MARINE COMMUNITIES

OCEANIC ZONES


There are zones in the ocean. Neritic is that area of water that is above the continental shelf, slope and rise, beyond that is the oceanic zone. Anything above the ocean floor is called pelagic and on or in the ocean floor or bottom is called benthic. The deep layer of the ocean is called the abyss from the Greek a (without) byssos (bottom). Areas within trenches are called hadal.


Click here to read about organisms of the abyss and the mystery of blobs thought to be from the abyss.

HABITAT - where an organism lives.

NICHE - what function an organism performs in a community.


Symbiotic Relationships

Symbiosis is usually defined as two organisms providing benefit to each other, however a broader interpretation includes the long-term interaction between organisms that produce both good and bad effects.

Mutualism: both organisms benefit. Examples include the clown fish living in an anemone. The fish if protected and in return the anemone gets food from the clown fish. Another example is the dinoflagellate, zooxanthellae, that live in the cells of coral providing carbohydrates and the ability to lay down a calcium carbonate shell while the phytoplanton is provided a constant source of carbon dioxide (CO2) and protection. Still another example are the fish that feed on the skin of larger fish. The smaller fish get food while the larger fish have parasitic organisms removed.

Commensalism: one of the organisms benefits while there is neither a positive nor negative effect for the other. Examples include the pilot fish that follows the shark and gets the scraps of food left after a kill. The shark is neither helped nor harmed.

Parasitism: one organism is harmed while the other is helped. There are many parasitic relationships in the ocean. Many of them are species-species specific meaning the parasite can only live on or in a specific host. Parasites must establish a delicate balance in taking energy or food from the host or the relationship will end.

There is, of course, predator-prey relationships in the ocean. Some predators or parasites are species-dependent or species-specific. They can only have only one prey or live in or on one host. These organisms are totally dependent on the the specific prey or host for survival. If the population of the host declines, so does the population of the predator or parasite.


VARIOUS COMMUNITIES - Succession, climax - Inter-tidal, sand, cobble beach, salt marsh, estuary, coral reef, open ocean, deep sea, detritus, vent communities.


VENT COMMUNITIES - They have giant clams, (Calyptogena magnifica), the size of a man's shoe, giant tube worms, (Riftia), with chemosynthetic bacteria growing within these organisms. Other vent organism, such as shrimp, (Rimicaris exoculata), feed upon the bacteria and the remains of other organisms. These shrimp have no eyes but have a heat sensing organ that helps them avoid the hot 350