Information about the coral reef:
coral reefs are among the most species-rich and sensitive ecosystems in the world. The underwater structures of the coral reefs consist of calcium carbonate, which has been stored by the corals for many thousands of years.
Corals are so-called sessile cnidarians, i. they can not move and are therefore firmly bound to their location. Food is primarily water-filtered plankton. But even more important for food intake is the symbiotic relationship (symbiosis) between algae and coral. Unicellular algae (Zooxanthellae) are found on the corals. While the corals provide a safe habitat for the algae, the algae deliver glucose to the coral during photosynthesis.
Almost all coral species occur only in the range of tropical latitudes, because only there prevail ideal conditions. Temperatures between 20 * C and 30 * C, clean water and plenty of sunlight (photosynthesis for the algae) are essential for the growth of corals. Even a slight deviation from the ideal conditions can lead to a quick death.
Basically, there are two different types of corals: soft corals and hard corals. The latter are responsible for the formation of coral reefs. During the growth of the corals, these constantly store lime (calcium carbonate). If a coral dies, its limestone skeleton remains and is overgrown by a young coral. Over the centuries, coral reefs grow into imposing structures.
Animals in the coral reef
The large biodiversity of the coral reefs is comparable to that of the tropical rainforest. No other ecosystems have such a high number of different species. Following a small excerpt of some animals from the coral reefs:
fishes: more than 1000 different fish species
cnidarians: Corals and jellyfish
crustaceans: Crabs and crabs
Stachelhдuter: Sea urchins and starfish
molluscs: Mussels, snails and cuttlefish
The Great Barrier Reef
The Great Barrier Reef off the coast of Australia is the largest coral reef on earth. With a size of more than 200,000kmІ over a length of more than 2000km, the reef is about as big as the UK. According to estimates, the Great Barrier Reef has already lost between 30 and 50% of its original size in the last 50 years. In addition to anthropogenic (man-made) influences, such as water pollution, fishing, Цlpest, culprits are, in particular, earth-warming. If water gets only a few degrees warmer, algae on corals begin production of poisons. The corals then repel the algae. Only the white calcareous skeleton remains, which is why this phenomenon is also known under the term coral bleaching. Although the corals are not yet dead at this point in time, they are clearly limited in their lifecycle, as they are now lacking the nutrients that algae supply them. If no new algae settle on the coral, they die after a few weeks.