Health

Watching nature on TV can boost wellbeing, finds new study

Watching high quality nature programmes on TV can uplift people's moods, reduce negative emotions, and help alleviate the kind of boredom associated with being isolated indoors, according to a new study published today in ...

Medical research

The healing power of love handles

Question: when is a bit of surplus belly fat a good thing? Answer: when it can help to heal a broken bone.

Health

Ah, spring . . . and a snakebite alert

(HealthDay)—As temperatures rise and spring rains fall, snakes in the U.S. Southwest—including venomous snakes—leave their winter hideouts and become more active. That puts people and their pets at greater risk for ...

Ophthalmology

Your eyes are half a billion years old

Look after your eyes – they are at least half a billion years old, and a good deal older than your brain. The eyes are one of our most remarkable and precious organs, yet their origins have been shrouded in mystery until ...

Genetics

Viruses in the human gut show dynamic response to diet

The digestive system is home to a myriad of viruses, but how they are involved in health and disease is poorly understood. In a study published online today in Genome Research, researchers have investigated the dynamics of ...

Coral

Alcyonaria    Alcyonacea    Helioporacea Zoantharia    Antipatharia    Corallimorpharia    Scleractinia    Zoanthidea   See Anthozoa for details

Corals are marine organisms from the class Anthozoa and exist as small sea anemone-like polyps, typically in colonies of many identical individuals. The group includes the important reef builders that are found in tropical oceans, which secrete calcium carbonate to form a hard skeleton.

A coral "head", commonly perceived to be a single organism, is formed from myriads of individual but genetically identical polyps, each polyp only a few millimeters in diameter. Over thousands of generations, the polyps lay down a skeleton that is characteristic of their species. An individual head of coral grows by asexual reproduction of the individual polyps. Corals also breed sexually by spawning, with corals of the same species releasing gametes simultaneously over a period of one to several nights around a full moon.

Although corals can catch small fish and animals such as plankton using stinging cells on their tentacles, these animals obtain most of their nutrients from photosynthetic unicellular algae called zooxanthellae. Consequently, most corals depend on sunlight and grow in clear and shallow water, typically at depths shallower than 60 m (200 ft). These corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not have associated algae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3000 m. Examples of these can be found living on the Darwin Mounds located north-west of Cape Wrath, Scotland. Corals have also been found off the coast of Washington State and the Aleutian Islands in Alaska.

Corals coordinate behaviour by communicating with each other.

This text uses material from Wikipedia, licensed under CC BY-SA