- The Great Barrier Reef is the world's largest complex of coral reefs and islands.
- The Great Barrier Reef stretches along the east coast of Australia for more than 2,000 km.
- His total area- 348,698 sq. km, more than the area of Great Britain.
- Depths not more than 50 m
- Clear water
- normal salinity
- Temperature not lower than 20 degrees Celsius
- 400 types of hard and soft corals: mushroom corals, brain corals and antlers in all shades from red and yellow to black
- over 4,000 species of mollusks, from chitons and gastropods to giant bivalves and octopuses, plus countless sponges, sea anemones, worms, crustaceans and echinoderms
- more than 1,500 species of fish live
- Several types of whales: minke whale, killer whale and humpback whale. These waters are breeding grounds for the humpback whale.
- It is home to six of the world's seven species of sea turtles.
- Mysterious dugong
- More than 240 species nest on the coral islands: petrels, phaetons, frigatebirds, six species of terns, including the pink tern, fulmar, 6-bellied sea eagle and osprey.
- TRIDACNA GIANT (Tridacna gigas) - "king-shell". Reaches a length of almost 1.5 m and a mass of 250 kg; moreover, the mass of the actual body of such giants does not exceed 30 kg, the rest falls on the shell. Age, according to various estimates, is 100, 200 and even 300 years. The Great Barrier Reef off the coast of Eastern Australia is the real kingdom of tridacnids.
- Tridacna is a filter feeder, it also feeds on its own zooxanthellae, which it “breeds” in the tissues of the mantle edge illuminated by the sun. A person wandering on a reef can not only injure himself on the sharp edges of the shell of a giant tridacna immersed in the ground, but also be trapped, hitting his foot between the valves.
Coral reefs One of the oldest ecosystems on the planet (primitive coral reefs already existed 500 million years ago; many of the groups of organisms now living on reefs are found in fossils 50 million years old; some are entirely from the Carboniferous period - 100 million years) Widely distributed in shallow waters of warm seas. They are among the most productive and taxonomically diverse communities.
"Riff" or "Reef" - a word of Dutch origin, denotes a transverse row of ties passed through the sail (to reduce the area of \u200b\u200bthe sail). from the German "Ripple" - rib - sharp underwater or surface elevations of the bottom in the shallow waters of the oceans, formed as a result of the destruction of the rocky bottom and coasts or being the construction of colonial polyps.
All three types have a similar geomorphological profile Reefs are formed at a shallow depth In clear, flowing water On an initially rocky substrate At a water temperature of at least +21 C In general, reefs are distributed between degrees of northern and southern latitude
Corals are animals of the Coelenterata type. However, the coral reef is not a heterotrophic community, but a complete ecosystem with a large mass of plants. Algae are of great (defining importance) in the functioning of the reef; a reef is a coral-algae system
Zooxanthellae and skeletal algae quickly and continuously remove carbon dioxide from coral tissues and contribute to the formation of insoluble calcium carbonate (CaCO 3) - the main material of the reef framework. The rate of formation of the skeleton of reef-building corals is 10 times greater than that of non-reef-building corals, but simply living on a reef. The dependence of corals on endozoan and skeletal algae determines their requirements for the amount of incoming light. Reef growth is limited to a maximum depth of meters (average depth is 40 meters) depending on the transparency of the water. Temperature (not lower than 21 degrees) limits the physiological process of calcium carbonate formation.
Nutrients once taken up by reef corals can be recirculated (many times) between coral and algae. Therefore, loss of nutrients by the reef is very slow. Symbiont algae significantly increase the ability of the coral to build a skeleton. The rate of calcification by the reef is about 10 times higher in the light (i.e. when the algae "work") than in the dark.
The COMMUNITY of the coral reef includes: Six-pointed corals (Hexacorallia) - scleractinia Eight-pointed corals (Octocarallia) - gorgonians, alcyonaria Hydroid polyps - millepora Red crustaceous algae - corallines Green calcareous algae (the most common genus Halimeda on reefs) Green filamentous and lamellar algae (Ulva , Cladophora) Diatoms Blue-green algae Brown algae (Sargassum, Dyctiota, Cystoseira) Sea grasses (genus Halophila, Thalassia)
The Great Australian Barrier Reef Was discovered back in 1768 by James Cook Stretches for more than 2,000 km Consists of approximately 3,000 separate coral islands connected under water, separated by narrow channels The maximum width of the reef at Cape Manifold reaches 320 km.
Contemporary Issues of coral reefs RegionShare of the total area of reefs, % Problems Southeast Asia30Most (60-70%) under the influence of fishing, the entry of pollutants Pacific Ocean25Up to 30% under the influence of fishing, introduction of predatory species. pollution Indian Ocean24About 20% influenced by pollution and fishing Caribbean9Riparian pollution, tourism, weakening of hydrodynamics Atlantic Ocean (except Caribbean)6Coastal infrastructure development, tourism, pollution Central Asia6Shipping, oil spills, tourism
slide 2
Coral reefs and their inhabitants
Who lives in a coral reef? Coral reefs are a hospitable home for many fish and marine animals. Most of the creatures that inhabit the reef feed on corals or find shelter in their thickets, or both. Bright coral fish singly or in schools swim between the corals, plucking off the polyps they feed on. Their shape and coloring are very diverse. There are red, blue, yellow, green and black fish. They are very shy as they constantly live among immobile corals. Every moving object makes them seek refuge in the reefs. The fish species are very large. For example: a wandering grouper; clown fish; moray eel mediterranean; mustachioed shark; brown-striped catshark, etc.
slide 3
Is it safe where the coral reefs are?
Where coral reefs are located is not always safe. People love to watch the fish and the seabed, but not everyone follows the rules. Some people think that scuba diving is very expensive, thus they end up in danger. There are very dangerous organisms near the reefs, for example, jellyfish, sea urchins, even sharks. Some are poisonous and let poison into a person, while others can tear a person to shreds.
slide 4
Dolphins
Dolphins are mammals of the cetacean order, suborder of toothed whales. The brain size of dolphins in relation to their body size is much larger than that of chimpanzees, and their behavior indicates a high degree of mental development. The brain of an adult dolphin weighs about 1700 grams, while that of a human weighs 1400. A dolphin has twice as many convolutions in the cerebral cortex as a human. More than once there were cases when dolphins saved people.
slide 5
sharks
Sharks - belonging to the subclass of elasmogills, and having the following distinctive features: an elongated body of a more or less torpedo shape, a large heterocercal caudal fin, usually a large number of sharp teeth on each jaw. The word "shark" comes from the Old Norse "hakall". The most ancient representatives existed already about 420-450 million years ago. To date, more than 450 species of sharks are known: from deep-sea shallow, only 17 centimeters long, to whale shark) - the largest fish (its length reaches 20 meters). Representatives are widespread in the seas and oceans, from the surface to a depth of more than 2000 meters. They mostly live in sea water, but some species can also live in fresh water. Most sharks are so-called real predators, but 3 species - whale, giant and large-mouthed sharks - filter feeders, they feed on plankton, squid and small fish.
slide 6
Clown fish
Clownfish are a genus of marine fish from the pomacenter family. Most often under this name there is an aquarium fish - an orange amphiprion. Clownfish are characterized by various types actinium. At first, the fish lightly touches the anemone, allowing it to sting itself and finding out the exact composition of the mucus that the anemone is covered with - this mucus is needed by the anemone so that it does not sting itself. Then the clown fish reproduces this composition and after that it can hide from enemies among the anemone tentacles. The clownfish takes care of the sea anemones by ventilating the water and carrying away undigested food. Fish never move far from "their" sea anemones. Males drive away males from her, females - females. Territorial behavior, apparently, was the reason for the contrasting coloration. Protandric hermaphrodites: all juveniles are males, however, during the life of the fish changes sex. The stimulus that triggers the sex change is the death of the female. The color of the fish varies from rich purple to fiery orange, red and yellow.
Slide 7
Jellyfish
Jellyfish are very beautiful, but at the same time the most dangerous. Every jellyfish has a venomous stinger. In some jellyfish, the hairs themselves can grow up to 60 m. For example, the Portuguese boat jellyfish is very poisonous, has the shape of an inflated ball in the form of a boat. Likes to be on dry land. People, not knowing that the jellyfish is dangerous and just basking in the sun, take it in their hands, thereby not knowing, I don’t feel that 1 million stings that are on those curls inject poison into the body. From the beginning, a person does not feel pain for 1 hour, bite marks appear, unbearable pain, redness of that place, which means that the poison has penetrated you. Be careful! Call an ambulance and most importantly beware of jellyfish!!!
Slide 8
Octopuses
Octopuses, or octopuses, are the most famous representatives of cephalopods. Typical octopuses, which are described in this article, are representatives of the Incirrina suborder, demersal animals. But some representatives of this suborder and all species of the second suborder, Cirrina, are pelagic animals that live in the water column, and many of them are found only at great depths. The common octopus has the ability to change color, adapting to environment. This is due to the presence in his skin of cells with various pigments, capable of stretching or contracting under the influence of impulses from the central nervous system, depending on the perception of the senses. The usual color is brown. If the octopus is scared, it turns white, if angry, it turns red. Some are poisonous.
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