Fungi in lake ecosystems

Abstract

This review highlights the presence and ecological roles of fungi in lakes, and aims to stimulate research in aquatic mycology. In the study of lentic systems, this field is an almost completely neglected topic and, if considered at all, has often been restricted to specific groups of fungi, such as yeasts, filamentous fungi (e.g. aquatic hyphomycetes), or phycomycetes (an obsolete taxonomic category that included various fungal and fungal-like organisms). We document that aquatic fungi are common in various lentic habitats. They play potentially crucial roles in nutrient and carbon cycling and interact with other organisms, thereby influencing food web dynamics. The development and application of molecular methods have greatly increased the potential for unraveling the biodiversity and ecological roles of fungi in lake ecosystems. We searched the literature for reports on all fungi occurring in lake ecosystems. The present study summarizes information on the highly diverse mycoflora in lake microhabitats and highlights the main processes they influence. We also point out ecological niches of fungi in lakes that have been examined only superficially or ignored completely. We demonstrate that we now have the methodology to perform systematic studies to finally fill in some of the large gaps in this field.

Multi-year assessment of coastal planktonic fungi reveals environmental drivers of diversity and abundance

“…Active fungal communities within deep sub-seafloor sediments also show similar positive links to changes in the availability of organic material (Orsi et al, 2013a), and the expression of metabolic pathways involved in the cycling of a variety of organic substrates (Orsi et al, 2013b). The utilisation of particulate organic matter by benthic and pelagic marine fungi is analogous to the well-established functional roles of fungi in freshwater ecosystems, such as lakes (Wurzbacher et al, 2010).…”

Microbial biomass in sediments affects greenhouse gas effluxes in Poyang Lake in China

“…In recent years, Poyang Lake has suffered severely from water pollution, lake dredging, and water level fluctuations due to human activities and climate change (Lake et al 2000;Fang et al 2006). These changes might have influenced microbial communities in the sediments which, in turn, may further affect lake GHG emissions (Quayle et al 2002;Davidson & Janssens 2006;Hart 2006;Wurzbacher et al 2010;Cantarel et al 2012). Therefore, it is necessary to explore the effects of microbial biomass on GHG emissions in Poyang Lake, which can provide a firm basis for understanding GHG production and emissions from a microbial point of view.…”

Aerobic microbial transformation of pesticides in surface water

“…The static littoral zone, especially the surfaces of leaf litters and sediments, is known as hot spots for fungi that participate in degrading particulate organic matters. 26,27) Niemi et al 74) reported mesophilic fungi and Actinomycetes as common species in Finnish rivers and lakes, with their occurrence being related to runoff from soil. Several degradative enzymes, including phenol oxidases, contribute to the fungal decomposition of litters, and the products are utilized by co-existing bacteria as organic nutrients for their growth.…”

“…3,8,18) Bacteria are more diversely populated, with their activity depending on the habitat, 25) while fungi tend to grow on a substratum, such as detritus, rather than in water. 26,27) Bacteria metabolize pesticides via various enzymatic reactions, 28) and extra-cellular enzymes such as laccases, 29) may participate in their fungal degradation. In addition to an active uptake by microbes, pesticides are adsorbed onto surfaces of microbes and biofilm, a gel-type complex mixture of microbial cells, detritus, and extra-cellular polymeric substances (EPS).…”