Thank you for signing up to keep in touch with the Coral Conservation Project. Pictured above, you will find your coral frame as it was few days after construction. Your personal page will allow you to see more regular updates and amazing facts about the corals and animals living on your frame. By now having all the updates on one page, seeing the progress of your frame will be much easier and convenient. If you want to satisfy your curiosity even more, you can take a look at our Marine Blog Life and videos from the Marine Lab Diary or connect with us for more information.
Here is the start of a healthy coral reef relationship!
In your framework we find another super guest: the sailfin tang (Zebrasoma veliferum). It is a marine reef tang in the fish family Acanthuridae. They may live at water depths of 1 – 60 m (3 – 200 ft) or more. The fish grow to a maximum length of 40 cm (15.8 in). It has an extensive range throughout Oceania, the Indian Ocean, and the South Pacific. They are herbivorous fish specializing in filamentous algae. Though their skin is light beige with stripes, it can turn dark brown under stress. The sailfin tang is decorated with broad, pale yellow bands that alternate with darker bands over its body. The bending extends into both dorsal and anal fins. On the darker bands are yellow dots and stripes. The caudal fin is yellow. The head of the fish is white adorned with yellow dots. A dark band with yellow dots runs across the eye and another dark band with dots is located right behind the eye. Juvenile specimens look similar to the adult fish, but with more yellow colouring.
We would like to give some information about this colony of Acropora digitifera that lives on your coral frame. This species forms digitate colonies; the branches may be 1 cm in diameter and up to 10 cm long. This species strongly prefers shallow water. It is usually cream or light brown in color with blue branch tips, but can also be brown with purple tips. It is common near reef crests’ as it prefers strong water movement and it is very common in the Maldives. The most important known threat is the reduction of coral reef habitat due to bleaching, disease and predation. However, it seems to be strong enough to resist to habitat loss more than other species of corals. However, since the current situation with multiple stresses (mainly rising temperature of the ocean) acting simultaneously the species is considered Near Threatened by the International Union for Conservation of Nature (IUCN).
The Dascyllus aruanus, known commonly as humbug damselfish, has found in your coral frame its home. This particular fish is known by multiple common names, such as three stripe damselfish, humbug dascyllus, or black and white damselfish. They only reach an adult size of 3-4 inches (7.6-10 cm). Sporting three broad black stripes on a white body, the humbug damselfish has a zebra like appearance. The stripes run slightly off vertical through the eyes and mouth, midbody and bisecting the caudal peduncle, making it half black and half white. There are several contestants for the title of most important reef fish family, but the Damselfish are certainly one of the front-runners. Not only are there numerous species, but also many of these species are present on Maldivian reefs in prodigious numbers. The humbug damselfish that you can see in the picture is associated with isolated coral heads in sheltered inshore habitats. Like all damselfish, they can be territorial and aggressive, especially as they get older.
Have you ever wondered how corals are eating and defending themselves … here you will see some small extensions/tentacles protruding from each of the polyp housings. They are referred to as the defensive/offensive stinging mechanisms similar to sweeper tentacles and are often linked to their feeding and defending. Inside each of the polyps are the small animals that look similar to an upside-down jellyfish with tentacles that surround the mouth part, depending on the coral species, the amount of tentacles may vary. They will move around to collect small particles floating in the water, usually plankton. These tentacles are also used for defending themselves against predators such as the coral eating snail, Drupella sp or the invasive Crown of Thorns Starfish. They also keep smaller predators such as crabs and invertebrates away. These tentacles are seldom seen, but do come out when they are feeling threatened or during feeding.
Have you ever wondered how do corals grow bigger or how their branches are getting longer? Coral reefs are mainly built by stony or hard corals, together with their endosymbiotic algae (algae living into the corals), zooxanthellae. To give you some information on how the calcification process works. The main elements needed to build the skeleton are Ca2+ (Calcium ions) and DIC (Dissolved Inorganic Carbon). Both these elements are transported into a specific area of the coral called the “calcifying region”, which is situated under each single polyp. Here, the calcium carbonate (CaCO3) is formed throughout a chemical reaction. Finally, the calcium carbonate (or technically crystals of aragonite) is deposited to form the skeleton. The process involves the polyp’s cells and the zooxanthellae and by the mutualistic work of these two counterparts the skeleton is formed. However, if for any reasons (i.e. high temperature) one of the two parts is not working properly the process stops and the coral may die.
This is your 6 month frame progress update. Your frame is doing fantastic!
Looking at your frame, we can see lots of new growth, especially of the acropora corals (the branching & fast growing corals). We can see some of the corals are competing for space, which is a good problem to have, it means your frame is thriving. We can also see that your frame is contributing to the overall health of the coral ecosystem. We see lots of life such as little fish, crabs, worms and mollusks around your frame. Overall your frame has survived the warm months of March, April and May just fine, unfortunately some of the other frames in our colony weren’t so lucky.
Over the following months we will continue with maintenance to keep harmful algae and predators off your frame and to give your frame the best chance for successful growth.
Have you ever wondered why some corals are more colorful than others… That is because some corals increase the production of colourful protein pigments (such as these purple tips) when they are exposed to more intense sunlight and this colony, of a branching Acropora, is simply amazing. Scientist have found that these pink, blue and/or purple proteins act as sunscreens for the corals by removing substantial light components that might otherwise become harmful to the algae hosted in their tissue. Corals rely on these light-dependent miniature plants, the so-called zooxanthellae, since they provide a substantial amount of food. Furthermore, these tips consist of a particular polyp called an “apical polyp”. It is responsible of the growth of the particular branch. For instance, it will reproduce asexually by cloning itself, potentially an infinite number of times throughout its lifetime. Here and there, one of the “radial polyps” will differentiate becoming a new apical polyp with its distinguished purple color, driving the growth of a new branch.
Humans get a sun tan – corals become more colourful.
Some great news!!! Your frame seems to be an attraction for baby corals, such as the small Pocillopora species in the picture. Most of the coral species reproduce by ejecting sperm and eggs in the water that subsequently merge and form planula larvae which can swim and is naturally attracted by chemical substances and light. After a couple of weeks, fertilized planulae larvae fall back to the ocean floor and attach themselves to a hard surface such as a coral frame. An attached planula makes the metamorphosis into a coral polyp and begins to grow—dividing itself in half and making exact genetic copies of itself. As more and more polyps are added, a coral colony develops. Eventually, the coral colony becomes mature, begins reproducing, and the cycle of life continues.
Coral reefs are built and made up of thousands of tiny animals called coral “polyps” that can live individually (like many mushroom corals do) or in large colonies that comprise an entire reef structure. A polyp has a sac-like body and an opening, or mouth, encircled by stinging tentacles called nematocysts or cnidae (imagine an upside down jellyfish). The polyp extracts calcium and carbonate ions from seawater to build itself a hard, cup-shaped skeleton made of calcium carbonate (limestone). This limestone skeleton protects the soft, delicate body of the polyp. Coral polyps are usually nocturnal, meaning that they stay inside their skeletons during the day. At night, polyps extend their tentacles to feed. Most coral polyps have clear bodies whereas their skeletons are completely white, like human bones. Generally, their brilliant color comes from the zooxanthellae (tiny algae) living inside their tissues. Several million zooxanthellae live and produce pigments in just one square inch of coral. These pigments are visible through the clear body of the polyp and are what gives coral its beautiful color.
As you can see from the picture, your coral frame are colonized by some little, brown and green organisms called Ascidia. The species is called Didemnum molle (also known as the green barrel sea squirt or the green reef sea-squirt.) and is very common in the Indo-Pacific area. Ascidia is a filter-feeder, feeding on suspended plankton and detritus and its green color is given by the algae living in symbiosis with them, in this way the algae is protected by the predation and the Ascidia can receive energy from its little hosts. Luckily they don’t possess any threat to the corals when they are few in numbers, however they can colonize quite quickly on the frames through asexual budding, as such they are regularly removed to minimize competition with growing corals.
We have noticed that some fragments such as this one pictured have some damage and as a result they die completely. This happens from time to time that fragments might receive very high stress levels due to increased water temperatures and they lose the symbiotic algae Zooxanthellae that they need to survive. Sometimes corals also need to compete with invasive algae that grow over the polyps and when this happens they will also die off. During the maintenance these pieces of dead coral is usually removed while the live part remains attached.
Looking at your frame, you will see that it is doing amazing and the corals are really growing well since the last update even after the heated months and some stormy weather. We have done some recent maintenance on all the frames which include cleaning them, removing the invasive algae and coral predators to maximize growth. In the upcoming post we will show you close-ups of your frame and the coral fragments, with some interesting facts and findings about those that are on your frame. After 6 months you will see a similar post showing once again the progress of your frame.
Your frame seems to be an attraction for baby corals, such as the small, 2 cm, coral colony in the picture. Most of the coral species reproduce by ejecting sperm and eggs in the water that subsequently merge and form planula larvae which can swim and is naturally attracted by chemical substances and light. After a couple of weeks, planulae fall back to the ocean floor and attach themselves to a hard surface. An attached planula makes the metamorphosis into a coral polyp and begins to grow—dividing itself in half and making exact genetic copies of itself. As more and more polyps are added, a coral colony develops. Eventually, the coral colony becomes mature, begins reproducing, and the cycle of life continues.