Successional Change in Microbial Communities of Benthic Phormidium-Dominated Biofilms

Abstract

Benthic cyanobacterial blooms are increasing worldwide and can be harmful to human and animal health if they contain toxin-producing species. Microbial interactions are important in the formation of benthic biofilms and can lead to increased dominance and/or toxin production of one or few taxa. This study investigated how microbial interactions contribute to proliferation of benthic blooms dominated by the neurotoxin-producing Phormidium autumnale. Following a rainfall event that cleared the substrate, biofilm succession was characterised at a site on the Hutt River (New Zealand) by sampling every 2-3 days over 32 days. A combination of morphological and molecular community analyses (automated ribosomal intergenic spacer analysis and Illumina™ MiSeq sequencing) identified three distinct phases of succession in both the micro-algal and bacterial communities within P. autumnale-dominated biofilms. Bacterial composition shifted between the phases, and these changes occurred several days before those of the micro-algal community. Alphaproteobacteria and Betaproteobacteria dominate in the early phase; Alphaproteobacteria, Betaproteobacteria, Sphingobacteria and Flavobacteria in the mid-phase; and Sphingobacteria and Flavobacteria in the late phase. Collectively, the results suggest that succession is driven by bacteria in the early stages but becomes dependent on micro-algae in the mid- and late stages of biofilm formation.

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

“…A. minutissimum is reported as a pioneering species during the initial processes of biofilm formation (Sekar et al, 2004;Leinweber and Kroth, 2015). It is often the most numerous diatom occuring in P. autumnale and P. favosum-dominated microbial mats (Kelly, 2012;Brasell et al, 2015), as was the case in Krčić Spring, where it could efficiently utilise potency by forming pads and stalks, thus additionally anchoring the biofilm.…”

Cyanobacterial and algal diversity in the vicinity of two different seabird colonies in Spitsbergen

“…Both P. crispa and P. autumnale increased their proportion in the habitat in the direction of places more distant to Uria lomvia and Rissa tridactyla colonies. Phormidium autumnale is a species with a wide spectrum of occurrence in polar regions Strunecký et al 2010) and prefers sites with higher nitrogen concentrations but does not occur in sites with high phosphorus concentrations (Heath et al 2014;Brasell et al 2015). Similarly, Prasiola crispa is a typical species in cold-temperate regions, where it is usually associated with habitats rich in organic nitrogen (Graeve et al 2002;Holzinger et al 2006;Matuła et al 2007;Richter et al 2009;Broady et al 2012;Richter et al 2014Richter et al , 2015.…”

Influence of phosphorus availability on the community structure and physiology of cultured biofilms

“…That's to say, the metabolic activity of the same algal species changes with the environmental conditions. Microbial succession in biofilms was found to be driven by bacteria in the early stages, and the initial attachment of bacteria to substrate surface was random (Brasell et al, 2015). Previous studies reported that the succession of bacterial assemblages in biofilms was mostly determined by the age of biofilms (Artigas et al, 2012).…”