Fringing Reef. Coral polyps can obtain most of their nutrition from algae, called zooxanthellae. Change ), You are commenting using your Facebook account. In contrast, many of the coral bleaching events observed in the 1980s occurred over large geographic regions and at all depths. This course explains coral reefs for the exam UPSC CSE. It is stretched for over 2,300 kilometres over an area of approximately 344,400 square kilometres. Dec 06, 2020 - Island and Coral Reefs UPSC Notes | EduRev is made by best teachers of UPSC. Conditions Required for Healthy Growth of Coral Reef. Generally, such bleaching events are rare and confined to relatively small, near shore areas. Sale! Conditions for Growth of Coral Reefs 1. The coral species that build coral reefs are known as hermatypic or"hard" corals because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies. ; Coral reefs on India’s east coast are making a comeback. if the stress continues and depleted zooxanthellae populations do not recover, the coral host eventually dies . The Great Barrier Reef is the world’s largest coral reef system composed of over 2,900 individual reefs and 900 islands. Corals rarely develop in water deeper than 165 feet (50 meters). It is due to the subtropical climatic conditions, there are a very few coral reefs in India. If zooxanthellae loss is prolonged, i.e. Rapid dilution of reef waters from storm-generated precipitation and runoff has been demonstrated to cause coral reef bleaching. Primary References: NCERT Geography, Spectrum’s Geography [Amazon and Flipkart] and Savindra Singh [Amazon and Flipkart], Filed Under: Geography, Oceanography, Physical Geography, Your email address will not be published. Corals need to grow in shallow water where sunlight can reach them. Sensitive habitats can be destroyed or disturbed by the dredging of deep-water channels or marinas, and through the dumping of waste materials. They are an integral part of many cultures and our natural heritage. This is why corals don’t live in areas where rivers drain fresh water into the ocean (“estuaries”). Coral reefs are the skeletons of stony coral polyps cemented together. All rights reserved | Terms & Privacy | Amazon Affiliate Disclosure. & does not flourish in cold currents. Change ), You are commenting using your Twitter account. Remember to never fish or boat near a reef, and don't litter on the beach or in the ocean. Coral species live within a relatively narrow temperature margin, and. Sudden exposure of reef flat corals to the atmosphere during events such as extreme low tides, ENSO-related sea level drops or tectonic uplift can potentially induce bleaching. Zooxanthellae live symbiotically within the coral polyp tissues and, The host coral polyp in return provides its zooxanthellae with a, The symbiotic relationship allows the slow growing corals to compete with the faster growing multicellular algaes. Coral reefs are being degraded by an accumulation of stresses arising from anthropogenic activities and changes in the natural environment. About Great Barrier Reef. Though warm waters as a result of global warming results in coral bleaching, it could be offset by diversity the algae renders to corals. Different corals living in different regions can withstand various temperature fluctuations. As a rule they thrive well only in warmer tropical seas, with water temp. The coral reef are natural barriers to storm surges, particularly in regions that are susceptible to hurricanes. Most reefs recovered, with low levels of coral deaths, but damage has been severe at places. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. As these corals grow and die, they leave behind their calcium carbonate skeletons. ( Log Out / Coral reefs are large underwater structures composed of the skeletons of coral, which are marine invertebrate animals. 1 Year Validity == Validity of the Download links (both Static & Current Affairs) is 1 Year from the date of purchase. About Great Barrier Reef . When I joined Ocean Quest Global, I was introduced to a completely new technique of growing corals.This method is based on an entirely organic approach without introducing any artificial structures, like plastic pipes, tires or metal structures, to the marine … Kutch Region (Gujarat) Gulf of Mannar; Lakshadweep islands. This video is highly rated by UPSC students and has been viewed 1 times. Copyright © 2016-20 Pmfias.com. UPSC Civil Services Examination UPSC Notes GS-I [Geography] Topic: Coral Reefs ... Growth conditions for Coral Reefs 1. Suitable environmental conditions required for Coral Reefs Hard Surface: Presence of hard surface of sub-marine platform of the continental shelf or mid-oceanic ridges. Key demand of the question. Approx Read Time: 4 minutes In News: Scientists have discovered that coral reefs along the Gulf of Mannar off the coast of Tamil Nadu and Palk Bay, which suffered damage by mass bleaching earlier this year, have sprung back to life within a few months. The corals in Puerto Rico and Hawaii were in good condition. Coral reefs are large underwater structures composed of the skeletons of coral, which are marine invertebrate animals. Corals grow very slowly - some grow only about 3-20mm per year. Pollution alters the natural flow of water, greater amounts of fresh water, nutrients and sediment can reach the reefs causing further degradation. Coral reefs grow better in shallow water having a depth less than 50 m. In turn zooxanthellae are responsible for the colors and diversity of them to polyps. Warm water temperature: Reef-building corals require warm water conditions to survive. Corals need clear water that lets sunlight through; they don’t thrive well when the water is opaque. Fishing with dynamite, cyanide and other damaging methods can damage entire reefs and is 100% unsustainable. Coral bleaching has occurred mostly during the summer seasons or near the end of a protracted warming period. #ias2020 #UPSC #environment In this lecture, we discuss Environment & Ecology for UPSC CSE Prelims and Mains Examination by ADITI SHARMA … Some reefs are even older than our old-growth redwood forests. Scientists in east Africa have discovered a rare ocean refuge for coral where species are still thriving despite the accelerating climate crisis impacting other nearby reefs. Many U.S. coral reefs were alive and thriving centuries ago. The condition virtually limits the areal distribution of corals to the tropical, and sub-tropical zones. The present one is the longest and most severe so far. Bleaching events occur during sudden temperature drops accompanying intense upwelling episodes [El-Nino], seasonal cold-air outbreaks. But rising temperatures mean reduction in the concentration of these UV absorbing compounds in corals. Significance. The tissues of corals themselves are actually not the beautiful colors of the coral reef, but are instead clear. When corals are exposed to high concentrations of chemical contaminants like copper, herbicides and oil, coral bleaching happens. While corals form the backbone of reefs, the reefs are not a one-man show, and they incorporate a variety of plants and animals into their framework. Sediment and plankton can cloud water, which decreases the amount of sunlight that reaches the zooxanthellae. It will impact marine ecosystem, as coral reefs are some of the most bio diverse and productive ecosystems. Reefs act as natural barriers to shorelines, protecting them from the effects of moving water. Published on 19-Sept-2019 – Coral Reefs. Coral bleaching has occurred mostly during the summer seasons or near the end of a protracted warming period. Zooxanthellae live symbiotically within the polyps. The temperature of the water should not be below 20°C. The conditions favor localised heating and high ultraviolet (UV) radiation. The reef-building corals survive best under the following conditions: The surface water temperature of the ocean must not be less than 20 degrees Celsius. The issue is related to GS-1 syllabus under the following heading- Salient features of world’s physical geography. The zooxanthellae return to the polyps when the water cools, but repeated bleaching events lead to the death of the coral polyps. not falling below 20*C approx. Importance of Corals The reef is located in the Coral Sea, off the coast of Queensland, Australia. They support fish stocks on which some 500 million people are dependent globally. 2 Year Validity == Validity of the Download links (both Static & Current Affairs) is 2 Years from the date of purchase. They are reported to have taken place during times of low wind velocity, clear skies, calm seas and low turbidity. Today, these important habitats are threatened by a range of human activities. To watch all lessons click here:- | Download the Unacademy Learning App from the . The temperature should not exceed 35°C. not falling below 20*C approx. Ocean Acidification: Due to rise in carbon dioxide levels, oceans absorb more carbon dioxide. The coral reefs that are found very close to the land and forms a shallow lagoon known as Boat Channel are called Fringing Coral Reefs. They are found in following areas in a major way in India: Andaman and Nicobar Islands (the highest coral reef area in India). The third global coral bleaching is in progress (2015-16) — after events in 1998 and 2010. This increases the acidity of ocean water and inhibits the corals ability to create calcareous skeletons, which is essential for their survival. The Great Barrier Reef is the world’s largest coral reef system composed of over 2,900 individual reefs and 900 islands. The coral species that build coral reefs are known as hermatypic or “hard” corals because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies. Posted on 05/22/2020 05/22/2020 by apho2018. 8 million tones of plastic rubbish enters the world’s oceans every single year. The consequent exposure to high or low temperatures, increased solar radiation, desiccation, and sea water dilution by heavy rains could all play a role in zooxanthellae loss, but could also very well lead to coral death. Coral reefs are huge deposits made up dead shells and secretions of marine organisms like Corals, Calcarious algae, stomatopteroids, gartopods Mollusca etc. The relationship between corals and photosynthetic algae living inside their tissues is the best example of mutualism. Corals are sensitive to changes in water conditions brought about by natural or man-made causes, and therefore, are good indicators of a healthy marine environment. This hard surface is a precondition for compaction, cementation and solidification of unconsolidated skeletons of Coral Polyps. Most coral diseases cause patchy or whole colony death and sloughing of soft tissues, resulting in a white skeleton (not to be confused with bleached corals). Since zooxanthellae are responsible for the colors of many corals, when coral polyps expel their zooxanthellae, the coral turn white, a phenomenon called coral bleaching. Coral reefs need clean water to thrive. Therefore, some reefs form over several million years (Veron, 2000). When coral polyps are too hot, they expel their zooxanthellae. Coral Reefs in India. Bleaching happens when the densities of zooxanthellae decline or when the concentration of photosynthetic pigments within the zooxanthellae fall. Coral bleaching accompanied some of the mortality events prior to the 1980s during periods of elevated sea water temperature, but these disturbances were geographically isolated and restricted to particular reefs zones. Created by the erosive force of waves and currents against limestone and animal shells, as well as by the grinding teeth of certain fish, coral sand gets trapped in openings along the reef. ( Log Out / Prices Down by 10% + Save 50% + Extra 10% OFF, Coral Reef Bleaching and Ideal Conditions for Coral Growth, Coral Reef: Fringing Reef, Barrier Reef & Atoll. The corals actually contain UV-absorbing compounds which can block potentially damaging UV radiation. Favourable conditions for Coral Reefs. The Great Barrier Reef is the world’s largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres over an area of approximately 344,400 square kilometres. 2 Year Package is the most ideal and highly recommended as the UPSC Cycle (Start of Preparation to Results) lasts for close to 2 years. The coral and the associated organisms and algae, which are the most common reef builders are confined to the tropical belt. Geography for UPSC Civil Service Exam – Overview Of Coral Reefs. The underwater tiny organism polyps form the coral reefs. The corals receive their coloration from the ZOOXANTHELLAE living within their tissues. Coral reefs are also living museums and reflect thousands of years of history. Recent accelerated coral reef decline is related mostly to anthropogenic impacts, Natural disturbances which cause damage to coral reefs include. Over-fishing of certain species on or adjacent to coral reefs can affect the reef’s ecological balance and biodiversity. Prior to the 1980s, most mass coral moralities were related to non-thermal disturbances such as storms, aerial exposures during extreme low tides, and Acanthaster outbreaks. Posłuchaj, aby w końcu się nauczyć. Change ), You are commenting using your Google account. Coral Bleaching is a typical stress response of corals to disturbances in the conditions of corals. They use the traditional cnidarian strategy of capturing tiny planktonic organisms with their tentacles (All about Phylum Cnidaria is given in NCERT). It also encourages the growth of algae, which compete with corals for space on the reef. Conditions required for … In UPSC mains exam, question demanding a direct explanation and importance of a particular geographic entity/ phenomena are commonly asked. The polyps extract calcium salts from sea water to form these hard skeletons. Coral reef ecosystems are less than 0.1% of the ocean area but provide food and shelter to 25% of all marine species. Many discarded plastic is broken down into what is known as microplastics, tiny pieces that are mistaken by coral polyps as food and ingested.
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