Diversity and Characterization of Culturable Fungi from Marine Sediment Collected from St. Helena Bay, South Africa

Abstract

Marine fungi are known to originate from a wide variety of habitats within the marine environment. Marine sediment represents one environmental niche, with most fungi occurring in these sediments being facultative marine fungi with terrestrial origins. It has not been proven whether these fungi merely survive the harsh environmental conditions presented by the ocean sediment, as opposed to playing an active role in this ecological niche. During this study, marine sediment was collected from St. Helena Bay, on the west coast of the Western Cape, South Africa. Using dilution, enrichment, and repetitive culturing techniques, 59 fungal isolates were obtained from marine sediments and identified to at least genus level using morphological and molecular methods. Moreover, a series of tests were performed to characterize the physical and physicochemical attributes of the isolates. Results showed that the isolates not only survived but also had the potential to grow in the natural conditions present in this environment. Extracellular cellulase was produced by the filamentous fungal isolates indicating their probable role in detrital decay processes and therefore the carbon cycle on the ocean bed. Also, denitrification patterns were observed when isolates were grown in liquid media amended with NaNO(2), NaNO(3), and (NH(4))SO(4), implicating that these fungi have the potential to play an active role in denitrification, co-denitrification, and ammonification phases of nitrogen cycles occurring in the marine sediments.

Fungal diversity of marine biofilms on artificial reefs in the north-central Gulf of Mexico

“…Our characterization of artificial reef fungal biofilm communities represents the first step towards understanding the fungal component of microbial diversity of hard substrata within the MS Sound, an economically productive estuary for fisheries including shellfish. Considering the increasing number of reports on the occurrence of marine fungi and their involvement in detrital processing, it can be concluded that the current microbial loop model neglects the role of fungi in the processing of organic matter in marine environments (Hyde et al 1998, Singh et al 2010, Gutiérrez et al 2011, Mouton et al 2012). Further research is needed to determine fungal roles in marine ecological processes in hopes of providing a more complete model of organic material degradation in coastal ecosystems, foundational to food webs and nutrient cycling (Gutiérrez et al 2011, Mouton et al 2012.…”

“…Considering the increasing number of reports on the occurrence of marine fungi and their involvement in detrital processing, it can be concluded that the current microbial loop model neglects the role of fungi in the processing of organic matter in marine environments (Hyde et al 1998, Singh et al 2010, Gutiérrez et al 2011, Mouton et al 2012). Further research is needed to determine fungal roles in marine ecological processes in hopes of providing a more complete model of organic material degradation in coastal ecosystems, foundational to food webs and nutrient cycling (Gutiérrez et al 2011, Mouton et al 2012. Our approach has afforded the collection of baseline data to help improve the understanding of underlying fungal diversity present in artificial reef biofilms.…”

“…Hladyz et al (2011) reported that substrate composition is a crucial factor in marine biofilm development and later growth of the artificial reef; substrate differences revealed by stable isotope analysis have an effect on energy flow to primary consumers in aquatic food webs. Biofilm microbial communities are important in the production and decomposition of organic matter and in the cycling of limiting nutrients (Mouton et al 2012).…”

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

“…Li et al (2013) also found that the biomass of sulfate-reducing bacteria was correlated to the N 2 O efflux in a laboratory experiment. In particular, N 2 O effluxes varied linearly with fungi biomass in freshwater sediments (Takaya 2009;Seo & DeLaune 2010;Mouton et al 2012). However, although it has been reported that microbial biomass influenced GHG emissions in terrestrial soils (Radl et al 2007;Burke et al 2012;Narvaez et al 2013), few studies have focused on investigating the effects of microbial biomass on GHG emissions in lake sediments.…”

“…Previous studies found that fungi were involved in denitrification processes by reducing nitrate or nitrite to N 2 O in freshwater sediments (Takaya 2009;Seo & DeLaune 2010;Mouton et al 2012;Reed & Martiny 2013;S anchez-Andrea et al 2012). In particular, cell-free nitrate reductase (Nar) and nitrite reductase (Nir) activities which also included a unique cytochrome P450 acted as nitric oxide reductase played important roles in the anaerobic denitrification process of fungi (Usuda et al 1995).…”