Species composition and cyanotoxin production in periphyton mats from three lakes of varying trophic status

Abstract

In lakes, benthic micro-algae and cyanobacteria (periphyton) can contribute significantly to total primary productivity and provide important food sources for benthic invertebrates. Despite recognition of their importance, few studies have explored the diversity of the algal and cyanobacterial composition of periphyton mats in temperate lakes. In this study, we sampled periphyton from three New Zealand lakes: Tikitapu (oligotrophic), Ōkāreka (mesotrophic) and Rotoiti (eutrophic). Statistical analysis of morphological data showed a clear delineation in community structure among lakes and highlighted the importance of cyanobacteria. Automated rRNA intergenic spacer analysis (ARISA) and 16S rRNA gene clone libraries were used to investigate cyanobacterial diversity. Despite the close geographic proximity of the lakes, cyanobacterial species differed markedly. The 16S rRNA gene sequence analysis identified eight cyanobacterial OTUs. A comparison with other known cyanobacterial sequences in GenBank showed relatively low similarities (91-97%). Cyanotoxin analysis identified nodularin in all mats from Lake Tikitapu. ndaF gene sequences from these samples had very low (≤ 89%) homology to sequences in other known nodularin producers. To our knowledge, this is the first detection of nodularin in a freshwater environment in the absence of Nodularia. Six cyanobacteria species were isolated from Lake Tikitapu mats. None were found to produce nodularin. Five of the species shared low (< 97%) 16S rRNA gene sequence similarities with other cultured cyanobacteria.

Successional Change in Microbial Communities of Benthic Phormidium-Dominated Biofilms

“…Phormidium autumnale co-occurs in these mats with other microbial taxa, such as bacteria, diatoms and green algae [18], but the relative proportions of these, and how they change temporally, are unknown. Factors that influence the microbial composition of benthic biofilms are typically environmental factors, such as river velocity, temperature and nutrients.…”

MIB-producing cyanobacteria (Planktothrix sp.) in a drinking water reservoir: Distribution and odor producing potential

“…Most previous studies addressing T&O have thus mainly focused on eutrophic water bodies as the blooming of cyanobacteria is usually associated with nutrient-rich water bodies (Yang et al, 2008;Paerl and Huisman, 2008;Adam et al, 2011;Naselli-Flores, 2011;Brookes and Carey, 2011). However, the occurrence of odors produced by benthic or low irradiance specialist cyanobacteria is also frequently reported in drinking water reservoirs which are in a mesotrophic or even oligotrophic state (Mez et al, 1998;Wood et al, 2012;Catherine et al, 2013). Oligotrophic conditions limit the growth of the surface living cyanobacteria, resulting in high water transparency, which is vital for the growth of the deep living and benthic cyanobacteria (Scott and Marcarelli, 2012;Catherine et al, 2013).…”

Cyanobacteria, Lyngbya aestuarii and Aphanothece bullosa as antifungal and antileishmanial drug resources

“…However, antifungal activity is also reported with crude extract and pure compounds from other freshwater cyanobacteria such as Anabaena, Nostoc, Aphanocapsa, Synechocystis, Synechococcus, Oscillatoria, Nodularia, Calothrix [20,21,[36][37][38][39] , while marine cyanobacteria are little explored with regard to antifungal activity except various species of as Leishmania confervoides, Leishmania majuscula [12,13] . This activity was caused due to species specific biomolecules as specific secondary metabolite produces in specific organism and in specific habitat [5][6][7] . In antifungal study pure compound fluconazole was also used as control but its inhibition zone was double time bigger than crude although its concentration was 100 µg/mL.…”

“…Secondary metabolites produced from cyanobacteria are found to be antibacterial, antifungal, antialgal, anticancerous and antimalarial with many more activitys [3,4] . Microbial productions of metabolites are greatly influenced by factors such as pH, temperature, and light intensity [5][6][7][8] . However, species specificity of secondary metabolites is well established [9] .…”