What organisms live on the bottom of the lake?

Beyond 2 m of depth, at the bottom level, light favors the formation of a thin layer of cyanobacteria that provide oxygen to the deeper waters through photosynthesis. This layer also supports the community that lives on the surface: aquatic insects such as Heteroptera, Ephemeroptera and Coleoptera, which feed on the organic matter deposited on the bottom.
Under the layer of cyanobacteria, given the absence of oxygen, Bacteria and Archaea live, which contribute to the Carbon and Sulfur cycles. The absence of oxygen prevents the presence of fossorial organisms such as bivalves and oligochaetes. The lack of fish, efficient predators, allows planktonic microcrustaceans and aquatic insects to thrive and distribute themselves practically at every level (coastal and deep) of the lake's waters.