of-life hypothesis.
Credits and further reading
Actual underwater footage: NOAA Ocean Exploration (2011, 2016 and 2022 voyages), and Ifremer MoMARSAT 2018/ROV Victor 6000 material under Creative Commons Attribution 4.0, edited and excerpted. Illustrations used to explain science are original. NASA Galileo and Cassini mission images are credited as original mission material. Licensed original photographic sources and credits are tracked individually in the documentary source ledger.
Visit NOAA’s original Mid-Cayman shrimp footage, Marianas vent video and Ifremer’s licensed chimney footage.
Also on Fact Book: San Francisco 1906: The Fire That Changed a City.
Scientific sources: NOAA: What is a hydrothermal vent?; NOAA: Ocean floor features; NOAA: Photosynthesis and chemosynthesis. This is an independent original explanatory article, not a transcript of 1977 footage.
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