Coral reefs rainforests of the ocean What is a coral reef? - “A tract of corals growing on a massive wave resistant structure which is mainly built by skeletons of ongoing generations of corals and other calcifying (limestone building) reef organism” Terry Done - Australian Institute of Marine Science - calcifying organisms create a three dimensional complex structure over many generations http://greatbarrierreefgeographyproject.blogspot.com/ What is a coral reef? - - coral reefs are a rich and complex ecological system associated with one third of all known marine species (fish, snails, clams, worms, etc.), but only covering about 0,2% of the world’s oceans “rainforests of the oceans” http://cdn.neonsky.com/4bd5ec0079abc/images/05May-CR1-2.jpg Where do we find coral reefs? The majority of reef building corals are found in tropical and subtropical waters. These typically occur http://oceanservice.noaa.gov/education/kits/corals/media/supp_coral05a.html between 30° north and 30° south latitudes. Favorable conditions & limitations - optimum temperature range: 23°C - 29°C (some in extreme conditions 18 40°C) clear and shallow waters: growth is limited by light due to the photosynthetic algae living in their tissue high salinity low nutrients: high nutrients favor algae growth which are in concurrence with corals highest species diversity in the coral triangle Types of coral reefs - Fringing reefs Barrier reefs Atolls how does a coral reef grow? - corals are calcifying organisms secrete limestone which makes up their skeleton and creates a reef framework growing upwards and outwards http://biopublisher.ca/files/upfiles/4-big%281%29.png https://visualbiology.files.wordpress.com/2013/11/formation_content.jpg http://www.skepticalscience.com/pics/gbr_changes.jpg https://upload.wikimedia.org/wikipedia/commons/d/d8/Coral_atoll_formation_animation.gif What is a coral? Is it an animal? Is it a plant? What is a coral? - The corals we normally see on a reef are coral colonies These are made of many small polyps which are all clones of each other - - each coral colony starts of as a single polyp Corals are closely related to jellyfish but “why are corals so colorful?” http://belizeadventure.com/wp-content/uploads/2010/07/coralpolyp.jpg http://www.infovisual.info/storage/app/media/02/img_en/013%20Life%20cycle%20of%20a%20jellyfish.jpg What is a coral? - Coral host and algal symbionts mutual (both profit) symbiosis (living together) single celled algae (zooxanthellae) http://www.ecoreef.com.br/images/blog/zooxantela.jpg Types of corals and growth forms - - Hard-corals (calcifying corals with a skeleton) - Branching corals - massive corals - columnar corals - encrusting corals - fire corals Soft-corals Acropora branching Acropora corals are the most common branching corals. With around 60 species in Thailand with many different growth forms Acropora tabulate On e.g. the similan islands they make up 10 - 30% of the coral cover http://coral.aims.gov.au/factsheet.jsp?speciesCode=0046 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0018 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0036 Acropora digitate covered with many polyps on the sides and a single bigger polyp on top of each branch http://coral.aims.gov.au/factsheet.jsp?speciesCode=0035 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0048 Pocillopora: branching colonies, branches thick, blunt to fine. Colony surface covered with thick bumps http://coral.aims.gov.au/factsheet.jsp?speciesCode=0342 Stylophora: Thick branching colonies with blunt flattened tips, corallites more smooth than in pocillopora http://coral.aims.gov.au/factsheet.jsp?speciesCode=0310 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0307 http://www.austinreefclub.com/gallery/image/4564-rainbow-stylophora/ http://www.arkive.org/smooth-cauliflower-coral/stylophora-pistillata/imageG26525.html Porites coral: most common species around phuket Porites lutea. On many reefs they make up around 50% of the coral cover http://coral.aims.gov.au/factsheet.jsp?speciesCode=0046 Most porites corals around phuket are massive and some encrusting corals, but some form branches and columns http://coral.aims.gov.au/factsheet.jsp?speciesCode=0018 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0036 Porites corals have small polyps a yellow/brown to purplish color and are very robust and resilient. They survived many of of the past bleaching events around Thailand http://coral.aims.gov.au/factsheet.jsp?speciesCode=0035 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0048 Diploastrea (brain coral): massive sometimes encrusting. Common around phuket. Very large and typical polyps. grey-brown to green http://coral.aims.gov.au/factsheet.jsp?speciesCode=0046 Favia (brain coral): Massive and encrusting. Big and irregular polyps. Yellow-brown http://coral.aims.gov.au/factsheet.jsp?speciesCode=0018 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0036 Leptoria (brain coral): http://coral.aims.gov.au/factsheet.jsp?speciesCode=0035 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0048 Goniopora: massive sometimes columns. elongated polyps when they are folly extended. http://coral.aims.gov.au/factsheet.jsp?speciesCode=0046 Fungia (mushroom coral): single coral polyp http://coral.aims.gov.au/factsheet.jsp?speciesCode=0018 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0036 Montipora: small polyps and mainly encrusting but often combinations of different growth forms in one colony with many bumps and ridges http://coral.aims.gov.au/factsheet.jsp?speciesCode=0035 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0048 Gorgonia (sea fan): belonging to the family of soft coral. in areas of strong currents. catch plankton http://coral.aims.gov.au/factsheet.jsp?speciesCode=0046 Heliopora (blue corals): skeleton is blue. belonging to the family of soft corals. Around Phuket mainly in shallow waters (1-10m) http://coral.aims.gov.au/factsheet.jsp?speciesCode=0018 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0036 Millepora (Fire coral): Stings! Many different growth forms. May be confused with heliopora but more “hary”. http://coral.aims.gov.au/factsheet.jsp?speciesCode=0035 http://coral.aims.gov.au/factsheet.jsp?speciesCode=0048 Coral reef fish - fish that live amongst or in close relation with coral reefs Coral reefs cover less than 1% of ocean:s surface but inhabit around 25% of all marine fish species The coral reef provides food in waters which are otherwise poor in nutrients corals and the reef structure provide different habitats and places to hide coral reef fish have various adaptations to coral reefs, sharp or poisonous fin spines, coloration to confuse predatos, well camouflaged many fish are important for the health of the coral reef when the coral reef dies the fishes disappear as well Parrotfish: About 90 descovered species. Mainly feeds on algae. Alae are in concurrence with corals for space and light, thus it helps the corals in their competition. They have sharp teeth which form a “beak” to scratch of corals form rock. When feeding they eat a lot of rock too which gets grinded to sand. So their poop is mainly sand. Fish of large species may “produce” 400kg of sand per year! So some of the sand on the beach is parrotfish poop Triggerfish: about 40 different species, some very colourful. Strong teeth! They feed on crustaceans, mollusks and sea urchins build nests where some species defend their territory viciously, which is expanding conelike to the top. They may attack divers and snorkelers. Anemone fish: 30 species, they live in mutual symbiosis with sea anemones. The anemone protects the fish. Due to the movement of the fish water circulation increases. anemones sting but the anemonefish develops immunity to the toxines. The fish forms a layer of mucus on its skin Angelfish: very distinct colors which are species specific. feed on algae, small fish or jellyfish. When they are young they have different colours Bannerfish: distinctive dorsal fin “banner”. typical coloration. mainly in pairs or schools. Moorish idol: easy to confuse with banner fish. elongated mouth with distinct colouring. Scorpionfish: very well camouflaged. wait for their prey, small fish to come close and rapidly attack. When they open their mouth it causes a suction pulling in the prey. They have poisonous spines can you spot it/them? Barracuda: carnivore hunting alone or in schools (depending on the species). Sometimes the meat of barracudas is poisonous, depending on the fish they eat. White tip/black tip reef shark: sharks have more senses than humans. They can detect very low electric currents and feel the electric impulse of neurons as created during the heartbeat or muscle movement of their prey. Whale shark: largest fish in the world, up to 12 meters long and weigh up to 20 tons. Filter feeders, eat plankton Coral reef invertebrates - Animals that don’t have a spine Octopus, cuttlefish, squid, nudibranchs, shells & clams starfish, sea urchins, sea cucumbers Crabs, shrimp, lobsters tube-worms cuttlefish: one of the best adaptive camouflage skills. Changing colour and texture. they mate turning face to face, males have a specialized tentacles to insert a sperm sac near the female’s mouth large male cuttlefish who have a female to mate with may be tricked by small males. These behave like females to get in range of the real female what are these flatworms doing? The mantis shrimp and it’s super weapon Threats to coral reefs Climate change and its effects Sea surface temperature and coral bleaching - Man made climate change, due to ongoing emissions of greenhouse gases as carbon dioxide not only increases temperatures on land average ocean sea surface temperatures as well increase this causes one of the big threats to coral reefs During some years when temperatures spike (as in 2010 or 2016) temperatures in the sea become too warm for corals These high temperatures and increased irradiation from the sun causes coral bleaching But, “what is coral bleaching?” Sea surface temperature and coral bleaching - - The small algae, the symbionts of the corals, harvest the sun’s energy by photosynthesis as other plants They provide about 90% of this energy to their coral host (the animal) When temperatures get too high the photosynthetic mechanism gets out of balance and the algae produce toxins This stresses the coral host and it expels, with compulsory movements, the algae in its tissue to protect itself, however, in return losing the main source of its energy by losing their algal symbiont they lose their colour - the coral is then considered bleached However, a bleached coral is not dead yet, it can survive without the symbionts for weeks up to a few months, and regain them when temperatures decline ocean acidification and the impact on corals - - What is ocean acidification? When CO2 levels increase in the atmosphere, CO2 levels as well increases in the ocean - they are in balance, about 30% of the CO2 dissolves in the oceans When atmospheric CO2 levels rise dissolved CO2 in the oceans rises with it ocean acidification and the impact on corals - increasing acidity makes it harder for corals to build up their skeleton at the same time the more acidic waters dissolves their calcium carbonate (limestone skeleton) on a faster rate Not only corals suffer under these circumstances All other marine organisms which build up shells or skeletons from limestone The pictures show what happens to a shell in sea water with a pH/acidity estimated for the year 2100 overfishing, nutrient pollution and phase shifts not all’s lost :) Thank you for your attention
