The Deep Sea is a territory widely unknown yet famous for its fancy faunal community, a crowd of mesmerizingly bizarre, often alien-looking creatures that seem to compete in singularity and strangeness. There is the firefly squid that produces dumbfounding lightshows, its mysterious cousin, the Colossal Squid that can grow up to an estimated size of 14 meters and is the largest invertebrate on earth, there are anglerfish and lanternfish, flappy-eared dumbo-octopuses, and all sorts of cnydarians floating through the dark in wait for prey. They occasionally light up and display that spectacular phenomenon called bioluminescence, the only source of light in the deep sea and a means of camouflage, prey and mate
attraction in most of its illustrious inhabitants. One of them is Praya Dubia, the Swimming Bell. It is not exactly one but a plurality of organisms, a so-called siphonophore, that can grow up to a length of 40 to 50 meters, maybe the longest organism (or, for that matter, chain of organisms) on earth. Most siphonophores are bioluminescent and display a wide range of iridescence and fluorescence in their phenotype. The infamous Portuguese-Men-o'-War, often falsely labeled a jellyfish, is one of them, though not really representative of the group since most siphonophores are found below surface, in the open ocean. Many of the only recently discovered deep-sea species are siphonomores, and it has been suggested that they rank among the most effective carnivores in the oceans. Praya Dubia, for example, is made up of many tiny individual units called zooids that are connected along a central stem and all fulfill different purposes: there are feeding and reproductive units, such responsible for propulsion, and others that take care of attack and defense. The organism has first been described in the 19th century, but since Praya specimen are extremely frangible and more than difficult to collect (they have a hydrostatic skeleton designed for an average pressure of 0.47 tons per cubic centimeter and burst when they are surfaced) more profound scientific analysis had to wait until the advent of high tech submersibles in the 80's that could indeed shed a completely new light on the communities that inhabit the deeper layers of the oceans, the Mesoplagic and Bathypepelagic zones of the Deep Sea. Praya dubia hunts krill, jellies, and even small fishes. Once adequate prey is detected, a plurality of individual attack units will deploy thousands of stinging tentacles in order to capture and then stuff the unfortunate other into the nearest mouth. The feed will eventually be distributed via the central stem. Another remarkable syphonophore is physophora hydrostatica. Also known as "the hula-skirt siphonophore", this colony rather looks like a stack of transparent jelly bells put on cold fire. It in fact consists of a gas-filled float and numerous wildly colored tentacles that might cause painful stings. At 8-12 cm length, this syphonophore is comparably small and feeds mainly on zooplankton.