Map of the reefs on Earth
Red = Fringing reefs / Green = Barrier reefs / Orange = Atolls
1. How is each reef structure formed? A reef structure is form by what is known as “Coral.” Corals are different groups of cnidarians but only some have the ability to build reefs. In reef-building, corals/polyps produce calcium carbonate skeletons, where as billions of these tiny skeletons unite as one to form a massive reef. The most important reef builders are the scleractinian corals, also known as the "stony" or "true" corals. Most reef-building corals contain symbiotic zooxanthellae. It helps the corals make their calcium carbonate skeletons. However, as much as for the corals, it is the help of the symbiotic zooxanthellae that construct the reefs framework, where as without it-there would be no reefs.
2. Where is each reef structure found? There are three different types of reefs. They are called the fringing reef, barrier reef and atoll. The fringing reefs are located close to shore and are seperated from land by shallow water or no water at all. Barrier reefs are lacated farther from shore seperated from land by a lagoon ten meters deep. Atolls are also found far offshore. They are ring-shaped reefs that enclose a circular lagoon and are also known as coral islands.
3. What is the trophic structure of a reef? The trophic structure of a reef is the reprocess of nutrients, where as then the ocean water lacks nutrients. However, the reef is able to provide some of its own nutrients, which make it very productive. Coral reefs are amongst those who have the highest rate of nitrogen fixation. The nitrogen is fixed on the reef, where as the zooplankton and nutrients that transpire in the water are used efficiently.
4. How does the location and type of reef influence the trophic structure? It is theorized that each type of reef and/or an entire reef structure differentiates in age. The fringing reef is known to be the youngest, where as the corals colonize at the shallow area close to the land. If the sea levels rise or the land subsides, the reef structure keeps up with the changing depths by growing upward. A shallow area with no coral growth will then form behind the main reef, called a lagoon; proceeding to a barrier reef. However, if the sea level or land subsides too much, it will cause the land to disappear below the water surface and an atoll will form. Each type of reef is also divided into various zones within each reef.
5. Examples of the types of corals found on reefs. Corals are divided into two kinds but both are stationary on the ocean bottom. There are the hard corals and the soft corals. The hard corals are considered to be the brain, star, staghorn, elkhorn and pillar corals, which have rigid exoskeletons, or corallites, that protect their soft delicate bodies. The soft corals on the other hand are also known as the "gorgonians," which are the sea fans, sea whips, and sea rods, that sway with the currents and lack an exoskeleton.
6. Examples of competition, predation, and grazing. *Competition is the interaction that results when a resource is in short supply and one organism uses the resource at the expense of another. For example: Sessile coral reef organisms must compete for space, however, corals and seaweeds compete for light as well. The two effective ways in which corals compete for space are by overgrowing their neighbors and by directly attacking them. *Predation is the act of an animal, or predator, eating another organism or prey, where as a top predator is one that feeds at the top of the food chain. When predation takes place on corals, it only occurs when a variety of animals eat corals, but instead of killing the coral and eating it entirely, most coral predators eat or bite off pieces of individual polyps. This leads to the survival of the coral colony, where as it can then grow back the portion that was eaten. *A grazer is an organism that feeds primarily on plants, where as grazing is the process of transplantation, removal and caging. A damselfishe is an example of a grazer. It grazes on seaweeds inside territories that they vigorously defend, chasing away other fishes that happen to venture inside, where as their territories are so called their "farm."
SIMILARITIES
*have all types of coral reefs and also grow several types of coral
*home to many different organisms
*contain reef flats and reef slopes
DIFFERENCES*
*atolls grow on top of sunken volcanic land and grown around lagoons
*fringing reefs form along the coastline
*barrier reefs separate lagoons
