Algae range in size from simple unicellular plants, to multicellular branching forms.
The two organisms benefit each other in many ways. For example, the coral gives off ammonia as waste, while the zooxanthellae eat the ammonia for nourishment
Made up of masses of very fine thread-like filaments, that spread out in thin layers over the reef rock surface.
One type of calcareous algae known as Halimeda produces about fifty percent of the sand found on some of our beaches in the Caribbean.
PLANTS: Algae Sea grasses They are primary producers and provide the basic food supply for the entire reef ecosystem.
ALGAE: unicellular multicellular Two main types ofAlgae range in size multicellular algae found on reefs are coralline algae and calcareous
Unicellular algae: symbiotic relationships Most corals need sunlight because they are colonized by colorful, photosynthesizing algae called zooxanthellae. Zooxanthellae
Coralline algaePorolithon Lithothamnio n Produce a “skeleton” of calcium carbonate. Contribute to reef growth. Encrusting coralline red algae grow in rock hard sheets over the surface of the reef. These rock hard sheets is tough enough to withstand waves and help keep it from washing away.
Calcareous algae do not encrust like coralline algae, but grow erect. They too produce calcium carbonate (limestone). The limestone in turn produces the sand that is found on theHalimeda beaches when thesesp. degenerate.
Seagrass Seagrassbeds are often found in areas where coral reefs grow. Unlike algae, seagrassesare true flowering plants.manatee shoalgrass grass Turtle grass
Seagrasses serve as a habitat and shelter for reef animals such as the young or juveniles of conch and lobsters. These plants also provide food for many herbivorous reef fish. The leaves of seagrass are also a habitat for very tiny organisms. Seagrasses have extensive interwoven underground creeping stems with roots attached. These stems are called rhizomes.
Animals: Coral reefs house at least 25% of life in the ocean. Animals use these as a shelter and these also are a prime source of food for them.
Body shape: In the complex coral reef environment however, a premium is placed upon maneuverability rather than sheer speed.
Body shape: Thus, many reef dwelling fishes have evolved a body plan that maximizes their ability to make rapid turns and stop quickly, highly useful traits for an animal attempting to avoid predators in physically complex habitats.
Adaptive Coloration: The patterns have different functions. Some unmistakable contrasting patterns are used to warn predators that the fish has venomous spines or poisonous flesh.The lionfish, a venomous coral reeffish, displays vivid warningcoloration.
Adaptive Coloration:gets its namefrom a largedark spot on therear portion ofeach side of thebody. This spotis surroundedby a brilliantwhite ring,resembling aneyespot. Four-eyed Butterflyfish
Adaptive Coloration: Sometimes they camouflage the fish when the fish rests in places with the right background. Gobies Tassledscorpionfish
Adaptive Coloration: clownfish Coloration may also be used for species recognition, to facilitate mating success.
Feeding strategies With the unusual variety of prey items available, it is not surprising that coral reef fish adaptations include highly specialized jaws, mouths and teeth suited to particular kinds of food sources commonly found in coral reef habitats. Eat algae growing on reef surfaces, utilizing mouths like beaks well adapted to scrape off their food. Parrotfish
Feeding strategies are generalized feeders with more standard jaw and mouth structures that allow them to forage on a wide range of animal prey types, including small Snappers fishes and invertebrates.
Anemones are common coral reef animals, they have a defense mechanism called nematocysts. Some coral reef dwelling anemones form close symbiotic relationships with other animals, most notably certain fishes. Clownfish have adapted to shelter among anemone tentacles. They do so by first performing a ritualistic "dance" with a potential host anemone, lightly brushing up against the tentacles until a relationship is established.
Coral Bleaching What causes this? There are a number of stresses or environmental changes that may cause bleaching including disease, excess shade, increased levels of ultraviolet radiation, sedimentation, pollution, salinity changes, and increased temperatures.
El Niño: A change in weather patterns and surface currents, brings unusually warm water to many parts of the ocean. Widespread coral bleaching and mortality occurs.
Sediments Fine sediment like silt is very harmful to corals. Even a thin layer of sediment on the colony surface smothers the coral To remove the sediment, corals use mucus opposite opposite in the way they use it to feed. Corals don’t do well in places where there is a lot of sediment, unless there is enough wave action to wash the sediment away.
Sediments Human activities that increase the sediment in coral reefs: Mining Logging Construction Dredging This can all lead to erosion. Also, mangrove trees and seagrasses, which normally act as filters for sediment, are also being rapidly destroyed. This has led to an increase in the amount of sediment reaching coral reefs.
Pollution Corals are so sensitive to pollution of many kinds. Even low concentrations of chemicals like pesticides and industrial wastes can harm them. High concentrations of nutrients may harm the reef growth. Humans release tremendous amount of nutrients in sewage and fertilizers that are washed from farmland and carried to the sea.
Pollution More important, increased nutrients can alter the ecological balance of the community. eutrophication Coral reefs usually grow in water that is very low in nutrients.In such nutrient-poor water, seaweeds do not grow very rapidly andare kept under control by grazers.This allows corals to compete successfully for space and light.When nutrients are added, sea weeds may grow much faster andshade and choke out the slow-growing corals.
Fishing Methods Aggressive fishing methods have hurt coral reefs as well, especially in south and southeast Asia. There, fishermen dynamite reefs and inject cyanide into the water. Both these methods stun the fish, making them easier to catch. Some estimates indicate that 90 percent of the coral reefs in the Philippines have been harmed so much that they probably cant recover.
Overfishing: This is a problem in many parts of the world. Many people know the problems cod and salmon fishermen have faced with a smaller supply of fish. However, overfishing of certain species near coral reefs can easily affect the reefs ecological balance and biodiversity.
Heres one example. Grouper is a very popular fish to eat. However, their removal in some cases has led to an increase in damselfish, which groupers feed upon. Damselfish, in turn, create pockets in coral. Thats where the algae the damselfish feed upon grow. In time, these algae can take over a reef, essentially smothering it. Overfishing of herbivorous (plant-eating) fish can also lead to high levels of algal growth. Damselfish add to the destruction of coral reef as they create holes in the coral to eat. Algae then grows in those holes and eventually smother the coral.