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 regular updates and amazing facts about the corals and animals living on your frame. By having all the updates on one page, you will be able to track the progress of your frame and see how your contribution is benefiting the ecosystem. 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!
Your frame is the start of a new beginning for the Thudufushi House Reef! Your coral frame is part of an experimental trial. We are trying to determine if we can start a coral frame chain that will act as an artificial reef. The “frame chain” is currently located on the sandy seafloor in front of the Main Bar & Water Villa Jetty.
A few concerns we are having with this location are the shallow water, which might make the corals more prone to bleaching due to warm waters. We are also concerned about the stand and possible turbidity that might not allow enough light to penetrate for photosynthesis.
So why did we choose this spot? As we are trying to expand our coral reef and help corals take back areas they used to inhabit before the big bleaching in 2016 we need to expand frame locations past the already existing reef. Furthermore the location is easily accessible for the biologist to monitor and clean the coral frame and react to any changes quickly.
Let’s cross our fingers and hope the corals will adjust to their new location well.
Look at this amazing visitor to your frame! These are just a few of the species that would often visit the coral frames and are extremely helpful at times when cleaning the frames. This species is called the Moon Wrasse (Thalassoma lunare) a very typical and brightly colored species of fish found in the Maldives. It belongs to the wrasse family which consists of over 600 described species that range on average around 20 cm although the Humphead and Napoleon wrasse can grow up to 2 meters! They are carnivores by nature, feeding on a wide range of small invertebrates such as crabs or snails. Many smaller wrasses follow the feeding trails of larger fish, picking up invertebrates disturbed by their passing.
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.
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.
This is your 6 month frame progress update. Unfortunately your frame is struggling!
Looking at your frame, we can notice lots of bleached corals as well as dead coral fragments. Unfortunately the warm months of March, April and May have been really rough on your frame. We are trying our best to keep the damage to a minimum by cleaning harmful algae off bleached corals. We also started moving extremely bleached frames under the Water Villa Restaurant to protect them from further damage through UV radiation. We hope to see some of your bleached corals recover over the next couple of months, but it will be a slow process. Now that the water temperatures are slightly decreasing the next step of action will be to replace dead coral fragments with new healthy fragments.
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.
We’ve had another very warm spring this year; March, April and May have been consistently warm and lead to a lot of coral bleaching on many of our frames as well as the house reef. Because your frame has been showing extreme signs of bleaching, we decided to move it into the shade. Your coral frame will be under the Water Villa Restaurant until we see your corals recover.
Research shows that corals can display bleaching from high temperatures but also that UV light can damage already stressed corals. This is one of the reasons we moved your frame out of the direct sun light and into the shade. Furthermore the temperatures in the shade are a little lower than the exposed sunny spot your frame used to call home.
Over the next couple of months it is one of our priorities to clean your frame frequently to minimize harmful algae from smothering your coral frame.
Acropora corals are among the most common genera of corals in tropical reefs with up to 150 species already described. Corals are composed of tiny individual polyps each that resemble an upside-down jellyfish with the mouth in the middle, surrounded by the tentacles. Here you can also see the tiny polyps in this picture (each tiny bump is a coral polyp). Furthermore, Acropora corals are called hexacorallia since each polyp has six, or multiples of six, tentacles. Such structures are used for hunting prey, microorganisms, but are also used for defense. These tentacles are armed with unicellular weapon needle-like structures composed with a strong mix of toxins. Humans are not harmed by these toxins but it may cause inflammation along with some itching if touched.
We have some unfortunate news this month as we are starting to see some evidence of bleaching around the coral frames. Coral bleaching can be ascribed to warming ocean waters for extended periods of time where the symbiotic algae (Zooxanthellae) living inside the tissue coral is expelled by their host and in turn leave behind a bleaching white skeleton. This algae shares a mutualistic relationship with the corals; the coral provides shelter to the algae and in turn the algae can provide as much as 90% of the nutrients produced by photosynthesis which is used towards their growth. Corals can survive bleaching events such as this, but if they are subject to more stress or prolonged heated waters, they will surely die. Unfortunately, your frame is also showing minor signs of bleaching of around 20%. This is a rough estimate based on the amount of bleaching fragments of the entire frame. As you can see from the images, their white skeletons are not something anyone can miss, especially in the water. The degree of bleaching on your frame varies from fragment to fragment and mostly range anything between minor bleaching on the branching tips and those bleached on the surface (those directly exposed to the sun’s rays), intermediate bleaching (still some symbiotic algae present.
Unfortunately, there is not much we can do at this stage, but wait to see whether they recover or not in the next months. Should they not recover and they are completely dead, they will be removed from the frame and replaced with new live ones. This is of course a major setback for our coral conservation project, but it is also the reality we are dealing with today.
Here you will see the partial shape of the cable ties that we used to stabilize this particular fragment to the iron frame which is really great, this means the coral are still growing. In two months we can already see that this Acropora have started to overgrow this plastic tie and will soon be part of the skeleton forever. Plastic cable ties are a good compromise for attaching corals to the structure, since the material is cheap, resistant and the results are great, however we are looking into using different materials to improve our techniques of reducing plastics in the ocean. When this colony have reached the minimum size for spawning it will release its gametes in the water that ultimately leads to the formation of new colonies elsewhere on the reef.
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.
As you can see from your first post, we have already done the first maintenance on your frame which is to remove the cable ties and move the frame with the other frames. Some information about the fragments that we put on your frame, most of them belong to the genus Acropora which is one of the fastest growing corals and almost 149 species described. Over the next few months we will show you some close-up pictures of the fragments with some interesting facts and the creatures that now lives on your frame. After 6 months we will show you the progress of your frame in a new post.
