Bioavailable Nutrients (N and P) and Precipitation Patterns Drive Cyanobacterial Blooms in Missisquoi Bay, Lake Champlain

Anthropogenic activities release large amounts of nitrogen (N) and phosphorus (P) nutrients into the environment. Sources of nutrients include surface and sub-surface runoffs from agricultural practices with the application of chemical fertilizers and manure as well as combined sewer overflows (CSOs). Nutrient runoffs contribute to the eutrophication of aquatic ecosystems and enhance the growth of cyanobacteria. Precipitation is an important driving force behind the runoff of nutrients from agricultural fields into surrounding water bodies. To understand the dynamics between nutrient input, precipitation and cyanobacterial growth in Missisquoi Bay, Lake Champlain (Quebec), one location in Pike River (a major tributary into the bay) and four locations in Missisquoi Bay were monitored from April to November in 2017 and 2018. Biweekly water samples were analyzed using chemical methods and high-throughput sequencing of 16S rRNA gene amplicons. High concentrations of N and P were typically measured in April and May. Three major spikes in nutrient concentrations were observed in early and mid-summer as well as early fall, all of which were associated with intense cumulative precipitation events of 40 to 100 mm within 7 days prior to sampling. Despite the high concentrations of nutrients in the spring and early summer, the cyanobacterial blooms appeared in mid to late summer as the water temperature increased. Dolichospermum sp. was the major bloom-forming cyanobacterium during both summers. A second intense bloom event of Microcystis was also observed in the fall (October and November) for both years. Variation in the cyanobacteria population was strongly associated with inorganic and readily available fractions of N and P such as nitrites and nitrates (NOx), ammonia (NH3) and dissolved organic phosphorus (DOP). During blooms, total Kjeldahl nitrogen (TKN) and total particulate phosphorus (TPP) fractions had a substantial influence on total nitrogen (TN) and total phosphorus (TP) concentrations, respectively. The abundance of bacteria involved in the metabolism of nitrogen compared to that of phosphorus revealed the importance of nitrogen on overall microbial dynamics as well as CB formation in the bay. Our findings emphasize the combined influence of precipitation events, temperature and several bioavailable fractions of nitrogen and phosphorus on cyanobacterial bloom episodes.

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Phylogenetic Differences in Attached and Free-Living Bacterial Communities in a Temperate Coastal Lagoon during Summer, Revealed via High-Throughput 16S rRNA Gene Sequencing

Applied and Environmental Microbiology ◽

10.1128/aem.02916-13 ◽

2014 ◽

Vol 80 (7) ◽

pp. 2071-2083 ◽

Cited By ~ 59

Author(s):

Vani Mohit ◽

Philippe Archambault ◽

Nicolas Toupoint ◽

Connie Lovejoy

Keyword(s):

Bacterial Diversity ◽

High Throughput ◽

High Throughput Sequencing ◽

Anthropogenic Activities ◽

Late Summer ◽

16S Rrna Gene Sequencing ◽

Rrna Gene ◽

Free Living ◽

Content Type ◽

Bacterial Phyla

ABSTRACTMost of what is known about coastal free-living and attached bacterial diversity is based on open coasts, with high particulate and nutrient riverine supply, terrestrial runoffs, and anthropogenic activities. The Magdalen Islands in the Gulf of St. Lawrence (Canada) are dominated by shallow lagoons with small, relatively pristine catchments and no freshwater input apart from rain. Such conditions provided an opportunity to investigate coastal free-living and attached marine bacterial diversity in the absence of confounding effects of steep freshwater gradients. We found significant differences between the two communities and marked temporal patterns in both. Taxonomic richness and diversity were greater in the attached than in the free-living community, increasing over summer, especially within the least abundant bacterial phyla. The highest number of reads fell within the SAR 11 clade (Pelagibacter,Alphaproteobacteria), which dominated free-living communities. The attached communities had deeper phylum-level diversity than the free-living fraction. Distance-based redundancy analysis indicated that the particulate organic matter (POM) concentration was the main variable separating early and late summer samples with salinity and temperature changes also significantly correlated to bacterial community structure. Our approach using high-throughput sequencing detected differences in free-living versus attached bacteria in the absence of riverine input, in keeping with the concept that marine attached communities are distinct from cooccurring free-living taxa. This diversity likely reflects the diverse microhabitats of available particles, implying that the total bacterial diversity in coastal systems is linked to particle supply and variability, with implications for understanding microbial biodiversity in marine systems.

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Occurrence and possible causes of a severe cyanobacterial bloom in Lake Cargelligo, New South Wales

Marine and Freshwater Research ◽

10.1071/mf9940737 ◽

1994 ◽

Vol 45 (5) ◽

pp. 737 ◽

Cited By ~ 24

Author(s):

L Bowling

Keyword(s):

New South ◽

New South Wales ◽

Cyanobacterial Bloom ◽

Cyanobacterial Blooms ◽

Toxicity Tests ◽

Cylindrospermopsis Raciborskii ◽

Nutrient Concentrations ◽

Cell Numbers ◽

South Wales ◽

Physico Chemical

Although smaller cyanobacterial blooms had occurred in Lake Cargelligo in previous summers, a severe bloom of Anabaena circinalis occurred in the lake in November 1990. Cell numbers exceeded 100 000 cells m L -1 , and toxicity tests revealed the bloom to be highly hepatotoxic. This resulted in the first known closure of a town water supply due to cyanobacteria in New South Wales. Blooms of Microcystis aeruginosa, Aphanizomenon issatschenkoi, Oscillatoria rnougeotii and Cylindrospermopsis raciborskii also occurred in the lake at similar very high cell numbers during the summer and autumn of 1990-91. All five species persisted until May 1991, although there was no detectable toxicity from January onwards. Severe flooding in the Lachlan River valley upstream of Lake Cargelligo during the winter of 1990 led to nutrient enrlched inflows to the lake. These elevated nutrient concentrations would have been a major factor contributing to the bloom. However, other physico-chemical factors were also suitable for cyanobacterial growth.

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Monitoring Changing Toxigenicity of a Cyanobacterial Bloom by Molecular Methods

Applied and Environmental Microbiology ◽

10.1128/aem.68.12.6070-6076.2002 ◽

2002 ◽

Vol 68 (12) ◽

pp. 6070-6076 ◽

Cited By ~ 63

Author(s):

Judith A. Baker ◽

Barrie Entsch ◽

Brett A. Neilan ◽

David B. McKay

Keyword(s):

Water Supply ◽

Direct Detection ◽

Health Hazard ◽

Cyanobacterial Bloom ◽

Pcr Amplification ◽

Cyanobacterial Blooms ◽

Mouse Bioassay ◽

Rrna Gene ◽

Potential Health ◽

Intergenic Spacer Region

ABSTRACT Cyanobacterial blooms are potential health hazards in water supply reservoirs. This paper reports analyses of a cyanobacterial bloom by use of PCR-based methods for direct detection and identification of strains present and determination of their toxigenicity. Serial samples from Malpas Dam, in the New England region of Australia, were analyzed during a prolonged, mixed cyanobacterial bloom in the summer of 2000 to 2001. Malpas Dam has been shown in the past to have toxic blooms of Microcystis aeruginosa that have caused liver damage in the human population drinking from this water supply reservoir. Cyanobacterial genera were detected at low cell numbers by PCR amplification of the phycocyanin intergenic spacer region between the genes for the β and α subunits. The potential for microcystin production was determined by PCR amplification of a gene in the microcystin biosynthesis pathway. The potential for saxitoxin production was determined by PCR amplification of a region of the 16S rRNA gene of Anabaena circinalis strains. Toxicity of samples was established by mouse bioassay and high-pressure liquid chromatography. We show that bloom components can be identified and monitored for toxigenicity by PCR more effectively than by other methods such as microscopy and mouse bioassay. We also show that toxigenic strains of Anabaena and Microcystis spp. occur at this site and that, over the course of the bloom, the cell types and toxicity changed. This work demonstrates that PCR detection of potential toxicity can enhance the management of a significant public health hazard.

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Impact of exogenous nitrogen on cyanobacterial abundance and community in oil-contaminated sediment mesocosms

10.1101/322743 ◽

2018 ◽

Author(s):

Kaikai Sun ◽

Minbo Qi ◽

Panpan Zhu ◽

Haixia Wang ◽

Zhenmei Lu

Keyword(s):

Nitrogen Limitation ◽

Contaminated Sediments ◽

Cyanobacterial Blooms ◽

Rrna Gene ◽

Contaminated Sediment ◽

16S Rrna Gene Analysis ◽

Treatment Groups ◽

High Concentrations ◽

Exogenous Nitrogen ◽

Comprehensive Study

ABSTRACTHigh concentrations of crude oil are toxic to cyanobacteria but can facilitate the emergence of cyanobacterial aggregation at an appropriate concentration range; however, the exact inducing factor has never been clearly elucidated. We hypothesized that increasing exposure to elevated concentrations of nitrogen would inhibit the accumulation of cyanobacteria in oil-contaminated sediments. To test this hypothesis, we simulated an oil spill in estuarine sediment microcosms with and without the removal of nitrogen limitation by supplementation of exogenous nitrogen. An integrated MiSeq sequencing of 16S rRNA gene analysis along with metatranscriptome sequence was performed to achieve a comprehensive study of cyanobacterial blooms. The number of cyanobacterial sequences increased over time in both oil-contaminated and non-oil-contaminated sediments at different time points after 42 days of incubation. And, supplementation with a nitrogen resource could accelerate cyanobacterial blooms under uncontaminated microcosms but delay the bloom phenomenon and reduce the cyanobacterial abundance to a great degree when exposed to oil. Our results clearly illustrated that nitrogen limitation was a vital driver of the increased abundance of cyanobacteria in oil-contaminated mesocosms. In addition, the abundance and compositions of blooming cyanobacteria varied significantly among the different treatment groups, andOscillatoriamay play a potential and non-negligible role in oil-contaminated mesocosms.

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A Novel Microbial Zearalenone Transformation through Phosphorylation

Toxins ◽

10.3390/toxins13050294 ◽

2021 ◽

Vol 13 (5) ◽

pp. 294

Author(s):

Yan Zhu ◽

Pascal Drouin ◽

Dion Lepp ◽

Xiu-Zhen Li ◽

Honghui Zhu ◽

...

Keyword(s):

Microbial Transformation ◽

Acid Tolerance ◽

Transformation Product ◽

The United States ◽

Corn Silage ◽

Rrna Gene ◽

Bacillus Spp ◽

High Concentrations ◽

The 16S Rrna Gene ◽

Bacillus Strains

Zearalenone (ZEA) is a mycotoxin widely occurring in many agricultural commodities. In this study, a purified bacterial isolate, Bacillus sp. S62-W, obtained from one of 104 corn silage samples from various silos located in the United States, exhibited activity to transform the mycotoxin ZEA. A novel microbial transformation product, ZEA-14-phosphate, was detected, purified, and identified by HPLC, LC-MS, and NMR analyses. The isolate has been identified as belonging to the genus Bacillus according to phylogenetic analysis of the 16S rRNA gene and whole genome alignments. The isolate showed high efficacy in transforming ZEA to ZEA-14-phosphate (100% transformation within 24 h) and possessed advantages of acid tolerance (work at pH = 4.0), working under a broad range of temperatures (22–42 °C), and a capability of transforming ZEA at high concentrations (up to 200 µg/mL). In addition, 23 Bacillus strains of various species were tested for their ZEA phosphorylation activity. Thirteen of the Bacillus strains showed phosphorylation functionality at an efficacy of between 20.3% and 99.4% after 24 h incubation, suggesting the metabolism pathway is widely conserved in Bacillus spp. This study established a new transformation system for potential application of controlling ZEA although the metabolism and toxicity of ZEA-14-phosphate requires further investigation.

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Gut Microbiome Changes in Captive Plateau Zokors (Eospalax baileyi)

Evolutionary Bioinformatics ◽

10.1177/1176934321996353 ◽

2021 ◽

Vol 17 ◽

pp. 117693432199635

Author(s):

Daoxin Liu ◽

Pengfei Song ◽

Jingyan Yan ◽

Haijing Wang ◽

Zhenyuan Cai ◽

...

Keyword(s):

Gut Microbiota ◽

Gut Microbiome ◽

High Throughput Sequencing ◽

Tibet Plateau ◽

Rrna Gene ◽

Diversity Analysis ◽

Bacterial Phyla ◽

In Captivity ◽

Relative Abundances ◽

Plateau Zokor

Wild-caught animals must cope with drastic lifestyle and dietary changes after being induced to captivity. How the gut microbiome structure of these animals will change in response receives increasing attention. The plateau zokor ( Eospalax baileyi), a typic subterranean rodent endemic to the Qinghai-Tibet plateau, spends almost the whole life underground and is well adapted to the environmental pressures of both plateau and underground. However, how the gut microbiome of the plateau zokor will change in response to captivity has not been reported to date. This study compared the microbial community structure and functions of 22 plateau zokors before (the WS group) and after being kept in captivity for 15 days (the LS group, fed on carrots) using the 16S rRNA gene via high-throughput sequencing technology. The results showed that the LS group retained 973 of the 977 operational taxonomic units (OTUs) in the WS group, and no new OTUs were found in the LS group. The dominant bacterial phyla were Bacteroides and Firmicutes in both groups. In alpha diversity analysis, the Shannon, Sobs, and ACE indexes of the LS group were significantly lower than those of the WS group. A remarkable difference ( P < 0.01) between groups was also detected in beta diversity analysis. The UPGMA clustering, NMDS, PCoA, and Anosim results all showed that the intergroup difference was significantly greater than the intragroup difference. And compared with the WS group, the intragroup difference of the gut microbiota in the LS group was much larger, which failed to support the assumption that similar diets should drive convergence of gut microbial communities. PICRUSt revealed that although some functional categories displayed significant differences between groups, the relative abundances of these categories were very close in both groups. Based on all the results, we conclude that as plateau zokors enter captivity for a short time, although the relative abundances of different gut microbiota categories shifted significantly, they can maintain almost all the OTUs and the functions of the gut microbiota in the wild. So, the use of wild-caught plateau zokors in gut microbial studies is acceptable if the time in captivity is short.

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The Fecal Bacterial Microbiota in Horses with Equine Recurrent Uveitis

Animals ◽

10.3390/ani11030745 ◽

2021 ◽

Vol 11 (3) ◽

pp. 745

Author(s):

Michelle Martin de Bustamante ◽

Diego Gomez ◽

Jennifer MacNicol ◽

Ralph Hamor ◽

Caryn Plummer

Keyword(s):

Beta Diversity ◽

High Throughput Sequencing ◽

Illumina Miseq ◽

Diversity Indices ◽

Rrna Gene ◽

Linear Discriminant ◽

Alpha And Beta Diversity ◽

Bacterial Microbiota ◽

Healthy Control ◽

Equine Recurrent Uveitis

The objective of this study was to describe and compare the fecal bacterial microbiota of horses with equine recurrent uveitis (ERU) and healthy horses using next-generation sequencing techniques. Fecal samples were collected from 15 client-owned horses previously diagnosed with ERU on complete ophthalmic examination. For each fecal sample obtained from a horse with ERU, a sample was collected from an environmentally matched healthy control with no evidence of ocular disease. The Illumina MiSeq sequencer was used for high-throughput sequencing of the V4 region of the 16S rRNA gene. The relative abundance of predominant taxa, and alpha and beta diversity indices were calculated and compared between groups. The phyla Firmicutes, Bacteroidetes, Verrucomicrobia, and Proteobacteria predominated in both ERU and control horses, accounting for greater than 60% of sequences. Based on linear discriminant analysis effect size (LEfSe), no taxa were found to be enriched in either group. No significant differences were observed in alpha and beta diversity indices between groups (p > 0.05 for all tests). Equine recurrent uveitis is not associated with alteration of the gastrointestinal bacterial microbiota when compared with healthy controls.

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16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

Polar Biology ◽

10.1007/s00300-021-02843-2 ◽

2021 ◽

Author(s):

Eleanor E. Jackson ◽

Ian Hawes ◽

Anne D. Jungblut

Keyword(s):

16S Rrna ◽

18S Rrna ◽

High Throughput Sequencing ◽

Microbial Mats ◽

Gene Diversity ◽

Salinity Gradient ◽

18S Rrna Gene ◽

Rrna Gene ◽

Ice Shelf ◽

The Impact

AbstractThe undulating ice of the McMurdo Ice Shelf, Southern Victoria Land, supports one of the largest networks of ice-based, multiyear meltwater pond habitats in Antarctica, where microbial mats are abundant and contribute most of the biomass and biodiversity. We used 16S rRNA and 18S rRNA gene high-throughput sequencing to compare variance of the community structure in microbial mats within and between ponds with different salinities and pH. Proteobacteria and Cyanobacteria were the most abundant phyla, and composition at OTU level was highly specific for the meltwater ponds with strong community sorting along the salinity gradient. Our study provides the first detailed evaluation of eukaryote communities for the McMurdo Ice Shelf using the 18S rRNA gene. They were dominated by Ochrophyta, Chlorophyta and Ciliophora, consistent with previous microscopic analyses, but many OTUs belonging to less well-described heterotrophic protists from Antarctic ice shelves were also identified including Amoebozoa, Rhizaria and Labyrinthulea. Comparison of 16S and 18S rRNA gene communities showed that the Eukaryotes had lower richness and greater similarity between ponds in comparison with Bacteria and Archaea communities on the McMurdo Ice shelf. While there was a weak correlation between community dissimilarity and geographic distance, the congruity of microbial assemblages within ponds, especially for Bacteria and Archaea, implies strong habitat filtering in ice shelf meltwater pond ecosystems, especially due to salinity. These findings help to understand processes that are important in sustaining biodiversity and the impact of climate change on ice-based aquatic habitats in Antarctica.

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Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA

Biogeochemistry ◽

10.1007/s10533-021-00760-4 ◽

2021 ◽

Author(s):

Patricia M. Glibert ◽

Cynthia A. Heil ◽

Christopher J. Madden ◽

Stephen P. Kelly

Keyword(s):

Water Quality ◽

Anthropogenic Activities ◽

Florida Bay ◽

Climate Conditions ◽

Regime Changes ◽

Physico Chemical ◽

Organic Nutrients ◽

High Concentrations ◽

Chemical Conditions ◽

Favorable Conditions

AbstractThe availability of dissolved inorganic and organic nutrients and their transformations along the fresh to marine continuum are being modified by various natural and anthropogenic activities and climate-related changes. Subtropical central and eastern Florida Bay, located at the southern end of the Florida peninsula, is classically considered to have inorganic nutrient conditions that are in higher-than-Redfield ratio proportions, and high levels of organic and chemically-reduced forms of nitrogen. However, salinity, pH and nutrients, both organic and inorganic, change with changes in freshwater flows to the bay. Here, using a time series of water quality and physico-chemical conditions from 2009 to 2019, the impacts of distinct changes in managed flow, drought, El Niño-related increases in precipitation, and intensive storms and hurricanes are explored with respect to changes in water quality and resulting ecosystem effects, with a focus on understanding why picocyanobacterial blooms formed when they did. Drought produced hyper-salinity conditions that were associated with a seagrass die-off. Years later, increases in precipitation resulting from intensive storms and a hurricane were associated with high loads of organic nutrients, and declines in pH, likely due to high organic acid input and decaying organic matter, collectively leading to physiologically favorable conditions for growth of the picocyanobacterium, Synechococcus spp. These conditions, including very high concentrations of NH4+, were likely inhibiting for seagrass recovery and for growth of competing phytoplankton or their grazers. Given projected future climate conditions, and anticipated cycles of drought and intensive storms, the likelihood of future seagrass die-offs and picocyanobacterial blooms is high.

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