Place a pencil on the edge of the note nearest you and roll the paper loosely around the pencil. Press on the sticky portion to make the tube. Use tape to close off one end of the tube and hold the note in its new shape. Use scissors to make 4 evenly spaced cuts about halfway down from the top of the cylinder. One at a time, roll the cut strips back around your finger to give them a slight curl, opening the top of the cylinder. In order to thrive in aquariums, hard corals need powerful lighting and supplemental minerals.
Hard corals need about 5 watts of light per gallon of aquarium water. Since hard corals absorb calcium and other minerals to make their skeletons, you need to provide extra calcium. You can provide this with liquid supplements, calcium-rich substrates and specialized equipment like calcium reactors.
You should always position hard corals at least 6 inches from each other, since many species unfurl sweeper tentacles to sting nearby encroaching corals. Soft corals require specialized care, but less than hard corals do.
Still, both types of corals include a huge range of species, so exceptions exist in the form of difficult soft corals and easy hard corals. These skeletons are a framework of molecular crystals made in their calcifying space and excreted to form the reef structure.
Coral skeletons fuse together to create coral reefs. Corals get their energy in two different ways. This alga lives inside coral tissues and photosynthesizes energy for them both. Corals capture the remaining ten percent of energy themselves. Nematocycts function like harpoons with a barb that shoots forward from a spring to pierce their prey. Other Cnidarians, like jellyfish, are more famous for their nematocycts!
Corals reproduce in two different ways - sexually and asexually. On a healthy reef, when corals break, the broken pieces can lodge in cracks and crevices and grow into new colonies that are clones of the parent. Spawning is the synchronized release of "gametes" sperm and eggs that then mix together in the water to create new, genetically unique coral babies.
Most corals will spawn just once a year during a full moon. Coral reefs are vital ecosystems. More than million people worldwide live in the direct vicinity of coral reefs and around million people live within km of coral reefs. Coral reefs support more than a million different species. They provide marine life with nursery, spawning, and hunting grounds.
Coral reefs provide crucial coastal protection. The protection that reefs offer allow for sea grass beds and mangrove ecosystems to flourish. These ecosystems are also important habitats in their own right, but together they create positive feedback loops, ensuring the balance of life in shallow seas. Reefs underpin commercial and recreational fishing industries, as well as tourism-based economies.
Although reefs have survived the last five mass extinctions, they can no longer keep up with the speed of global environmental changes caused by human activity. Reefs are under threat as a result of both local and global stressors. Soft corals tend to be brightly coloured, with bright pinks and mauves rarely seen in hard corals. A number of animals, such as different species of fish, prawns and sea slugs, like to make their home in the branches of soft corals.
Often, these animals are camouflaged by having the identical colour pattern to the soft coral that they live on. Soft corals are always in danger of being eaten by other animals such as fish, snails and crustaceans. They fight back by producing chemicals in their tissues that make them distasteful or even poisonous to those animals.
Soft corals also have spiky spicules which function like thorns on a rose bush. Colonies of boulder coral — which can live up to one thousand years — are likely to be the longest living corals on the Great Barrier Reef. These corals grow in height at about one centimetre each year. Some branching coral species, such as staghorn corals, can grow up to 30 centimetres each year, while the porites stony corals with finger-like structures grow at an annual average of one to three millimetres.
Soft corals grow relatively quickly and may double or triple the size of their colonies over a year.
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