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Which of the following are the results of El Nino? 1. Reduction in the amount of planktons which further reduces the number of fish in the sea. 2. Irregularities in the evaporation of sea water. 3. Distortion of equatorial atmospheric circulation. Select the correct answer using the code given below :
Explanation
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), characterized by the unusual warming of surface waters in the eastern tropical Pacific [6]. This phenomenon has significant biological and physical impacts. First, it suppresses the normal upwelling of nutrient-rich cold water, leading to a drastic reduction in phytoplankton (plankton) populations, which causes starvation in the marine food web and a subsequent decline in fish populations [7]. Second, the anomalous warming of sea surface temperatures (SST) creates irregularities in evaporation and precipitation patterns, leading to heavy rains in some regions and severe droughts in others [5]. Third, El Niño is intrinsically linked to the Southern Oscillation, which involves a see-saw shift in surface air pressure and a distortion of the equatorial atmospheric circulation, specifically affecting the Walker Circulation and general atmospheric patterns [5]. Therefore, all three statements are correct results of El Niño.
Sources
- [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > el nino (southern oscillation) and indian Monsoon > p. 54
- [6] https://svs.gsfc.nasa.gov/12176
- [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 29: El Nino, La Nina & El Nino Modoki > Effects of El Nino & ENSO > p. 414
- [7] https://education.nationalgeographic.org/resource/el-nino/
- [5] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > Possible Causes of El-Nino > p. 13
- [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 29: El Nino, La Nina & El Nino Modoki > El Nino Southern Oscillation (ENSO) > p. 413
- [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 9: Atmospheric Circulation and Weather Systems > General Atmospheric Circulation and its Effects on Oceans > p. 80