What conditions does a coral reef need?

Question

I want to know what conditions a coral reef needs (eg. temperature, water, etc.)

Answer 1

To be left alone, this is a very fragile ecosystem and damaged by people dumping into mother earth.

Answer 2

Reef-building corals require a delicate balance of oceanographic conditions before they can occur in sufficient numbers to build reefs. The first of these is a seawater temperature of 16-35 °C, with optimum temperatures of 23-25 °C.

Another condition that must be met for the development of reef-building corals is the absence of major rivers that bring silt and fresh water down to the sea. Excessive silt reduces light, thereby inhibiting photosynthesis by the symbiotic algae which are found in coral tissues. Silt may also block the mouths of corals, preventing feeding.

Reef-building corals need light to support the symbiotic algae that they contain, so they cannot develop in deep water below the zone in which sufficient light is available to support photosynthesis. Thus they are usually restricted to water depths of less than 70m. It is for this reason that coral reefs are only found adjacent to landmasses or on the summits of undersea mountains.

Inside of the coral reef structure, there is a lot of variance as to what specific condition are preferred by what types of polyps, and this is what gives us the structure for the reefs.

For more info, check out the links below.

Answer 3

Warm salt water, nutrients, dissolved oxygen, and sunlight to photosynthesize.

Answer 4

The building blocks of coral reefs are the generations of reef-building corals, and other organisms that are composed of calcium carbonate. For example, as a coral head grows, it lays down a skeletal structure encasing each new polyp. Waves, grazing fish (such as parrotfish), sea urchins, sponges, and other forces and organisms break down the coral skeletons into fragments that settle into spaces in the reef structure. Many other organisms living in the reef community contribute their skeletal calcium carbonate in the same manner. Coralline algae [i.e zooxanthelate,filamentous algae] are important contributors to the structure of the reef in those parts of the reef subjected to the greatest forces by waves (such as the reef front facing the open ocean). These algae contribute to reef-building by depositing limestone in sheets over the surface of the reef and thereby contributing to the structural integrity of the reef.

Reef-building or hermatypic corals are only found in the photic zone (above 50 m depth), the depth to which sufficient sunlight penetrates the water for photosynthesis to occur. The coral polyps do not photosynthesize, but have a symbiotic relationship with single-celled algae called zooxanthellae; these algal cells within the tissues of the coral polyps carry out photosynthesis and produce excess organic nutrients that are then used by the coral polyps. Because of this relationship, coral reefs grow much faster in clear water, which admits more sunlight. Indeed, the relationship is responsible for coral reefs in the sense that without their symbionts, coral growth would be too slow for the corals to form impressive reef structures. Corals can get up to 90% of their nutrients from their zooxanthellae symbionts.[2]

Although corals are found growing in most areas of a healthy coral reef, the elevation of the reef flat relative to sea level (and considering tidal range) imposes significant constraints on coral growth. In general, only a small number of hardy coral species can thrive on the reef flat, and these cannot grow above a certain height because the polyps can withstand only limited exposure to the air at low tide. Of course some reef flats carry a meter or so of water over the surface, and then coral growth can be prolific. It is the upward growth of coralline algae on the outer part of the reef flat that ultimately results in an overall rise in the surface elevation of a reef, which typically slopes gently downward in towards the shore or lagoon and very steeply downward in the seaward direction. Prolific growth of these algae is a response to water motion bringing in inorganic nutrients and removing waste products. The damaging effects of exposure at low tide on the algae is ameliorated somewhat by constantly breaking waves on the reef edge. Nonetheless, it is the case that mature reefs are in equilibrium with both sea level and wave regime with respect to their elevation, and excess production of limestone moves away from the margin to expand the reef laterally and fill in low areas.

The more prolific growths of corals are to be found in water deeper than where the bottom is exposed at low tides: on the frontal reef slope (forereef), in lagoons, and along reef channels that bisect the flat. Under conditions of clear, moving seawater, corals provide the bulk of the skeletal material comprising the reef and the structural complexity that results in a high diversity of reef associated fishes and invertebrates.

Answer 5

Coral reefs are aragonite structures produced by living organisms, found in shallow, tropical marine waters with little to no nutrients in the water. High nutrient levels such as that found in runoff from agricultural areas can harm the reef by encouraging the growth of algae.[1] In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate (limestone). The accumulation of skeletal material, broken and piled up by wave action and bioeroders, produces a massive calcareous formation that supports the living corals and a great variety of other animal and plant life. Although corals are found both in temperate and tropical waters, reefs are formed only in a zone extending at most from 30°N to 30°S of the equator; the reef-forming corals do not grow at depths of over 30 m (100 ft) or where the water temperature falls below 22 °C (72 °F). To have all of your questions answered go here. / http://en.wikipedia.org/wiki/Coral_reefs /  The section on coral reefs is very long and very detailed and very good!

Answer 6

The three previous answers here do an outstanding job of answering your question.  I just wanted to tip my hat to those and say bravo for a response well done.