The most biologically diverse reefs in the world can be found in a region known as the Coral Triangle in Southeast Asia. Among the biggest and best-known are the reef systems of the Great Barrier Reef of Australia, which is around 2,300 kilometres long. Polyps grow slowly, forming different shapes and sizes depending on their species.ДЄssisted by other animals with calcium carbonate skeletons and also coralline algae, corals form complex, three-dimensional reefs.Д¬oral reefs provide an important ecosystem for marine life, offering food and shelter among their crevices and branches for animals including fishes, molluscs, sea urchins and sponges.Д¬orals are found in all of Earth's oceans, from tropical to freezing temperatures, however they only build coral reefs in warm, shallow seas in the tropics. These marine invertebrate animals have hard exoskeletons made of calcium carbonate, and are sessile, meaning permanently fixed in one place. Its high salt content increases the water's density, which is why people float in the Dead Sea more easily than in the ocean.Д¬oral reefs are made up of colonies of hundreds to thousands of tiny individual corals, called polyps. Isolated bodies of water can become extra salty, or hypersaline, through evaporation. Underwater volcanoes and hydrothermal vents on the seabed can also release salts into the ocean. The leftover minerals have built up in concentration over millions of years. Some mineral ions are used by marine animals and plants, removing them from the water. Around 3.5% of the weight of seawater comes from dissolved salts. Sodium and chloride, the main constituents of the type of salt used in cooking, make up over 90% of all the ions found in seawater. These ions are carried with runoff water and ultimately reach the ocean. When rain falls, it weathers rocks, releasing mineral salts that separate into ions. вЂњBecause it helps us set up specific management plans to protect killer whales - apex predators that are very beneficial to marine ecosystems.Salt in the sea, or ocean salinity, is mainly caused by rain washing mineral ions from the land into water.Д¬arbon dioxide in the air dissolves into rainwater, making it slightly acidic. вЂњUnderstanding the population dynamics or community structure of a species is so important, McInnes said. These killer whales may form a population of their own, or they may be part of a transient orca community, said McInnes, noting itвЂ™s difficult to study killer whales given their speed and the distances they travel.Д«ut more research is needed to study all orcas and their possible subgroups, he stressed. The whales often have a specific type of ocean barnacle on their dorsal fin and tell-tale bite marks and scarring from a small parasitic shark with razor-sharp teeth called the cookie cutter shark, which frequents deep, warm ocean waters far from shore. This group of orcas donвЂ™t seem to be associated with other transient groups and are most commonly seen up to 300 kilometres offshore. Little is known about these вЂњoceanicвЂќ killer whales, with 48 being identified so far, he said.

ThereвЂ™s even emerging evidence to suggest thereвЂ™s potentially an additional subtype of orca that inhabits the deep ocean hundreds and hundreds of kilometres offshore, McInnes said. More research is needed to sort out whether the outer coast whales are genetically different in some way from the transients farther north, and what other dividing lines beyond geography exist between the two groups. The orcas also prey on other smaller cetaceans, such as dolphins, porpoises, and minke whales, as well as seals. The pods rely on similar techniques when hunting gray whales, but they also throw the sea lions into the air as they try to tire and drown them. When gray whales are absent, the outer coast killer whales predominately prey on California sea lions that can weigh up to 900 pounds and are capable of fighting back, he said. The remains donвЂ™t go to waste, said McInnes, noting many marine organisms derive nutrients as the carcass sinks to the ocean bottom. If successful, the orcas will often feed on a calf for up to two days. The killer whales work to separate the offspring from the adults and repeatedly ram the calves to incapacitate them. The hunts, though gruesome, are very dramatic as the orcas take turns chasing the gray whales to exhaust the calves, which canвЂ™t keep up.

The orcas congregate in the ocean canyon at Monterey, particularly in April and May, to ambush the gray whales.

Playrix games with whales and seals