1) Corals mostly thrive in clear, sunlit, salt water. Recently a coral reef system was found at
a. Krishna Godavari Delta
b. Mouth of Amazon River
c. Near Andaman and Nicobar Islands
d. In midst of the Nile river
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Answer
Explanation
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ANSWER: Mouth of Amazon River
Explanation:
- A huge 9,300 sq km coral reef system has been found below the muddy waters off the mouth of the river Amazon, astonishing scientists.
- The existence of the 600-mile-long (nearly 966 kilometer) reef, which ranges from about 30-120 m deep and stretches from French Guiana to Brazil’s Maranhao state, was not suspected because many of the world’s great rivers produce major gaps in reef systems where no corals grow.
- In addition, there was little previous evidence because corals mostly thrive in clear, sunlit, salt water, and the equatorial waters near the mouth of the Amazon are some of the muddiest in the world, with vast quantities of sediment washed thousands of miles down the river and swept hundreds of miles out to sea.
- But the reef appears to be thriving below the freshwater “plume,” or outflow, of the Amazon. Compared to many other reefs, the scientists say in a recent paper in Science Advances , it is relatively “impoverished.” Nevertheless, they found over 60 species of sponges, 73 species of fish, spiny lobsters, stars and much other reef life.
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2) For the first time the indigenously-developed Remotely Operated Vehicle (PROVe) is used for
a. Mapping the coral reefs in Andaman & Nicobar Islands
b. Mapping the Indian Ocean Floor
c. Charting course in the Himalayas
d. Work in inaccessible areas for logistics and surveillance
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Answer
Explanation
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ANSWER: Mapping the coral reefs in Andaman & Nicobar Islands
Explanation:
- Andaman and Nicobar Islands of India are the hot-spots of biodiversity with their unique Coral Reef bio-reserve.
- Currently, there is no mechanism other than Scuba diving to examine the corals and assess the extent of damage or rejuvenation that might be taking place since the great damages happened earlier.
- National Institute of Ocean Technology (NIOT), for the first time, used the indigenously-developed Remotely Operated Vehicle (PROVe), to map the coral reefs in Andaman & Nicobar Islands (North Bay and Chidiyatapu) and that the ROV can be used for this purpose efficiently.
- The ROV can effectively map 4-6 sq.km. of coral reefs in a day, whereas the same job takes about a week for a Scuba diver. The images of corals recorded by the ROV are useful to study the biodiversity of coral reefs and their evolution.
- The radiometer attached on the ROV provided the spectral signatures of different types of corals in Andaman.
- The spectral signatures of the corals are valuable in developing algorithms to map the coral reefs using sensing techniques, especially the satellite remote sensing.
- Good news is that there are no evidences of coral bleaching at Andaman reef during the mapping period in April 2016 but will require constant monitoring to know what would happen when the temperature rises further.
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3) Which of the following statements is/are correct about Coral reefs?
1. Coral reefs are rare along the west coasts of the Americas and Africa.
2. Corals are seldom found along the coastline of South Asia
a. Only 1
b. Only 2
c. Both
d. None
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Answer
Explanation
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ANSWER: Both
Explanation:
- Coral reefs are rare along the west coasts of the Americas and Africa. due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas (respectively the Peru, Benguela and Canary streams).
- Corals are seldom found along the coastline of South Asia—from the eastern tip of India (Chennai) to the Bangladesh and Myanmar borders as well as along the coasts of northeastern South America and Bangladesh, due to the freshwater release from the Amazon and Ganges Rivers respectively.
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4) What percent of ocean surface is covered by coral reefs?
a. 0.1%
b. 1%
c. 10%
d. 0.01%
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Answer
Explanation
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ANSWER: 0.1%
Explanation:
- They are Often called "rainforests of the sea"
- Shallow coral reefs form some of the most diverse ecosystems on Earth.
- They occupy less than 0.1% of the world's ocean surface, about half the area of France, yet they provide a home for at least 25% of all marine species,including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians.
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5) Which of the following statements is/are correct about Coral reefs?
1. Coral reefs are diverse underwater ecosystems held together by Calcium iodide.
2. Reefs grow best in cold, shallow, clear, sunny and agitated waters.
a. Only 1
b. Only 2
c. Both
d. None
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Answer
Explanation
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ANSWER: None
Explanation:
- Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals.
- Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups.
- The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish.
- Unlike sea anemones, corals secrete hard carbonate exoskeletons which support and protect the coral polyps.
- Reefs grow best in warm, shallow, clear, sunny and agitated waters.
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