Les lacs de cratère

Worldwide, crater lakes are relatively rare, usually small and specialised freshwater habitats formed in geological depressions. But, they are well represented in tropical Africa, especially in the Lower Guinean rainforest zone of Cameroon (figure 20.06), where there may be 36 or more (McGregor Reid & Gibson, 2011). Crater lakes may contain a substantial number of endemic organisms, including fishes. All Cameroonian crater lakes are formed through volcanism and are calderas (deep inverted cones) or maars (shallow cones with a low profile) . For example Lake Nyos (see frame Nyos an extreme example, chapter The diversity of aquatic environments) is a simple maar lake, but a relatively deep one, whereas Lake Barombi Mbo is formed in a caldera.