Nowadays, though, most are associated with a combination of phenomena including overfishing, warmer waters and, often, the washing into the sea of farm fertilisers and sewage.
然而现在，大多数赤潮与包括过度捕捞、海水升温和经常被冲入海里的农用肥料和污水的联合作用有关。
2
Pollution from sewage or farm waste can cause excess algae growth, starving the water of oxygen and causing fish and other species to die off.
Israel's ban on fertilisers had helped his plan to replace fertiliser with compost made from sewage that otherwise spills into the sea, and turn Gaza into a big organic farm.