Oceans cover approximately three-quarters of our planet. Oceanic organisms are placed into one of two divisions, the pelagic (open waters) and benthic (ocean floor) divisions.
The pelagic division includes the neritic province and the oceanic province. The neritic province contains a greater concentration of organisms than the oceanic province because sunlight penetrates these waters and it contains the most nutrients. Phytoplankton is food not only for zooplankton but also for small fishes. These small fishes in turn are food for commercial fishes–herring, cod, and flounder.
The oceanic province is further divided into zones called the epipelagic, mesopelagic, and bathypelagic zones. The epipelagic zone does not have a high concentration of phytoplankton because of the lack of nutrients. These photosynthesizers, however, still
The benthic division includes organisms that live on the continental shelf, the continental slope, and the abyssal plain. The organisms of the benthic division are dependent upon debris that floats down from above.
The flat abyssal plain is interrupted by enormous underwater mountain chains called oceanic ridges. Along the axes of the ridges, crustal plates spread apart and molten magma rises to fill the gap. At specific sites of these tectonic spreading zones, seawater percolates through cracks and is heated to about 350° C, causing sulfate to react with water and form hydrogen sulfide. The water found to support communities that contain huge tubeworms and clams. Chemosynthetic bacteria that obtain energy from oxidizing hydrogen sulfide live within these organisms.
The bathypelagic zone is in complete darkness except for an occ
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