Oligotrophic and eutrophic lakes can be described in terms of productivity, in which an oligotrophic lake, tanks to its low nutrient level and generally inhospitable environment for life, is said to be less productive while the more life-sustaining eutrophic lake type is said to be more productive.
In general, lakes can progress from being oligotrophic when they are first formed to being eutrophic as they mature and gain the qualities of a life-sustaining ecosystem. For example, a lake that forms in a land depression caused by a receding glacier may start out with very little life and nutrients, but microorganisms that are able to gain a foothold there begin digesting and composting organic material, making for a more fertile nutrient base that beings to sustain more plant life.
