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!
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.
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.
Coral reefs are one of the most diverse systems on the planet, and sometimes corals can be new substrate for sessile gastropods, such as Ceraesignum maximum or otherwise known as an Operculate Worm Snail (Vermetidae, Mollusca). Individuals of C. maximum live in tubes embedded in the carbonate framework of the reef flat and secrete mucus nets extending ~10 cm around the individuals. The sticky nets billow under the turbulent action of impinging waves and indiscriminately trap suspended particles. The nets are withdrawn at regular intervals and consumed. In the picture it is visible the aperture of the tube, on an Acropora living on your frame.
Do you know that even under the water we can find cobwebs? The invertebrate responsible for this mesh is not a spider, but rather a gastropod mollusk called Ceraesignum maximum. As all Vermeidae, this mollusk species is sessile and houses themselves within tubular shells. They are common dwellers of shallow water in coral reefs and rocky shores. These nets are called mucus nets that can expand around the individual up to 10 cm in diameter. Waves and currents fill the net with tiny particles. After a few hours the mollusk will inhale the net with all of its yummy goods caught inside.
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.
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 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.
Have you ever wondered how corals are eating and defending themself… 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 animal that look similar to an upside-down jellyfish with tentacles that surrounds the mouth part, depending on the coral species, the amount of tentacles may vary. They will move around to collect anything that passes around in the water, usually small plankton where after they will maneuver it towards their mouth where the food will digested and passed down. 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 the smaller predators such as crabs or invertebrates away. These tentacles are seldom seen but do come out when they are feeling threatened or when they are feeding.
Coral reefs are one of the most diverse systems on the planet, and sometimes corals can be new substrate for sessile gastropods, such as Ceraesignum maximum (Vermetidae, Mollusca). Individuals of C. maximum live in tubes embedded in the carbonate framework of the reef flat and secrete mucus nets extending ~10 cm around the individuals. The sticky nets billow under the turbulent action of impinging waves and indiscriminately trap suspended particles. The nets are withdrawn at regular intervals and consumed. In the picture it is visible the aperture of the tube, below an Acropora living on your frame.
Check out this intriguing creature we found on your coral frame… this is called a hermit crab, one of the 1110 species found today, so we cannot be too sure about the specific species. These specific groups of animals are called marine hermit crabs and they spend most of their life underwater. Most species have long, spirally curved abdomens which are soft, unlike their calcified relatives. This soft abdomen is protected from predators by a salvaged empty seashells usually abandoned by other gastropods. Often times they will use the shells of sea snails or other hermit crabs. Like all hermit crabs, as they grow bigger, they require bigger shells and often times when resources are limited there can be some competition between crabs for new shells. Their diets consist of algae and plankton but they are also omnivorous and depend on a reasonable amount of scavenging. They find the easiest ways to collect the plankton is by utilizing their claws to guide food into their mouths and suck in anything that is within reach.
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.
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.
Corals are marine animals that are able to deposit calcium carbonate in order to build their hard skeleton. Since they are also calcifying organisms, they are facing a continuous threat that is climate change! Ocean Acidification (OA) and increasing temperatures are of the main reasons for this change. While increased temperature causes bleaching events, ocean acidification act as a stressor not often noticed. OA is caused by the increased production of manmade greenhouses gasses, which dissolves in the ocean water and causes a decrease of the marine pH, as such the water becomes more. This decrease in pH levels impacts not only the calcium carbonate structures by dissolving them, but also affects the metabolism of marine organisms causing the energy to be relocated and as a result influences the early life stage history.
