Although it was long thought that the midnight zone had few microbes, recent studies have found abundant microbial life, including bacteria, archaea, and viruses, all of which play a role in consuming and recycling carbon that has fallen from the surface. They are also studying microbes in this zone. Scientists are particularly interested in the various ways animals here bioluminesce and how their visual systems are adapted to detect this natural glow. More recent imaging systems use red-filtered light, because the visual systems of animals in the midnight zone don’t detect red wavelengths, rendering the artificial lights invisible to residents of this area. Because of the darkness, ROVs have bright lights that allow their cameras to see the surroundings, but introducing light into a naturally dark habitat may alter behavior and scare away creatures of interest. These vehicles are piloted remotely from ships to which they are tethered and collect water samples, organisms, video, and still photos of life in the depths.
Research expeditions use remote-operated vehicles (ROVs) to explore the depths of the midnight zone. What are ocean scientists doing to better understand the midnight zone? These include well developed visual systems, bioluminescence used both to lure prey and attract mates, and well-developed auditory systems that allow them to hear other animals moving nearby. Despite the extreme environment, organisms here must find food and mates and avoid predators, just as they do in any ecosystem, and they have special adaptations that allow them to do so. Pressure varies with depth, and in this zone it ranges from 100 to 400 atmospheres. Life that exists in this zone must be able to function in cold temperatures and withstand extreme hydrostatic pressure. In addition to the lack of light, the midnight zone is characterized by a steady temperature of around 4° Celsius (39° Fahrenheit). The resulting bathypelagic, or midnight, zone extends to about 4,000 meters (about 13,100 feet), which reaches the ocean floor in many places. By about 1,000 meters (about 3,300 feet) depth, even the faintest light has been extinguished, leaving these deep ocean waters in perpetual darkness. Red, orange, and yellow are absorbed quickly, leaving water a brilliant blue, but even these wavelengths disappear as light travels deeper. Sunlight is rapidly absorbed as it travels through water. Other Expeditions Highlighting WHOI Research.Expedition to Stellwagen Bank National Marine Sanctuary.How do polynyas help feed emperor penguins?.Why is pressure different in the ocean?.What’s the difference between climate and weather?.
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