Terminal Proterozoic cyanobacterial blooms and phosphogenesis documented by the Doushantuo granular phosphorites I: In situ micro-analysis of textures and composition

2013 ◽  
Vol 235 ◽  
pp. 20-35 ◽  
Author(s):  
Zhenbing She ◽  
Paul Strother ◽  
Gregory McMahon ◽  
Larry R. Nittler ◽  
Jianhua Wang ◽  
...  
Keyword(s):  
Cyanobacterial Blooms ◽  
Micro Analysis

Development of polymerase chain reaction and fluorescent in situ hybridisation techniques for the detection of a bacterial strain that degrades the cyanobacterial toxin microcystin LR

2005 ◽  
Vol 56 (8) ◽  
pp. 1127 ◽  
Author(s):  
D. G. Bourne ◽  
R. L. Blakeley ◽  
P. Riddles ◽  
G. J. Jones
Keyword(s):  
Polymerase Chain Reaction ◽  
Environmental Samples ◽  
In Situ Hybridisation ◽  
Cyanobacterial Blooms ◽  
Chain Reaction ◽  
Fluorescent In Situ Hybridisation ◽  
Cyanobacterial Toxin ◽  
Specific Amplification ◽  
Polymerase Chain

Polymerase chain reaction (PCR) and fluorescent in situ hybridisation (FISH) techniques were developed for the detection of a Sphingomonas bacterium (strain MJ-PV), previously demonstrated to degrade the cyanobacterial toxin microcystin LR. A PCR amplification protocol using the primer set Sph-f1008/Sph-r1243 demonstrated specific amplification of the target 16S ribosomal DNA (rDNA) of strain MJ-PV. A 16S ribosomal RNA (rRNA) targeted probe, Sph-r1264, labelled with a rhodamine fluorescent dye was successfully used in whole-cell FISH for the detection of MJ-PV in seeded controls. DNA primers and a PCR protocol were developed for the specific amplification of a gene, mlrA, which codes for the enzyme MlrA, responsible for hydrolysis of the cyanobacterial toxin microcystin LR. A survey using 16S rDNA and mlrA primers on extracted DNA from environmental samples of a lake that suffers regular toxic cyanobacterial blooms demonstrated no amplified products indicative of the presence of MJ-PV or mlrA. Although not detecting the MJ-PV strain in the tested environmental samples, these developed methods are useful to study the distribution of strain MJ-PV demonstrated to degrade mycrocystin LR in seeded bioremediation trails, as well as the distribution and the regulation of mlrA shown to be involved in mycrocystin LR degradation.

Grazing of the copepod Cyclops vicinus on toxic Microcystis aeruginosa: potential for controlling cyanobacterial blooms and transfer of toxins

2018 ◽  
Vol 47 (3) ◽  
pp. 296-302 ◽  
Author(s):  
Zakaria A. Mohamed ◽  
Asmaa A. Bakr ◽  
Hamed A. Ghramh
Keyword(s):  
Microcystis Aeruginosa ◽  
Grazing Rate ◽  
Cyanobacterial Blooms ◽  
Feeding Experiments ◽  
Cyclops Vicinus ◽  
Ankistrodesmus Falcatus ◽  
Toxic Cyanobacteria ◽  
Study Laboratory ◽  
Grazer Species

Abstract Grazing of zooplankton on phytoplankton may contribute to a reduction of harmful cyanobacteria in eutrophic waters. However, the feeding capacity and interaction between zooplankton and toxic cyanobacteria vary among grazer species. In this study, laboratory feeding experiments were designed to measure the grazing rate of the copepod Cyclops vicinus on Microcystis aeruginosa and the potential microcystin (MC) accumulation in the grazer. Copepods were fed a mixed diet of the edible green alga Ankistrodesmus falcatus and toxic M. aeruginosa for 10 days. The results showed that C. vicinus efficiently ingested toxic Microcystis cells with high grazing rates, varying during the feeding period (68.9–606.3 Microcystis cells animal-1 d-1) along with Microcystis cell density. Microcystis cells exhibited a remarkable induction in MC production under grazing conditions with concentrations 1.67–12.5 times higher than those in control cultures. Furthermore, C. vicinus was found to accumulate MCs in its body with concentrations increasing during the experiment (0.05–3.21 μg MC animal-1). Further in situ studies are needed to investigate the ability of Cyclops and other copepods to assimilate and detoxify MCs at environmentally relevant concentrations before deciding on the biocontrol of Microcystis blooms by copepods.

Remote sensing of cyanobacterial blooms in Lake Champlain, USA

2013 ◽  
Vol 13 (5) ◽  
pp. 1402-1409
Author(s):  
Adam Trescott ◽  
Elizabeth Isenstein ◽  
Mi-Hyun Park
Keyword(s):  
Remote Sensing ◽  
Satellite Images ◽  
Monitoring Program ◽  
In Situ Monitoring ◽  
Cyanobacterial Blooms ◽  
Lake Champlain ◽  
Initiation And Propagation ◽  
Landsat 7

The objective of this study was to develop cyanobacteria remote sensing models using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) as an alternative to shipboard monitoring efforts in Lake Champlain. The approach allowed for estimation of cyanobacteria directly from satellite images, calibrated and validated with 4 years of in situ monitoring data from Lake Champlain's Long-Term Water Quality and Biological Monitoring Program (LTMP). The resulting stepwise regression model was applied to entire satellite images to provide distribution of cyanobacteria throughout the surface waters of Lake Champlain. The results demonstrate the utility of remote sensing for estimating the distribution of cyanobacteria in inland waters, which can be further used for presenting the initiation and propagation of cyanobacterial blooms in Lake Champlain.

In situ evaluation of options for chemical treatment of hepatotoxic cyanobacterial blooms

1997 ◽  
Vol 54 (8) ◽  
pp. 1736-1742 ◽  
Author(s):  
A K-Y Lam ◽  
E E Prepas
Keyword(s):  
Water Column ◽  
Cyanobacterial Blooms ◽  
Laboratory Studies ◽  
Surrounding Water ◽  
Potential Health ◽  
Cyanobacteria Blooms ◽  
Ph Shock ◽  
Alum Treatment ◽  
Phytoplankton Cells

Closed-bottom limnocorrals were placed in a hardwater lake in central Alberta to compare the effect of two alternative approaches to chemical removal of toxic phytoplankton blooms. Reglone A, which lyses phytoplankton cells, and lime-alum, which precipitates intact phytoplankton cells out of the water column were both effective in removing phytoplankton from the water column. Our results were consistent with laboratory studies in that treatment with Reglone A removed phytoplankton (primarily cyanobacteria) blooms with a concomitant increase in dissolved microcystin (exo-MCYST) and phosphorus concentrations in the surrounding water whereas lime-alum treatment did not. Maximum exo-MCYST concentrations in the water phase of the lime-alum treated limnocorrals were 32-fold lower than those recorded in the Reglone-treated limnocorrals. Treatment with lime alone caused a sharp rise in pH (to >10), and the observed increase in exo-MCYST was likely due to pH shock. Exo-MCYST concentration in the Reglone-treated enclosures remained high for the duration of the experiment (>5 days). As microcystin did not partition onto lake sediments in laboratory studies, our limnocorrals results were probably a good indication of microcystin dynamics in lakes. Thus, the use of chemicals such as lime-alum that precipitate out intact phytoplankton cells lessens the potential health risk where microcystins are present.

scholarly journals Reconstructing N<sub>2</sub>-fixing cyanobacterial blooms in the Baltic Sea beyond observations using 6- and 7-methylheptadecane in sediments as specific biomarkers

2020 ◽  
Vol 17 (9) ◽  
pp. 2579-2591
Author(s):  
Jérôme Kaiser ◽  
Norbert Wasmund ◽  
Mati Kahru ◽  
Anna K. Wittenborn ◽  
Regina Hansen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Cyanobacterial Blooms ◽  
Phosphorus Loading ◽  
The Baltic Sea ◽  
Natural Processes ◽  
Baltic Sea Region ◽  
History Of ◽  
Diazotrophic Cyanobacteria ◽  
The Baltic

Abstract. Summer cyanobacterial blooms represent a threat to the Baltic Sea ecosystem, causing deoxygenation of the bottom water and the spread of the so-called dead zones. The history of the Baltic Sea cyanobacterial blooms is known from in situ and satellite observations since the early 1980s but is still not well understood. By comparing both weekly resolved sediment trap material and a well-dated sediment core from the eastern Gotland Basin with monitoring and satellite cyanobacterial data of the last ca. 35 years, it is shown here that 6- and 7-methylheptadecane lipids (expressed as 6+7Me-C17 : 0) may be potentially considered semiquantitative biomarkers for diazotrophic cyanobacteria, and more specifically for Nodularia spumigena. Using this organic proxy, it was thus possible to reconstruct the history of cyanobacterial blooms beyond the observational period with a resolution of 2–4 years since 1860. Cyanobacteria were constantly present but in relatively low abundance until 1920, when they started to alternate between periods with high and low abundance. Interestingly, there seems to be no significant increase in cyanobacterial abundance in the 1950s, when eutrophication and deoxygenation of the Baltic Sea increased considerably. While the early increase in cyanobacteria may be related to a small increase in phosphorus loading, decadal to multi-decadal fluctuations are likely related to variability in the Baltic Sea surface temperature and, ultimately, to the Atlantic Multi-decadal Oscillation. A 7000-year 6+7Me-C17 : 0 record from the Bothnian Sea also suggests a relationship with the mean summer temperature in the Baltic Sea region but at a multi-centennial to multi-millennial timescale. The intensity of the cyanobacterial blooms in the Baltic Sea is thus likely mainly related to natural processes such as temperature variability, at least at a multi-decadal to multi-millennial timescale.

scholarly journals In situ oxygen isotope micro-analysis of faunal material and human teeth using a SHRIMP II: a new tool for palaeo-ecology and archaeology

2012 ◽  
Vol 39 (10) ◽  
pp. 3184-3194 ◽  
Author(s):  
Maxime Aubert ◽  
Ian S. Williams ◽  
Katarina Boljkovac ◽  
Ian Moffat ◽  
Marie-Hélène Moncel ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Human Teeth ◽  
Micro Analysis

scholarly journals Cyanobacterial biomass: a striking factor to decrease polyaluminium chloride (PACl) coagulation efficiency during a successive bloom

2021 ◽  
Author(s):  
Weijun Song ◽  
Jie Zeng ◽  
Xi Li ◽  
Yu Xie ◽  
Xunfang Wu
Keyword(s):  
Water Treatment ◽  
Cell Density ◽  
Ph Value ◽  
Cyanobacterial Blooms ◽  
Water Treatment Process ◽  
Treatment Processes ◽  
Coagulation Process ◽  
Cyanobacterial Biomass ◽  
Source Waters

Abstract Occurrence of cyanobacterial blooms in source waters challenges water treatment processes. During a successive bloom, typical characteristics of elevated cell-density and pH was observed from development to maintenance stage. However, studies about their influences on coagulation process were limited. Here, PACl coagulation experiments were conducted to investigate Microcystis removal with varied pH and cell-density. Results showed that PACl coagulation alone was sufficient to remove Microcystis with low cell-density (105–106 cells mL−1), since elevated pH value (8.5–9.5) can promote PACl coagulation possibly ascribed to sweeping cells via neutral gelatinous precipitate of alum. Nevertheless, elevated cyanobacterial biomass was a striking factor to decrease Microcystis removal (80–100%) by PACl coagulation, since its inhibitory effects on coagulation process could not be offset by in situ elevated pH value. Chlorination-assisted (1 mg L−1) coagulation was recommended to treat cyanobacteria-laden source waters with high cell-density of &gt;107 cells mL−1, as it promoted cyanobacterial removal and achieved the highest removal ratio of DOC and turbidity among these treatments. These findings would provide an important reference for water supplies to choose proper water treatment process to treat cyanobacteria-laden source waters during a successive bloom.

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