Chapter Four

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2.8 Freshwater fungi
Freshwater fungi are any species relying on free freshwater for some part of
their life cycle, or any species colonizing substrates that are predominantly aquatic or
semi-aquatic in nature. In other words, their habitats may be clearly of an aquatic
nature or they may colonize submerged plant parts in freshwater environments
(Thomas, 1996). Hence, freshwater fungi are an ubiquitous and diverse group of
organisms (Goh and Hyde, 1996). Freshwater fungi are an ecological group and
comprise all major taxa; ascomycetes, basidiomycetes, coelomycetes, hyphomycetes,
trichomycetes, Zygomycota, Chitridiales and chromista (Sivichai and Boonyene,
2004). Several previous examinations of freshwater fungi in the tropics and subtropics
have yielded numerous fungi including zoosporic fungi, basidiomycetes,
zygomycetes, tricomycetes (Goh and Hyde, 1996), hyphomycetes (Wood-
Eggenschwiler and Bärlocher, 1985; Goh and Hyde, 1996; Goh et al., 1997),
coelomycetes (Goh and Hyde, 1996) and ascomycetes (Magnes and Hafellner, 1991;
Udaiyan and Hosagoudar, 1991; Shearer, 1993; Goh and Hyde, 1996; Shearer et al.,
1999; Cai et al., 2002). The main role of higher fungi in freshwater ecosystems is in
the degradation of dead plant material and woody material that find their way into the
water. The decay of dead plant tissues is a result of the ability of the fungi to degrade
lignocellulose. The success of freshwater fungi in colonizing submerged woody
material lies in their ability to form soft-rot cavities and to be antagonistic against
other fungi (Goh and Hyde, 1996).
Sivichai and Boonyene (2004) have concluded that fungi which are found in
freshwater habitats can be grouped into three categories according to their
morphology and ability to degrade substrata in the environment: