An oligotrophic environment, often a body of water, is an environment low in nutrients.
In these environments, biomass is generally low but biodiversity is high, because the organisms that evolve in these environments have developed original and specialised strategies.
Consequently, any enrichment (eutrophisation) of these environments would often threaten their biodiversity.
The coral reef environment is very low in nutrients. This oligotrophy is the cause of the incredible biological diversity that has developed there. © Ian Robertson CC by-nc 2.0