With reference to the "EL-NINO", which of the following statement/s is/are correct? (1) El-Nino involves appearance of a warm current off the coast of Peru in the eastern Pacific. (2) This warm current increases the temperature of water on the Peruvian coast, thereby increasing the amount of plankton in the sea. Select the correct answer using the code given below:
- (a)Only 2
- (b)Both 1 and 2
- (c)Only 1
- (d)Neither 1 nor 2
Correct — C, Only 1. Statement 1 is right: El Nino is marked by the appearance of an abnormally warm current off the coast of Peru in the eastern equatorial Pacific, displacing the usual cold Peru (Humboldt) Current. Statement 2 is wrong: that warm surface water SUPPRESSES the upwelling of cold, nutrient-rich water along the Peruvian coast, so plankton — and the anchovy fisheries that feed on it — DECLINE sharply. El Nino reduces plankton, it does not increase it. Since only statement 1 holds, the answer is 'Only 1'.
- (a)Only 2 — This reverses the truth: statement 2 (that El Nino increases plankton) is precisely the FALSE one, while statement 1 is correct.
- (b)Both 1 and 2 — Statement 2 is false — El Nino cuts off cold-water upwelling and reduces plankton — so both statements cannot be correct.
- (d)Neither 1 nor 2 — Statement 1 is a correct textbook description of El Nino (a warm current off Peru), so 'neither' is wrong.
El Nino is the warm phase of the El Nino-Southern Oscillation (ENSO). Normally, strong Pacific trade winds pile warm water in the west while cold, nutrient-rich water upwells off Peru, feeding vast plankton and anchovy stocks. During El Nino the trade winds weaken, warm water spreads east to the South American coast, upwelling is choked off, plankton and fisheries collapse, and global weather is disrupted — including a weaker Indian south-west monsoon.
The question targets one classic misconception — that warm El Nino water boosts marine life. The opposite is true: the warm surface layer caps the cold nutrient upwelling and starves plankton. Statement 1 is textbook-correct, so spotting statement 2 as the flawed one yields 'Only 1'.
- El Nino = appearance of a warm current off Peru in the eastern equatorial Pacific, replacing the cold Peru/Humboldt Current.
- It suppresses cold-water upwelling, so plankton and anchovy fisheries DECLINE — a fishery collapse, not a bloom.
- El Nino typically weakens the Indian south-west monsoon; La Nina generally strengthens it.
- El Nino is the warm phase of ENSO; the Spanish name ('the boy child') reflects its usual onset around Christmas off Peru.
Statement 1 (warm current off Peru) is true; statement 2 (more plankton) is false — El Nino reduces plankton.
- Believing warm El Nino water increases plankton/fish (it decreases them).
- Confusing El Nino (warm) with La Nina (cold) and their opposite effects on the monsoon.
Statement-based ENSO questions — they test the direction of the temperature anomaly, the upwelling/plankton effect, and the impact on the Indian monsoon.
A new type of El Nino called El Nino Modoki appeared in the news. In this context, consider the following statements: 1. Normal El Nino forms in the Central Pacific ocean whereas El Nino Modoki forms in Eastern Pacific ocean. 2. Normal El Nino results in diminished hurricanes in the Atlantic ocean but El Nino Modoki results in a greater number of hurricanes with greater frequency. Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer(b) 2 only
Both hinge on where El Nino warming appears in the Pacific — classic El Nino warms the eastern Pacific off Peru, tested here via the Modoki (central-Pacific) variant.
La Nina is suspected to have caused recent floods in Australia. How is La Nina different from El Nino? 1. La Nina is characterised by unusually cold ocean temperature in equatorial Indian Ocean whereas El Nino is characterised by unusually warm ocean temperature in the equatorial Pacific Ocean. 2. El Nino has adverse effect on south-west monsoon of India, but La Nina has no effect on monsoon climate. Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer(d) Neither 1 nor 2
Same ENSO concept — El Nino as warm equatorial-Pacific water and its monsoon effect, contrasted with La Nina.
- practice — not a real PYQ
During an El Nino year, the Indian south-west monsoon most commonly:
- (a)Strengthens
- (b)Weakens
- (c)Is unaffected
- (d)Reverses direction
Answer(b) Weakens — El Nino is generally associated with a weaker, deficient Indian monsoon.
- practice — not a real PYQ
The cold, nutrient-rich current that normally flows along the Peruvian coast is the:
- (a)Kuroshio Current
- (b)Humboldt (Peru) Current
- (c)Benguela Current
- (d)Gulf Stream
Answer(b) Humboldt (Peru) Current — its upwelling supports rich anchovy fisheries, which El Nino disrupts.