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Wetlands, Mangroves and Coral Reefs: Ramsar Sites and PYQs

Exam notes on wetlands, mangroves and coral reefs: the Ramsar Convention, India's famous wetlands, mangrove adaptations, reef types and coral bleaching.

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Wetlands, Mangroves and Coral Reefs: Ramsar Sites and PYQs — GK24 title card
Wetlands, Mangroves and Coral Reefs: Ramsar Sites and PYQs — GK24 title card

A wetland is land that stays wet for all or part of the year, so that water, not soil or air, decides what lives there. The Ramsar Convention defines wetlands as areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including marine water whose depth at low tide does not exceed six metres. Mangroves and coral reefs are two special wetland systems of the coast, and examiners treat the three together because the questions overlap.

Why wetlands matter

Wetlands are called the kidneys of the landscape because they filter sediment and nutrients out of the water that passes through them. They are also called biological supermarkets, since their shallow, nutrient-rich water supports a dense food web. They recharge groundwater, hold flood water, trap carbon in waterlogged peat and break the force of storms before it reaches the land behind. They are among the most productive ecosystems on earth, and also among the fastest disappearing, because they are drained for farmland and built over for cities.

The Ramsar Convention

The Convention on Wetlands was signed on 2 February 1971 in the Iranian city of Ramsar, on the shore of the Caspian Sea, and came into force in 1975. It is the oldest of the modern multilateral environmental agreements and the only one devoted to a single ecosystem type. Its secretariat sits at Gland in Switzerland. India became a party on 1 October 1982, and the first two Indian sites placed on the list were Chilika Lake in Odisha and Keoladeo National Park at Bharatpur in Rajasthan, both entered in 1981. World Wetlands Day is observed on 2 February, the anniversary of the signing.

A site on the Ramsar list whose ecological character has changed, is changing or is likely to change because of pollution, human interference or other causes is put on the Montreux Record. Keoladeo National Park and Loktak Lake are the Indian sites on it. Chilika Lake was placed on the record and then removed in 2002 after a new sea mouth was opened and the lagoon recovered, the first site in Asia to be taken off in this way.

Wetlands of India worth remembering

WetlandStateWhat it is known for
Chilika LakeOdishaLargest brackish water lagoon in India; Irrawaddy dolphins; Nalabana bird sanctuary
Keoladeo National ParkRajasthanBharatpur bird sanctuary; a man-made wetland; World Heritage Site
Loktak LakeManipurFloating mats of vegetation called phumdis; Keibul Lamjao, the only floating national park, home of the sangai deer
Wular LakeJammu and KashmirLargest freshwater lake in India, fed by the Jhelum
Sambhar LakeRajasthanLargest inland saline wetland in India; salt production
Harike WetlandPunjabMan-made wetland at the confluence of the Beas and the Sutlej
BhitarkanikaOdishaMangrove wetland; saltwater crocodile; near Gahirmatha turtle beach

Mangroves

Mangroves are salt-tolerant, or halophytic, trees and shrubs that grow in the intertidal zone of sheltered tropical and subtropical coasts, chiefly in deltas, estuaries and lagoons where a river brings silt to the sea. The soil there is waterlogged, saline and starved of oxygen, and mangroves have three famous adaptations to it. Pneumatophores, or breathing roots, grow upward out of the mud and take in air through pores called lenticels. Stilt or prop roots arch out of the trunk and anchor the tree in soft mud against tide and wave. Vivipary means the seed germinates while still attached to the parent plant and drops as a ready seedling, which can root before the tide carries it away. Many species also excrete surplus salt through glands on the leaves.

The Sundarbans, in the delta of the Ganga, Brahmaputra and Meghna and shared between India and Bangladesh, is the largest mangrove forest in the world. It is named after the sundari tree, it holds the only mangrove population of the Royal Bengal tiger, and the Indian part is a national park, a biosphere reserve and a World Heritage Site. Bhitarkanika in Odisha is the next largest mangrove tract in India, Pichavaram in Tamil Nadu and Coringa in Andhra Pradesh are the other well-known ones. Among the states West Bengal has the largest mangrove cover, followed by Gujarat. The International Day for the Conservation of the Mangrove Ecosystem falls on 26 July.

Coral reefs

A coral reef is built by coral polyps, tiny animals of the phylum Cnidaria that secrete a skeleton of calcium carbonate around themselves; generation upon generation of skeletons make the reef. Inside the tissue of the polyp live single-celled algae called zooxanthellae, which photosynthesise, pass food to the polyp and give the reef its colour. Because that partnership needs sunlight, reefs grow only in clear, shallow, warm sea water, roughly between 20 and 30 degrees Celsius, with normal salinity and little silt, which is why reefs are absent at river mouths. Reefs cover a very small part of the ocean floor yet shelter a large share of its species, so they are called the rainforests of the sea.

Reefs are of three forms. A fringing reef lies against the shore itself. A barrier reef runs parallel to the coast with a lagoon between, the Great Barrier Reef off Queensland in Australia being the largest. An atoll is a ring of reef around a central lagoon, formed, as Charles Darwin argued, when a volcanic island subsides while the reef around it keeps growing upward. India has four major reef areas: the Gulf of Mannar and the Gulf of Kachchh, which are fringing, the Andaman and Nicobar Islands, and Lakshadweep, which is atoll country. The Gulf of Mannar was declared India's first marine biosphere reserve.

When sea water stays too warm for too long the polyp expels its zooxanthellae, the reef loses colour and turns white. This is coral bleaching. A bleached coral is not yet dead and can recover if the stress passes, but prolonged bleaching kills it. Ocean acidification, caused by the sea absorbing carbon dioxide, makes it harder for polyps to build their calcium carbonate skeletons, and silt, sewage, trawling and reef mining finish the damage.

Protection in India

Wetlands outside forests are governed by the Wetlands (Conservation and Management) Rules, 2017, which forbid setting up industry, dumping waste and permanently converting a notified wetland. Mangroves and coral reefs are treated as ecologically sensitive areas under the coastal regulation zone notification, and both are protected inside national parks and sanctuaries under the Wild Life (Protection) Act, 1972. The National Plan for Conservation of Aquatic Ecosystems merged the older wetland and lake programmes into a single central scheme.

Exam Point of View

Four kinds of question come from this chapter. First, the Ramsar facts: the year and place of signing, the year India joined, World Wetlands Day on 2 February, and the meaning of the Montreux Record. Second, site to state matching, where Chilika, Keoladeo, Loktak, Wular, Sambhar and Harike are asked again and again, often as a pair with a river or a species; the trap is a look-alike name from another state, as with Surinsar-Mansar. Third, mangrove biology: pneumatophores, vivipary, stilt roots and the Sundarbans as the largest such forest. Fourth, coral reefs: zooxanthellae, the conditions corals need, the three reef forms, Darwin's theory of atolls and India's four reef areas. Avoid memorising the current number of Ramsar sites, because it rises with every new designation and the figure in an old book is already wrong.

Important Facts

Ramsar Convention signed2 February 1971, at Ramsar, Iran; in force 1975
India joined Ramsar1 October 1982
First Indian Ramsar sitesChilika Lake (Odisha) and Keoladeo National Park (Rajasthan), 1981
World Wetlands Day2 February
Largest freshwater lake in IndiaWular Lake, Jammu and Kashmir
Largest brackish lagoon in IndiaChilika Lake, Odisha
Largest inland saline wetlandSambhar Lake, Rajasthan
Only floating national parkKeibul Lamjao on Loktak Lake, Manipur
Largest mangrove forestThe Sundarbans, shared by India and Bangladesh
Mangrove day26 July, International Day for the Conservation of the Mangrove Ecosystem
Coral symbiontZooxanthellae, algae living inside the polyp
First marine biosphere reserveGulf of Mannar
Wetland rules in IndiaWetlands (Conservation and Management) Rules, 2017

Practice MCQs on this topic

Q1.Environment & EcologyAsked in: Uttar Pradesh · 24 Oct, 2021Medium

Which of the following Ramsar sites is not situated in Uttar Pradesh?

  1. A.Sur Sarovar
  2. B.Samaspur Bird Sanctuary
  3. C.Sarsai Nawar Jheel
  4. D.Surinsar-Mansar Lakes
Show answer

Correct answer: D. Surinsar-Mansar Lakes

Explanation

The correct answer is D, Surinsar-Mansar Lakes. These twin lakes lie near Jammu in the Jammu and Kashmir region, not in Uttar Pradesh, so they are the odd one out in this list. Option A is wrong because Sur Sarovar, also called Keetham Lake, lies close to Agra in Uttar Pradesh and is named after the poet Surdas. Option B is wrong because the Samaspur Bird Sanctuary is in the Rae Bareli district of Uttar Pradesh and is a winter haven for migratory waterfowl. Option C is wrong because Sarsai Nawar Jheel lies in the Etawah district of Uttar Pradesh and is known for the sarus crane, the state bird. The trap in such questions is that the names sound alike; fix the state of each site by the district it belongs to, and remember that Uttar Pradesh holds a large cluster of Ramsar wetlands along the Ganga plain.

Q2.Environment & EcologyAsked in: UPSC Civil Services · 24 Aug 2014Hard

Consider the following pairs of wetlands and the confluence of rivers they lie at:

  1. Harike Wetland – confluence of the Beas and the Sutlej
  2. Keoladeo Ghana National Park – confluence of the Banas and the Chambal
  3. Kolleru Lake – confluence of the Musi and the Krishna

Which of the above pairs is/are correctly matched?

  1. A.1 only
  2. B.2 and 3 only
  3. C.1 and 3 only
  4. D.1, 2 and 3
Show answer

Correct answer: A. 1 only

Explanation

The correct answer is A, 1 only. The Harike Wetland in Punjab was created by building a barrage just below the point where the Beas joins the Sutlej, so the first pair is correct and it is the only one. Option B is wrong because it accepts the second pair, and Keoladeo Ghana National Park at Bharatpur is a man-made wetland fed by the Gambhir and Banganga through the Ajan Bandh, not a site at the meeting of the Banas and the Chambal. Option C is wrong because it accepts the third pair, and Kolleru Lake in Andhra Pradesh lies between the deltas of the Krishna and the Godavari, drained by the Upputeru, and not at any confluence of the Musi with the Krishna. Option D is wrong because it accepts both of those mismatched pairs. In matching questions of this kind, one certain pair is often enough to reach the answer by elimination.

Q3.Environment & EcologyEasy

The Convention on Wetlands, known as the Ramsar Convention, was signed in 1971 in which country?

  1. A.Iran
  2. B.Iraq
  3. C.Switzerland
  4. D.Kenya
Show answer

Correct answer: A. Iran

Explanation

The correct answer is A, Iran. The convention takes its name from Ramsar, a town on the Caspian coast of Iran, where it was signed on 2 February 1971; it came into force in 1975 and is the oldest of the modern global environmental treaties. Option B is wrong because Iraq, though a neighbour of Iran, has no connection with the signing. Option C is wrong for a reason worth noting: Switzerland hosts the secretariat of the convention at Gland, so it is the administrative home of the treaty, but not the place of signature, and this is exactly the confusion the option is placed to create. Option D is wrong because Kenya is the seat of the United Nations Environment Programme at Nairobi, another agency easily mixed up with wetland administration. Remember the pair: signed at Ramsar in Iran, administered from Gland in Switzerland.

Q4.Environment & EcologyEasy

World Wetlands Day is observed every year on which date?

  1. A.22 March
  2. B.2 February
  3. C.5 June
  4. D.26 July
Show answer

Correct answer: B. 2 February

Explanation

The correct answer is B, 2 February, the anniversary of the signing of the Ramsar Convention in 1971, which is why the day carries that date. Option A is wrong because 22 March is World Water Day, about fresh water in general rather than wetlands, and it is the commonest wrong choice here. Option C is wrong because 5 June is World Environment Day, observed to mark the opening of the Stockholm Conference of 1972. Option D is wrong because 26 July is the International Day for the Conservation of the Mangrove Ecosystem, which is about one wetland type only and is itself a favourite examination fact. Keeping these four dates apart is the whole point of the question, so learn them as a set: 2 February wetlands, 22 March water, 5 June environment, 26 July mangroves.

Q5.Environment & EcologyMedium

Keibul Lamjao, the only floating national park in the world, lies on which lake?

  1. A.Wular Lake
  2. B.Chilika Lake
  3. C.Loktak Lake
  4. D.Kolleru Lake
Show answer

Correct answer: C. Loktak Lake

Explanation

The correct answer is C, Loktak Lake, the large freshwater lake of Manipur whose surface carries floating mats of soil and vegetation called phumdis. Keibul Lamjao National Park rests on these mats and is the last natural home of the sangai, the brow-antlered deer of Manipur. Option A is wrong because Wular Lake in the Jhelum valley is the largest freshwater lake in the country but has no floating park. Option B is wrong because Chilika in Odisha is a brackish lagoon famous for Irrawaddy dolphins and the Nalabana bird sanctuary, not for phumdis. Option D is wrong because Kolleru Lake in Andhra Pradesh, between the Krishna and the Godavari deltas, is a shallow freshwater lake known for pelicans. Link the three words together in revision: Loktak, phumdi, sangai, all in Manipur, and remember that Loktak is on the Montreux Record.

Q6.Environment & EcologyEasy

Which of the following is the largest mangrove forest in the world?

  1. A.Bhitarkanika
  2. B.The Sundarbans
  3. C.Pichavaram
  4. D.Coringa
Show answer

Correct answer: B. The Sundarbans

Explanation

The correct answer is B, the Sundarbans, which spreads over the delta of the Ganga, the Brahmaputra and the Meghna and is shared between India and Bangladesh. It is named after the sundari tree, holds the only mangrove population of the Royal Bengal tiger, and the Indian portion is a national park, a biosphere reserve and a World Heritage Site. Option A is wrong because Bhitarkanika in Odisha, though the next largest mangrove tract in India and famous for the saltwater crocodile, is much smaller. Option C is wrong because Pichavaram in Tamil Nadu is a compact mangrove of about a thousand hectares, visited for its boat channels. Option D is wrong because Coringa lies in the Godavari delta of Andhra Pradesh and is a sanctuary of modest size. Note also that among Indian states West Bengal has the largest mangrove cover, followed by Gujarat.

Q7.Environment & EcologyMedium

The upward growing breathing roots of mangrove plants are called:

  1. A.Pneumatophores
  2. B.Haustoria
  3. C.Velamen roots
  4. D.Tap roots
Show answer

Correct answer: A. Pneumatophores

Explanation

The correct answer is A, pneumatophores. Mangrove mud is waterlogged and short of oxygen, so these roots grow vertically out of the soil and take in air through small pores called lenticels; they are the classic adaptation asked about in examinations, along with stilt roots and vivipary. Option B is wrong because haustoria are the absorbing organs of parasitic plants such as Cuscuta, which draw food from a host, a matter of parasitism and not of respiration. Option C is wrong because velamen is the spongy covering on the hanging roots of epiphytic orchids, which absorbs moisture from humid air and belongs to a very different habitat. Option D is wrong because a tap root is the ordinary single main root of a dicotyledonous plant and has no special role in breathing. Remember the trio for mangroves: pneumatophores, stilt roots and viviparous seeds.

Q8.Environment & EcologyMedium

The algae that live inside coral polyps and give reefs their colour are called:

  1. A.Diatoms
  2. B.Zooxanthellae
  3. C.Sargassum
  4. D.Chlorella
Show answer

Correct answer: B. Zooxanthellae

Explanation

The correct answer is B, zooxanthellae. These single-celled algae live within the tissue of the coral polyp, photosynthesise, hand most of the food they make to the polyp and give the reef its colour; the polyp in return offers shelter and nutrients, a textbook case of symbiosis. When heat stress makes the polyp expel them the reef turns white, which is coral bleaching. Option A is wrong because diatoms are free-floating algae with silica walls, an important part of marine plankton but not reef symbionts. Option C is wrong because Sargassum is a large brown seaweed that floats in mats, best known from the Sargasso Sea. Option D is wrong because Chlorella is a green alga of fresh water, grown for food supplements and used in laboratory work. Bleaching questions always begin from this partnership, so fix the name firmly.

Q9.Environment & EcologyHard

Which of the following is not one of the four major coral reef areas of India?

  1. A.Gulf of Kachchh
  2. B.Gulf of Mannar
  3. C.Gulf of Khambhat
  4. D.Lakshadweep
Show answer

Correct answer: C. Gulf of Khambhat

Explanation

The correct answer is C, the Gulf of Khambhat. Its water is muddy, its tidal range is among the highest in the country and several rivers empty into it, so the clear, silt-free conditions that corals need are absent; it is known instead for tidal energy potential. Option A is wrong because the Gulf of Kachchh in Gujarat carries fringing reefs and a marine national park, the first of its kind in India. Option B is wrong because the Gulf of Mannar between Tamil Nadu and Sri Lanka has a chain of reef-bearing islands and was declared the country's first marine biosphere reserve. Option D is wrong because Lakshadweep is built of atolls, the ring-shaped reefs of the Arabian Sea, and is the classic Indian example of that reef type. The fourth true reef area, not listed here, is the Andaman and Nicobar Islands.

Q10.Environment & EcologyEasy

A ring shaped coral reef enclosing a central lagoon is known as:

  1. A.A fringing reef
  2. B.A barrier reef
  3. C.An atoll
  4. D.A patch reef
Show answer

Correct answer: C. An atoll

Explanation

The correct answer is C, an atoll. Charles Darwin explained its formation: a fringing reef grows around a volcanic island, the island slowly subsides, the reef keeps growing upward towards the light, and in the end only a ring of reef and a lagoon are left where the island stood. Lakshadweep and the Maldives are the familiar examples. Option A is wrong because a fringing reef lies directly against the shore with little or no lagoon between, the commonest and youngest form. Option B is wrong because a barrier reef runs parallel to the coast but is separated from it by a wide, deep lagoon, the Great Barrier Reef off Queensland being the largest in the world. Option D is wrong because a patch reef is only a small isolated outcrop of coral inside a lagoon or on a shelf, not a landform type in this classification.

Q11.Environment & EcologyMedium

The Montreux Record under the Ramsar Convention is a register of:

  1. A.Newly added wetlands of international importance
  2. B.Listed wetlands whose ecological character is threatened
  3. C.Wetlands that are also World Heritage Sites
  4. D.Wetlands closed to all human activity
Show answer

Correct answer: B. Listed wetlands whose ecological character is threatened

Explanation

The correct answer is B. The Montreux Record lists Ramsar sites where the ecological character has changed, is changing or is likely to change because of pollution, encroachment, siltation or other interference, so that the parties can direct attention and assistance there. From India, Keoladeo National Park and Loktak Lake are on it, while Chilika was entered and then removed in 2002 after restoration, the first Asian site to be taken off. Option A is wrong because a newly designated wetland simply joins the Ramsar List, which is a separate register. Option C is wrong because World Heritage status comes from a different treaty administered by UNESCO and has nothing to do with this record. Option D is wrong because Ramsar rests on wise use rather than exclusion, and fishing and grazing often continue on listed sites.

Q12.Environment & EcologyEasy

Chilika Lake, the largest brackish water lagoon in India, lies in which state?

  1. A.Andhra Pradesh
  2. B.West Bengal
  3. C.Odisha
  4. D.Tamil Nadu
Show answer

Correct answer: C. Odisha

Explanation

The correct answer is C, Odisha. Chilika is a shallow lagoon on the Bay of Bengal coast, separated from the sea by a sandy ridge and joined to it by a narrow mouth, which is why its water is brackish. It was among the first two Indian sites on the Ramsar List, it shelters the Irrawaddy dolphin, and the island of Nalabana within it is a bird sanctuary that fills with migratory birds in winter. Option A is wrong because the large lagoon of Andhra Pradesh is Pulicat, which is shared with Tamil Nadu and ranks second in the country. Option B is wrong because West Bengal is the land of the Sundarbans delta, not of a large lagoon. Option D is wrong because Tamil Nadu has the Point Calimere and Pichavaram wetlands and the southern part of Pulicat, but Chilika does not reach it.

Frequently Asked Questions

Why are wetlands called the kidneys of the landscape?

Because water passing through a wetland slows down, so sediment settles and plants and microbes take up nutrients and pollutants. The water that leaves is cleaner than the water that entered, which is the same service a kidney performs for the body.

What is the difference between the Ramsar List and the Montreux Record?

The Ramsar List names wetlands of international importance designated by their countries. The Montreux Record is a shorter register within it, holding only those listed sites whose ecological character has changed or is under threat and which therefore need priority attention.

What is a phumdi?

A phumdi is a floating mat of soil, decaying plant matter and living vegetation found on Loktak Lake in Manipur. The largest phumdi carries Keibul Lamjao National Park, the only floating national park in the world and the last home of the sangai deer.

Why do coral reefs not grow near the mouths of large rivers?

River mouths bring fresh water and silt. The fresh water lowers salinity below what corals tolerate, and the silt clouds the water and settles on the polyps, cutting the sunlight that their zooxanthellae need for photosynthesis.

Is a bleached coral dead?

Not immediately. Bleaching means the polyp has expelled its zooxanthellae and lost its colour. If the water cools and the stress passes, the algae can return and the coral recovers; if the stress lasts, the polyp starves and the reef dies.

Sources

  • The Convention on Wetlands and its Mission — Ramsar Convention Secretariat
  • Wetlands (Conservation and Management) Rules, 2017 — Ministry of Environment, Forest and Climate Change
  • Biology, Class XII, Chapter on Ecosystem and Biodiversity — NCERT
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