Researchers from the California Academy of Sciences have some very exciting news: they have just unveiled the first “twilight zone” exhibit at the Academy’s Steinhart Aquarium. The twilight zone is the name given to the dark, mysterious area of the ocean 200-500 feet below the surface, where very little light penetrates but reefs, fish, and invertebrates flourish.Diving to such depths takes a huge amount of training and preparation, and a new piece of technology called a rebreather. While regular scuba divers breath a mixture of nitrogen and oxygen, divers descending to 400 feet must breath helium. As Luiz Rocha, fish curator at the Academy explains, “If we breathe nitrogen, which is what most of the air we breathe is composed of, it makes us drunk, and we won’t want to be drunk at 400 feet.” And the rebreather? “There’s a canister on our back that filters the carbon dioxide out, and then we keep breathing the same helium over and over again and add oxygen as we need it.”To safely collect specimens and bring them to the surface, researchers invented a submersible portable decompression chamber; they place the creatures inside, and seal it up. The chamber maintains a stable pressure for its inhabitants until they return to the aquarium, where scientists are able to slowly acclimate their finds to surface conditions.This is an exciting development in our quest to understand the ocean and all its fascinating ecosystems.