Journal articles: 'Algal bloom control'

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Jiang, Hao, Jian Liang Rui, Hai Lin Li, De Hua Zhao, Jing Jing Fu, and Shu Qing An. "Research on Algal Bloom Control for Environment Engineering." Applied Mechanics and Materials 340 (July 2013): 971–74. http://dx.doi.org/10.4028/www.scientific.net/amm.340.971.

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Aquatic plants inhibit algae through nutrient competition, sludge sedimentation and the release of allelochemicals in three ways. Investigating Pistia stratiotes L in East Lake, Shao (2001) observed removal rate of the BOD5 achieved more than 70%; the total nitrogen removal efficiency was 60%, the total phosphorus removal efficiency was approximately 70% or more, and this biochemical inhibitory effect may promote algal settlement. Ho Pool (1999) found that the Rhizoma AcoriGraminei could cause a water total nitrogen (TN) removal rate of 87.4%, a total phosphorus (TP) removal rate of 43.9%, and a dissolved oxygen (DO) increase of 26.6%. These studies suggest that through the promotion of the lake TN and TP, aquatic plants influence bio-deposition into sediments, in addition to their role in the nutrient cycling of lakes. Furthermore, many studies have shown that aquatic macrophytes can produce allelochemicals that could inhibit the growth of algae (Donk & Bund, 2002; A. Gross & Boyd, 1998; Elisabeth M. Gross, 2003; E. M. Gross & Sütfeld, 1994; Mulderij, Smolders, & Van Donk, 2006; Mulderij, Van Nes, & Van Donk, 2007).

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Jing, Yuanyuan, Yuchao Zhang, Minqi Hu, Qiao Chu, and Ronghua Ma. "MODIS-Satellite-Based Analysis of Long-Term Temporal-Spatial Dynamics and Drivers of Algal Blooms in a Plateau Lake Dianchi, China." Remote Sensing 11, no. 21 (November 4, 2019): 2582. http://dx.doi.org/10.3390/rs11212582.

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Algal blooms in eutrophic lakes have been a global issue to environmental ecology. Although great progress on prevention and control of algae have been made in many lakes, systematic research on long-term temporal-spatial dynamics and drivers of algal blooms in a plateau Lake Dianchi is so far insufficient. Therefore, the algae pixel-growing algorithm (APA) was used to accurately identify algal bloom areas at the sub-pixel level on the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 2000 to 2018. The results showed that algal blooms were observed all year round, with a reduced frequency in winter–spring and an increased frequency in summer–autumn, which lasted a long time for about 310–350 days. The outbreak areas were concentrated in 20–80 km2 and the top three largest areas were observed in 2002, 2008, and 2017, reaching 168.80 km2, 126.51 km2, and 156.34 km2, respectively. After deriving the temporal-spatial distribution of algal blooms, principal component analysis (PCA) and redundancy analysis (RDA) were applied to explore the effects of meteorological, water quality and human activities. Of the variables analyzed, mean temperature (Tmean) and wind speed (WS) were the main drivers of daily algal bloom areas and spatial distribution. The precipitation (P), pH, and water temperature (WT) had a strong positive correlation, while WS and sunshine hours (SH) had a negative correlation with monthly maximum algal bloom areas and frequency. Total nitrogen (TN) and dissolved oxygen (DO) were the main influencing factors of annual frequency, initiation, and duration of algal blooms. Also, the discharge of wastewater and the southwest and southeast monsoons may contribute to the distribution of algal blooms mainly in the north of the lake. However, different regions of the lake show substantial variations, so further zoning and quantitative joint studies of influencing factors are required to more accurately understand the true mechanisms of algae in Lake Dianchi.

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Zhang, Yuchao, Steven Loiselle, Kun Shi, Tao Han, Min Zhang, Minqi Hu, Yuanyuan Jing, Lai Lai, and Pengfei Zhan. "Wind Effects for Floating Algae Dynamics in Eutrophic Lakes." Remote Sensing 13, no. 4 (February 22, 2021): 800. http://dx.doi.org/10.3390/rs13040800.

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Wind-speed decline is an important impact of climate change on the eastern Asian atmospheric circulation. Although wind does not determine algae biomass in eutrophic lakes, it is a decisive factor in the formation and severity of algae blooms. Based on 2000–2018 MODIS images, this study compared the effects of wind speed on algal blooms in three typical eutrophic lakes in China: Lake Taihu, Lake Chaohu and Lake Dianchi. The results indicate that climate change has different effects on the wind speed of the three lakes, but a common effect on the vertical distribution of algae. A wind speed of 3.0 m/s was identified as the critical threshold in the vertical distribution of chlorophyll-a concentrations in the three study lakes. The basic characteristics of the periodic variation of wind speed were different, but there was a significant negative correlation between wind speed and floating algal bloom area in all three lakes. In addition, considering lake bathymetry, wind direction could be used to identify locations that were particularly susceptible to algae blooms. We estimated that algal bloom conditions will worsen in the coming decades due to the continuous decline of wind, especially in Lake Taihu, even though the provincial and national governments have made major efforts to reduce eutrophication drivers and restore lake conditions. These results suggest that early warning systems should include a wind-speed threshold of 3.0 m/s to improve control and mitigation of algal blooms on these intensively utilized lakes.

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Mayali, Xavier, Peter J. S. Franks, and Farooq Azam. "Cultivation and Ecosystem Role of a Marine Roseobacter Clade-Affiliated Cluster Bacterium." Applied and Environmental Microbiology 74, no. 9 (March 7, 2008): 2595–603. http://dx.doi.org/10.1128/aem.02191-07.

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ABSTRACT Isolation and cultivation are a crucial step in elucidating the physiology, biogeochemistry, and ecosystem role of microorganisms. Many abundant marine bacteria, including the widespread Roseobacter clade-affiliated (RCA) cluster group, have not been cultured with traditional methods. Using novel techniques of cocultivation with algal cultures, we have accomplished successful isolation and propagation of a strain of the RCA cluster. Our experiments revealed that, in addition to growing on alga-excreted organic matter, additions of washed bacterial cells led to significant biomass decrease of dinoflagellate cultures as measured by in vivo fluorescence. Bacterial filtrate did not adversely affect the algal cultures, suggesting attachment-mediated activity. Using an RCA cluster-specific rRNA probe, we documented increasing attachment of these algicidal bacteria during a dinoflagellate bloom, with a maximum of 70% of the algal cells colonized just prior to bloom termination. Cross-correlation analyses between algal abundances and RCA bacterial colonization were statistically significant, in agreement with predator-prey models suggesting that RCA cluster bacteria caused algal bloom decline. Further investigation of molecular databases revealed that RCA cluster bacteria were numerically abundant during algal blooms sampled worldwide. Our findings suggest that the widespread RCA cluster bacteria may exert significant control over phytoplankton biomass and community structure in the oceans. We also suggest that coculture with phytoplankton may be a useful strategy to isolate and successfully grow previously uncultured but ecologically abundant marine heterotrophs.

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Qingxin, Yang. "Algal bloom in Taihu Lake and its control." Journal of Lake Sciences 8, no. 1 (1996): 67–74. http://dx.doi.org/10.18307/1996.0109.

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Zeng, Guoming, Jing Luo, Xiaowan Liu, Maolan Zhang, and Hengjun Tang. "Research on the changes of physiological characteristics of algal cells in the process of algae dissolving by immobilized white rot fungi." E3S Web of Conferences 165 (2020): 05033. http://dx.doi.org/10.1051/e3sconf/202016505033.

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With the increasing of water pollution, water eutrophication is seriously affecting people’s daily life and production. Therefore, it is particularly important to explore safe and efficient algae control technology. In the current algal bloom treatment methods, the physical method is not complete in algae dissolving, and the cost of algal control is high. The chemical method is easy to produce secondary pollution and toxic by-products, and the safety is not high. However, the biological method has the advantages of low cost, high ecological security and good ecological compatibility. It is considered to be a more promising method to remove algae and biological toxins, and it is also an inevitable trend to control water eutrophication in the future.

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Lathrop, Richard C., Stephen R. Carpenter, Craig A. Stow, Patricia A. Soranno, and John C. Panuska. "Phosphorus loading reductions needed to control blue-green algal blooms in Lake Mendota." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 5 (May 1, 1998): 1169–78. http://dx.doi.org/10.1139/f97-317.

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We evaluated the reductions in P loading needed to control blue-green algal blooms in Lake Mendota, Wisconsin. After developing a 21-year loading data set, we used a P mass balance model expressed as a difference equation with an annual time step indexed from mid-April. We defined and estimated a loss parameter lambda as the proportion of the lake's April P concentration lost through sedimentation and outflow during the following year. Using the distribution of annual lambda 's and input loadings, we predicted the steady-state distribution of April P concentrations that would result from scenarios of altered inputs due to changes in management practices. These results were then linked to the probability of summer blue-green algal blooms. For no load reduction, the probability of a bloom (>2 mg algae ·L-1) on any summer day is about 60%. This probability decreases to 20% with a load reduction of 50%. Our approach illustrates how managers can consider reducing the frequency of extreme events like algal blooms, which may correspond more to the public's perception of lake water quality than average conditions.

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Simões, Erik, Renato Campos Vieira, Mathias Alberto Schramm, Danielle Ferraz Mello, Vitor De Almeida Pontinha, Patrícia Mirella da Silva, and Margherita Anna Barracco. "Impact of harmful algal blooms (Dinophysis acuminata) on the immune system of oysters and mussels from Santa Catarina, Brazil." Journal of the Marine Biological Association of the United Kingdom 95, no. 4 (December 1, 2014): 773–81. http://dx.doi.org/10.1017/s0025315414001702.

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Blooms of the harmful alga Dinophysis acuminata, which produces okadaic acid (OA), are becoming recurrent in Santa Catarina coast, where most of the shellfish marine farms in Brazil are located. We evaluated the impact of D. acuminata blooms on various haemato-immunological parameters and on tissue integrity of cultivated oysters (Crassostrea gigas) and mussels (Perna perna). Animals were sampled during two natural algal blooms, one at Praia Alegre (PA: 2950 cells l−1) and the other at Praia de Zimbros (PZ: 4150 cells l−1). Control animals were sampled at the same sites, 30 days after the end of the bloom. The assayed parameters were: total (THC) and differential (DHC) haemocyte counts, percentage of apoptotic haemocytes (AH), phenoloxidase activity (PO), agglutinating titre (AT) and total protein concentration in haemolymph (PC). Histological analyses were carried out in oysters from PZ. The results showed that some immune parameters were modulated during the toxic blooms, but not in a consistent manner, especially in mussels that accumulated more OA (10×) than oysters. For example, mussel THC decreased significantly (54%) during the bloom at PA, whereas it augmented markedly (64%) at PZ. PO activity was significantly altered by the algal blooms in both bivalve species, while PC increased significantly (66%) only in mussels from PZ bloom. The other parameters (DHC, AH and AT) did not vary in both bivalve species. Histological analyses showed an intense haemocytic infiltration throughout the oyster digestive epithelium, particularly into the stomach lumen during the algal bloom.

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Ohadi, Sara, Amar Godar, John Madsen, and Kassim Al-Khatib. "Response of Rice Algal Assemblage to Fertilizer and Chemical Application: Implications for Early Algal Bloom Management." Agronomy 11, no. 3 (March 13, 2021): 542. http://dx.doi.org/10.3390/agronomy11030542.

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California water-seeded rice is challenged with the rapid growth of nuisance algae at the beginning of the season. Rice seedlings entangled in the algal mat may not be established, causing empty rice patches in the field. Two separate studies were conducted to (1) evaluate the effect of nutrients (nitrogen and phosphorous) on algae growth, and (2) test various chemical options to control algae. Both studies utilized 19 L buckets inoculated with algae collected from a rice field. In the nutrient evaluation study, 36 nutrient treatments obtained from a combination of nitrogen (0, 60, 120, 180, 240 and 300 kg ha−1) and phosphorous (0, 20, 40, 60, 80 and 100 kg ha−1) rates were applied into the buckets, while eight chemicals with potential for algae control (two Protox inhibitor herbicides, four copper-based compounds, hydrogen peroxide, Zinc sulfate) were tested in the second experiment. In addition, a yeast extract-based surfactant (AMP activator) was tested in combination with a chelated copper formulation (Algimycin) and hydrogen peroxide. The studies had a completely randomized design with three replicates and each study was repeated two times. The result from the nutrient evaluation study showed that nitrogen and phosphorus can independently cause change in algae growth as reflected in the fresh and dry biomass. Moreover, low rates of either nitrogen or phosphorus resulted in a rapid increase in algae biomass and water chlorophyll a content, whereas the growth of algae declined at higher rates of applied fertilizer. Among tested chemicals in the second experiment, the chelated formulation of copper (Algimycin PWF) controlled algae (85%) better than the ethanolamine formulations [Cutrine-Ultra (70%) and Cutrine-Plus (52%)] and elemental copper (crystalline copper sulfate) (75%). Protox herbicides (oxyfluorfen and oxadiazon) were able to control algae by up to 70%. Hydrogen peroxide controlled algae by 50% and its efficacy dropped dramatically five days after treatment (DAT). Zinc sulfate was only effective at 1 DAT and algae recovered rapidly after that. Combining fertilizer management practices with chemical options will enable us toward an integrative approach for early algal bloom in the rice cropping system.

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Bae, Jong Hyuk, Jae-Hyoung Joo, You Jung Lee, Myung-Soo Han, and Seong Hun Kim. "Fabrication of biodegradable polylactide foam for algal bloom control." Fibers and Polymers 16, no. 10 (October 2015): 2087–93. http://dx.doi.org/10.1007/s12221-015-5555-8.

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Chung, Se-Woong, Heungsoo Lee, and Yongrock Jung. "The effect of hydrodynamic flow regimes on the algal bloom in a monomictic reservoir." Water Science and Technology 58, no. 6 (October 1, 2008): 1291–98. http://dx.doi.org/10.2166/wst.2008.482.

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The effectiveness of a proposed curtain weir to be installed in the transitional zone of a eutrophic reservoir located in monsoon areas on the control of algal blooms in the lacustrine zone where drinking water withdrawals occur was assessed with various hydrodynamic flow regimes. A two-dimensional hydrodynamic and eutrophication model that can accommodate vertical displacement of the weir following the water surface changes was developed and validated using field data obtained from two distinctive hydrological years; drought (2001) and wet (2004). The model adequately reproduced the temporal and spatial variations of temperature, nutrients and phytoplankton concentrations in the reservoir. The efficacy of the curtain weir method found to be diverse for different hydrological conditions and dependent on the inflow densimetric Froude number (Fri). Algal blooming was considerably mitigated by curtailing the transport of nutrients and algae from riverine zone to lacustrine epilimnion zone during the drought year as long as Fri<1.0. However, some flood events with Fri>1.0 transported nutrients and algae built upstream of the weir into the downstream euphotic zone by strong entrainments in 2004. Numerical experiments revealed that the efficiency of the weir on the control of algal blooming becomes marginal if the Fri>3.0.

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Yu, Li, Weihua Li, Rong Wang, and Qiang Yuan. "Effects of nutrient addition on algae pigments during the early stages of phytoplankton bloom." E3S Web of Conferences 136 (2019): 06033. http://dx.doi.org/10.1051/e3sconf/201913606033.

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To clarify the effects of nutrient addition on algal growth during the early stages of phytoplankton bloom, an microcosm experiment was conducted in early spring; it included two groups of in situ samples: sediment plus lake water (S+W), representing the nominal “control”, and sediment plus 50% BG11 medium and 50% lake water (S+BW), representing the treatment of nutrient addition. The results demonstrated the recruitment biomass of non-cyanobacteria in the treatment group was about 46.7% of that in the control group, and the recruitment biomass of cyanobacteria in the treatment group was approximately 5 times than that in the control. After recruitment, nutrient addition generated remarkable stimulation of the growth of all algae, especially cyanobacteria. The results suggested that the stimulation by nutrient addition of algal growth after recruitment may be responsible for the occurrence of phytoplankton blooms, and the more pronounced promotion of cyanobacteria than non-cyanobacteria was explainable for the strengthening of the dominance of cyanobacteria during eutrophication.

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Mitra, Aditee, and Kevin J. Flynn. "Promotion of harmful algal blooms by zooplankton predatory activity." Biology Letters 2, no. 2 (March 2006): 194–97. http://dx.doi.org/10.1098/rsbl.2006.0447.

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The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios.

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Tiwari, Pankaj Kumar, Sudip Samanta, Jocirei D. Ferreira, and Arvind Kumar Misra. "A Mathematical Model for the Effects of Nitrogen and Phosphorus on Algal Blooms." International Journal of Bifurcation and Chaos 29, no. 10 (September 2019): 1950129. http://dx.doi.org/10.1142/s0218127419501293.

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The increase of nutrients in lakes typically stimulates the growth of algae in this environment. Therefore, it is important to understand the connection between nutrient concentration and algal biomass to manage the water pollution caused by excessive plant nutrients. It is worth observing that phosphorus and nitrogen are often considered as the principal limiting nutrients for aquatic algal production due to their short supply compared to cellular growth requirements. In freshwaters, phosphorus is the least abundant among the nutrients needed in large quantity by photosynthetic organisms, hence this is the primary nutrient that limits their growth. The purpose of this work is to compare the effects of nitrogen and phosphorus on the growth of algae in lakes. By using a sensitivity analysis technique, we found that the sources of phosphorus provide a greater risk for bloom of algae than that of nitrogen. Therefore, to reduce the occurrence of algal bloom more attention should be paid for the control of phosphorus input into the lake but the inflow of nitrogen cannot be ignored. The existence of a transcritical bifurcation is discussed and its direction is investigated by applying the projection method technique. Further, to make the system more realistic, time delay involved in the conversion of detritus into nutrients is considered. We show that for increasing values of time delay, the system undergoes an Andronov–Hopf-bifurcation. Some simulations are presented to verify the analytical findings. The results of our study can be helpful for the policy makers to mitigate algal blooms from lakes.

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Chen, Feiran, Zhenggao Xiao, Le Yue, Jing Wang, Yan Feng, Xiaoshan Zhu, Zhenyu Wang, and Baoshan Xing. "Algae response to engineered nanoparticles: current understanding, mechanisms and implications." Environmental Science: Nano 6, no. 4 (2019): 1026–42. http://dx.doi.org/10.1039/c8en01368c.

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Liu, Ting Ting, Yu Fu Peng, Li Liu, and Xue Shan Xia. "Isolation and Characterization of the Algicidal Bacterium DCJ-2." Advanced Materials Research 1065-1069 (December 2014): 3077–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.3077.

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Algicidal bacteria as part of the microbial populations in natural waters, is possible toinhibit the growth of algae or kill algae, dissolve algal cells in a direct or indirect way. In this study,four algicidal bacteria were isolated from cyanobacteria bloom water of Lake Dianchi, designated asDCJ-1, DCJ-2, DCJ-3, DCJ-4 respectively. The algicidal range and algicidal activity assay of the fouralgicidal bacteria showed that they have different algicidal range on the 10 tested algal species, whichstrain DCJ-2 has the best algicidal activity. The results indicated that bacterial strain DCJ-2 has highalgicidal activity against the Plectonema boryanum and exhibited algicidal activity through directattack. The lytic effect of strain DCJ-2 against Plectonema boryanum was time-dependent. It could be a potential bio-agent to control the blooms of cyanobacteria.

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Yin, Wei, Xiao Kang Xin, and Hai Yan Jia. "Preliminary Research on Hydrodynamic Dispatch Method of Algal Blooms in Three Gorges Reservoir Bays." Applied Mechanics and Materials 675-677 (October 2014): 811–17. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.811.

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Spring algal happened in the bays area frequently after Three Gorges Reservoir’s impoundment. Algal bloom is closely related with nutrients, light, temperature and flow velocity. This paper carried out preliminary research on algal blooms hydrodynamic control method by optimizing reservoirs dispatch on main and tributary channels. Making use of software MIKE 21, a Xiangxi River-Three Gorges Reservoir integrate hydrodynamic numerical model has been established, and a series of conditions have been simulated and studied. The result shows that if Three Gorges Reservoir operates alone, velocity at Xiangxi River mouth is less than 0.05m/s, and if Xiangxi Reservoir operates alone, velocity at Xiangxi River mouth is larger than 0.05m/s in wet year. It implies that Three Gorges Reservoir’s water level change has little to do with improvement of tributaries’ velocity, but reservoir in main and tributary channels dispatch together can improve the velocity obviously, which can control algal bloom in tributary bays.

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GHOSH, MINI. "MODELING BIOLOGICAL CONTROL OF ALGAL BLOOM IN A LAKE CAUSED BY DISCHARGE OF NUTRIENTS." Journal of Biological Systems 18, no. 01 (March 2010): 161–72. http://dx.doi.org/10.1142/s021833901000324x.

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This paper proposes and analyzes a nonlinear model for the biological control of algal bloom in a lake. Algal bloom often occurs in a lake due to excessive flow of nutrients from domestic drainage, industrial and agricultural waste, and this causes the decrease in the concentration of dissolved oxygen in the lake. Hence, it threatens the survival of other species of the ecosystem indirectly, and it is also responsible for the degradation of water quality in the lake because of less oxygen content. In this work we study biological control which means the introduction of predatory fish, i.e. the release of algae-eating fish into the lake to control the rapid growth of algae. We formulate our model by assuming Michaelis-Menten type ratio-dependent prey-predator interaction. The equilibrium of the mathematical model is found and also the stability is discussed in detail. It is observed that the positive equilibria is locally asymptotically stable under certain conditions on the parameters. Also the system is simulated for various sets of parameters and it is found that system may oscillate for some realistic set of parameters. In fact we found that the parameter m, which is the half saturation constant, is very sensitive and with the decrease in this parameter steady state solution of the system changes to stable oscillation. On the practical side, it means that the method of biological control by introducing predatory fish is not always beneficial because outcome of this method depends upon the actual value of the parameter. Here we get the paradox of biological control, which says that it is not possible to have low level of steady state equilibrium of prey population.

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Hu, Hongying, and Yu Hong. "Algal-bloom control by allelopathy of aquatic macrophytes — A review." Frontiers of Environmental Science & Engineering in China 2, no. 4 (December 2008): 421–38. http://dx.doi.org/10.1007/s11783-008-0070-4.

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Liao, Chunli, Xiaobo Liu, and Linna Shan. "Optimization of liquid media and biosafety assessment for algae-lysing bacterium NP23." Canadian Journal of Microbiology 60, no. 9 (September 2014): 593–97. http://dx.doi.org/10.1139/cjm-2014-0322.

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To control algal bloom caused by nutrient pollution, a wild-type algae-lysing bacterium was isolated from the Baiguishan reservoir in Henan province of China and identified as Enterobacter sp. strain NP23. Algal culture medium was optimized by applying a Placket–Burman design to obtain a high cell concentration of NP23. Three minerals (i.e., 0.6% KNO3, 0.001% MnSO4·H2O, and 0.3% K2HPO4) were found to be independent factors critical for obtaining the highest cell concentration of 1013 CFU/mL, which was 104 times that of the control. In the algae-lysing experiment, the strain exhibited a high lysis rate for the 4 algae test species, namely, Chlorella vulgari, Scenedesmus, Microcystis wesenbergii, and Chlorella pyrenoidosa. Acute toxicity and mutagenicity tests showed that the bacterium NP23 had no toxic and mutagenic effects on fish, even in large doses such as 107 or 109 CFU/mL. Thus, Enterobacter sp. strain NP23 has strong potential application in the microbial algae-lysing project.

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Kim, Hee-Jun, Gui-Sook Nam, Jung-Seok Jang, Chan-Hee Won, and Hyun-Woo Kim. "Cold Plasma Treatment for Efficient Control over Algal Bloom Products in Surface Water." Water 11, no. 7 (July 21, 2019): 1513. http://dx.doi.org/10.3390/w11071513.

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Algal bloom significantly alters the physicochemical properties of water due to drastic pH change, dissolved oxygen depletion/super-saturation, and toxicity, which lead to ecosystem destruction. To prevent this, this study evaluated the reduction performance of algal biomass by applying a non-thermal or cold plasma process. We used chlorophyll-a (chl-a), suspended solids (SS), and turbidity as indicators of the biomass. Results demonstrated that their removal efficiencies were in the ranges 88–98%, 70%–90%, and 53%–91%, respectively. Field emission scanning electron microscopy indicated how the cell wall of microalgae was destroyed by cold plasma. Also, the removal kinetics of cold plasma confirmed the enhanced removal rate constants. The estimated required times for 99% removal were 0.4–1.2 d (chl-a), 1.3–3.4 d (SS), and 1.6–6.2 d (turbidity), respectively. Overall, cold plasma could be a useful option to effectively treat pollution associated with algal bloom in surface water.

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Pan, Gang, Xiaojun Miao, Lei Bi, Honggang Zhang, Lei Wang, Lijing Wang, Zhibin Wang, et al. "Modified Local Soil (MLS) Technology for Harmful Algal Bloom Control, Sediment Remediation, and Ecological Restoration." Water 11, no. 6 (May 29, 2019): 1123. http://dx.doi.org/10.3390/w11061123.

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Harmful algal blooms (HABs), eutrophication, and internal pollutant sources from sediment, represent serious problems for public health, water quality, and ecological restoration worldwide. Previous studies have indicated that Modified Local Soil (MLS) technology is an efficient and cost-effective method to flocculate the HABs from water and settle them onto sediment. Additionally, MLS capping treatment can reduce the resuspension of algae flocs from the sediment, and convert the algal cells, along with any excessive nutrients in-situ into fertilisers for the restoration of submerged macrophytes in shallow water systems. Furthermore, the capping treatment using oxygen nanobubble-MLS materials can also mitigate sediment anoxia, causing a reduction in the release of internal pollutants, such as nutrients and greenhouse gases. This paper reviews and quantifies the main features of MLS by investigating the effect of MLS treatment in five pilot-scale whole-pond field experiments carried out in Lake Tai, South China, and in Cetian Reservoir in Datong city, North China. Data obtained from field monitoring showed that the algae-dominated waters transform into a macrophyte-dominated state within four months of MLS treatment in shallow water systems. The sediment-water nutrient fluxes were substantially reduced, whilst water quality (TN, TP, and transparency) and biodiversity were significantly improved in the treatment ponds, compared to the control ponds within a duration ranging from one day to three years. The sediment anoxia remediation effect by oxygen nanobubble-MLS treatment may further contribute to deep water hypoxia remediation and eutrophication control. Combined with the integrated management of external loads control, MLS technology can provide an environmentally friendly geo-engineering method to accelerate ecological restoration and control eutrophication.

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Cao, Mengmeng, Kebiao Mao, Xinyi Shen, Tongren Xu, Yibo Yan, and Zijin Yuan. "Monitoring the Spatial and Temporal Variations in The Water Surface and Floating Algal Bloom Areas in Dongting Lake Using a Long-Term MODIS Image Time Series." Remote Sensing 12, no. 21 (November 4, 2020): 3622. http://dx.doi.org/10.3390/rs12213622.

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Significant water quality changes have been observed in the Dongting Lake region due to environmental changes and the strong influence of human activities. To protect and manage Dongting Lake, the long-term dynamics of the water surface and algal bloom areas were systematically analyzed and quantified for the first time based on 17 years of Moderate Resolution Imaging Spectroradiometer (MODIS) observations. The traditional methods (index-based threshold algorithms) were optimized by a dynamic learning neural network (DL-NN) to extract and identify the water surface area and algal bloom area while reducing the extraction complexity and improving the extraction accuracy. The extraction accuracy exceeded 94.5% for the water and algal bloom areas, and the analysis showed decreases in the algal bloom and water surface areas from 2001–2017. Additionally, the variations in the water surface and algal bloom areas are greatly affected by human activities and climatic factors. The results of these analyses can help us better monitor human contamination in Dongting Lake and take measures to control the water quality during certain periods, which is crucial for future management. Moreover, the traditional methods optimized by the DL-NN used in this study can be extended to other inland lakes to assess and monitor long-term temporal and spatial variations in algal bloom areas and can also be used to acquire baseline information for future assessments of the water quality of lakes.

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Knapp, Abigail S., and Adam M. Milewski. "Spatiotemporal Relationships of Phytoplankton Blooms, Drought, and Rainstorms in Freshwater Reservoirs." Water 12, no. 2 (February 3, 2020): 404. http://dx.doi.org/10.3390/w12020404.

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Algal blooms, especially those composed of toxic phytoplankton, are a global threat to eutrophic and mesotrophic freshwater reservoirs. While extreme hydrologic events such as flooding and drought have been shown to control bloom onset and success, the spatiotemporal dynamics of these relationships are still unclear for mesotrophic reservoirs. In this study, the relationships between hydrologic events and phytoplankton in Lake Allatoona and Lake Lanier, Georgia, United States, were characterized using historical and satellite datasets from 2008 to 2017 and statistical modeling. Results showed that the impact of stormflow and rainstorm events varied systematically from riverine to lacustrine reaches of the two reservoirs on weekly and monthly scales. Precipitation duration and stormflow were the most significant and best-fitting predictors of algal bloom biomass in deeper reaches of the two reservoirs, suggesting that algal blooms in more lacustrine environments may be better equipped for wet and stormy regimes than has been previously hypothesized.

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Kim, Sok, Changsu Lee, Thi-Thao Vo, Sang-Il Han, and Yoon-E. Choi. "Eco-friendly Control of Harmful Algal Bloom Species Using Biological Predators." Korean Journal of Environmental Biology 34, no. 2 (June 30, 2016): 91–96. http://dx.doi.org/10.11626/kjeb.2016.34.2.091.

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Mallin, Michael A., and Lawrence B. Cahoon. "The Hidden Impacts of Phosphorus Pollution to Streams and Rivers." BioScience 70, no. 4 (February 19, 2020): 315–29. http://dx.doi.org/10.1093/biosci/biaa001.

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Abstract Phosphorus (P) enrichment to streams, lakes, and estuaries is increasing throughout the United States. P loading is typically viewed from a harmful algal bloom perspective; if added P causes excess growths of phytoplankton or macroalgae, it may become targeted for control. However, P loading also contributes to two other non–algae-based aquatic problems. Field and experimental evidence shows that P loading directly stimulates growth of aquatic bacteria, which can increase to concentrations that exert a significant biochemical oxygen demand on water bodies, contributing to hypoxia, a widespread impairment. Experimental evidence also demonstrates that fecal bacterial growth can be significantly stimulated by P loading, increasing health risks through exposure or the consumption of contaminated shellfish and causing economic losses from beach and shellfish area closures. Resource managers need to look beyond algal bloom stimulation and should consider the broader roles that excess P loading can have on ecosystem function and microbiological safety for humans.

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Paerl, Hans W., Rolland S. Fulton, Pia H. Moisander, and Julianne Dyble. "Harmful Freshwater Algal Blooms, With an Emphasis on Cyanobacteria." Scientific World JOURNAL 1 (2001): 76–113. http://dx.doi.org/10.1100/tsw.2001.16.

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Suspended algae, or phytoplankton, are the prime source of organic matter supporting food webs in freshwater ecosystems. Phytoplankton productivity is reliant on adequate nutrient supplies; however, increasing rates of nutrient supply, much of it manmade, fuels accelerating primary production or eutrophication. An obvious and problematic symptom of eutrophication is rapid growth and accumulations of phytoplankton, leading to discoloration of affected waters. These events are termed blooms. Blooms are a prime agent of water quality deterioration, including foul odors and tastes, deoxygenation of bottom waters (hypoxia and anoxia), toxicity, fish kills, and food web alterations. Toxins produced by blooms can adversely affect animal (including human) health in waters used for recreational and drinking purposes. Numerous freshwater genera within the diverse phyla comprising the phytoplankton are capable of forming blooms; however, the blue-green algae (or cyanobacteria) are the most notorious bloom formers. This is especially true for harmful toxic, surface-dwelling, scum-forming genera (e.g., Anabaena, Aphanizomenon, Nodularia, Microcystis) and some subsurface bloom-formers (Cylindrospermopsis, Oscillatoria) that are adept at exploiting nutrient-enriched conditions. They thrive in highly productive waters by being able to rapidly migrate between radiance-rich surface waters and nutrient-rich bottom waters. Furthermore, many harmful species are tolerant of extreme environmental conditions, including very high light levels, high temperatures, various degrees of desiccation, and periodic nutrient deprivation. Some of the most noxious cyanobacterial bloom genera (e.g., Anabaena, Aphanizomenon, Cylindrospermopsis, Nodularia) are capable of fixing atmospheric nitrogen (N2), enabling them to periodically dominate under nitrogen-limited conditions. Cyanobacteria produce a range of organic compounds, including those that are toxic to higher-ranked consumers, from zooplankton to further up the food chain. Both N2- and non-N2-fixing genera participate in mutualistic and symbiotic associations with microorganisms, higher plants, and animals. These associations appear to be of great benefit to their survival and periodic dominance. In this review, we address the ecological impacts and environmental controls of harmful blooms, with an emphasis on the ecology, physiology, and management of cyanobacterial bloom taxa. Combinations of physical, chemical, and biotic features of natural waters function in a synergistic fashion to determine the sensitivity of water bodies. In waters susceptible to blooms, human activities in water- and airsheds have been linked to the extent and magnitudes of blooms. Control and management of cyanobacterial and other phytoplankton blooms invariably includes nutrient input constraints, most often focused on nitrogen (N) and/or phosphorus (P). The types and amount of nutrient input constraints depend on hydrologic, climatic, geographic, and geologic factors, which interact with anthropogenic and natural nutrient input regimes. While single nutrient input constraints may be effective in some water bodies, dual N and P input reductions are usually required for effective long-term control and management of harmful blooms. In some systems where hydrologic manipulations (i.e., plentiful water supplies) are possible, reducing the water residence time by enhanced flushing and artificial mixing (in conjunction with nutrient input constraints) can be particularly effective alternatives. Implications of various management strategies, based on combined ecophysiological and environmental considerations, are discussed.

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Xie, Zheng Chao, In Chio Lou, Wai Kin Ung, and Kai Meng Mok. "A Prediction Model for Phytoplankton Abundance Based on Relevance Vector Machine." Applied Mechanics and Materials 145 (December 2011): 314–19. http://dx.doi.org/10.4028/www.scientific.net/amm.145.314.

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Freshwater algal bloom is caused by rapid increases or accumulations of phytoplankton abundance due to the excess of nutrients in eutrophic lakes or reservoirs. The population dynamics in such ecosystem is difficult to explain and predict due to the high non-linearity of the relationship between phytoplankton abundance and water variables. Thus the capacity of model is a crucial point for system simulation and information abstraction about the target ecosystem. Recently relevance vector machine (RVM) has been reported to be able to work more effectively with simpler algorithm, faster convergence and better accuracy than other prediction approaches, such as artificial neural network (ANN). This work for the first time adopts the RVM to develop a prediction model for phytoplankton abundance given ten water parameters including temperature, turbidity, conductivity, nitrate, total nitrogen (TN), orthophosphate (PO43-), total phosphorus (TP), TN/TP, hydraulic retention time (HRT) and water level in Macau Reservoir. The measured data are used to test and validate the model for predicting the phytoplankton abundance. The preliminary results show that the RVM based model is feasible in understanding the algal bloom problem and simulating the onset of algal bloom caused by phytoplankton abundance, thus providing a useful guide for practical algal bloom control.

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Sarkar, R. R., B. Mukhopadhyay, R. Bhattacharyya, and Sandip Banerjee. "Time lags can control algal bloom in two harmful phytoplankton–zooplankton system." Applied Mathematics and Computation 186, no. 1 (March 2007): 445–59. http://dx.doi.org/10.1016/j.amc.2006.07.113.

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Kalinichenko, Antonina, Pavlo Pisarenko, and Maksym Kulyk. "Algae in urban water bodies - control of growth and use as a biomass." E3S Web of Conferences 45 (2018): 00028. http://dx.doi.org/10.1051/e3sconf/20184500028.

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Enhancing the ecology security of Ukraine and other developing countries is predetermined by the environmental problems of cities. It prompts studies on the contamination of city's and adjacent water bodies. The control of blue-green algae distribution and the use of its biomass for production of the biofuels, energy, oils, medicine, etc. is one of the contributing factors to the well-balanced development of infrastructure of cities. The intensity of the processes of eutrophication and the species composition of the algae, which cause algal blooming, was investigated based on data of the Vorskla River in Poltava city (Ukraine). Relevant methods, statistical data of Ukrainian Environmental Service, personal observations, laboratory analysis and analytical studies were applied for the study. The comparative estimation of influence of separate biogenic and chemical substances on eutrophication processes was carried out. The approaches for prevention of processes of water bloom have been presented. The mechanism of using the species composition of algae as an indicator of the state of eutrophication processes was studied.

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Kim, Young-Hyo, En-Mi Gwon, Ha-Kyung Kim, In-Hwan Cho, Hyuk Lee, and Baik-Ho Kim. "Control of Nuisance Cyanobacteria in Drinking Water Resources Using Alternative Algae-Blocking Mats." Water 12, no. 6 (May 31, 2020): 1576. http://dx.doi.org/10.3390/w12061576.

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The water intake facility of Paldangho Lake (PIF), constructed in 1988, supplies drinking water to the Seoul metropolitan area and satellite city (ca. 20 million inhabitants) in South Korea. A nuisance cyanobacterial bloom (CB) has been observed every year in the PIF. Thus, related governments have been funding the control of CBs and algal-originated materials (AOMs). In this study, an algae-blocking mat (ABM) was developed to protect against CBs and AOMs considering temperature and water depth. We evaluated the daily and monthly performance of the ABM on phytoplankton, pH, dissolved oxygen, chlorophyll-a, and light intensity between April and October 2015. Although the average cell abundance of cyanobacteria between July and September approached the warning level of the Korea alert system, the highest algal removal efficiency was recorded as 92% in August when the cyanobacterial cells were over 66,000 cells/mL. On average, the ABM showed a low removal efficiency of 26% on both geosmin and 2-methylisoborneol, whereas total phytoplankton was more than 30%. In conclusion, our results indicate that the ABM may be an economical blocking tool for nuisance cyanobacteria in drinking water resources, considering AOMs and total phytoplankton.

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Jing, Yuan Shu, Zhi Hao Jing, Jing Yuan Hu, and Fei Chen. "Meteorological Conditions Influences on the Variability of Algae Bloom in Taihu Lake and its Risk Prediction." Applied Mechanics and Materials 253-255 (December 2012): 935–38. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.935.

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Lake eutrophication and algal bloom is one of the most important environmental problems facing China's lakes, and it is also the focus of lake eutrophication control of the world's attention. The monitoring data on chlorophyll concentration was analyzed every one month, combined with corresponding weather conditions from 2004 to 2006. According to the degree of eutrophication in Taihu Lake, it is divided into five Lakes: heavy eutrophication region V, eutrophication region IV, middle-level eutrophication region III, light eutrophication region II and nutrition region I. Based on fuzzy factor optimization method, the average wind speed, average pressure, average temperature and sunshine hours was selected to discuss the influence mechanism of meteorological factors on the algae bloom in Taihu Lake. Considered the four meteorological factors as the input layer nodes, BP neural network model was applied to build the zoning monitoring and early warning model of blue algae in Taihu Lake.

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Kim, D. W., J. H. Min, M. Yoo, M. Kang, and K. Kim. "Long-term effects of hydrometeorological and water quality conditions on algal dynamics in the Paldang dam watershed, Korea." Water Supply 14, no. 4 (February 27, 2014): 601–8. http://dx.doi.org/10.2166/ws.2014.014.

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The primary goal of this study is to shed light on some important factors that control algal bloom in a large-scale regulated river system. Long-term impacts of environmental conditions on algal dynamics were investigated in the Paldang dam watershed, Korea. Dam inflow, water temperature, chlorophyll-a, TN, PO4-P and TP data collected at five major dams located on the North Han River (NHR) and at four water quality monitoring sites on the South Han River were analyzed for 21 years (1992 to 2012) to examine spatio-temporal variations in each. A pattern of slightly increasing chlorophyll-a and nutrient levels in the NHR since 2001 indicates that algal dynamics were affected by the increased nutrient levels as well as the reduced flow conditions (−10% to −37%). The temporal variations in monthly averaged data collected during summer monsoon seasons (mainly July) over the two decades show that high chlorophyll-a levels observed in both rivers corresponded to the relatively lower flow condition, which means a reduced amount of dam water release due to low or no rainfall over a short period of time, and abnormally high water temperature. This study shows that flow control is most critical for effectively managing algal level in the rivers in the short term, and nutrient management in the watershed is the key to reducing the potential for algal bloom in the long term.

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Wang, Changhui, Leilei Bai, He-Long Jiang, and Huacheng Xu. "Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents." Science of The Total Environment 557-558 (July 2016): 479–88. http://dx.doi.org/10.1016/j.scitotenv.2016.03.082.

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Yang, Jing, Kai Qiao, Junping Lv, Qi Liu, Fangru Nan, Shulian Xie, and Jia Feng. "Isolation and Identification of Two Algae-Lysing Bacteria against Microcystis aeruginosa." Water 12, no. 9 (September 5, 2020): 2485. http://dx.doi.org/10.3390/w12092485.

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Algae blooms present an environmental problem worldwide. In response to the outbreak of harmful algal blooms in cyanobacteria, the role of biological control has drawn wide attention, particularly for algicidal bacteria. The mechanism underlying algicidal activity was determined in our study. Algae-lysing bacteria used were separated from water and sediment collected from the Fenhe scenic spot of Taiyuan. Genetic and molecular identification was conducted by polymerase chain reaction amplification based on 16S rDNA gene. These bacterial strains were identified as Raoultella planticola and Aeromonas sp. The algae-lysing characteristics were evaluated on Microcystis aeruginosa. For the two algicidal bacteria, the high inoculation ratio (>8%) of bacteria strains contributed to the lytic effect. M. aeruginosa could be completely removed by these strains at different cell ages. However, the time used decreased with an increase in cell age. The removal rate was increased while M. aeruginosa was in the lag and logarithmic phases. The earlier bacteria strains could be inoculated, the sooner all algae could be removed. Both algicidal substances were protein, which could destroy the photosynthetic systems and break the cell of M. aeruginosa. The algicidal bacteria strain has important theoretical and practical significance for economic and feasible algae removal and provides good germplasm resources and technical support for the control of cyanobacterial bloom.

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Lan, Yu, Qi Chen, Ting Gou, Kaifeng Sun, Jin Zhang, Dong Sun, and Shunshan Duan. "Algicidal Activity of Cyperus rotundus Aqueous Extracts Reflected by Photosynthetic Efficiency and Cell Integrity of Harmful Algae Phaeocystis globosa." Water 12, no. 11 (November 20, 2020): 3256. http://dx.doi.org/10.3390/w12113256.

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Phaeocystis globosa is regarded as a notoriously harmful algal bloom species. Suppressing harmful algae using algicidal substances extracted from plants is considered an effective method. The physiological and biochemical processes of P. globosa were explored by exposure to different concentrations of aqueous extracts of Cyperus rotundus. All treatments indicated various inhibitory effects on the algal growth compared to the control samples without adding extracts. At 48 h, the 4, 8, and 16 mg/mL treatment groups showed a significant inhibitory effect, consistent with a decrease in the chlorophyll-a content and photosynthetic efficiency. The images of the transmission electron microscope (TEM) further confirmed that a subset of the cells in the treatment groups exhibited morphological anomalies. The algicidal active substances were mainly identified as phenolic acids containing maximal content of quinic acid in aqueous extracts according to the results of ultra-high-performance liquid chromatography-tandem time-of-flight mass spectrometer (UPLC-HRMS). The 50% anti-algal effect concentration of quinic acid was 22 mg/L at 96 h (EC50–96h). Thus, the phenolic acids might be considered as major inhibitors of the growth of P. globosa. These results demonstrated that the aqueous extracts of C. rotundus could potentially control the growth of P. globosa.

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Nagasaki, Keizo, Kenji Tarutani, and Mineo Yamaguchi. "Growth Characteristics of Heterosigma akashiwo Virus and Its Possible Use as a Microbiological Agent for Red Tide Control." Applied and Environmental Microbiology 65, no. 3 (March 1, 1999): 898–902. http://dx.doi.org/10.1128/aem.65.3.898-902.1999.

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ABSTRACT The growth characteristics of Heterosigma akashiwovirus clone 01 (HaV01) were examined by performing a one-step growth experiment. The virus had a latent period of 30 to 33 h and a burst size of 7.7 × 102 lysis-causing units in an infected cell. Transmission electron microscopy showed that the virus particles formed on the peripheries of viroplasms, as observed in a natural H. akashiwo cell. Inoculation of HaV01 into a mixed algal culture containing four phytoplankton species, H. akashiwo H93616 , Chattonella antiqua (a member of the family Raphidophyceae), Heterocapsa triquetra (a member of the family Dinophyceae), and Ditylum brightwellii (a member of the family Bacillariophyceae), resulted in selective growth inhibition of H. akashiwo. Inoculation of HaV01 andH. akashiwo H93616 into a natural seawater sample produced similar results. However, a natural H. akashiwo red tide sample did not exhibit any conspicuous sensitivity to HaV01, presumably because of the great diversity of the host species with respect to virus infection. The growth characteristics of the lytic virus infecting the noxious harmful algal bloom-causing alga were considered, and the possibility of using this virus as a microbiological agent against H. akashiwo red tides is discussed.

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Kang, Hye-Eun, Tae-Ho Yoon, Sunyoung Yoon, Hak Jun Kim, Hyun Park, Chang-Keun Kang, and Hyun-Woo Kim. "Genomic analysis of red-tide water bloomed with Heterosigma akashiwo in Geoje." PeerJ 6 (May 29, 2018): e4854. http://dx.doi.org/10.7717/peerj.4854.

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Microbial community structures of harmful algal bloom (HAB) caused by Heterosigma akashiwo in Geoje were analyzed using the MiSeq platform. To analyze phytoplankton communities without cross-reactivity with predominant bacteria, a new phytoplankton-specific 23S universal primer set was designed by modifying two previously used ones. The new universal primer set turned out to be a useful tool for the analysis of the phytoplankton community; it showed a high specificity for phytoplankton without cross-reactivity to bacterial sequences as well as the wide taxon coverage presenting from prokaryotic cyanobacteria to eukaryotic algae. Next Generation Sequencing (NGS) data generated by two universal primer sets (16S and 23S) provided useful information about the H. akashiwo bloom. According to the 23S universal primer set, proportions of H. akashiwo increased by more than 200-fold as the bloom occurred and its numbers were high enough to detect in control sites. Its operational taxonomic units (OTUs) were detected in the bloom sites at low proportions suggesting that the 16S universal primer set may not be as effective for monitoring harmful algal blooming (HAB) as the 23S universal primer set. In addition, several abundant OTUs in Chlorophyta were not presented by the 16S universal primer set in this study. However, the 16S primer set was useful for detecting decreases in Foraminifera as HAB occurred suggesting that genomic analyses using two universal primer sets would provide more reliable data for understanding microbial community changes by various environmental or ecological events, including HAB. Genomic analyses using two universal primer sets was also useful for determining a correlation between microbial components as HAB occurred. Heterosigma akashiwo was positively correlated with other bloom species, including Karenia mikimotoi, Teleaulax amphioxeia, and bacteria in Verrucomicrobia.

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SANO, Akira, Yumina OGURA, Shinichi BABA, Ryuichi EZAKI, and Masashi SUZUKI. "Algal Bloom and Water Quality Control Using Environmental Reclamation Sand Recycled from Casting Waste." Journal of Japan Society on Water Environment 38, no. 4 (2015): 101–7. http://dx.doi.org/10.2965/jswe.38.101.

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Park, Jungsu, Younggyu Son, and Woo Hyoung Lee. "Variation of efficiencies and limits of ultrasonication for practical algal bloom control in fields." Ultrasonics Sonochemistry 55 (July 2019): 8–17. http://dx.doi.org/10.1016/j.ultsonch.2019.03.007.

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Donaghay, Percy L., and Thomas R. Osborn. "Toward a theory of biological-physical control of harmful algal bloom dynamics and impacts." Limnology and Oceanography 42, no. 5part2 (July 1997): 1283–96. http://dx.doi.org/10.4319/lo.1997.42.5_part_2.1283.

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Zhang, L., S. T. Liu, T. Liu, C. Yu, and Z. Hu. "Control effect of periodic variation on the growth of harmful algal bloom causative species." Communications in Nonlinear Science and Numerical Simulation 54 (January 2018): 185–201. http://dx.doi.org/10.1016/j.cnsns.2017.05.023.

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Wang, Zhifu, Zhiming Yu, Xiuxian Song, Xihua Cao, and Xiaotian Han. "Effects of modified clay on cysts of Scrippsiella trochoidea for harmful algal bloom control." Chinese Journal of Oceanology and Limnology 32, no. 6 (August 7, 2014): 1373–82. http://dx.doi.org/10.1007/s00343-015-4008-y.

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Kenefick, S. L., S. E. Hrudey, H. G. Peterson, and E. E. Prepas. "Toxin Release from Microcystis Aeruginosa after Chemical Treatment." Water Science and Technology 27, no. 3-4 (February 1, 1993): 433–40. http://dx.doi.org/10.2166/wst.1993.0387.

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Cyanobacterial (blue-green algal) blooms in agricultural dugouts and eutrophic lakes or reservoirs are common across the Canadian prairies. These blooms have caused livestock and wildlife poisonings that have been attributed to neurotoxins and/or hepatotoxins produced by various species of cyanobacteria. The hepatotoxins are extremely potent acute poisons. For example, microcystin LR has an LD50 of 50 µg/kg, by intraperitoneal injection, in mice. Hepatotoxins may also pose chronic health risks. Consequently, their presence in drinking water sources is attracting increasing attention. Chemical treatment with copper sulfate is the most common technique used to control algal blooms in drinking water reservoirs. Application of lime (calcium hydroxide) is an alternative treatment for the control of blooms. The effects of copper sulfate versus lime treatment on the release of microcystin LR from a naturally occurring bloom, involving three species of cyanobacteria including toxin-producing Microcystis aeruginosa, were studied. Water samples collected after chemical treatment of algal bloom material were monitored for microcystin LR at specific time intervals. In three replicate trials, the cells treated with coppa- sulfate released the majority of the toxin present within cellular biomass during the first three days after treatment. Substantial toxin release was not observed when cells were untreated (control) or treated with lime. After release, the persistence of microcystin LR was monitored. The aqueous toxin concentrations declined according to first order kinetics with a decay constant of 0.25 d−1. The experimental conditions, involving high biomass content, may have favoured toxin degradation. The microcystin LR half life, under laboratory conditions, was 3 d from the time of maximum toxin release (2 to 4 d after chemical treatment), meaning that a 99% reduction would take approximately 3 weeks. These findings indicate that copper sulfate should not be used to treat potentially toxic cyanobacterial blooms in waters to be consumed by humans or animals within several weeks following treatment.

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Korosi, Jennifer B., Samantha M. Burke, Joshua R. Thienpont, and John P. Smol. "Anomalous rise in algal production linked to lakewater calcium decline through food web interactions." Proceedings of the Royal Society B: Biological Sciences 279, no. 1731 (September 28, 2011): 1210–17. http://dx.doi.org/10.1098/rspb.2011.1411.

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Increased algal blooms are a threat to aquatic ecosystems worldwide, although the combined effects of multiple stressors make it difficult to determine the underlying causes. We explore whether changes in trophic interactions in response to declining calcium (Ca) concentrations, a water quality issue only recently recognized in Europe and North America, can be linked with unexplained bloom production. Using a palaeolimnological approach analysing the remains of Cladocera (herbivorous grazers) and visual reflectance spectroscopically inferred chlorophyll a from the sediments of a Nova Scotia (Canada) lake, we show that a keystone grazer, Daphnia , declined in the early 1990s and was replaced by a less effective grazer, Bosmina , while inferred chlorophyll a levels tripled at constant total phosphorus (TP) concentrations. The decline in Daphnia cannot be attributed to changes in pH, thermal stratification or predation, but instead is linked to declining lakewater [Ca]. The consistency in the timing of changes in Daphnia and inferred chlorophyll a suggests top-down control on algal production, providing, to our knowledge, the first evidence of a link between lakewater [Ca] decline and elevated algal production mediated through the effects of [Ca] decline on Daphnia . [Ca] decline has severe implications for whole-lake food webs, and presents yet another mechanism for potential increases in algal blooms.

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Huang, Yawen, Yong Pang, Guoxiang Wang, Ruiming Han, Jianjian Wang, Peng Zhang, and Lei Xu. "Using PAC-modified clays to control black-bloom-induced black suspended matter in Lake Taihu: deposition and resuspension of black matter/clay flocs." Water Supply 16, no. 1 (August 17, 2015): 180–85. http://dx.doi.org/10.2166/ws.2015.126.

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Flocculation using modified clays is a technique widely applied in the management of harmful algal blooms (HABs). Polyaluminum chloride (PAC) modified clay is an efficient flocculating agent in HAB control; however its effectiveness in black bloom management is still largely unknown. In the present study, PAC-modified clay was used to flocculate a black bloom under simulated flows. The deposition and resuspension of the black matter/clay flocs and the impact of the spreading of quartz sand to the flocs were quantitatively studied. The results showed that a dosage of 1.8 g/L PAC-modified clay (0.8 g/L PAC and 1 g/L diatomite) could reduce turbidity by more than 90% in 1 h. The resuspension of flocs could be generated by a threshold bed shear stress of 0.045 N/m2. The addition of quartz sand inhibited the resuspension of flocs. We suggest that quartz sand can be used to effectively inhibit floc resuspension caused by waves and flow currents as the subsequent treatment of black bloom flocculation in Lake Taihu.

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Shoaib Shariati. "Algal bloom inhibition through cobalt nano particles to control Oscillatoria growth in fresh water lakes." GSC Advanced Research and Reviews 3, no. 2 (May 30, 2020): 031–38. http://dx.doi.org/10.30574/gscarr.2020.3.2.0035.

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Purcell, Diane, Simon A. Parsons, Bruce Jefferson, Stuart Holden, Andrew Campbell, Anna Wallen, Michael Chipps, Barry Holden, and Adam Ellingham. "Experiences of algal bloom control using green solutions barley straw and ultrasound, an industry perspective." Water and Environment Journal 27, no. 2 (August 16, 2012): 148–56. http://dx.doi.org/10.1111/j.1747-6593.2012.00338.x.

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Tan, Yi, Jia Li, Linglei Zhang, Min Chen, Yaowen Zhang, and Ruidong An. "Mechanism Underlying Flow Velocity and Its Corresponding Influence on the Growth of Euglena gracilis, a Dominant Bloom Species in Reservoirs." International Journal of Environmental Research and Public Health 16, no. 23 (November 22, 2019): 4641. http://dx.doi.org/10.3390/ijerph16234641.

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The effects of hydrodynamics on algae growth have received considerable attention, and flow velocity is one of the most frequently discussed factors. For Euglena gracilis, which aggregates resources and is highly resistant to environmental changes, the mechanism underlying the impact of flow velocity on its growth is poorly understood. Experiments were conducted to examine the response of algae growth to different velocities, and several enzymes were tested to determine their physiological mechanisms. Significant differences in the growth of E. gracilis were found at different flow velocities, and this phenomenon is unique compared to the growth of other algal species. With increasing flow velocity and time, the growth of E. gracilis is gradually inhibited. In particular, we found that the pioneer enzyme is peroxidase (POD) and that the main antioxidant enzyme is catalase (CAT) when E. gracilis experiences flow velocity stress. Hysteresis between total phosphorus (TP) consumption and alkaline phosphatase (AKP) synthesis was observed. Under experimental control conditions, the results indicate that flow velocities above 0.1 m/s may inhibit growth and that E. gracilis prefers a relatively slow or even static flow velocity, and this finding could be beneficial for the control of E. gracilis blooms.

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Park, Myung-Hwan, Keonhee Kim, and Soon-Jin Hwang. "Differential Effects of the Allelochemical Juglone on Growth of Harmful and Non-Target Freshwater Algae." Applied Sciences 10, no. 8 (April 21, 2020): 2873. http://dx.doi.org/10.3390/app10082873.

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Allelopathy has been applied to control nuisance algae in aquatic systems, but the effects of allelochemicals on the broad spectrum of algae are not well understood. We investigate algicidal effects of the allelochemical juglone on the bloom-forming, harmful algae Microcystis aeruginosa and Stephanodiscus hantzschii, and on several non-target algal species including cyanobacteria (Anabaena flos–aquae, Oscillatoria curviceps, and Phormidium subfuscum), diatoms (Asterionella formosa, Fragilaria crotonensis, and Synedra acus), and green algae (Chlorella vulgaris, Scenedesmus ecornis, and Scenedesmus quadricauda), in laboratory and field enclosure bioassays. Under three treatment concentrations (0.01, 0.1, and 1 mg L−1) of juglone, Microcystis cell density is significantly reduced by 35–93%. Concentrations of 0.1 and 1 mg L−1 inhibits Stephanodiscus growth almost equally (66% and 75%, respectively). To contrast, juglone produces a stimulatory allelopathic effect on three green algae, and other tested diatoms showed hormesis. Overall, the cyanobacteria are more sensitive to juglone than the green algae and diatoms. These results indicate that the allelopathic effects of juglone on microalgae vary depending on their characteristic cellular morphology and anatomy.

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Journal articles on the topic 'Algal bloom control'

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