Lake Bermin (sometimes spelled Bemin or Beme) is a small lake in the volcanic chain in the Southwest Region of

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

. It is a

volcanic lake A volcanogenic lake is a lake formed as a result of volcanic activity. They are generally a body of water inside an inactive volcanic crater (crater lakes) but can also be large volumes of molten lava within an active volcanic crater ( lava lakes) ...

with a diameter of about Martin; Cutler; Friel; Touokong; Coop; and Wainwright (2015). Complex histories of repeated gene flow in Cameroon crater lake cichlids cast doubt on one of the clearest examples of sympatric speciation. Evolution 69-6: 1406–1422. and a crater rim that rises to a height of about .Dickinson, C. (2005).
The Tilapia of Lake Bernin, Cameroon.
'' Modern Aquarium -Greater City A.S. (NY): 15–16 This highly isolated lake is roughly circular in shape, lacks an inflow, but has an outflow into the Cross River system.Schliewen, U.K., Tautz, D., and Pääbo, S. (1994). ''Sympatric speciation suggested by monophyly of crater lake cichlids.''

Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...

368(6472): 629–632.

Biology

Despite its very small size, it supports nine

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

species of coptodonine cichlid fishes ('' C. bakossiorum'', '' C. bemini'', '' C. bythobates'', '' C. flava'', '' C. gutturosa'', '' C. imbriferna'', '' C. snyderae'', '' C. spongotroktis'', and '' C. thysi''). This number of endemic fishes per area is the highest recorded anywhere.Freshwater Ecoregions of the World (2008).
Western Equatorial Crater Lakes.
'' Early genetic evidence suggested that these probably were the result of sympatric speciation. Later studies indicate a level of secondary gene flow between the Bermin cichlids and Cross River '' C. guineensis'', although it is unclear if this facilitated speciation among the former group. They are a relatively recent radiation.Thieme, M.L.; R. Abell; N. Burgess; B. Lehner; E. Dinerstein; and D. Olson (2005). Freshwater Ecoregions of Africa and Madagascar: A Conservation Assessment, pp. 58–60. Island Press. They are quite similar in their general appearance and

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

but vary greatly in feeding behavior, including specialists like ''C. spongotroktis'' that eat pieces of the large

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

s that grow in the lake. The Lake Bermin cichlids are small fish, none surpassing in standard length. At up to in standard length, ''C. snyderae'' is the smallest known

tilapia Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most ...

. All the Bermin cichlids are critically endangered by

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

from human activities, and potentially also by large emissions of

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

(CO₂) from the lake's bottom (compare

Lake Nyos Lake Nyos ( ) is a crater lake in the Region of Cameroon, located about northwest of Yaoundé, the capital. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcanic activity ...

), although Bermin is too shallow to contain very high amounts of this gas.Freeth, S.J.; C.O. Ofoegbu; and K.M. Onuoha (1992). Natural Hazards in West and Central Africa, pp. 50–52.

References

{{DEFAULTSORT:Bermin Volcanic crater lakes Lakes of Cameroon Southwest Region (Cameroon)

Biology

See also

References