- 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 no more than 50 m
- Clear water
- Normal salinity
- Temperature not lower than 20 degrees Celsius
- 400 species of hard and soft corals: mushroom corals, brain corals and staghorn corals in all shades from red and yellow to black
- more than 4,000 species of molluscs, from chitons and gastropods to giant bivalves and octopuses, as well as 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 the breeding territory of 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 roseate terns, fulmars, grey-bellied sea eagle and osprey.
- TRIDAKNA GIANT (Tridacna gigas) - “king-shell”. Reaches a length of almost 1.5 m and a weight of 250 kg; Moreover, the actual body mass of such giants does not exceed 30 kg, the rest being 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's feeding method is a filter feeder; it also feeds on its own zooxanthellae, which it “breeds” in the sunlit tissues of the edge of the mantle. A person wandering around the reef can not only injure himself on the sharp edges of the shell of a giant tridacna submerged in the ground, but also find himself trapped with his foot caught between the valves.
Coral reefs Some of the oldest ecosystems on the planet (primitive coral reefs existed as early as 500 million years ago; many of the groups of living organisms living on reefs are found in fossils dating back 50 million years; some date entirely back to the Carboniferous period - 100 million years) Widely distributed in shallow waters of warm seas. They are one of the most productive and taxonomically diverse communities
"Riff" or "Reef" - a word of Dutch origin, refers to a transverse row of strings passed through the sail (to reduce the sail area). from the German “Ripple” - rib - sharp underwater or surface elevations of the bottom in shallow oceans, formed as a result of the destruction of the rocky bottom and shores or as the construction of colonial polyps.
All three types have a similar geomorphological profile. Reefs are formed at shallow depths 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 north and south latitude
Corals are animals of the Coelenterata type. However, a coral reef is not a heterotrophic community, but a full-fledged ecosystem with a large mass of plants. Algae have a huge (determining) role in the functioning of the reef, i.e. 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 frame. The rate of skeleton formation of reef-forming corals is 10 times faster than that of non-reef-forming corals, but simply those living on the reef. The dependence of corals on endozoic and skeleton-forming 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 water clarity. Temperature (not lower than 21 degrees) limits the physiological process of calcium carbonate formation.
Nutrients, once absorbed by reef corals, can be repeatedly circulated between the coral and the algae. Therefore, the loss of nutrients by the reef occurs very slowly. Symbiont algae significantly increase the ability of the coral to build a skeleton. The rate of calcification by the reef is approximately 10 times higher in the light (i.e., when the algae are “working”) than in the dark
The coral reef COMMUNITY includes: Six-rayed corals (Hexacorallia) - scleractinians Eight-rayed corals (Octocarallia) - gorgonians, alcyonarians Hydroid polyps - millepores Red crust algae - corallines Green calcareous algae (the most common genus on reefs is Halimeda) Green filamentous and lamellar algae (Ul va , 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. It stretches for more than 2000 km. It consists of approximately 3000 individual coral islets connected underwater, separated by narrow channels. The maximum width of the reef at Cape Manifold reaches 320 km.
Contemporary issues coral reefs RegionShare of the total reef area, % Problems Southeast Asia30Most (60-70%) under the influence of fishing, 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 Caribbean9Coastal 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, take refuge in them, or do both. Brightly colored coral fish swim alone or in schools between the corals, pinching off polyps on which they feed. 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 motionless corals. Every moving object forces them to seek refuge in the reefs. The varieties of fish are very large. For example: a wandering grouper; clown fish; moray eel mediterranean; whiskered shark; brown striped catshark, etc.
Slide 3
Is it safe where there are coral reefs?
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, thereby putting themselves in danger. Near the reefs there are very dangerous organisms, such as jellyfish, sea urchins, even sharks. Some are poisonous and release poison into a person, while others can tear a person to shreds.
Slide 4
Dolphins
Dolphins are mammals of the order Cetacea, suborder of toothed whales. Dolphins' brain size 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 1,700 grams, while that of a human weighs 1,400. A dolphin has twice as many convolutions in the cerebral cortex as a human. There have been many cases when dolphins saved people.
Slide 5
Sharks
Sharks - belong to the subclass of elasmobranchs, and have the following distinctive features: an elongated body more or less torpedo-shaped, a large heterocercal caudal fin, usually a large number of sharp teeth on each jaw. The word “shark” comes from the ancient 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 the deep-sea shallow one, only 17 centimeters long, to the whale shark - the largest fish (its length reaches 20 meters). Representatives are widely distributed in the seas and oceans, from the surface to depths of more than 2000 meters. They mainly live in sea water, but some species can also live in fresh water. Most sharks are so-called true predators, but 3 species - whale, basking and largemouth sharks - are filter feeders; they feed on plankton, squid and small fish.
Slide 6
Clown fish
Clownfish are a genus of marine fish from the Pomacentra family. Most often, the aquarium fish that appears under this name is the orange amphiprion. Clown fish are characterized by various types actinium. First, the fish lightly touches the sea anemone, allowing it to sting itself and finding out the exact composition of the mucus with which the sea anemone is covered - this mucus is needed by the sea anemone so that it does not sting itself. The clown fish then reproduces this composition and can then hide from enemies among the tentacles of the sea anemone. The clown fish takes care of the sea anemone - it ventilates the water and carries away undigested food debris. The fish never move far from “their” sea anemone. Males drive males away from her, females drive away females. Territorial behavior appears to be the reason for the contrasting coloration. Protandrous hermaphrodites: all young fish are males, but the fish changes sex throughout its life. The stimulus that triggers sex change is the death of the female. The color of the fish varies from deep 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 man-of-war jellyfish is very poisonous and has the shape of an inflated ball in the shape of a boat. Loves to be on dry land. People, not knowing that the jellyfish is dangerous and is simply basking in the sun, take it in their hands and step on it, thereby not knowing, I don’t feel that the 1 million stings that are on those curls inject poison into the body. From the beginning, a person does not feel pain; within 1 hour, bite marks appear, unbearable pain, redness of that place, this means that the poison has penetrated into 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, the description of which is given in this article, are representatives of the suborder Incirrina, benthic 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 to adapt to environment. This is explained by the presence in his skin of cells with various pigments that, under the influence of impulses from the central nervous system, can stretch or contract 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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