7/30/18—The twilight zone, or mesopelagic, is a region of the ocean between 200 and 1,000 meters (660 to 3,300 feet) depth where very little sunlight reaches, but that is teeming with life. WHOI biologist Heidi Sosik is helping lead WHOI’s efforts to expand our knowledge of the twilight zone and its importance to life on Earth.

» More about Heidi Sosik