Dynamics of a cyanobacterial bloom in a hypereutrophic, stratified weir pool

2003 ◽  
Vol 54 (1) ◽  
pp. 27 ◽  
Author(s):  
P. A. Thompson ◽  
A. M. Waite ◽  
K. McMahon
Keyword(s):  
Growth Rates ◽  
Algal Blooms ◽  
Dissolved Inorganic Carbon ◽  
Cyanobacterial Bloom ◽  
Nutrient Concentrations ◽  
P Availability ◽  
The Public ◽  
Limiting Nutrient ◽  
Bottom Waters ◽  
Oxygenated Water

In summer 1997–1998, a bloom of the cyanobacteria Anabaena circinalis (Rabenhorst) and Anabaena spiroides (Klebahn) contaminated the Canning River (Perth, WA), forcing its closure to the public for swimming and fishing. We investigated the major nutrient fluctuations before, during and after the bloom. The river was persistently temperature stratified at least 1 month prior to the bloom. The surface and bottom layers of water had distinctly different nutrient concentrations, which meant that biomass and growth rates of the phytoplankton within each layer were limited by different nutrients. At the peak of the bloom, in the bottom waters growth rates were light limited and biomass was nitrogen limited, whereas in the surface waters biomass was controlled by phosphorus (P) availability and growth rates were probably limited by the lack of dissolved inorganic carbon. Another consequence of stratification was that, at the peak of the bloom (0.25 mg chlorophyll L−1), the mostly buoyant cyanobacteria could not access 83% of the P released from sediments during the summer period of anoxia. In this situation, the injection of oxygenated water, tested as a remediation measure for algal blooms, is likely to exacerbate a bloom by providing more of the limiting nutrient to the surface layer. However, aeration prior to the bloom may reduce P release from the sediments by preventing anoxia.

Hydrography, nutrients, and plankton along the longitudinal section of the Ombla Estuary (south-eastern Adriatic)

2012 ◽  
Vol 92 (6) ◽  
pp. 1227-1242 ◽  
Author(s):  
Marina Carić ◽  
Nenad Jasprica ◽  
Frano Kršinić ◽  
Ivica Vilibić ◽  
Mirna Batistić
Keyword(s):  
Algal Blooms ◽  
Marine Species ◽  
Longitudinal Section ◽  
Early Spring ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Surface Salinity ◽  
South Eastern ◽  
Limiting Nutrient ◽  
Stratified Estuary

Abundance and structure of phytoplankton and zooplankton, along with their relationship to hydrographic conditions were determined in the highly stratified estuary of the karstic Ombla River, south-eastern Adriatic. Sampling was carried out during 17 cruises within a one year period. River discharge lowered surface salinity and enriched the estuary with NO3 and SiO4. Nutrient ratios suggested that PO4 was the most likely limiting nutrient for phytoplankton growth in the estuary. Diatoms were present in low numbers and dominated the winter–early spring period. Dinoflagellates dominated from the end of May to August. Phytoplankton and zooplankton were composed mostly of marine species and their abundance decreased in seaward direction. Planktonic populations are controlled by the river runoff, temperature, salinity, nutrient concentrations and grazing. The results were consistent with the hypothesis that no algal blooms have been recorded due to short renewal time.

Roles of Nutrients in Controlling Growth of Epilithon in Oligotrophic Lakes of Low Alkalinity

1994 ◽  
Vol 51 (12) ◽  
pp. 2784-2793 ◽  
Author(s):  
Michael A. Turner ◽  
E. Todd Howell ◽  
Gordon G. C. Robinson ◽  
Paul Campbell ◽  
Robert E. Hecky ◽  
...  
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Dissolved Inorganic Carbon ◽  
Optimal Growth ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
P Availability ◽  
Experimental Lakes Area ◽  
Diffusive Resistance ◽  
Pelagic Food Webs ◽  
Algal Photosynthesis

The ability of nutrients to control photosynthesis was compared in epilithon (the association on rock surfaces in the littoral zone) and phytoplankton of 13 low alkalinity lakes of the Experimental Lakes Area of northwestern Ontario. The study included (1) surveys of lakes varying in nutrient concentrations; (2) experimental additions to lakes of carbon and nitrogen (N), with or without phosphorus (P); and (3) experimental additions to lakes of sulfuric and nitric acids. Nutrient controls of planktonic and epilithic algal photosynthesis differed consistently. Phosphorus limited planktonic algal photosynthesis. In contrast, dissolved inorganic carbon (DIC) limited epilithic photosynthesis in both perturbed and unperturbed lakes because diffusive resistance kept the effective supply of DIC below the level needed for optimal growth. Epilithic photosynthesis was lowered when lake disturbances (e.g., acidification) reduced epilimnetic concentrations of DIC. Expected increases in atmospheric carbon dioxide can, therefore, differentially affect the littoral and pelagic food webs in low DIC lakes. Epilithic photosynthesis in all study lakes was unrelated to N or P availability despite apparent N and P deficiencies, based upon particulate nutrient ratios. Rates of epilithic respiration were, however, correlated with epilimnetic concentrations of inorganic N.

scholarly journals Occurrence of a single-species cyanobacterial bloom in a lake in Cyprus: monitoring and treatment with hydrogen peroxide-releasing granules

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Eleni Keliri ◽  
Christia Paraskeva ◽  
Angelos Sofokleous ◽  
Assaf Sukenik ◽  
Dariusz Dziga ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Animal Health ◽  
Cyanobacterial Bloom ◽  
Single Species ◽  
Eutrophic Lake ◽  
Liquid Hydrogen ◽  
Bioactive Metabolites ◽  
Forest Park

AbstractBackgroundExcess loads of nutrients finding their way into waterbodies can cause rapid and excessive growth of phytoplankton species and lead to the formation of cyanobacterial harmful algal blooms (cyano-HABs). Toxic cyanobacteria produce a broad range of bioactive metabolites, some of which are known as cyanotoxins. These metabolites can negatively impact the ecosystem, and human and animal health, thus their presence needs to be closely monitored and mitigated. This study aimed to monitor St. George Lake (Athalassa National Forest Park, Cyprus) for its water quality characteristics, and initiate a new methodology to control the bloom that occurred in the lake during summer 2019, by comparing hydrogen peroxide treatment with novel metallic peroxide granules as source of hydrogen peroxide.ResultsLake monitoring showed that pH, salinity, total dissolved solids and conductivity varied throughout the year, and nutrients concentration was high, indicating a eutrophic lake. The cyanobacteriumMerismopediasp. bloomed in the lake between June and September 2019, comprising up to 99% of the phytoplankton biovolume. The presence of microcystin synthase encoding gene (mcyB, mcyE) was documented, however microcystins were not detected by tandem mass spectroscopy. Treatment with liquid hydrogen peroxide in concentrations 1 to 5 mg L−1had no effect on the phycocyanin fluorescence (Ft) and quantum yield of PSII (Fv/Fm) indicating an ineffective treatment for the denseMerismopediabloom (1 million cells mL−1 ± 20%). Metallic peroxide granules tested for their H2O2releasing capacity in St. George Lake water, showing that CaO2released higher H2O2concentration and therefore have better mitigation efficiency than MgO2granules.ConclusionThe present study highlights the importance of monitoring several water parameters to conclude on the different actions to be taken to limit eutrophication in the catchment area. The findings demonstrated that testing for the presence of genes involved in cyanotoxin production may not be sufficient to follow cyanotoxins in the water, therefore it should be accompanied with analytical confirmation. Treatment experiments indicated that slow release of H2O2from peroxide granules may be an alternative to liquid hydrogen peroxide when applied in appropriate doses, but further investigation is needed before it is applied at the field.Graphic Abstract

scholarly journals A Review of Nontraditional Biomanipulation

2008 ◽  
Vol 8 ◽  
pp. 1184-1196 ◽  
Author(s):  
Xia Zhang ◽  
Ping Xie ◽  
Xiaoping Huang
Keyword(s):  
Algal Blooms ◽  
Algal Species ◽  
Planktivorous Fish ◽  
Bighead Carp ◽  
Cyanobacterial Blooms ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Effective Management ◽  
Nuisance Algae ◽  
The Impact

The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels.Although small enclosures increase spatial overlap between predators and prey, leading to overestimates of the impact of predation, microcosm and whole-lake experiments have revealed similar community responses to major factors that regulate lake communities, such as nutrients and planktivorous fish. Both enclosure experiments and large-scale observations revealed that the initial phytoplankton community composition greatly impacted the success of biomanipulation. Long-term observations in Lake Donghu and Lake Qiandaohu have documented that silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) (two filter-feeding planktivorous species commonly used in management) can suppress Microcystis blooms efficiently. The introduction of silver and bighead carp could be an effective management technique in eutrophic systems that lack macrozooplankton. We confirmed that nontraditional biomanipulation is only appropriate if the primary aim is to reduce nuisance blooms of large algal species, which cannot be controlled effectively by large herbivorous zooplankton. Alternatively, this type of biomanipulation did not work efficiently in less eutrophic systems where nanophytoplankton dominated.

Study on the SCC Growth of Alloy 182 Under Constant Displacement Condition in High Temperature Oxygenated Water

2004 ◽  
Author(s):  
Shunichi Suzuki ◽  
Katsuhiko Kumagai ◽  
Satoshi Namatame ◽  
Masaaki Kikuchi ◽  
Mikiro Itow ◽  
...  
Keyword(s):  
Residual Stress ◽  
Growth Rates ◽  
Loading Condition ◽  
Growth Behavior ◽  
Stress Profile ◽  
Constant Loading ◽  
Compression Region ◽  
Displacement Condition ◽  
Oxygenated Water ◽  
Constant Displacement

SCC initiates and propagates along the fusion line or in the weld metal in BWR and many SCC initiation & propagation studies have been performed so far (Saito, et al. (1997), Kikuchi, et al. (1997), Itow, et al. (1997, 2000), Suzuki (1999), Namatame, et al. (2001)). SCC growth behavior can be evaluated by conjunction of SCC growth rates and the residual stress of the welded component, which consists of tension/compression region. Especially, thick components such as core shrouds have increasing and decreasing tensile stress profile under constant displacement. In general, SCC growth rates are obtained from CT specimens under constant loading condition. This study shows that SCC growth rates depend on dK/dt as well as on K and that their growth rates under constant displacement with decreasing K are lower than those under constant loading condition with increasing K.

scholarly journals Deep Learning for Simulating Harmful Algal Blooms Using Ocean Numerical Model

2021 ◽  
Vol 8 ◽  
Author(s):  
Sang-Soo Baek ◽  
JongCheol Pyo ◽  
Yong Sung Kwon ◽  
Seong-Jun Chun ◽  
Seung Ho Baek ◽  
...  
Keyword(s):  
Deep Learning ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Effective Means ◽  
Ocean Model ◽  
Alexandrium Catenella ◽  
The Public ◽  
Global Issue ◽  
Simulated Distribution ◽  
Classification And Regression

In several countries, the public health and fishery industries have suffered from harmful algal blooms (HABs) that have escalated to become a global issue. Though computational modeling offers an effective means to understand and mitigate the adverse effects of HABs, it is challenging to design models that adequately reflect the complexity of HAB dynamics. This paper presents a method involving the application of deep learning to an ocean model for simulating blooms of Alexandrium catenella. The classification and regression convolutional neural network (CNN) models are used for simulating the blooms. The classification CNN determines the bloom initiation while the regression CNN estimates the bloom density. GoogleNet and Resnet 101 are identified as the best structures for the classification and regression CNNs, respectively. The corresponding accuracy and root means square error values are determined as 96.8% and 1.20 [log(cells L–1)], respectively. The results obtained in this study reveal the simulated distribution to follow the Alexandrium catenella bloom. Moreover, Grad-CAM identifies that the salinity and temperature contributed to the initiation of the bloom whereas NH4-N influenced the growth of the bloom.

Major cyanobacterial bloom in the Barwon-Darling River, Australia, in 1991, and underlying limnological conditions

1996 ◽  
Vol 47 (4) ◽  
pp. 643 ◽  
Author(s):  
LC Bowling ◽  
PD Baker
Keyword(s):  
New South ◽  
Cyanobacterial Bloom ◽  
Low Flow ◽  
Nutrient Concentrations ◽  
Mouse Bioassay ◽  
Contributing Factors ◽  
South Wales ◽  
High Ammonia ◽  
High Nutrient ◽  
Very High

The occurrence of a severe cyanobacterial bloom is described. This bloom affected almost 1000 km of the Barwon-Darling River, New South Wales, Australia, in November and December 1991 and was dominated by Anabaena circinalis Rabenhorst. This cyanobacterium was present in concentrations of around half a million cells per millilitre at some localities during its peak in mid November. Moderate to very high toxicity was demonstrated by mouse bioassay at many localities during this time. The bloom was attributed to very low flow conditions and high nutrient concentrations, especially of total phosphorus. However, warm water temperatures, elevated pH, reduced turbidity, and improved water transparency would also have been contributing factors. Very high ammonia concentrations were also observed during the bloom. The bloom declined during December and was eventually flushed from the river by increased flows following heavy catchment rainfall between mid December and early January.

scholarly journals Biotic vs. abiotic forcing on plankton assemblages varies with season and size class in a large temperate estuary

2020 ◽  
Vol 42 (2) ◽  
pp. 221-237 ◽  
Author(s):  
Gretchen Rollwagen-Bollens ◽  
Stephen Bollens ◽  
Eric Dexter ◽  
Jeffery Cordell
Keyword(s):  
Community Dynamics ◽  
Abiotic Factors ◽  
River Estuary ◽  
Multiple Time Scales ◽  
Nutrient Concentrations ◽  
Winter Period ◽  
Zooplankton Abundance ◽  
Multiple Time ◽  
P Availability ◽  
Lower Estuary

Abstract Large river estuaries experience multiple anthropogenic stressors. Understanding plankton community dynamics in these estuaries provides insights into the patterns of natural variability and effects of human activity. We undertook a 2-year study in the Columbia River Estuary to assess the potential impacts of abiotic and biotic factors on planktonic community structure over multiple time scales. We measured microplankton and zooplankton abundance, biomass and composition monthly, concurrent with measurements of chlorophyll a, nutrient concentrations, temperature and salinity, from a dock in the lower estuary. We then statistically assessed the associations among the abundances of planktonic groups and environmental and biological factors. During the late spring high flow period of both years, the lower estuary was dominated by freshwater and low salinity-adapted planktonic taxa, and zooplankton grazers were more strongly associated with the autotroph-dominated microplankton assemblage than abiotic factors. During the early winter period of higher salinity and lower flow, nutrient (P) availability exerted a strong influence on microplankton taxa, while only temperature and upwelling strength were associated with the zooplankton assemblage. Our results indicate that the relative influence of biotic (grazers) and abiotic (salinity, flow, nutrients and upwelling) factors varies seasonally and inter-annually, and among different size classes in the estuarine food web.

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