How does El Nino affects an ecosystem?
An ecosystem is made of plants, tress, animals, soil, humans, etc. To me it seems it affects the marine life(sea level, climate, rainfall), but I'm not quite sure.
Well, what you are saying is true, about it affecting marine life. But it also affects the weather patterns on the North American and South American continents. El Nino can and has produced both droughts and floods, severe weather and the lack thereof, resulting in agricultural destitution. All that affects both you and me, living here in a continental ecosystem. El Nino is caused by a reversal in air pressure systems at the western and eastern ends of the Pacific Ocean. It occurs every three to five years, causing a reversal in the normal progression of the trade winds, which normally blow from east to west. This normal progression causes cold, nutrient-rich water to upwell from the bottom of the Pacific Ocean, resulting in normal weather patterns and good fishing. When El Nino reverses the trade winds, warmer, nutrient-poor water stays, fishing suffers, and severe weather patterns ensue.