Oceanographers studying creatures in the ocean twilight zone are facing an optical dilemma.
Oceanographers studying creatures in the ocean twilight zone are facing an optical dilemma. They need to observe the fish in order to study them, but at ocean depths of 200 meters and beyond, there’s very little natural light trickling down from the surface. This means that submersibles developed to image and track these animals need to be equipped with lights that can illuminate the animals—and do so without scaring them off.
“If we want to get down there and see the animals in their natural habitats, we need to shine lights on them,” said Joel Llopiz, a biologist at Woods Hole Oceanographic Institution. “But we’re not sure yet how they’ll respond to different types of lights.”
Lighting up a dimly-lit world
Twilight zone fish spend most of their lives bathed in blue-green light. The light starts off as part of a rainbow of wavelengths as sunlight hits ocean’s surface, but unlike other colors which get absorbed by seawater before making it to the twilight zone, blue-green penetrates well into that region. The environment is so dimly lit, however, that fish have had to anatomically adapt with larger eyes and higher levels of visual pigment in order to see.
Read more at Woods Hole Oceanographic Institution
