Global Impacts of El Niño: PTE Listening: Fill in the Blanks practice questions

During typical conditions across the tropical Pacific, steady trade winds push surface waters westward, allowing cold, nutrient-rich water to rise along the South American coastline. When an El Niño event develops, these winds weaken considerably, which alters the normal pattern of ocean currents. Without strong upwelling, the supply of vital nutrients drops sharply, causing plankton populations to rapidly. Consequently, coastal fish stocks face severe food shortages, leading to widespread disruptions throughout the marine food web. Marine biologists have observed that commercial fisheries experience substantial financial during these periods, illustrating how atmospheric directly affect biological productivity across vast marine ecosystems.

The eastward migration of warm surface water during an El Niño episode fundamentally reorganises atmospheric moisture transport. Areas that typically enjoy moderate rainfall may experience prolonged , resulting in severe crop failures and water shortages across multiple continents. Meanwhile, typically arid coastal regions often endure torrential downpours that trigger devastating flash floods and across steep hillsides. Meteorologists track these changes through advanced satellite systems, which record subtle variations in sea surface temperatures. Understanding how these tropical thermal anomalies influence distant weather patterns helps regional planners develop more emergency strategies to mitigate damage to agricultural infrastructure and civilian areas.

Elevated sea surface temperatures associated with major El Niño episodes pose an immediate to fragile tropical reef systems worldwide. When water temperatures exceed normal summer thresholds for several consecutive weeks, corals undergo severe physiological and expel their symbiotic algae. This separation leaves the reef structures visibly white, a phenomenon known as mass bleaching. Without their primary source of energy, corals become highly to infectious diseases and starvation. Marine ecologists emphasise that repeated thermal events severely the natural recovery capacity of these ecosystems, threatening countless marine species that rely on healthy coral structures for essential and nursery habitats.