Recent studies have revealed that 50 % of the world's coral reefs have already been destroyed, and another 40% could be lost over the next 30 years. The majority of coral reefs are found in shallow water near the shore. As a result, they are particularly vulnerable to the effects of human activities, both directly through the exploitation of reef resources and indirectly from human activities on land and in the coastal zone. Many of the human activities that degrade coral reefs are intricately linked to regional coastal communities' social, cultural, and economic fabric. Chronic threats include overfishing, pollution, and coastal development. Other threats include climate change, ocean acidification, pollution, coral bleaching, alien species invasion, unsustainable tourism, and more. This article will explain to you the Threats to Coral Reefs which will be helpful in Environment preparation for the UPSC Civil Service Exam.

What Are Coral Reefs?

• Coral reefs are large underwater structures made up of the skeletons of coral, which are colonial marine invertebrates.
• Coral reefs are built and maintained by thousands of tiny animals known as coral "polyps," which are related to anemones and jellyfish.
• Corals are cemented calcareous rocky masses that grow upwards and outwards as tubular skeletons.

The Importance Of Coral Reefs

• Coastal Protection: Coral reefs act as a barrier, shielding coastal communities from strong ocean currents and waves.
• They protect against ocean storms and cyclones. With the increased frequency of cyclones in India as a result of climate change, natural barriers have become increasingly important.
• Source Of Food Supply: Fish that live in and around coral reefs provide a healthy source of protein to billions of people, the majority of whom live along coastlines.
• Some fishing industries rely entirely on coral reefs and the wildlife they attract.
• Medicinal Properties Some of the fish that the corals attract leave chemical compounds.
• Tourism: Reefs provide food, income, and protection to over half a billion people. Local businesses benefit from fishing, and diving on and near reefs.

Threats to Coral Reefs

• Coral reefs are affected by various human and non-human factors.
• To create inexpensive land and foster economic development, certain coral reefs are covered with sand, rock, and concrete.
• Others are dredged or blasted for the limestone they contain or to improve navigational access and safety.
• Coral reefs are also affected by long-term changes in the oceans and atmosphere (increasing sea temperatures and CO2 levels), as well as acute stresses such as extremely changeable seasons, strong storms, earthquakes, and volcanic eruptions.

Overfishing

• A study shows that Overfishing has destroyed 55 percent of the world's coral reefs.
• Overfishing of deep-water commercial fish and vital reef species has resulted from rising demand for food fish and tourism.
• Overfishing of certain species near coral reefs has the potential to disrupt the biological balance and biodiversity of the reef.
• Overfishing of herbivorous fish, for example, can result in excessive algal growth.
• When fish numbers decline, especially those that eat algae, algae can grow out of control, suffocating corals.

Climate Change

• In a decade, global warming has killed 14 % of the world's coral reefs, and more will be wiped away if ocean temperatures continue to rise.
• The greatest danger to coral reefs is climate change.
• Since pre-industrial times, anthropogenic greenhouse gas emissions have produced a 1°C increase in global surface temperature.
• As a result of this, unprecedented mass coral bleaching episodes have occurred, making coral reefs one of the most vulnerable ecosystems on the planet.
• Corals eject the symbiotic algae dwelling in their tissues, which are responsible for their color when environmental factors such as temperature change.
• Bleaching can occur when one coral that has been bleached for an extended period of time will finally perish.

Coral Bleaching

• When corals lose their brilliant colors and turn white, this is known as coral bleaching.
• Bleaching or the paling of coral color occurs when
• the density of zooxanthellae decreases and/or
• the concentration of photosynthetic pigments inside the zooxanthellae decreases.
• Coral is brilliant and colorful due to zooxanthellae, a type of microscopic algae.
• The zooxanthellae live in a mutually beneficial relationship within the coral, one assisting the other to survive.
• When coral is stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.

*To know more about the topic, click this link Coral Bleaching

Destructive Fishing Method

• Explosive fishing, cyanide fishing, and other practices devastate the fragile coral reef and make them unsustainable.
• The fish are stunned with dynamite and cyanide, making them easier to catch.
• Fishermen claim they have no other choice if they want to compete with trawlers and overcome a lower fish supply due to earlier overfishing.
• These procedures rarely select or target specific fish species, and they frequently result in the death of coral reefs.
• Damage to the coral reef habitat on which the fish rely will lower the area's productivity, further affecting fishermen's livelihoods.

Invasive Species

• A non-native species that have been introduced to a region and has a negative economic, ecological, or environmental impact on the local ecosystem is known as an invasive species.
• Due to a lack of competition or predation from native creatures, invasive species spread and thrive in the environments they invade.
• The lionfish, which is native to the Pacific and is currently invading the Caribbean Sea and Atlantic due to its ravenous appetite and lack of natural predators, is often referred to as an invasive species in the context of coral reefs.
• The lionfish invasion can disrupt a coral reef ecosystem through a number of mechanisms.
• The predation of natural herbivores is one hypothesized mechanism. Because of their aggressive appetite, lionfish have the ability to wipe out all grazers in a coral reef environment.
• The ecology is very prone to massive algal blooms once all of the grazers have been predated.
• Overgrowth of algae can destroy coral reefs by blocking sunlight and nutrients from reaching the coral, causing the symbiotic interaction between the coral and zooxanthellae to break down. This could result in widespread coral bleaching.

Unsustainable Tourism

• Tourism pressures, on the other hand, might harm the ecosystem on which the sector depends if they are left unchecked.
• Contact with reckless swimmers, divers, and badly set boat anchors can cause physical damage to coral reefs.
• Untreated sewage and wastewater from hotels and resorts may also be discharged into the ocean, contaminating the water and stimulating the growth of algae, which competes with corals for space on the reef.

Coastal Development

• The development of coastal settlements and towns poses a variety of dangers to coral reefs in the area.
• Airports and other development projects may be built on land recovered from the sea if space is restricted.
• Dredging efforts for deep-water channels or marinas, as well as the dumping of waste materials, can harm or disturb sensitive habitats.
• Greater amounts of fresh water, fertilizers, and sediment can reach the reefs when land expansion changes the natural flow of water, causing severe damage.

Global Aquarium Trade

• According to recent surveys, nearly 2 million individuals keep marine aquariums around the world.
• The vast majority of marine aquariums are supplied with wild-caught species. The transfer of iconic fish species across borders is a result of this rapidly increasing trade.
• The use of cyanide in the collection, over-harvesting of target organisms, and high levels of mortality related to inadequate husbandry standards and insensitive shipping are all threats posed by the trade.
• Some regulations have been put in place to encourage the adoption of environmentally friendly collection methods and enhance industry standards.

Sedimentation

• Only a few cases of coral bleaching have been connected to sedimentation alone.
• Coastal development, urban stormwater runoff, forestry, and agriculture all contribute to sedimentation.
• Sedimentation has been identified as a major stressor for coral species and their environments' survival and recovery.
• Sediment accumulated on reefs can suffocate corals, preventing them from feeding, growing, and reproducing.

Other Threats

• Ocean Acidification: The increasing acidification of the ocean occurs when oceans absorb massive amounts of carbon dioxide released into the atmosphere by the combustion of fossil fuels.
• The rise in carbon dioxide levels increases the acidity of ocean water and inhibits the ability of corals to create calcareous skeletons.
• High amounts of solar radiation lead to the decline of coral due to global warming.
• Water Pollution: Water pollution caused by agricultural pesticides and fertilizers, oil and gasoline, sewage discharge, and sediment from eroded landscapes make it difficult for coral to thrive.
• It harms the complex relationships that exist between the plants, coral, and other animals that make up the reef ecosystem.
• Bacterial Infection: The prevalence of coral disease appears to have increased considerably during the last ten years, contributing to the global decline of coral reef communities.
• The majority of diseases are caused by bacteria, fungi, and viruses.
• Because the coral disease has been proven to proliferate after coral bleaching events, the evidence for a link between warmer-than-normal water and coral disease is growing.

Government Actions

International Coral Reefs Initiative (ICRI)

• The International Coral Reef Initiative (ICRI) is indeed a broad alliance of nations and organizations working to protect coral reefs and related ecosystems all over the world.
• Australia, France, Japan, Jamaica, the Philippines, Sweden, the United Kingdom, and the United States of America launched the Initiative in 1994.
• India is a member of the International Conference on Religion and Development (ICRI).
• The following are the main objectives:
• Encourage the use of best practices for the long-term management of coral reefs and their ecosystems.
• Capacity Building
• Raise global awareness of the plight of coral reefs at all levels.
• The International Coral Reef Initiative (ICRI) has designated 2018 as the third International Year of the Reef (IYOR).

Global Coral Reef Monitoring Network

• The International Coral Reef Initiative's Global Coral Reef Monitoring Network (GCRMN) is an operational network that strives to offer the best available scientific information on the status and trends of coral reef ecosystems for conservation and management.
• The Global Coral Reef Monitoring Network (GCRMN) is a global network of scientists, managers, and organizations that track the health of coral reefs across the world.
• The GCRMN is made up of ten regional nodes.
• The Status of Coral Reefs of the World report, which describes the status and trends of coral reefs around the world, is the GCRMN's flagship publication.

International Coral Reef Action Network (ICRAN)

• The International Coral Reef Action Network (ICRAN) is a non-profit organization (ICRAN)
• ICRAN is a global alliance of business and governmental organizations working to address coral reef ecosystem management and the needs of the communities that rely on them.
• It works to strengthen reef management by sharing and promoting traditional knowledge, current research, and best practices.

Coral Triangle Initiative

• The Coral Triangle Initiative on Coral Reefs, Fisheries, and Food Security (CTI-CFF) is sometimes known as the Coral Triangle Initiative (CTI).
• At the junction of the Western Pacific and Indian Oceans, the "Coral Triangle" (CT) region is located near the equator.
• It is multinational cooperation of six countries focused on coral reefs, fisheries, and food security (Indonesia, Malaysia, Philippines, Papua New Guinea, Solomon Islands, and Timor-Leste).
• They collaborate to ensure the long-term viability of marine and coastal resources by addressing critical concerns like food security, climate change, and marine biodiversity which pose a threat to the corals.

Conclusion

The majority of coral reefs are found in shallow water near the shore. As a result, they are particularly vulnerable to the effects of human activities, both directly through the exploitation of reef resources and indirectly from human activities on land and in the coastal zone. Many of the human activities that degrade coral reefs are intricately linked to regional coastal communities' social, cultural, and economic fabric.

FAQs

MCQs

1. Which of the following is a major cause of coral bleaching?

A) Ocean acidification
B) Rising sea temperatures
C) Overfishing
D) Coastal erosion

2. Which factor contributes to ocean acidification?

A) Increase in sea temperature
B) Pollution from fertilizers
C) Excess carbon dioxide in the atmosphere
D) Coastal development

3. Which of the following is a direct impact of coral reef destruction?

A) Increased biodiversity
B) Enhanced coastal protection
C) Loss of marine species habitat
D) Reduced ocean acidification

4. Which of the following measures is most effective in preventing coral reef damage?

A) Using plastic materials in construction
B) Establishing marine protected areas
C) Increasing fishing activities
D) Allowing unrestricted coastal development

5. Which human activity is directly linked to coral reef degradation?

A) Renewable energy production
B) Destructive fishing practices
C) Organic farming
D) Recycling of plastic waste

GS Mains Questions and Model Answers

Q1: Discuss the major threats to coral reefs and their implications for marine biodiversity.

Answer: Coral reefs face several major threats, including climate change, ocean acidification, pollution, overfishing, and coastal development. Climate change leads to coral bleaching, where corals expel their symbiotic algae due to rising sea temperatures, weakening their resilience. Ocean acidification, caused by excess CO2, reduces the availability of calcium carbonate, which corals need to build their skeletons. Pollution, particularly plastic and chemical waste, harms coral health, while overfishing depletes the fish species that rely on the reefs. Coastal development often leads to habitat destruction and increased sedimentation, which smothers coral reefs. These threats not only affect coral health but also disrupt marine biodiversity by reducing the habitat available for fish and other marine organisms, ultimately affecting the livelihoods of coastal communities.

Q2: How can coral reef conservation contribute to global climate change mitigation efforts?

Answer: Coral reefs contribute to climate change mitigation by acting as carbon sinks, absorbing carbon dioxide from the atmosphere. Healthy reefs also play a vital role in protecting coastal areas from storm surges and erosion, reducing the impact of climate change on coastal populations. By preserving coral reefs, we help maintain their role in carbon sequestration and coastal protection, which can reduce the vulnerability of coastal regions to the effects of climate change. Conservation efforts, such as reducing emissions, promoting sustainable tourism, and limiting overfishing, help protect these ecosystems and contribute to broader climate change mitigation strategies.

Q3: What are the socioeconomic impacts of coral reef degradation in developing countries?

Answer: Coral reef degradation in developing countries has significant socioeconomic impacts. Many coastal communities rely on healthy coral reefs for their livelihoods through fishing, tourism, and coastal protection. As reefs degrade, fish stocks diminish, affecting local economies that depend on fishing. Additionally, coral reef-based tourism declines, reducing income from eco-tourism activities. Degraded reefs also result in a loss of natural coastal protection, making communities more vulnerable to the impacts of storms and rising sea levels. The loss of coral reefs thus not only threatens marine biodiversity but also exacerbates poverty and undermines economic stability in coastal areas, particularly in developing countries.

Previous Year Questions on Coral Reefs

1. UPSC CSE Prelims 2020:

Question: Which of the following is considered a major cause of coral reef degradation?

A) Coastal development
B) Climate change
C) Pollution
D) All of the above

Answer: (D)

Explanation: Coral reef degradation is caused by a combination of factors, including coastal development, climate change, and pollution, all of which contribute to the decline of coral health and biodiversity.

2. UPSC CSE Mains 2019 (GS Paper 3):

Question: Explain the role of coral reefs in the marine ecosystem and the challenges they face due to human activities.

Answer: Coral reefs play a vital role in the marine ecosystem by providing habitat for a wide variety of marine species, acting as nurseries for fish, and maintaining biodiversity. They also offer protection to coastal areas from erosion and storm surges. However, human activities such as overfishing, pollution, and coastal development, as well as the impacts of climate change, including ocean acidification and rising sea temperatures, pose significant threats to coral reefs. Conservation measures, such as marine protected areas, sustainable fishing practices, and reducing emissions, are crucial to preserving these ecosystems for future generations.