Answer: I think that it would be C because blooms are due to eutrophication, which means that there are high levels of phosphate in the water. Phosphate is a main ingredient in pesticides, which can run-off into rivers.
The answer is; Warm water moves to the east instead of to the west
Normally, when the waters in the Pacific warm up, the prevailing winds that blow from east to west drag the warm surface currents westwards and upwelling of cold currents occur at the west coast of South America. However, in El Nino, the Pacific ocean waters heat more than usual. The prevailing winds weaken and begin to blow predominantly towards the east. The warm currents are therefore dragged to the east and cause torrential rains in Western coast South Americas.
A population....... I think
