bloom

Whitish powdery or waxlike coating over the surface of certain fruits that easily rubs off when handled. It often contains yeasts that live on the sugars in the fruit.

The term bloom is also used to describe a rapid increase in number of certain species of algae found in lakes, ponds, and oceans.

Algal blooms may be natural but are often the result of nitrate pollution, in which artificial fertilizers, applied to surrounding fields, leach out into the waterways. This type of bloom can lead to the death of almost every other organism in the water; because light cannot penetrate the algal growth, the plants beneath can no longer photosynthesize and therefore do not release oxygen into the water. Only those organisms that are adapted to very low levels of oxygen survive.