Effects of hydrology and river management on the distribution, abundance and persistence of cyanobacterial blooms in the Murray River, Australia

Bowling, Lee C.; Merrick, Chester; Swann, Judy; Green, Damian; Smith, Greg Sambrook; Neilan, Brett A.

doi:10.1016/j.hal.2013.08.002

Cited by 54 publications

(31 citation statements)

References 40 publications

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“…Only a few surveys of environmental samples without prior strain isolation have been carried out, however, findings similar to this study have been obtained in Greece, where amplification of the sxtI gene was twice as common as PST detection (Gkelis and Zaoutsos, 2014) and during a three-year survey of lakes in Åland Islands in Finland using the same methods as in this study (Savela et al, 2015) with the exception of the new sxtS primers. The observed lack of correlation is not limited to Europe; in Australia, neither the presence of sxtA nor the gene's increasing copy numbers did indicate a detectable presence or growing concentrations of PSTs in the environment (Al-Tebrineh et al, 2012;Bowling et al, 2013). Comparisons of qPCR and HPLC-FLD data are complicated by the fact that qPCR can be extremely sensitive (Wittwer et al, 1997), whereas PSTs can be difficult to analyse in complex environmental sample extracts.…”

Section: Discussionmentioning

confidence: 96%

“…Other sxt genes, including sxtG, sxtB, sxtI and sxtX, have been studied to a lesser extent , Gkelis and Zaoutsos, 2014, Savela et al, 2015. Only a few studies have investigated the co-occurrence of sxt genes and PSTs in environmental samples in Europe (Gkelis and Zaoutsos, 2014;Savela et al, 2015) or elsewhere in the world (Al-Tebrineh et al, 2012;Bowling et al, 2013).…”

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confidence: 99%

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First report of cyanobacterial paralytic shellfish toxin biosynthesis genes and paralytic shellfish toxin production in Polish freshwater lakes

et al. 2017

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In central and southern Europe, Aphanizomenon spp., A. gracile Lemmermann in particular, have been associated with paralytic shellfish toxin (PST) production. In western Poland, A. gracile is very common, and Cylindrospermopsis raciborskii (Woloszyńska) Seenayya & Subba Raju, another potentially PST-producing species, is often found as well. To date it is, however, unknown if the cyanobacterial populations in this area harbour the genetic capability to produce PSTs, and to what extent toxin biosynthesis occurs. The objective of this study was to survey the prevalence of potentially PST-producing cyanobacteria by measuring paralytic shellfish toxin biosynthesis gene sxtB copy numbers, sxtA, sxtG and sxtS gene presence, and PST concentrations in Polish freshwater lakes. In total, 34 lakes in western Poland were sampled twice during summer 2010. The presence of PST biosynthesis genes sxtA, sxtG and sxtS was determined using conventional qualitative PCR. Quantitative PCR (qPCR) was used to measure sxtB copy numbers, and the samples were analysed for PSTs using ion-pair high performance liquid chromatography with post-column oxidation and fluorescence detection (HPLC-FLD). Cyanobacteria carrying the sxtB gene were present in 23.5% of all samples (n=16) and in 14 lakes of the studied 34. Gene copy numbers ranged from 8.2×104 to 5.1×107 sxtB copies L-1 (mean 3.8×106). The median was 4.5×105 sxtB gene copies L-1 and the majority of results clustered at the lower end of the sxtB qPCR linear range. In 12 out of the 16 samples positive for sxtB the gene co-occurred with the other three targeted PST biosynthesis genes sxtA, sxtG and sxtS. However, five additional samples lacked one or two of the targeted four genes. Thirteen samples contained PSTs, of which 12 samples at levels <0.072 µg L-1, i.e., close to or below the quantitative detection limit of the HPLC-FLD method (0.01 µg L-1). One sample contained 0.57 µg L-1 saxitoxin, co-occurring with all four sxt genes studied. No correlation between PST and sxt gene occurrence or copy numbers was observed. A. gracile and C. raciborskii occurred in 92% and 50% of samples, respectively, containing PSTs, sxt genes or both. In conclusion, the results confirm that potential PST producers constitute an established subpopulation of cyanobacteria in Polish freshwater lakes. However, none of the sxt genes targeted in this study could serve as a reliable marker for active PST biosynthesis.

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Section: Discussionmentioning

confidence: 96%

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confidence: 99%

First report of cyanobacterial paralytic shellfish toxin biosynthesis genes and paralytic shellfish toxin production in Polish freshwater lakes

et al. 2017

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“…Intensive water use places large demands on the basin ecosystem, and although water efficiency measures are being implemented, it is expected that changing climatic conditions will further contribute to reductions in flows within the river system (Kingsford, 2011;Grafton et al, 2013). As an indicator of future conditions, reduced river flows and increased water temperatures in the Murray River during 2009 saw the development of a cyanobacterial bloom spanning 1100 km of the river (Al-Tebrineh et al, 2011;Bowling et al, 2013). During the bloom, two potent cyanotoxins, cylindrospermopsin and saxitoxin, were observed, along with species with the genetic capacity to produce microcystins (Al-Tebrineh et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

et al. 2015

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The frequency of freshwater cyanobacterial blooms is at risk of increasing as a consequence of climate change and eutrophication of waterways. It is increasingly apparent that abiotic data are insufficient to explain variability within the cyanobacterial community, with biotic factors such as heterotrophic bacterioplankton, viruses and protists emerging as critical drivers. During the Australian summer of 2012-2013, a bloom that occurred in a shallow ephemeral lake over a 6-month period was comprised of 22 distinct cyanobacteria, including Microcystis, Dolichospermum, Oscillatoria and Sphaerospermopsis. Cyanobacterial cell densities, bacterial community composition and abiotic parameters were assessed over this period. Alpha-diversity indices and multivariate analysis were successful at differentiating three distinct bloom phases and the contribution of abiotic parameters to each. Network analysis, assessing correlations between biotic and abiotic variables, reproduced these phases and assessed the relative importance of both abiotic and biotic factors. Variables possessing elevated betweeness centrality included temperature, sodium and operational taxonomic units belonging to the phyla Verrucomicrobia, Planctomyces, Bacteroidetes and Actinobacteria. Species-specific associations between cyanobacteria and bacterioplankton, including the free-living Actinobacteria acI, Bacteroidetes, Betaproteobacteria and Verrucomicrobia, were also identified. We concluded that changes in the abundance and nature of freshwater cyanobacteria are associated with changes in the diversity and composition of lake bacterioplankton. Given this, an increase in the frequency of cyanobacteria blooms has the potential to alter nutrient cycling and contribute to long-term functional perturbation of freshwater systems.

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“…Diatoms predominate when turbulence related to inflow is greatest (spring, early summer) (Hall et al, 1999a), while flagellates (cryptophytes, chlorophytes, dinoflagellates) are increasingly common as inflow slows, turbulence declines, and thermal stratification may occur (Abirhire et al, in this issue;Dröscher et al, 2009;McGowan et al, 2005b). These patterns are in marked contrast to many natural lakes in the prairie ecozone (Donald et al, 2013;Leavitt et al, 2006;Pham et al, 2008), as well as some large reservoirs from continental interiors of China (Lv et al, 2014), Australia (Bowling et al, 2013), and South America (Fernandez et al, 2014), where high turbidity reflects dense blooms of cyanobacteria arising from excessive supply of P and N (Leigh et al, 2010;Sukenik et al, 2012). Differences in production between the large reservoirs of western North America and natural prairie lakes may reflect differences in the predominant source of nutrients to the water-column of artificial (allochthonous, riverine) and natural aquatic ecosystems (autochthonous, sedimentary) (e.g., Leavitt et al, 2006;Abirhire et al, in this issue;Patoine et al, 2006).…”

Section: Phytoplankton Abundancementioning

confidence: 99%

Decadal regulation of phytoplankton abundance and water clarity in a large continental reservoir by climatic, hydrologic and trophic processes

Vogt

Sharma

Leavitt

2015

Journal of Great Lakes Research

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Effects of hydrology and river management on the distribution, abundance and persistence of cyanobacterial blooms in the Murray River, Australia

Cited by 54 publications

References 40 publications

First report of cyanobacterial paralytic shellfish toxin biosynthesis genes and paralytic shellfish toxin production in Polish freshwater lakes

First report of cyanobacterial paralytic shellfish toxin biosynthesis genes and paralytic shellfish toxin production in Polish freshwater lakes

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

Decadal regulation of phytoplankton abundance and water clarity in a large continental reservoir by climatic, hydrologic and trophic processes

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