1, Coral Reefs

• These are large underwater structures primarily composed of living organisms known as coral polyps. These polyps secrete calcium carbonate to form hard, rock-like structures. Over time, these structures accumulate and create the complex reef systems that we associate with coral reefs.
• Coral reefs are often referred to as "rainforests of the sea" due to their incredible biodiversity. They provide a habitat to a wide variety of marine species, including fish, mollusks, crustaceans, and other invertebrates.
• These reefs are of immense economic importance as they support fisheries, tourism and other recreational activities, providing livelihoods to millions of people around the world.
• They also act as natural barriers that protect coastlines from the damaging effects of storms, hurricanes, and erosion. They absorb wave energy, reducing the impact on the shore.
• Coral reefs are mostly found in tropical and subtropical waters around the world, particularly in the Pacific, Indian, and Atlantic Oceans. Some of the most famous coral reefs are the Great Barrier Reef in Australia, the Mesoamerican Barrier Reef in the Caribbean, and the Coral Triangle in Southeast Asia.

Growth Conditions for Coral Reefs

• The temperature of the water should not be below 20°C. The most favourable temperature for the growth of the coral reefs is between 23°C to 25°C. The temperature should not exceed 35°C.
• Corals can survive only under saline conditions with an average salinity between 27% to 40%.
• Coral reefs grow better in shallow water having a depth less than 50 m. The depth of the water should not exceed 200m.

Types of Coral Reefs

Coral Reefs are differentiated into three categories based on their shape, nature and mode of occurrence.

1. Fringing Reef: 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. The Fringing Reefs develop along the islands and the continental margins. They grow from the deep bottom of the sea and have their seaward side sloping steeply into the deep sea. Fringing Reefs are the most commonly found coral reefs among the three. For example Sakau Island in New Hebrides, South Florida Reef.
2. Barrier Reef: Barrier Reefs are considered as the largest, highest and widest reefs among the three coral reefs. They develop off the coast and parallel to the shore as a broken and irregular ring. Being the largest reef among the all, they run for 100kms and is several kilometres wide. One example of Barrier Reef is the Great Barrier Reef of Australia which is 1200 mile long.
3. Atolls: An atoll can be defined as a reef that is roughly circular and surrounds a large central lagoon. This lagoon is mostly deep having a depth of 80-150 metres. The atolls are situated away from the deep sea platforms and are found around an island or on a submarine platform in an elliptical form. For example Fiji Atolls, Suvadivo in Maldives and Funafoothis Atoll of Ellice.

Importance of Coral Reefs

• They protect coastlines from the damaging effects of wave action and tropical storms.
• They provide habitats and shelter for many marine organisms.
• They are the source of nitrogen and other essential nutrients for marine food chains.
• They assist in carbon and nitrogen-fixing.
• They help with nutrient recycling.
• The study of coral reefs is essential for scientifically testable records of climatic events over the past million years.
• The fishing industry depends also on coral reefs. Many fish spawn there, and juvenile fish spend time there before making their way to the open sea. The Great Barrier Reef generates more than 1.5 billion dollars annually for the Australian economy from fishing and tourism.
• Coral reefs are also key indicators of global ecosystem health. They serve as an early warning sign of what may happen to other less sensitive systems, such as river deltas if climate change is not urgently addressed.

Coral Reefs in India

India has its coastline extending over 7500 kilometres. It is due to the subtropical climatic conditions, there are a very few coral reefs in India. The major coral reefs in India includes the Palk Bay, the Gulf of Mannar, the Gulf of Kutch, the Andaman and Nicobar Islands and Lakshadweep Islands. Among all these coral reefs, the Lakshadweep reef is an example of atoll while the rest are all fringing reefs.

1. Palk Bay - Situated in the south-east coast of India, Palk Bay is separated from the Gulf of Mannar by the Mandapam Peninsula and the Rameshwaram Island and is centred on 9 °17’N and 79° 15′. The one fringing reef in the Palk Bay is 25-30km long, and less than 200m wide lies in the east-west direction of the Pamban channel. This reef has a maximum depth of around 3 m.
2. The Gulf of Mannar - Situated around a chain of 21 islands, the Gulf of Mannar lies between Tuticorin and Rameswaram at a stretch of 140 km. These 21 islands fall between latitude 8°47′ N and 9° 15′ N and longitude 78° 12′ E and 79° 14’E and form a part of the Mannar Barrier Reef which is 140 km long and 25 km wide.
3. Andaman and Nicobar Islands - The Andaman and Nicobar Islands fall between 6°-14° N lat and 91 °-94° E longitude. They are situated at the south-eastern part of the Bay of Bengal and consist of 350 islands, of which only 38 are inhabited. These islands extend southward from the Irrawaddy Delta of Burma to the Arakan Yoma Range. All the islands of the Andaman and Nicobar groups are almost fringing reefs.
4. The Gulf of Kutch - The Gulf of Kutch is situated in the northern part of Saurashtra Peninsula and is located between 22°15′-23°40′ N Latitude and 68°20′-70°40′ East Longitude having an area of about 7350 sq km. These reefs are of a fringing type and are about 170 km long and 75 km wide at the mouth which narrows down at a longitude of 72° 20′. Due to the mud deposits on various coral reefs, these coral reefs are in a highly degraded condition.
5. Lakshadweep Islands - Located between 8°N – 12°3’N latitude and 71 °E- 74°E longitude, the Lakshadweep Islands which lies scattered in the Arabian Sea are situated at about 225 km to 450 km from the Kerala Coast. The islands covering an area of 32 km2 consist of 36 tiny islands, 12 atolls, 3 reefs and 5 submerged banks, with lagoons occupying about 4200 km². Due to the warm humid climate of these islands, the temperature of the water varies between 28-31 °C with salinity ranging from 34% – 37%.

Coral Bleaching

• The coral and the zooxanthellae share a symbiotic relationship and 90% of the nutrients that are produced by the algae are transferred to the coral hosts. But this relationship gets affected under severe environmental stress which causes the loss of symbiotic algae (zooxanthellae). As a result, the white calcium-carbonate exoskeleton is visible through its transparent tissue leading to a condition known as Coral Bleaching. The corals become vulnerable in the absence of the algae and begin to die if the temperature of the sea remains high for weeks.

Challenges in front of Coral Reefs ecosystem are:

• Climate Change: Rising sea temperatures can lead to coral bleaching, where corals expel the symbiotic algae that provide them with essential nutrients, causing them to lose their colour and vitality. Repeated bleaching events can result in coral death.
• Ocean Acidification: Increased levels of carbon dioxide (CO2) in the atmosphere lead to ocean acidification, where CO2 is absorbed by the oceans. This makes it more difficult for corals to build their calcium carbonate skeletons, weakening the reef structure and its ability to support marine life.
• Overfishing and Destructive Fishing Practices: Overfishing, as well as the use of destructive fishing practices like blast fishing, can deplete fish populations on coral reefs. This disrupts the delicate balance of the ecosystem as some species play key roles in reef health.
• Pollution: Runoff from land-based activities introduces pollutants, such as sediment, agricultural chemicals, and sewage, into coastal waters. These pollutants can reduce water quality, all of which can harm coral reefs.
• Tourism and Recreational Activities: Uncontrolled tourism and recreational activities, such as snorkeling and diving can lead to physical damage to corals.
• Invasive Species: Invasive species, such as crown-of-thorns starfish, can prey on and destroy corals, disrupting the reef ecosystem.

Coral Reef Breakthrough (CRB)

• Basically, the CRB is a science-based initiative with clear goals for the state and non-state actors (like NGOs) to collectively conserve, protect, and restore coral reefs.
• With investments of at least USD 12 billion, the CRB intends to safeguard the future of at least 125,000 km2 of shallow-water tropical coral reefs by 2030, thereby supporting the resilience of more than half a billion people worldwide.
• Achieving the targets of CRB will help in achieving the Sustainable Development Goals (SDGs), particularly SDG14- Life Below Water.
• CRB is based on four action points:

1. 1. To eliminate local factors that pose danger to coral reefs such asland-based sources of pollution, unplanned coastal development, overfishing etc.
   2. To double the area of coral reefs under effective protection and to promote resilience-based coral reef conservation efforts by aligning with global coastal protection targets including 30 by 30. This 30 by 30 is a global initiative to protect at least 30% of the Earth''s land and ocean area by 2030. This initiative was proposed during the UNCCD Conference of Parties (COP15).
   3. To assist in the development and implementation of creative solutions at large scale and to promote climate-smart designs that support coral adaptation to impact 30% of degraded reefs by 2030.
   4. To get investment of at least USD 12 billion by 2030 from public and private sources to conserve and restore the coral ecosystems.

Way Forward

• Efforts to address the above challenges include the establishment of marine protected areas, sustainable fishing practices, pollution control measures, coral restoration initiatives, and global action to reduce greenhouse gas emissions.
• Coral reef conservation requires collaboration among governments, communities, scientists, and conservation organizations to ensure the long-term survival of these valuable ecosystems.

International Coral Reef Initiative (ICRI)

• ICRI is a partnership of governments, international organizations, and the non-governmental organizations dedicated to the preservation and sustainable management of coral reefs and related ecosystems around the world.
• It was established in 1994 in response to growing concerns about the degradation and decline of coral reefs due to various environmental threats, including climate change, overfishing, pollution, and coastal development.
• Presently, ICRI has 101 members, including 45 countries (India is one of them).

Global Fund for Coral Reefs (GFCR)

• GFCR is a finance instrument to integrate action and resources to protect and restore the   coral reef ecosystems.
• Many UN Agencies, states, philanthropies, private investors and organisations have joined it.

High-Level Climate Champions (HLCC)

• HLCCs are appointed by the UN to increase the engagement of non-state actors such as businesses, cities, regions, and investors in supporting the goals of the Paris Agreement.

2, PET 46

• The discovery of PET46 has been made from deep-sea organisms belonging to the archaea domain.
• Archaea is a domain of single-celled microbes lacking cell nuclei and are therefore prokaryotes.
• It has the ability to degrade both very long-chain PET molecules (polymers) and short-chain PET molecules (oligomers), which means that degradation can be continuous.
• It uses a completely different mechanism for substrate binding than previously known PET-degrading enzymes.
• A ''lid'' of 45 amino acids above the enzyme''s active center is crucial for binding, whereas in other PET enzymes, aromatic amino acids close to the active site are typical.

Application of PET46:

• PET46 is similar molecularly to another enzyme- ferulic acid esterase.
• PET46 degrades the natural polymer lignin in plant cell walls by breaking down lignin polymers to release sugars from woody plant parts.
• The lignin and PET have many structural similarities, so the PET-degrading enzymes found in nature may be important for composting wood in forest soils.
• The biochemical properties of PET46 may be useful both for marine and terrestrial plastics and for biotechnology.
• The PET46 is more efficient at 70° Celsius than best-characterized PET-degrading enzymes from bacteria and composting plants at their respective optimum temperatures.

Polyethylene terephthalate (PET) plastic

• Polyethylene terephthalate is one of the most common plastics used in a variety of items from water bottles and product packaging to baby wipes, clothing, bedding and mattresses.
• PET doesn’t readily break down, contributing to plastic pollution.
• Plastics like PET can break down into tiny pieces called microplastics, which are prevalent in our oceans, bays, lakes, and even drinking water.
• Plastics break down into tiny pieces, but they never go away, as petroleum-derived plastic is not biodegradable.
• Microplastics are often consumed by aquatic life, both large and small and eventually leading to accumulation in humans.

3. Manis Mysteria

• Adding to the eight known species of pangolins, scientists recently discovered a ninth variety, tentatively named “Manis mysteria”.
• It is a newly discovered Pangolin species.
• The newly identified pangolin species emerged from a detailed study of scales seized in China’s Yunnan province in 2015 and 2019.
• This new species is believed to have diverged from its Philippine and Malayan relatives approximately five million years ago.

Pangolins

• They are mammals known for their distinctive appearance and protective scales.
• They are often referred to as "scaly anteaters" due to their characteristic scales and their diet, which primarily consists of ants and termites.
• Pangolins are found in parts of Africa and Asia and are known for their elusive nature and status as the most trafficked mammals in the world.

Features

• They are easily recognizable by their armor-like scales, which cover their bodies. These scales are made of keratin, the same protein found in human hair and nails. They are the only known mammals with this feature.
• When threatened, pangolins can curl into a tight ball, with their scales forming a protective barrier.
• Their diet consists mainly of ants and termites, which they capture using their long tongues (A pangolin’s tongue is longer than its body).
• Pangolins have no teeth; they chew with gravel and and keratinous spines inside the stomach.
• They are most active at night and are solitary creatures.

Threat

• All pangolin species are listed on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
• The Indian pangolin, also called thick-tailed pangolin, is classified as Endangered under the IUCN Red List.

4. Pink Bollworm

• It is one of the most destructive pests of cotton.
• Scientific name: Pectinophora gossypiella
• Distribution: Originally native to India, it is now recorded in nearly all the cotton-growing countries of the world.
• The adults are small moths about 3/8 inch long and are dark brown with markings on the fore wing.
• The larval stage is the destructive and identifiable stage.
• The larvae have distinctive pink bands and can reach a length of ½ inches right before they pupate.

Ecological Threat

• Pink bollworms are major pests of cotton.
• Adults only last for 2 weeks, but females will lay 200 or more eggs.
• Adults lay eggs on cotton bolls; once hatched, the larvae eat the seeds and damage the fibers of the cotton, reducing the yield and quality
• When the larvae mature, they cut out the boll and drop to the ground and cocoon near the soil surface.
• It has also been observed to attack hibiscus, okra, and hollyhock plants.

Prelims - Previous Year Questions (PYQs)

1. "Biorock technology" is talked about in which one of the following situations?

(a) Restoration of damaged coral reefs

(b) Development of building materials using plant residue

(c) Identification of areas for exploration/extraction of shale gas

(d) Providing salt licks for wild animals in forests/protected areas

Ans: (a)

2. Consider the following statements: (2018)

1. Most of the world’s coral reefs are in tropical waters.

2. More than one-third of the world’s coral reefs are located in the territories of Australia, Indonesia and Philippines.

3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Ans: (d)

3. Which of the following have coral reefs? (2014)

(1)  Andaman and Nicobar Islands

(2)  Gulf of Kachchh

(3) Gulf of Mannar

(4) Sunderbans

Select the correct answer using the code given below:

(a) 1, 2 and 3 only

(b) 2 and 4 only

(c) 1 and 3 only

(d) 1, 2, 3 and 4

Ans: (a)

4. The black cotton soil of India has been formed due to the weathering of (2021)

(a) brown forest soil

(b) fissure volcanic rock

(c) granite and schist

(d) shale and limestone

Ans: (b)

5. A state in India has the following characteristics: (2011)

1. Its northern part is arid and semi-arid.

2. Its central part produces cotton.

3. Cultivation of cash crops is predominant over food crops.

Which one of the following states has all of the above characteristics?

(a) Andhra Pradesh

(b) Gujarat

(c) Karnataka

(d) Tamil Nadu

Ans: (b)

6. Consider the following animals (2021):

1. Hedgehog

2. Marmot

3. Pangolin

To reduce the chance of being captured by predators which of the above organisms rolls up/roll up and protects/ protects its/their vulnerable parts?

(a) 1 and 2

(b) 2 only

(c) 3 only

(d) 1 and 3

Ans: (d)

7. Why is there a great concern about the ‘microbeads’ that are released into environment? (2019)

(a) They are considered harmful to marine ecosystems.

(b) They are considered to cause skin cancer in children.

(c) They are small enough to be absorbed by crop plants in irrigated fields.

(d) They are often found to be used as food adulterants.

Ans: (a)

8. In India, ‘extend producer responsibility’ was introduced as an important feature in which of the following? (2019)

(a) The Bio-medical Waste (Management and Handling) Rules, 1998

(b) The Recycled Plastic (Manufacturing and Usage) Rules, 1999

(c) The E-Waste (Management and Handling) Rules, 2011

(d) The Food Safety and Standard Regulations, 2011

Ans: (c)