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Coral Bleaching.pdf
- 1. ENVIRONMENTAL ISSUES CORAL BLEACHING For Abhinav (The Scientific presentation)
- 2. INTRODUCTION Coral bleaching is the phenomenon wherein the corals lose their vibrant colour and turn white due to environmental stressors. Bleached Corals continue to live , but they are more vulnerable to disease and starvation.
- 3. TIME LAPSE OF CORAL BLEACHING Source: Blue Planet Oceans from BBC America INTRODUCTION
- 4. HOW DOES A BLEACHED CORAL LOOK LIKE? Most bleached corals appear bright white but some are blue, yellow or pink due to the pigment protein present in the corals. BLEACHED CORALS IN THE PACIFIC Image taken from https://www.google.com/imghp?hl=en&authuser=0&ogbl
- 5. HOW DOES A BLEACHED CORAL LOOK LIKE? HEALTHY CORAL HEALTHY CORAL STRESSED CORAL STRESSED CORAL BLEACHED CORAL BLEACHED CORAL DEAD CORAL DEAD CORAL CHANGING CORAL COLORS Photo Credit- Dive Wananavu Fiji Photo Credit- Richard Vevers Photo Credit- Tim McClanahan Photo Credit- Richard Vevers Image taken from https://www.google.com/imghp?hl=en&authuser=0&ogbl
- 6. PROCESS Bleaching occurs when coral polyps expel zooxanthellae that live inside their tissue, causing corals to turn white. ENDOSYMBIOSIS IN CORALS Source- https://serc.carleton.edu/index.html
- 7. provides vibrant colour provides energy after photosynthesis Zooxanthellae Coral Polyp provides shelter provides carbon dioxide for photosynthesis ENDOSYMBIOSIS IN CORALS Images taken from https://www.google.com/imghp?hl=en&authuser=0&ogbl ENDOSYMBIOTIC RELATIONSHIP Photo Credit- Todd C. LaJeunesse Photo Credit- Charles LoBue/EPA
- 8. Tentacle of coral polyp containing zooxanthallae Zooxanthellae produces Reactive Oxygen Species Coral Polyps expel out the zooxanthellae PROCESS Under stressful environmental conditions, the zooxanthallae begins to produce reactive oxygen species, which are toxic for the coral polyps and resultantly corals expel the algae for short-term survival.
- 9. PROCESS Since, the zooxanthellae produce majority of coral coloration, the coral tissue becomes transparent, revealing the coral skeleton made of calcium carbonate. Endosymbiotic Relationship breaks Coral loses its color Coral Dies if it can restore normal conditions
- 10. CAUSES OF CORAL BLEACHING Rise in Ocean Temperature Ocean Acidification Solar Radiation and Ultraviolet Radiation Infectious Diseases Chemical Pollution Increased Sedimentation Human Induced Threats
- 11. MASS BLEACHING EVENTS HISTORY OF BLEACHING EVENTS Source: Our World in Data
- 12. MAJOR BLEACHING EVENTS 57/100 of the Worlds Total Coral Location were severely affected, while 16 locations were moderately affected. 1998 2005 A total of 40 coral locations were affected in the summers of 2005-2006 2010 53 coral locations were affected in 2010 mass bleaching event. 2016 Total 54 locations were affected in the time period of 2014-2017, with peak destruction in 2016. In the last 30 years, we have lost over 50% of the world’s Corals.
- 13. RECENT BLEACHING EVENTS 2020 During the 2020 event, 25% of reefs surveyed had severe levels of coral bleaching. 2021 In 2021-22, sea surface temperatures in Western Australia remained in the highest 10% of observations since 1900. In 2022, aerial surveys confirmed the fourth mass bleaching event to impact the Great Barrier Reef in seven years. 2022 Heat caused stress on coral reefs across the Gulf of Mexico, northern Atlantic Ocean, and the Caribbean Sea, as well as the eastern Pacific Ocean. The extreme heat stress triggered a large-scale coral bleaching event impacting nearly a dozen countries. Nearing mid-October, waters around the Florida Keys were under a bleaching watch. Further south, waters around parts of Cuba and the Bahamas remained at bleaching alert level 2, the highest level of the scale, signifying that severe bleaching and mortality are likely. JULY 2023 OCT 2023
- 14. WHY DOES CORAL BLEACHING MATTER? When corals die, reefs rarely come back. With few corals surviving, they struggle to reproduce, and entire reef ecosystems deteriorate. Bleaching also matters because it’s not an isolated phenomenon. According to the National Oceanic and Atmospheric Association, between 2014 and 2017 around 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching. For 30% of the world’s reefs, that heat-stress was enough to kill coral.
- 15. IMPACTS OF CORAL BLEACHING Affects the Food Chain Loss of Biodiversity A decline in Economy Affects Food Availability Impacts Coastal Protection BEFORE AND AFTER A BLEACHING EVENT Source: National Geographic
- 16. THE GREAT BARRIER REEF IS SUFFERING The 2015–2016 event resulted in the bleaching of more than half of all the coral in the Great Barrier Reef. Coral bleaching affected 91% of reefs surveyed along the Great Barrier Reef IN 2022, according to a report by government scientists that confirms the natural landmark has suffered its sixth mass bleaching event on record. IMAGE TAKEN FROM CANVA
- 17. IMPORTANCE OF CORAL REEFS 1. Coastal Protection 2. Provides Shelter 3. Enhanced Biodiversity 4. Economic Development 5. Water Filteration 6. Provides Nutrition
- 18. CAN WE RECOVER? Recovery from bleaching can take weeks to months, but recovered corals may grow slower and have reduced fertility and productivity as compared to previously unbleached corals. If local stressors to coral reefs are reduced, the corals have a better chance of recovering from an event such as coral bleaching, making the reefs more resilient.
- 19. INITIATIVES TO PROTECT CORALS International Coral Reef Initiative(ICRI) Global Coral Reef Monitoring Network (GCRMN) Coral Reef Alliance (CRA) Coral Research and Development Accelerator Platform(CoRDAP)
- 20. GOI launched National Coastal Mission Programme, to protect and sustain coral reefs in the country. INITIATIVES BY GOI The Ministry of Environment and Forests and Climate Change, India, has included the studies on coral reefs under the Coastal Zone Studies The Zoological Survey of India and Forest Department, Gujrat, has been attempting to restore coral reefs using BIOROCKS.
- 21. Don't use chemically enhanced pesticides and fertilizers Don't use chemically enhanced pesticides and fertilizers HOW CAN WE HELP? Don't pollute Be an informed consumer Conserve Water Reduce Greenhouse gas emission
- 22. Before Concluding, here’s a quote by Sylvia Earle: