Sunlight: Corals need to grow in shallow water where sunlight can reach them. Corals depend on the zooxanthellae (algae) that grow inside of them for oxygen and other things, and since these algae needs sunlight to survive, corals also need sunlight to survive.

Many grow optimally in water temperatures between 73° and 84° Fahrenheit (23°–29°Celsius), but some can tolerate temperatures as high as 104° Fahrenheit (40° Celsius) for short periods. Most reef-building corals also require very saline (salty) water ranging from 32 to 42 parts per thousand.

Corals bleach when ocean waters warm just 1-2°C (2-4°F) above normal summertime temperatures. Because those algae supply the coral with most of its food, prolonged bleaching and associated disease often kills corals.

In fact, over half of all known coral species are found in deep, dark waters where temperatures range from 4-12°C (39-54°F). For this reason, we call these corals the “cold-water” or “deepwater” corals. They are found all over the world.

With loads of sunshine, warm seas, refreshing sea breezes and a warm climate all year round, Tropical North Queensland weather is hard to beat….Great Barrier Reef Weather Chart.

EPA protects coral reefs by implementing Clean Water Act programs that protect water quality in watersheds and coastal zones of coral reef areas. EPA also supports efforts to monitor and assess the condition of U.S. coral reefs, and conducts research into the causes of coral reef deterioration.

Clean water is vital for both communities and coral reefs. For example, excess nitrogen from wastewater or fertilizer enables the overgrowth of algae which can kill corals by smothering them, blocking their access to sunlight and promoting the growth of harmful bacteria.

The world’s coral reefs are dying—here’s how scientists plan to save them. The coral reefs around Fiji cover 3,800 square miles and face threats from climate change, overfishing, and pollution.

Water Filtration Most corals and sponges are filter feeders, which means that they consume particulate matter suspended in the water column. This contributes to enhanced quality and clarity of our near shore waters.

Coral reefs are considered one of the most threatened ecosystems on the planet and are dying at alarming rates around the world. Scientists attribute coral bleaching and ultimately massive coral death to a number of environmental stressors, in particular, warming water temperatures due to climate change.

Coral reefs face many threats from local sources, including: Physical damage or destruction from coastal development, dredging, quarrying, destructive fishing practices and gear, boat anchors and groundings, and recreational misuse (touching or removing corals).

Although coral reefs have been around for over 500 million years, the Great Barrier Reef is relatively young at 500,000 years, and this most modern form is only 8,000 years old, having developed after the last ice age.

The Great Barrier Reef is the world’s largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres (1,400 mi) over an area of approximately 344,400 square kilometres (133,000 sq mi). The reef is located in the Coral Sea, off the coast of Queensland, Australia.