Bioluminescence
Bioluminescence is found in the sea at all levels.: planktonic, pelagic and benthic organisms. Some planktonic groups, such as dinoflagellates and ctenophores (comb jellies) use it in most species. Most deep-sea marine life use bioluminescence in one form or another. Usually, marine light-emission belongs in the blue and green light spectrum, the wavelengths that can transmit through seawater most easily.