Scientists call "Trapping Zone" a previously completely unknown ecosystem in the island kingdom of the Maldives: At 500 meters deep, the participants of the Necton Maldive Mission of Life discovered in the otherwise quite lifeless vastings of the Indian Ocean, report Alex Rogers from the University of Oxford and Co in a message. Large fish gather here to eat the immense quantities of zooplankton, which is found here every day on a Unterwasserberg.
These animals, called micronecton, are smaller fish, crabs and other organisms with a size of between 2 and 20 centimeters, which oscillate back and forth between greater water depths and the surface every day: a phenomenon that can even be detected acoustically. The micronecton rises at night and swims down again with the dawn.
At a Sato Rahaa, underwater mountain, cliffs and flat terraces of previous coral reefs prevent the animals from diving deeper than 500 meters. The topography ensures that you collect yourself as in a case, which in turn attracts predators. Tunfish swarms, sharks, parsfish, imperial bars and other species can be found in large numbers according to the observations of the divers and hunt for the micronectone. The researchers were particularly amazed at the great variety of different shark people: in addition to hammer and tiger sharks, they discovered citing and Kiemer sharks, silk and nail sharks.
However, the discovery raises some questions: why, for example, don't the animals of the micronekton migrate beyond the terraces further into the deep sea, where they would be safer? Do other underwater mountains also form similar traps? After all, these sunken mountains are in principle considered to be species-rich ecosystems in the sea; until now, it was assumed that this could be mainly due to the rise of nutrient-rich deep water, which is forced upwards by the obstacles.
The rise and descent of the necton, in turn, represents the largest animal migration on earth. The total mass of the organisms involved is estimated at at least ten billion tons. However, the phenomenon is largely unexplored.
