Coral Reefs Flashcards
Coral reefs
Corals are small, up to 0.25 to 12 inches, soft-bodied marine organisms, which are characterized by reef-building corals, forms of colonies, their polyps held together by calcium carbonate, coral’s secrete hard carbonate exoskeletons that support and protect them. Most coral reefs are built from stony corals whose polyps cluster in groups. Corals belong to the class Anthozoa in animal phylum Cnidaria, which also includes sea anemones and jellyfish. Corals are often called rainforest of sea and occupy about 0.1% of the world’s ocean area, but provide a home for at least 25% of all marine species. India has four coral reef areas, the Gulf of Mannar, Andaman and Nicobar Islands, Lakshadweep Islands, and Gulf of Kutch. Coral reefs protect the humanity from natural calamities and provide revenue and employment through tourism and recreation. They also provide habitats for fish, starfish, and sea anemones.
Ideal conditions for their growth:
Warm tropical oceans with minimum temperature of 25-30°C limited to tropical belt. In less than 18 or 33°C, corals tend to die. Corals need saline water with an average salinity of 27-40 ppm. They need shallow water less than 60-50 m, need submarine platforms, need sediment-free clear water. The waves ensure supply of oxygen.
Geographical distribution: Eastern coasts of North America and Australia on coasts where rivers bring large quantities of sediments from land. Corals are not found on the coasts of South America. Corals are not common in Pacific and Indian Ocean due to their shallow, warm, and clean water.
Types of coral reefs:
1) Fringing reef which develop on continental shelf and are connected to the coastline. For example, Gulf of Manara, Gulf of Kutch, coastline of Andaman and Ecobar Islands.
2) Barrier reefs are located offshore on continental shelf away and parallel to coastline. They are lagoons located between coastline and barrier reef. For example, the Great Barrier Reef of Australia.
3) Atoll reefs are located on mid-oceanic ridges. So they are circular or elliptical reefs surrounded by sea from all sides with a shallow lagoon in the center. For example, Maldives and the Lakshadweep.
Importance of coral reefs:
They are the source for millions of marine species
They protect the coastline from storms & erosion
Source of new medicines
Assist in carbon and nitrogen fixing as well as nutrient recycling
Provide billions of dollars in revenue for countries from tourism and fishing
Coral bleaching
How does bleaching occur?
When abnormal environmental conditions like warmer sea temperatures occur, it causes corals to expel tiny photosynthetic algae (zooxanthelae) which drains them of their color (calcified corals turn white). Algae are vital to corals because they use organic products of photosynthesis to help them grow. Loss of algae makes it vulnerable to diseases and it will eventually die. When corals are bleached, they are not dead and can recover if water temperature drops and algae are able to recolonize them.
Events implicated in coral reef bleaching:
Temperature rise, solar irradiance, sub aerial exposure, sedimentation, dilution of freshwater, inorganic nutrients, xenobiotics, epizootics, ozone depletion leading to an increase in solar radiation, algae bloom.
Australia’s Great Barrier Reef is the biggest coral reef in the world. It is recorded as a World Heritage Site since 1981. It is located in the Coral Sea in the north-east of Australia. It could suffer a bleaching event every two years by 2034 under the current level of greenhouse gas pollution.
Palau is the first country to ban sunscreen to protect coral reefs. It has banned common ingredients used in cosmetics including oxybenzone found in sunscreens. The Rock Islands in Palau is a UNESCO World Heritage Site. This is because sunscreens absorb UV radiations and make corals susceptible to bleaching. Following Palau, other states like Hawaii in the U.S. has also increased bans.
Some initiative for coral reefs protection
India begins coral restriction in the Gulf of Kutch through the Zoological Survey of India with the help of Gujarat Forest Department with the use of bio rock or mineral accretion technology. It uses a substance formed by electro-accumulation of minerals dissolved in seawater. This technology works by passing a small amount of electrical current through electrodes in water. As a result of process, calcium carbonate is formed and coral larvae adhere to CaCO3 and grow quickly. The International Coral Reef Initiative is an informal partnership between nation and organizations which strive to preserve coral reefs and related ecosystems around the world. The decisions are not binding on the members. It was formed in 1994. ICRI now has about 90 members including India. Under regulatory measures, Coastal Regulation Zone Notification 2018, Island Protection Zone 2019 for Andaman and Nicobar Islands for the holistic development of islands, government planning to open a blue economy, sustainable harnessing of ocean resources and allow ecotourism projects 20 meters from high tide line in smaller islands like Baratang, Havelock, c
Car Nicobar. In case of larger islands, 50 meters from high tide line is permitted. Allowance for ecotourism activities like mangrove walks, tree huts, nature trails in the Island Coastal Regulation Zone. Reef in Schedule 1 of Wildlife Protection Act of 1972 affords it the highest degree of protection. Further protected areas are national parks and sanctuaries. Marine Biosphere Reserve created all over the country under provisions of Wildlife Protection Act of 1972 to conserve marine life like coral reefs. Wildlife Crime Control Bureau set up to strengthen enforcement of law for control of poaching and illegal trade in wildlife and its products. Coastal Ocean Monitoring and Prediction System implemented from 1991 assesses the health of coastal waters and facilitates management of pollution related issues. It was restructured and modified from 2000 to 2001 to include pollution monitoring, liation, regulation and legislation. Land Ocean Interactions in Coastal Lines launched in 1995 investigates effects of global change on coastal zone, aims to develop on scientific basis integrated management of coastal environment. Integrated Coastal and Marine Area Management launched in 1998 aimed at integrated management of coastal and marine areas. Model plans for Chennai, Goa and the Gulf of Kutch being prepared. Society of Integrated Coastal Management launched in 2010 major national initiative to protect coastal ecosystems professional body with experts in various aspects of coastal science management. Institutes for coastal management include National Coastal Zone Management Authority, State Coastal Zone Management Authority for the enforcement and monitoring of CRZ notification. The National Center for Sustainable Coastal Management is a research institute under the Ministry of Environment, Forest and Climate Change. It is with a vision to manage the Indian coast in a sustainable manner located in Chennai. Namami Gange Action Plan is implemented the work program of National Ganga River Basin Authority implementing the World Bank supported National Ganga River Basin project to coordinate and oversee the implementation of projects sanctioned by the government of India under NGRBA and undertake any additional work or functions as may be assigned by the Department of Water Resources Rural Development and GR in the area of conservation of River Ganga make rules and regulations for the conduct of affairs of the NMCG and add or amend very or assign them from time to time except or to provide any grant of money loan securities or property of any kind and to undertake and accept the management of any endowment trust fund or donation not inconsistent with the objectives of NMCG take all such action and to entire and to enter all such actions as may appear necessary or incidental for the achievements of the objectives of the NGRBA. STARCOR stands for Satus and Protection of Coral Reef held at Bangaram Island in the Union Territory of Lakshadweep. Theme of conference Reef for Life.
