Coral is a living organism formed of hundreds of thousands of tiny water animals called ‘polyps’. Each polyp has one opening at a particular side of its body. It uses this to deliver deathly toxins to its microscopic food sources, then digests them out from the same opening. Coral reefs are formed when free-swimming coral larvae attach themselves to a rock or any other hard surface.
Coral reefs are one of the most diverse and valuable ecosystems on earth, supporting more species per mass than any other environment in the marine. They have also assisted in the development of many pharmaceutical drugs to prevent or cure human diseases.
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Despite their importance, they face many threats. Corals are one of the slowest growing ecosystems and often reefs can be overcome by algae before they have fully formed. In many cases, coral can recover from a single incident that causes physiological stress, nonetheless, repeated damage (often imposed by humans) could cause the reef to perish.
In this article, we are going to go into more detail about the growth of coral and how long it takes for a reef to form.
How long does coral take to grow?
The speed at which coral grows will depend on the environment and species, however, as previously stated, corals are one of the slowest growing organisms. Given their timely growth, they are also one of the oldest habitats in the oceans today with traces of the first coral appearing over 500 million years ago.
Per year coral can be expected to grow anywhere from half an inch up to 8 inches. The ‘massive coral’ species is the slowest growing, falling at the lower end of the scale. Species such as ‘branching’ and ‘staghorn’ can grow much faster. For a coral reef to fully form and produce a group of larvae, it could take anywhere between 100,000 to 30,000,000 years.
Factors of the growth process
It’s relatively unexplained why this cycle takes so long, however, it is largely due to the great amount of energy it takes for a coral to grow its skeleton. A coral’s skeleton is vital to survival by protecting the coral animals from predictors and also providing a substrate to which other free-swimming corals can attach themselves in order to expand.
Once the coral polyps have attached themselves to a hard surface, they will secrete their skeleton from the underside of its skin. The skeleton is conveniently made up of the calcium and carbonate provided amongst the water.
A corals’ growth success is also largely determined by their surroundings. Most coral species thrive in hotter water temperatures, generally between 70 degrees Fahrenheit and 84 degrees. They also prefer sunlight and benefit from environments closer to the water’s surface where they have access to the filters of sunlight on their symbiotic algae.
Although these corals can be found at depths as much as 250 feet, they will grow poorly at anything deeper than this. The remaining key factor in the success of coral growth is saltwater. This is essential for the coral to survive, and if located at the mouth of a river or places with excessive runoff they suffer an increased chance of perishing.
This being said, despite coral typically being related to hot climates, there is the deep-water coral, which can extend to much deeper, darker parts of the ocean than tropical coral.
In fact, this coral species can be found on surfaces near the abyss at depths beyond 5500 feet and in temperatures on average of 40 degrees Fahrenheit. This works because unlike tropical corals, deep-water corals do not need zooxanthellae to survive.
How to speed up coral growth?
As we have discussed, two of the most important factors to the coral animal’s survival are temperature and salinity (the saltiness of a body of water). Providing the aquarium with the ideal suggested amounts of these will aid in the healthy growth of coral. Nonetheless, this will not necessarily increase the growth time. Below are some ways that you can speed up the process;
Higher pH level and increased light exposure
Whilst the majority of fish can adjust to different levels of pH, corals need a higher level to grow at a normal rate. A common technique for this is using ‘light enhancement calcification’, which is a phenomenon in building aquarium reef corals.
By having increased exposure to light, or an increased light brightness, the corals themselves will create a higher level of pH condition between the skeleton and the tissues, deposited by the calcium and carbonate in the water.
Whilst the ocean used to have an average pH level of 8.2, it has decreased in recent years with the increase in carbon dioxide in the atmosphere, slowing down coral growth.
The ideal pH level in an aquarium can safely fluctuate between 7.8 and 8.4, however, for best results, centralized delivery systems can be used to keep the daytime peak at around 8.5, giving the coral a happy, fast-growing rate.
This method could speed up coral growth by 50 times the rate that it grows in nature. The natural growth process for corals is to expand in colonies, however, experts have found that when they break apart each individual polyp and place them back into the water in spaced out areas it dramatically speeds up the growing process.
Once corals are in their single form, they will grow much faster and form together again to make larger coral reefs that reach over extended areas. Repeating this process of separating and fusing over and over will keep the coral in all-out-growth mode.
Best foods to speed up coral growth
The most common time for corals to feed is during the evening in decreased light exposures. Feeding at this time will offer the best results. It is also recommended to turn down the circulation pump during this period so that the food doesn’t get washed away from the coral.
Start by feeding the coral once or twice a week and see how it responds. From here, you can increase or decrease as required.
As well as feeding coral natural substances such as small diced portions of fish or other sea mammals, there is a selection of pre-prepared coral food products which aid in the healthy growth of corals. Some of the highest-rated products are listed below;
- Red Sea Reef Energy (liquid)
- Reef-Roids (powder)
- Coral Frenzy (pellets)
- Benereef (powder)
- Fauna Marin (pellets)
- Kent Marine Phytoplex (liquid)
These products, or similar versions, can be found in various availabilities depending on your residing country.
It is also possible to feed corals purely natural sources, nonetheless, it will require much more maintenance. If you prefer this option, feeding coral animals fish species such as plankton or shrimp will aid in healthy growth.
Corals are a highly important, beneficial part of the ecosystem. Nonetheless, their slow growth rate leaves them vulnerable to risks from outside sources, to which if they are repeatedly exposed could cause them to perish.
Until recently, it did not seem possible for coral to grow inside an aquarium, however with new technology and developed knowledge, coral is now thriving in unnatural bodies of water. Using methods such as high pH, and offering substantial food sources will encourage the healthy growth of coral.
- How Do Coral Reefs Form? by National Oceanic and Atmospheric Administration https://oceanservice.noaa.gov/education/tutorial_corals/coral04_reefs.html
- Feeding a Coral Reef Aquarium, Marine Fish and Reef Annual 2000 published by Fancy Publications http://www.personal.psu.edu/sbj4/aquarium/reeffood/feeding.htm