These traps are constructed from polyvinyl chloride (PVC) and are designed with funnels at the entrances. Instead, we will rely on special benthic traps designed by engineers at Harbor Branch Oceanographic Institute (HBOI) to collect specimens. Thus, standard commercial traps and trawls cannot be used to collect these animals. Because their eyes are so sensitive to light, exposure to surface lights, even lights at night, permanently blinds them. Until recently, we have been unable to study the visual systems of these deep-sea species.
These specially designed traps isolate the shrimps and crabs inside from light and elevated water temperatures as they are brought to the surface. We hope that Eye-in-the-Sea will reveal behaviors and possibly even animals that no one has ever seen before. Franks recordings from the eyes of deep-sea animals, we believe this light should be invisible to the animals. After the camera comes on and records some of the bioluminescence, a red light turns on, revealing the animal. The camera is activated by a light sensor that detects bioluminescent flashes. The system uses an especially sensitive camera that can record bioluminescence. This deep-sea observation tool can be left on the sea bottom to record animal behaviors after the noisy, brightly-lit submersible leaves the vicinity. If we discover any new sources of bioluminescence, we will collect them for shipboard studies, such as measurement of the color of the light, known as the emission spectra.Īdditionally, we will be using a new camera system developed for ocean exploration called Eye-in-the-Sea. We also will be using an ultraviolet light to detect fluorescence, which can be, but is not always, an indicator of bioluminescence. To explore for new sources of bioluminescence in the benthic environment, we will use an underwater intensified silicon intensified target (ISIT) video camera mounted on the deep-sea submersible Johnson-Sea-Link (JSL). But little is known about bioluminescence on the deep-sea floor, and we know virtually nothing about the visual systems of these deep-sea inhabitants.Ī common source of bioluminescence in the pelagic zone include fish, squid, shrimp and jellyfish. Scientists hypothesize that the huge eyes of deep-sea benthic creatures are adapted for viewing bioluminescence. Common bioluminescent animals in the pelagic zone include fish, squid, shrimp and jellyfish. In fact, an estimated 90 percent of the animals that live below 500 m in the oceans pelagic zone are bioluminescent. However, bioluminescence is much more common in the ocean than on land. One familiar source of bioluminescence is the common firefly. The answer likely lies in the phenomenon known as bioluminescencelight generated by plants or animals. Why then, do benthic species have large eyes at depths where pelagic species have small eyes? The issue is confounded further by the fact that the eyes of pelagic animalscreatures that live in the water columndecrease in size after a certain depth, as sunlight penetration dims.
Many deep-sea benthic animals have very large eyes, but the sensitivity level of these eyes, as well as what they are used for, has remained a mystery.
Senior Scientist, Harbor Branch Oceanographic Institution Click image for larger view.īiological Oceanographer, Harbor Branch Oceanographic Institution Note the difference in the eye size (white arrows) of the pelagic species Systellaspis (above) that lives between 500-700 m depth, and Glyphocrangon (below) that lives between 700-1500 m depth.
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