| Popis: |
In the oceanic sphere, complete systems (producers, consumers and decomposers) exist almost exclusively in the epipelagic zone. It has been proposed for some time that food-chains on the deep-sea floor are sustained by the “organic snow” coming from the surface layers, where phytoplanktonic producers are living. Recent investigations (l) indicate that it is the relatively swift fall of faecal material together with molted cuticules (particularly from copepods), rather than the slow “perpetual snowfall of organic flakes” that provides most of the energy to the deep-sea benthos (with the possible exception of hydrothermal “oases” around tectonic spreading centers where chemolithotrophic microorganisms, similar to primary producers, are used as food source by suspension feeders). |
