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Dissertations / Theses on the topic 'Cyanobacterial bloom'

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Published: 10 December 2022
Last updated: 29 January 2023

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1

Tran, Thi Thu Huong, Trung Kien Nguyen, Thi Thuy Thi Nguyen, Phuong Thu Ha, Thi Phuong Quynh Le, Van Binh Do, Thi Hai Van Dinh, Quang Huy Trinh, and Thi Thuy Duong. "Nanoparticles as a control for cyanobacterial bloom." Technische Universität Dresden, 2016. https://tud.qucosa.de/id/qucosa%3A32610.

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This study aims to investigate the toxicity of copper material synthesized by chemical reduction method and effects of environmental variables on growth of phytoplankton community (dominated by Microcystis genus) in the Tien eutrophic lake, Hanoi, Vietnam. The variables analyzed include: physical (pH and Turbidity), chemical (content of NH4+, PO43- and copper metal), biological (content of Chlorophyll-a, cell density). The characteristic of nanomaterial was confirmed by using UVvisible spectrophotometer, XRD, SEM and TEM methods. The CuNPs showed they spherical form and uniform size about 20-40 nm. The experimental results showed that the treated with CuNPs inhibition on growth against phytoplankton after 8 days. The cell density of phytoplankton community and Microcystis genus in samples exposure with CuNPs declined after 8 days from 647.037 and 467.037 down to 381.111 and 202.592, respectively.
Mục đích của nghiên cứu này là khảo sát độc tính của vật liệu nano đồng được tổng hợp bằng phương pháp khử hóa học và ảnh hưởng của các yếu tố môi trường đến sinh trưởng và phát triển của quần xã thực vật nổi (chủ yếu là chi Microcystis) trong nước hồ Tiền phú dưỡng, tại Hà Nội, Việt Nam. Các thông số phân tích bao gồm: thủy lý (pH và độ đục), hóa học (hàm lượng amoni, photphat và hàm lượng đồng kim loại), sinh học (hàm lượng chất diệp lục, mật độ tế bào). Đặc trưng của vật liệu được xác định bằng các phương pháp quang phổ UV-VIS, XRD, SEM và TEM. Vật liệu nano đồng có dạng hình cầu, kích thước đồng nhất từ 20 đến 40 nm. Kết quả thử nghiệm sau 8 ngày cho thấy các mẫu có bổ sung vật liệu nano đồng ức chế sinh trưởng quần xã thực vật nổi ở nồng độ 1mg/l. Mật độ quần xã thực vật nổi và chi Microcystis trong mẫu xử lý với CuNPs đã giảm tương ứng sau 8 ngày từ 647.037 và 467.037 xuống còn 381.111 và 202.592.
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2

Du, Plooy Schalk Jacobus. "Ecophysiology and nutrient uptake mechanisms facilitating the prolonged bloom persistence by Cyanothece sp. in Lake St Lucia, South Africa." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/7344.

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Cyanobacterial blooms are becoming more frequent worldwide, with possible negative effects on human health. The effects of climate change and eutrophication have been associated with persistent cyanobacterial blooms becoming more frequent. Altered water characteristics, salinity in particular, influence ecosystem dynamics that may lead to conditions conducive to cyanobacterial blooms. The occurrence of an 18-month long Cyanothece sp. bloom (the longest for any cyanobacterium recorded so far worldwide and the first of the genus) from June 2009 to December 2010 in Africa’s largest estuarine lake, St Lucia, highlighted the susceptibility of ecosystems to anthropogenic alterations. This study investigated the long-term survival and physiological adaptations of Cyanothece sp. to various and dynamic environmental conditions that contributed towards its bloom persistence. The main findings are the high salinities at which Cyanothece sp. could perform important physiological processes such as N uptake, N2 fixation and photosynthesis. Nutrient uptake (both nitrogen and phosphorus) was observed over the full experimental salinity range (0-300) while N2 fixation was only observed up to a salinity of 120. Nutrient uptake rates significantly decreased at this threshold salinity of 120. Interestingly, photosystem II activity was not observed in Cyanothece sp. during this study, but photosystem I activity was robust. Salinity had a minor influence on electron transport rates by photosystem I, high temperature (> 30°C) did however increase electron transport rates. Rapid responses to hypo-osmotic shock (i.e. osmotic downshift during freshening events) by Cyanothece sp. cells also helped minimize cell rupture due to high turgor pressure. Zooplankton abundance within the St Lucia system was negatively correlated with salinity, while grazing experiments indicated that the typical estuarine zooplankton species are able to graze on Cyanothece sp. cells. Therefore, the disappearance of zooplankton at salinities above 60 must have been an important factor in the bloom persistence. Apart from the ecological factors that were at play in St Lucia during the bloom period, the persistence of the Cyanothece sp. bloom can be attributed to the robust nature of their nutrient uptake, nitrogen fixation and photosynthetic systems to maintain activity despite extreme hypersalinity levels.
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3

Tuttle, Taylor A. "Characterization of the Persistent Cyanobacterial Bloom, Planktothrix, in Sandusky Bay, Lake Erie." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1435180971.

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4

Akins, Leighannah. "Understanding the relationship between bacterial community composition and the morphology of bloom-forming Microcystis." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1543502274681124.

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5

Lange, Erik David. "Investigation of Microcystis Cell Density and Phosphorus in Benthic Sediment and Their Effect on Cyanobacterial Blooms on Western Lake Erie in the Summer of 2009." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1272581269.

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6

Lu, Songhui. "Ecological studies of phytoplankton and harmful algal blooms in Junk Bay, Hong Kong." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42576209.

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7

Wang, Jia Ph D. Massachusetts Institute of Technology. "Structural dynamics of community gene expression In a freshwater cyanobacterial bloom over a day-night cycle." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/70769.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 124-131).
Studies of community gene expression, or metatranscriptomics, provide a powerful approach for quantifying changes in both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic drinking water reservoir dominated by the toxigenic cyanobacterium Microcystis aeruginosa over a day-night cycle. Cyanobacterial blooms are a major problem in eutrophic lakes and reservoirs, negatively impacting the ecology of the water body through oxygen depletion upon bloom decay and in some cases through production of toxins. Waterborne Cyanobacterial toxins pose a public health risk through drinking and recreational exposure. The frequency of harmful Cyanobacterial blooms (CyanoHABs) is predicted to increase due to warming regional climates and increases in non-point source pollution due to urban expansion. CyanoHABs represent complex consortia of Cyanobacteria that live in association with diverse assemblages of heterotrophic and anoxygenic- photosynthetic bacteria, archaea, microbial Eukaryotes (algae, protozoa, and fungi) as well as viruses and zooplanktonic grazers. Water sampling was carried out at six time points over a 24 hour period to capture variability associated with changes in the balance between phototrophic and heterotrophic activity. Total RNA was extracted and subjected to ribosomal depletion followed by cDNA synthesis, sequencing, and quality control, generating 493,468 to 678,064 95-101 bp reads per sample. Hierarchical clustering of transcription profiles supported sorting of samples into two clusters corresponding to "day" and "night" collection times. Annotation of reads through the MGRAST pipeline (Metagenomics- Rapid Annotation using Subsystem Technology) revealed that the community taxonomic composition was relatively constant throughout the day-night cycle and was dominated by transcripts with highest identity to members of the phyla Cyanobacteria, Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes (in decreasing order) where Microcystis transcripts represented 15.3 to 25.6% of the total Bacterial transcriptomes (Eave=10~ ). Community transcripts were enriched with genes from the Cyanobacterial photosynthetic KEGG pathway during the day (p=0.004). In contrast, Proteobacterial transcripts were enriched at night (20.4% of the total Bacterial transcriptome compared to 14.3% in the day, p=0.039). Metatranscriptomic quantification of microbial community gene expression in a Cyanobacterial bloom dominated by M. aeruginosa contributes to a fundamental understanding of nutrient and energy cycling over a day-night cycle. A better understanding of the structure, function, and interaction between members of the complex communities that support the proliferation of toxigenic Cyanobacteria will improve our ability to prevent and control CyanoHABs.
by Jia Wang.
S.M.
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8

Ha, Joo Hyun. "A study on characteristics of microcystin-producing cyanobacterial bloom and microcystin production using real-time PCR." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/124526.

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9

Hipsher, Carissa. "Assessment of Chromophoric Dissolved Organic Matter and Thamnocephalus platyurus as Tools to Monitor Cyanobacterial Bloom Development and Toxicity." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1566210122121367.

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10

Wang, Kai. "INTERACTIONS OF CYANOBACTERIA AND CO-OCCURRING MICROORGANISMS DURING CYANOBACTERIAL HARMFUL ALGAL BLOOMS." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1619622253977384.

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11

Deng, Li. "Cyanophages of bloom-forming cyanobacteria." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492570.

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Cyanobacteria are an important and a diverse group of photo synthetic prokaryotes found in marine, freshwater and terrestrial environments. Over the past two decades, research has shown that cyanobacterial community structures are influenced through infection by cyanobacterial viruses (cyanophages). In marine systems cyanophages have been shown to play roles in the mortality of their hosts, as well as in driving the succession and evolution of phenotypes.
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12

Macário, Inês Adriana Patrunilho Efe. "Stepwise strategy for monitoring cyanobacterial blooms." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/12148.

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Mestrado em Gestão e Políticas Ambientais
O desenvolvimento de blooms cianobacterianos pode representar um risco para a saúde pública e, num contexto de alterações climáticas, o desenvolvimento de grandes concentrações destes organismos pode ser potenciado. Portugal, à semelhança de outros países, adoptou a metodologia para a monitorização de cianobactérias proposta pela Organização Mundial de Saúde, que considera a clorofila a e a densidade celular, como indicadores da presença de cianobactérias. Contudo, tendo em conta as limitações destes indicadores, o presente trabalho visa propor uma estratégia rápida, simples e menos onerosa, a médio prazo, para a monitorização de blooms cianobacterianos em sistemas de água doce utilizados para uso recreativo. Esta estratégia propõe uma abordagem sequencial: i) fluorimetria (análise de pigmentos); ii) determinação da clorofila a, observação microscópica e enumeração das espécies cianobacterianas dominantes; iii) técnicas moleculares, baseadas em PCR, para avaliação do potencial tóxico; e v) quantificação das cianotoxinas, apenas quando necessário. O trabalho incluiu a determinação de valores de referência para ficocianina, através de fluorimetria, por forma a poder aplicá-los na estratégia de monitorização proposta. Para esta determinação foram utilizadas as espécies Microcystis aeruginosa, Nostoc muscorum e Cylindrospermopsis raciborskii. Para validação da estratégia de monitorização proposta, foram amostrados nove sistemas lênticos de água doce, do norte, centro e sul de Portugal. Os dados de parâmetros físico-químicos e biológicos das amostras foram integrados, de modo a obter informação acerca do contexto ecológico do desenvolvimento de blooms. A determinação dos valores de referência de ficocianina mostrou diferenças inter-específicas, suportando a necessidade de existirem vários valores de referência, que possam ser utilizados de acordo com a espécie cianobacteriana dominante num bloom. A metodologia proposta, ao ser faseada, permitiu ir excluindo amostras à medida que o perigo de desenvolvimento de um bloom tóxico foi sendo descartado, tendo sido detetadas apenas 2 amostras tóxicas, na Lagoa da Vela e na albufeira da barragem da Aguieira (ambas com blooms de Microcystis spp.). Esta estratégia de monitorização provou ser uma mais-valia para o desenvolvimento de planos de gestão de prevenção e controlo do crescimento excessivo de cianobactérias em lagos e albufeiras.
The massive growth of cyanobacteria into blooms has risks to the public health and, under a context of climate change, the development of these organisms may be enhanced. Portugal, like other countries, has adopted the methodology proposed by the World Health Organization which uses chlorophyll a and cell density as indicators for cyanobacterial density assessment. However, these indicators have several limitations. Therefore, this study aims to propose a strategy for a faster, easier and more cost-effective monitoring of cyanobacterial blooms in lentic freshwater bodies used for recreation purposes. This strategy considers several steps, proposed sequentially: i) fluorometry (pigment analysis); ii) chlorophyll a determination, microscopic observation and enumeration of dominant cyanobacterial species; iii) PCR-based methodologies to screen the potential for cyanotoxins production; and v) cyanotoxins quantification, only if required. The study included the determination of phycocyanin thresholds though fluorometry in order to use them in the proposed monitoring strategy. The species used for this determination included Microcystis aeruginosa, Nostoc muscorum and Cylindrospermopsis raciborskii. For the validation of the monitoring strategy proposal, nine lentic freshwater bodies from northern, central and southern Portugal were sampled. The physico-chemical and biological parameters were integrated in order to provide information about the ecological context for the recorded cyanobacterial blooms. The determined phycocyanin thresholds showed inter-specific differences, highlighting the need for the proposal of not just a general threshold value for phycocyanin, but specific values, according to the dominant bloom-forming cyanobacterial species. The sequential stepwise strategy, allowed the exclusion of samples as the danger of the development of a toxic bloom is being discarded, remaining only two toxic samples at Vela Lake and Aguieira reservoir (both with Microcystis spp. blooms). This monitoring strategy proved to be a valuable and cost-effective tool for an early warning of cyanobacterial blooms, which may be important for the development of effective management plans to prevent and control the massive growth of cyanobacteria in target water bodies.
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13

Duan, Hongmei. "Monitoring and characterization of toxic cyanobacterial blooms." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66915.

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Molecular tools were used to monitor the dynamics of Microcystis populations and the potential microcystin producers in Missisquoi Bay (the Canadian part of Lake Champlain). This study showed the GF/C filters, which are typically used to prepare samples for microcystin analysis, were not ideal for the characterization of total bacterial communities, but were sufficient for the chemical analyses of cyanobacterial microcystins. The mcyD gene copy number determined by Q-PCR correlated well with the microcystin concentration determined by ELISA and HPLC in 2006; therefore mcyD Q-PCR could be used as a rapid and sensitive method and as an effective monitoring system for toxic cyanobacterial blooms in Lake Champlain. Escherichia coli was also monitored as an indicator of manure contamination of lake water. Manure application and rain events positively related to the high nitrogen concentration in the lake in 2006, suggested that good manure management is necessary for the reduction of agricultural nutrient loads into Missisquoi Bay, believed to be a major cause of cyanobacterial blooms.
Un suivi de la dynamique des populations de Microcystis qui ont la capacité de produire des toxines a été effectué à la baie Missisquoi (partie canadienne du lac Champlain) à l'aide d'outils moléculaires. Deux types de membranes ont été utilisés : un filtre standard (GF/C) pour quantifier les microcystines, et un filtre pour capturer les bactéries. Cette étude a démontré que le filtre standard (GF/C) est approprié pour déterminer les concentrations de microcystines, mais qu'il n'est pas adéquat pour caractériser avec des techniques moléculaires, les populations de bactéries et de cyanobactéries. Une bonne corrélation a été obtenue en 2006, entre les concentrations de microcystines déterminées par les méthodes ELISA et HPLC et le nombre de copies du gène mcyD (impliqué dans la biosynthèse des microcystines). Les résultats ont donc démontré le potentiel de cette méthode de PCR en temps réel, ciblant le gène mcyD, pour la détection et le suivi des proliférations de cyanobactéries qui produisent des toxines. La présence du pathogène fécal Escherichia coli a été évaluée afin de déterminer la relation entre l'application de lisier et de fumier et l'augmentation dans l'eau du lac, des nutriments qui causent les proliférations. Une bonne corrélation a été obtenue entre l'application du lisier et du fumier et les précipitations ainsi qu'entre les concentrations élevées d'azote dans le lac, suggérant qu'une meilleure gestion des matières fertilisantes est nécessaire pour réduire les apports de nutriments dans la baie Missisquoi.
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Lee, Seungjun. "Microbiome and Virome Dynamics in Lakes Impacted by Cyanobacterial Harmful Algal Blooms and the Fate of Cyanobacteria and Cyanotoxin in Crops and Soil." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1513690700478319.

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15

Richardson, Ralph William. "Florida Bay Microalgae Blooms: Physiological Characteristics and Competitive Strategies of Bloom Forming Cyanobacteria and Diatoms of Florida Bay." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000369.

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16

Zhang, Feng. "Cyanobacterial blooms: causes, innovative monitoring and human health impact." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405800137.

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17

Baptista, Ana Mafalda Saraiva. "Chemical factors related with freshwater blooms of cyanobacteria." Master's thesis, Porto : [s.n.], 2008. http://hdl.handle.net/10216/64181.

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Baptista, Ana Mafalda Saraiva. "Chemical factors related with freshwater blooms of cyanobacteria." Dissertação, Porto : [s.n.], 2008. http://catalogo.up.pt/F?func=find-b&local_base=FCB01&find_code=SYS&request=000103009.

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19

Kinsman, Robin. "Molecular and structural studies of gas vesicles of bloom-forming cyanobacteria." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240813.

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20

Dash, Padmanava. "SeaWiFS Algorithm for Mapping Phycocyanin in Incipient Freshwater Cyanobacterial Blooms." Bowling Green State University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1120594611.

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21

Jaffee, Brian Alexander. "Using Oxygen Depletion and Chlorophyll-a as Proxies for Estimates of Cyanobacteria Blooms to Create Predictive Lake Erie Hazardous Algae Bloom Models." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1435241581.

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22

Lips, Inga. "Abiotic factors controlling the cyanobacterail bloom ocurrence in the gulf on finland /." Online version, 2005. http://dspace.utlib.ee/dspace/bitstream/10062/940/5/lips.pdf.

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23

Hogfors, Hedvig. "Summer cyanobacterial blooms in the Baltic Sea - implications for copepod recruitment." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-81680.

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During summer, the Baltic Sea is subjected to the world’s largest cyanobacterial blooms. These blooms are linked to eutrophication and raise many questions concerning their effects on the ecosystem. To understand their impacts on the food web dynamics, it is essential to assess growth responses of grazers to these cyanobacteria. In the northern Baltic proper, copepods are the most important herbivores providing an essential link between the primary producers and higher trophic levels. In this Thesis, Papers I & II evaluate methods to estimate copepod growth in response to feeding conditions in situ. The most conspicuous diazotrophic filamentous cyanobacterium in the Baltic Sea is Nodularia spumigena, a producer of nodularin which is highly toxic to vertebrates, yet its ecological role is largely unknown. In Paper III, reciprocal interactions between cyanobacteria, sympatric algae and copepods are studied. The results suggest that nodularin is likely involved in allelopathic interactions, but it is not an inducible defense against grazers. Furthermore, the results of Papers IV & V, indicate that natural assemblages of N. spumigena and Anabaena spp. may support copepod reproduction and that total diazotrophic filamentous cyanobacteria appear to provide a beneficial feeding environment for the feeding stages of copepod nauplii, most probably by stimulating the microbial communities that nauplii feed upon. Since cyanobacterial blooms are projected to increase due to global climate change, the combined effects of toxic cyanobacteria, ocean acidification and global warming predicted for year 2100 are further investigated on copepods in Paper IV. Taken together, these studies indicate that filamentous diazotrophic cyanobacteria contribute to sustaining secondary productivity and have potential implications of management practices with respect to combating eutrophication, global climate change and sustaining fish feeding conditions.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.

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DeMarco, Jonathan R. "Cyanobacterial Blooms in Chautauqua Lake, NY: Nutrient Sources and Toxin Analyses." Bowling Green State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1625052848648708.

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Anselmo, António Eduardo Vicente. "The use of Corbicula fluminea in the remediation of cyanobacterial blooms." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/22395.

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Mestrado em Ecologia Aplicada
Cyanobacterial blooms are frequentetly linked to eutrophication in waterbodies and can be a problem for other organisms since some cyanobacteria are toxic, not only to aquatic organisms, but also to all those ingesting contaminated water or organisms that had previously accumulated toxins in their tissues. Studies exploring new strategies to control/remediate affected waters are thus of major relevance. This motivated the present study, where the assessment of the suitability of the freshwater bivalve Corbicula fluminea as a bioremediator agent within such scenarios was aimed. Although C. fluminea is a problematic invasive species, mostly in Europe and North America, its distribution is already wide, thus the exploitation of its powerful filtration capacities can become a valuable add-on in this pest’s management via compensating damage resulting from its impacts in invaded ecosystems. In a first stage, microscopic characterisation and genetic typing were carried out over a set of laboratory cyanobacteria cultures. These represent the most common taxa composing blooms that have been monitored in national waterbodies, including strains potentially producing cianotoxins. Some of the taxa considered were Anabaena cylindrica, Microcystis and Oscillatoriales. In a second stage, the capacity of the clams to filter and ingest each cyanobacteria was assessed, using short-term assays where each cyanobacteria was offered to the clams respecting densities typically found in blooms. The results often showed low filtration rates, especially compared to those reached as a green microalgae (Raphidocelis subcapitata) was offered. However, chlorophyll a mass balance analysis in the test system (Chl a filtered, retained in pseudofaeces and non-filtered) allowed some important outcomes. The agreggation and settling of filtered cyanobacteria promoted by C. fluminea through the production of pseudofaeces was notorious. This process resembles the use of flocculants to remove organic matter and microrganisms from the water column into the bottom for further aspiration, thus opening avenues to continuing assessing the possibility of using C. fluminea as a remediation for cyanobacterial blooms.
Os blooms cianobacterianos estão associados à eutrofização em massas de água. Isto pode ser um problema para os restantes organismos, já que algumas cianobactérias podem ser tóxicas, não só para organismos aquáticos, como para os que ingiram água contaminada ou que acumulem toxinas nos seus tecidos. É assim da maior relevância o desenvolvimento de estudos que explorem formas de controlar/remediar águas afetadas pelo problema. Tal constituiu a principal motivação do presente estudo, cujo objetivo geral foi a avaliação da capacidade de um bivalve de água doce, Corbicula fluminea, enquanto agente bioremediador nestes cenários. Embora C. fluminea seja uma espécie invasora problemática na Europa e América do Norte, a sua distribuição já é muito alargada, pelo que o aproveitamento do seu elevado poder de filtração poderá ser uma boa estratégia de gestão da peste via compensação de danos resultantes do seu impacto em ecossistemas invadidos. Numa primeira fase do trabalho foi caracterizado (com recurso a ferramentas de microscopia e de tipagem genética) um conjunto de culturas laboratoriais de cianobactérias representativo da composição mais comum dos blooms ocorrentes em massas de água nacionais, incluindo espécies potencialmente produtoras de cianotoxinas. Alguns dos taxa de cianobactérias consideradas foram Anabaena cylindrica; Microcystis ou Oscillatoriales. Na segunda fase do trabalho foi avaliada a capacidade de C. fluminea para filtrar e ingerir cada uma das cianobactérias, em ensaios de curta duração com cada cianobactéria, oferecida em densidade típica de bloom. Os resultados obtidos revelaram baixas taxas de filtração em muitos casos, sobretudo quando comparadas com as taxas de filtração atingidas quando foi oferecida uma microalga verde (Raphidocelis subcapitata). No entanto, a análise de balanço de massa de clorofila a no sistema (filtrada e ingerida, retida em pseudofezes e não filtrada) permitiu algumas anotações importantes. Foi notória a relevância da agregação e sedimentação de cianobactérias filtradas promovida por C. fluminea, através das pseudofezes. Este processo tem semelhanças com o que é conseguido com a aplicação de químicos floculantes, usados para remover matéria orgânica e organismos microscópicos indesejados da coluna de água (por sedimentação e posterior aspiração), assim abrindo caminho para a continuação da exploração da possibilidade de utilização de C. fluminea como agente de remediação de blooms cianobacterianos.
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26

Cong, Danni. "Cyanobacteria blooms: from impacts on the environment to management strategies." Kansas State University, 2015. http://hdl.handle.net/2097/18930.

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Master of Science
Department of Biological & Agricultural Engineering
Philip L. Barnes
Bloom-forming cyanobacteria are harmful to both environment and public health because of the release of water soluble toxins. This report provides a broad overview of cyanobacteria and cyanotoxins and the current state of knowledge about the bloom control management. Cyanobacteria blooms usually flourish in warm, lentic, and eutrophic waters. Several environmental factors such as temperature, nutrients, light intensity, and turbulence can affect cyanobacterial growth and the formation of bloom. Cyanobacteria can synthesize multiple types of toxins, which cause human and animal toxications worldwide. Cyanobacterial blooms also cause detrimental effects on aquatic ecosystems, and the taste and odor problems in drinking water supplies. Due to the adverse effects, treatments that are used for removing both cyanobacterial cells and aqueous cyanotoxins should be carried out once cyanobacterial blooms occur in freshwaters. Strategies based on physical, chemical, and biological methods are carried out to remove the cyanobacteria and cyanotoxins. All of these strategies have both advantages and disadvantages: some physical treatment methods can remove cyanotoxins within the intact molecules, but the cost is usually high and further processing is needed; some chemical methods are cheap and can degrade the cyanotoxins, however, the toxicological characterization of the chemical and the by-products needs to be investigated; some biological treatments are more environmentally friendly, but the long reaction time and some other external factors also pose some problems that affect the efficiency of the treatments. The paper concludes that the key to success is to find a reasonable balance between those advantages and disadvantages, and the specific conditions of each unique aquatic ecosystem should be taken into consideration. As well, some suggestions are also proposed for the further development of more robust monitoring and management strategies.
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27

Jonasson, Sara. "Monitoring the cellular phosphate status in bloom-forming cyanobacteria of the Baltic Sea /." Stockholm : Department of Botany, Stockholm university, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1302.

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28

Coyle, Sadie Marie. "Investigations of microcystins (cyanobacterial peptide toxins) : detection, purification and analysis." Thesis, Robert Gordon University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360091.

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29

Trowbridge, Peter J. "Forecasting cyanobacteria in Lake Rockwell using historical data." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510311070018351.

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30

Ren, Jie. "Mapping Cyanobacterial Blooms in the Western Basin of Lake Erie using MERIS." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1336150800.

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31

Gorham, Tyler James. "Investigation of cyanobacterial blooms as an environmental risk factorfor various cancer types." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494055981679989.

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32

Lawson, Gabriella Marie. "Seasonal Nutrient Limitations of Cyanobacteria, Phytoplankton, and Cyanotoxins in Utah Lake." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9183.

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Excess nutrients from human activity trigger toxic cyanobacterial and algal blooms, creating expansive hypoxic dead zones in lakes, damaging ecosystems, hurting local economies, undermining food and water security, and directly harming human health. To identify when and where nutrients limit phytoplankton and cyanobacterial growth, and cyanotoxin concentrations across Utah Lake, USA we conducted four in-situ bioassay studies (563 cubitainers or experimental units) that experimentally added N, P or N+P over the spring, early summer, summer, late summer, and fall in lake water from the top 20 cm of the water column. For our purpose, we defined total phytoplankton as all prokaryotic or eukaryotic organisms containing chlorophyll-a. We evaluated changes in chlorophyll-a and phycocyanin concentrations; the abundance of cyanobacterial species and total phytoplankton species or divisions; cyanotoxin concentrations of the microcystin, anatoxin-a, and cylindrospermopsin; DIN, SRP, TP, and TN concentrations; and other water chemistry parameters. We found that the nutrient limitation of cyanobacteria, and to a lesser extent phytoplankton, was influenced by season and space. Cyanobacteria were often co-limited in the spring or early summer, limited by a single nutrient in the summer, and not limited by N or P in the late summer and fall. Alternatively, phytoplankton were co-limited from the summer into the fall in the main body of the lake and either N limited or co-limited continually in Provo Bay. Microcystis, Aphanocapsa, Dolichospermum, Merismopedia, and Aphanizomenon spp., and Aulacoseira and Desmodesmus spp. and two taxonomical categories of algae (i.e., unicellular and colonial green algae) were primarily associated with cyanobacteria and phytoplankton nutrient limitations. Concentrations of the three cyanotoxins demonstrated a seasonal signal and loosely followed the growth of specific cyanobacteria but was not dependent on total cyanobacterial cell density. The DIN and SRP were biologically available in all water and nutrient treatments with nutrient concentrations declining over the incubation period, suggesting that nutrient levels were not oversaturated. Our results offer insights into specific nutrient targets, species, and, and cyanotoxins to consider in the future to manage Utah Lake.
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33

Medeiros, Leonardo Rafael. "Unraveling knowledge gaps about cyanobacterial blooms and proposing an alternative for lake restoration." PROGRAMA DE P?S-GRADUA??O EM ECOLOGIA, 2016. https://repositorio.ufrn.br/jspui/handle/123456789/22293.

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A eutrofiza??o artificial tem sido considerada um problema de grande preocupa??o nos ecossistemas aqu?ticos em todo o mundo. Desde 1960, os avan?os cient?ficos t?m sido feitos a fim de desenvolver t?cnicas que atenuem os efeitos da eutrofiza??o. V?rios procedimentos f?sicos, qu?micos e biol?gicos podem ser usados e combinados para recuperar lagos de flora??es de cianobact?rias, como a aplica??o de um floculante combinado com argila natural ou modificada. No entanto, a efic?cia dos solos de regi?es ?ridas na mitiga??o de flora??es ? desconhecida para lagos artificiais brasileiros. Neste artigo, apresentamos uma an?lise bibliom?trica da evolu??o de publica??es sobre flora??es de cianobact?rias e identificamos registros que diretamente objetivam superar a ocorr?ncia dessas flora??es. Al?m disso, avaliamos, por meio de experimentos laboratoriais, o efeito do uso combinado do floculante policloreto de alum?nio (PAC) e um solo local do entorno do lago (LS), como lastro, no controle de flora??es de cianobact?rias em um lago raso da regi?o semi?rida do Brasil. A pesquisa bibliom?trica foi conduzida com o banco de dados "Web of Science" atrav?s da fun??o de busca ?TS = ((cyanobacteri* or blue green algae or cyanoprokariote or cyanophyceae) and (mass accumulation or bloom or domina*))?, de 1969 a junho de 2016. Realizamos uma an?lise de freq??ncia de palavras-chave e quantificamos o n?mero de registros com uma abordagem de restaura??o. Al?m disso, foram realizadas tr?s s?ries de experimentos em tr?s momentos com flora??es diferentes em composi??o e biomassa no Reservat?rio Armando Ribeiro Gon?alves. Nossa pesquisa revelou que os estudos sobre as flora??es de cianobact?rias aumentaram exponencialmente e seu impacto quantitativo nas ci?ncias aqu?ticas aumentou significativamente ao longo dos anos (F = 97,52; p <0,0001). Os EUA se destacam como a na??o mais produtiva, seguida pela China e pa?ses europeus. A China aumentou impressionantemente sua contribui??o para essa ?rea, superando os EUA nos ?ltimos cinco anos. Estudos sobre Microcystis e toxinas, tais como microcistinas, s?o tend?ncias de investiga??o, devido a sua omnipresen?a e suas consequ?ncias negativas hist?ricas. Tamb?m enfatizamos a necessidade de mais estudos com o objetivo de desenvolver t?cnicas para resolver e/ou mitigar a quest?o das flora??es. Em vista disso, nossos experimentos revelaram que o uso de PAC e LS teve um efeito not?vel na biomassa de cianobact?rias da coluna de ?gua em todas as amostragens, reduzindo at? 90% a concentra??o de clorofila-a. O uso de LS sozinho foi ineficiente para remover a biomassa de algas azuis. Em duas amostragens, a combina??o de floculante e lastro apresentou a mesma efic?cia que o uso apenas de PAC. Mesmo assim, o uso de LS ? importante para garantir a sedimenta??o. Combinado com PAC, o LS foi um lastro t?o eficiente em remover cianobact?rias quanto uma argila modificada comercialmente dispon?vel (Phoslock?). Embora LS in natura tenha liberado quantidades consider?veis de f?sforo e n?o apresentou capacidade de adsor??o de P, tal argila conseguiu adsorver quantidades moderadas de f?sforo dissolvido ap?s a mat?ria org?nica ter sido removida por muflagem. Este estudo mostra que LS ? uma alternativa economicamente vi?vel e sustent?vel para ser utilizada como a??o de manejo em reservat?rios apresentando flora??es na regi?o semi?rida do Brasil.
Artificial eutrophication has been considered a problem of major concern in aquatic ecosystems around the world. Since 1960, scientific advances have been made in order to develop techniques that mitigate the effects of eutrophication. Several physical, chemical and biological procedures can be used and combined to recover lakes from cyanobacterial blooms, such as the application of a flocculant combined with natural or modified clay. However, the efficacy of local dryland soils in mitigating blooms is unknown for Brazilian manmade lakes. In this paper, we present a bibliometric analysis of the evolution of publications about cyanobacterial blooms and identify records that directly aim to overcome the occurrence of these blooms. Also, we evaluate, through laboratory experiments, the effect of the combined use of flocculent polyaluminum chloride (PAC) and a local soil from the lake catchment (LS), as ballast, in controlling cyanobacterial bloom in a shallow lake of the semiarid region of Brazil. The bibliometric research was conducted with the ?Web of Science? database through the search function ?TS = ((cyanobacteri* or blue green algae or cyanoprokariote or cyanophyceae) and (mass accumulation or bloom or domina*))?, from 1969 to June 2016. We performed a keyword frequency analysis and quantified the number of records with a restoration approach. Besides, three sets of experiments were performed in three sampling occasions with different bloom compositions and biomass in Armando Ribeiro Gon?alves Reservoir. Our study revealed that studies about cyanobacterial blooms increased exponentially and their quantitative impact on the aquatic sciences increased significantly along the years (F = 97.52; p < 0.0001). The USA stands out as the most productive nation, followed by China and European countries. China has impressively increased its contribution to this area, surpassing the USA in the last five years. Studies about Microcystis and toxins, such as microcystins, are trends in research, due to their ubiquitousness and historical negative consequences. We also emphasize the need for more studies aiming at developing techniques to solve and/or mitigate the issue of blooms. In view of this, our experiments revealed that the use of PAC and LS had a remarkable effect on cyanobacterial biomass in the water column in all samplings, reducing up to 90% top chlorophyll-a concentration. The use of LS alone was inefficient to settle blue-green-algal biomass. In two samplings, the combination of flocculant and ballast exhibited the same efficacy as the use of solely PAC. Even so, the use of LS is important to ensure sedimentation. Combined with PAC, LS was as efficient a ballast to remove cyanobacteria as a commercially available modified clay (Phoslock?). Althugh LS in natura released considerable amounts of phosphorus and did not present P adsorption capacity, it managed to adsorb some dissolved phosphorus after organic matter was removed through muffling. This study shows that LS is a cheap, feasible and environment-friendly alternative to be used as a management action in reservoirs undergoing blooms in the semiarid region of Brazil.
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34

Brunkalla, Roberta Joann. "Influence of Mixing and Buoyancy on Competition Between Cyanobacteria Species in Upper Klamath Lake." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3998.

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Cyanobacterial blooms in lakes impact human health, the economy, and ecosystem health. It is predicted that climate change will promote and increase the frequency and intensity of cyanobacterial blooms due to unique physiological adaptions that allow cyanobacteria to exploit warm stable water bodies. Key cyanobacteria physiological adaptions include nitrogen fixation, buoyancy regulation and higher optimum growth temperatures. The largest uncertainty of predicting the effect of climate change is in understanding how the interactions among species will change. Adding to the ambiguity, cyanobacteria physiological adaptions can vary based on lakespecific ecotypes and can have different sensitivities to temperature. It is critical to understand how cyanobacterial physiological adaptions impact species interactions in order to improve and devise adaptable, short‐term management methods for bloom control. This study investigated how weather patterns and algal buoyancy regulation influence the competition and accumulation of two bloom‐forming buoyant cyanobacteria species (Aphanizomenon flos‐aquae (APFA) and toxin‐forming Microcystis aeruginosa (MSAE)) in Upper Klamath Lake (UKL), Oregon. The focus was confirming the buoyancy rate of the APFA in Upper Klamath Lake and exploring whether short‐term weather conditions could lead to dangerous accumulations of APFA or MSAE. A sensitivity analysis was conducted on the model's buoyancy terms and growth curves to see if the outcome of competition was influenced by these parameters. UKL specific buoyancy rates were measured on APFA from samples taken directly from the lake in the summer of 2015. Tracking software was used to measure APFA movement through water, and individual colony movement was averaged to obtain a single buoyancy rate. There was a high degree of agreement between the calculated APFA buoyancy rate in UKL (0.89 ± 0.34 m hr-1) with the rate published by Walsby (1995; 0.9 ± 0.5 m hr-1). This study investigated how weather patterns and buoyancy regulation influenced the outcome of competition between APFA and MSAE. Weather and water column temperature data were collected from UKL in the summer of 2016. A onedimensional hydrodynamic model was used to calculate the lake's thermal and turbulence structure on days with contrasting weather patterns (hot/cool and windy/calm). A competition model was used to calculate the accumulation of APFA and MSAE cells in regular intervals through the water column under the various weather scenarios. MSAE accumulation was significantly influenced by the thermal and turbulence regimes, but APFA maintained high accumulations under every regime and was the better competitor under every thermal and turbulence regime. MSAE was more negatively impacted by high turbulence than low temperatures. APFA's optimum temperature growth curve was found to be important in determining the outcome of competition between APFA and MSAE. Surprisingly, competition was not sensitive to changes in buoyancy rates. Buoyancy was not found to be a function of algal accumulation under any thermal and turbulence regime. The impacts of climate change and human‐induced enrichment has the potential to change existing patterns of species interactions in lentic systems. Restoration and management efforts should consider the significance of cascading ecological responses to climate change. Understanding how key physiological adaptions operate is the first step to assessing the scope of this impact. While buoyancy might not play a large role in competition in UKL, it might be possible to use mixing to suppress MSAE because it is negatively impacted by high turbulence. If MSAE hot spots become a reoccurring problem in UKL, lakes managers might be able to use localized mixing to suppress MSAE blooms in these problem areas.
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35

Gorney, Rebecca Michelle. "Trophic Dynamics and Cyanobacteria Blooms In Shallow Eutrophic Bays Of Lake Champlain." ScholarWorks @ UVM, 2014. http://scholarworks.uvm.edu/graddis/3.

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This study was conducted to evaluate the relative roles of trophic dynamics and nutrient concentrations in the development of cyanobacteria blooms. The motivation for this research was to gain insights into how food webs respond to ecosystem-scale changes, using Lake Champlain as a case study. I sought to link field-based observations with experimentally derived data on mechanisms to better understand the processes that drive cyanobacteria blooms. My research addressed three specific topics: (1) associations among phytoplankton and nutrient concentration trends over time, (2) the impacts of planktivory by invasive fish on the ambient zooplankton community, and (3) the role of herbivore zooplankton grazers in determining the composition of the phytoplankton community. I found little evidence of a strong association between nutrient concentrations and phytoplankton community composition during summer months in shallow bays of Lake Champlain prone to annual cyanobacteria blooms. Fish diet analysis indicated that invasive white perch (Morone americana) and alewife (Alosa pseudoharengus) selectively graze on large zooplankton, which has likely led to substantial declines in zooplankton biomass. I used these results to inform the design of a mesocosm study, which tested the effects of zooplankton grazing on phytoplankton and provided support for the theory that large zooplankton grazing pressure changes the size structure, abundance and composition of phytoplankton. High nutrient concentrations support increased levels of ecosystem productivity, but cascading trophic dynamics are additional forces that are likely contributing to the determination of phytoplankton community composition. Collectively, my research suggests that in shallow bays of Lake Champlain, selective grazing by invasive planktivorous fish is shifting the size structure of the zooplankton grazer community and has likely contributed to conditions that favor dominance by cyanobacteria in summer.
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36

McNamara, Shari J. "Using multispectral sensor WASP-LITE to analyze harmful algal blooms /." Online version of thesis, 2007. http://hdl.handle.net/1850/5856.

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37

Wallström, Jenny. "Public’s behavioural responses to cyanobacterial blooms in Sweden : economic impact and demand for information." Thesis, Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-30824.

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Eutrophication caused by nutrient loads from human activities is considered as one of the most serious environmental threats to the Baltic Sea. Due to climate change, cyanobacterial blooms are expected to increase in the future. This could affect people’s utility of beach recreation negatively in countries surrounding the Baltic. Based on a web survey carried out in south-eastern Sweden, public’s reactions and attitudes to cyanobacterial blooms are analysed. Possible economic impact on Gotland of more widespread blooms are estimated, and public demand for better information is evaluated. The result shows that 30% of the respondents from south-eastern Sweden would consider cancelling their plans of travelling to Gotland with knowledge about forthcoming algal blooms around the island. Determinants of tourists’ tendency to cancel their travel arrangements are earlier negative experiences of algal blooms and concerns regarding their pets’ bathing. The annual local economic loss for Gotland’s tourism industry is estimated to between 15 and 221 million SEK. The median willingness to pay for a mobile application which provides one-day forecasts of algal blooms is 25 SEK on Gotland and 20 SEK in southeastern Sweden. Boat owners, people who visit beaches often and those who travel to Gotland frequently, are more likely to pay for the mobile application. People who think algal blooms are natural show less demand for information.
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38

Andrade, Fabiana Martins de. "Determinação de cianotoxinas em amostras de florações de cianobactérias coletadas em pesque-pagues e pisciculturas situadas na região do Alto Mogi." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-12112009-153503/.

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O crescimento acelerado da aqüicultura no estado de São Paulo, ou seja, a implantação de pesque-pagues e pisciculturas pode estar causando uma série de problemas ambientais. A contribuição para o processo de eutrofização é uma das conseqüências desses empreendimentos, pois tanto os tanques utilizados na piscicultura como os afluentes em torno desses estabelecimentos, estão sendo eutrofizados pelo excesso de nutrientes. Uma das conseqüências da eutrofização é o aparecimento de florações de cianobactérias, e a principal preocupação está nas toxinas liberadas por estas cianobactérias, que se ingeridas pelos seres humanos e animais, podem causar efeitos de intoxicação, como fraqueza, cefaléia, vômito e dependendo da concentração ingerida pode levar à morte. Desta forma é necessário que haja um programa de controle da qualidade da água dos tanques e reservatórios e também dos peixes que ali são criados, pois florações de cianobactérias vêm sendo encontradas em diversos corpos d\'água. Este estudo teve como foco a determinação da cianotoxina microcistina-LR, empregando técnicas como a extração em fase sólida e a cromatografia líquida para a detecção e quantificação da microcistina-LR em amostras de florações de cianobactérias. Os testes feitos com a extração em fase sólida demonstraram que esse procedimento não se faz necessário para todas as amostras, pois houve casos em que não se obteve diferença nos picos interferentes mais próximos ao tempo de retenção do analito de estudo. Como as matrizes desse tipo de amostras são muito complexas e variam muito conforme o meio em que se encontram, recomenda-se que sejam avaliados caso à caso a necessidade de se promover a extração em fase sólida, pois o mesmo é um processo que demanda um tempo maior de análise e conseqüente aumento nos custos. Foi determinado e validado um método cromatográfico considerado capaz de fornecer dados reproduzíveis e confiáveis, por meio de testes de seletividade, limite de detecção e de quantificação, linearidade, precisão, exatidão e recuperação, conforme critérios de aceitação da Resolução n°899 de 2003, da ANVISA. O limite de detecção do método ficou estipulado em 0,1 µg mL-1, e o limite inferior de quantificação em 0,5 µg mL-1, determinados conforme a relação sinal-ruído proposta pelo Guia de Validação de Métodos Bioanalíticos da ANVISA. A quantificação da microcistina-LR foi feita utilizando o método de superposição de matriz, que minimiza e/ou compensa o efeito de matriz ou de possíveis interferentes presentes na amostra, e a curva analítica obtida y = 1,5888+21,849 x, com um coeficiente de correlação de 0,997 mostra uma boa linearidade. Foram analisadas amostras de florações de cianobactérias, coletadas em pesque-pagues e pisciculturas situadas na região do Alto Mogi (subdivisão da bacia do Mogi Guaçu), conforme o método de extração e análise estudado.
The rapid growth of aquaculture in the state of São Paulo may be causing a number of environmental problems. The contribution to the eutrophication process is among the consequences of these undertakings, given that the tanks used in fish farming as well as the changes around these establishments are becoming eutrophic systems due to excessive nutrients. A frequent consequence of eutrophication in waters is the massive development of cyanobacteria.The occurrence of these blooms induces severe problems, as Microcystis aeruginosa, the most widespread distributed cyanobacteria, which can produce microcystin-LR. Toxic effects of MC have been described in liver, lungs, stomach, and intestine. Deaths in wildlife, livestock and human beings were also associated with microcystin exposition, which can occur directly by ingestion, inhalation, contact, intravenous inoculation of contaminated water (hemodialysis) or indirectly, by the consumption of animals, as fish and mollusks, the major ingestors of cyanobacteria and its toxins. Thus we need a program to control the quality of water tanks and reservoirs and also the fish breeded there, as cyanobacteria blooms have been found in various water bodies. This study focused on the determination of the cyanotoxins microcystin-LR, using techniques such as solid phase extraction and liquid chromatography for the detection and quantification of microcystin-LR in samples of cyanobacteria blooms. Tests performed with solid phase extraction showed that this procedure is not necessary for all the samples because there were cases where no difference was obtained in interfering peaks near the retention time of the analyte studied. As the parent of such samples are very complex and vary greatly, because the extracts contained too much coextrated material that interfered in the LC-UV detection, and depending on the way in which it is recommended to be assessed, case by case, the solid phase extraction needs to be promoted, because it is a process that demands a longer period of analysis and consequently an increase in costs. A liquid chromatography method was established and validated, which is deemed capable of providing reproducible and reliable data, by testing for selectivity, limit of detection and quantification, linearity, precision, accuracy and recovery, in accordance with the acceptance criteria of Resolution No. 899 of 2003 of ANVISA. The detection limit of the method was set at 0.1 µg mL-1, and the lower limit of quantification at 0.5 µg mL-1 determined according to the signal to noise ratio proposed by the Validation Guide of Bioanalytical Methods, ANVISA. Quantification of microcystin-LR was performed using the matrix-matched method, which minimizes and/or offsets the effect of possible matrix interference or present in the sample. The analytical curve obtained y = 1.5888 + 21.849 x, with a coefficient of correlation of 0.997 shows a good linearity. Real aquaculture samples were analyzed that were detected and quantified according to the method developed.
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39

Morimoto, Daichi. "Comprehensive studies on transcriptional dynamics of cyanoviruses infecting a bloom-forming cyanobacterium Microcystis aeruginosa." Kyoto University, 2019. http://hdl.handle.net/2433/242690.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21813号
農博第2326号
新制||農||1066(附属図書館)
学位論文||H31||N5185(農学部図書室)
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 左子 芳彦, 教授 澤山 茂樹, 准教授 吉田 天士
学位規則第4条第1項該当
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40

Wu, X. "The effects of ultrasonic treatment on cyanobacteria in surface waters." Thesis, Coventry University, 2010. http://curve.coventry.ac.uk/open/items/d0d31d7e-fe64-436a-88b3-24c2b4656eba/1.

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The effect of power ultrasound on algae blooms (Microcystis aeruginosa) over a 30 minute period was assessed using 200 and 400 mL suspensions of optical density of 2.0 at 680 nm. The frequencies employed were 20, 40, 580 (40%, 80%, and maximum intensity), 864 (40%, 80% and maximum intensity) and 1146 kHz (40%, 80% and maximum intensity). Ultrasound can induce two different effects on algal cells; inactivation at high power (≥ 0.0022 Wcm-3) and de-agglomeration at low power (≤ 0.0042 Wcm-3). Ultrasonic effects were observed using haemocytometer, optical density, UV-visible spectrometer, fluorospectrometer and flow cytometry. Using a 40 kHz bath (0.0214 Wcm-3) led to de-agglomeration resulting in an overall increase in algae of -0.28% by haemocytometer and -4.20% by optical density. The highest inactivation achieved was 91.54% (haemocytometer) and 44.63% (optical density) using 1146 kHz (maximum intensity, 0.0248 Wcm-3) and 200 mL suspension. In terms of efficiency to achieve inactivation (i.e. inactivation % / power) the best result was observed at 864 kHz (40% power setting, 0.0042 Wcm-3) with 200 mL suspension giving 8226.19 by haemocytometer and 5011.90 by optical density. This initial part of the study allowed a comparison to be made of the ultrasonic parameters that would lead to optimum algae removal in terms of acoustic energy input. The haemocytometer results for cells number were generally higher than those indicated by optical density which is probably due to the fact that the former records only cell numbers remaining whereas the latter is an overall measure of algae concentration (ruptured cells will still register, because their contents remain in suspension). Studies on de-agglomeration and inactivation were also undertaken using small or medium-scale ultrasonic equipment that were models for industrial scale systems. The following volumes of algae suspension and equipment were employed: Sonolator (Sonic Corporation, 5L flow), 16 kHz and 20 kHz Dual Frequency Reactor (DFR, Advanced Sonics LLC, 1L static and 3.5 L flow), 20 kHz Vibrating Tray (Advanced Sonics LLC, 1.5L static) and 20 kHz ultrasonic probe (made at Southeast University, 4L static). The most effective inactivation effects were obtained with the DFR reactor in static mode and 60% power setting for 10 minutes which achieved reductions calculated at 79.25% using haemocytometry and 60.44% by optical density. The third part of this study was to gain a greater understanding of the basic mechanisms of the action of ultrasound on algae and to interpret this in terms of its potential for algal cell removal and control. Algal cell activity was assessed by three methods: using a UV-visible spectrometer (Shimazu, 2450PC), a fluorometer (Shimazu, RF5301) and a flow cytometer (BD FACS Calibur). Ultrasonic damage to Chlorophyll A was revealed through observation of the loss in UV-Vis spectrophotometer peaks around 600 nm together with the decrease in fluorometer results for peaks around 500 and 680 nm. Flow cytometer results were able to identify the number of both intact cells and damaged/ruptured cells thus giving greater insight into the mechanism of ultrasonic inactivation. The direct rupture of cells by power ultrasound was prevalent at low frequencies ≤ 40 kHz due to the mechanical effects of cavitation collapse and inactivation of algal cells by free radicals occurred at high frequencies ≥ 100 kHz and medium powers where mechanical effects are much reduced. In conclusion, this work has shown that power ultrasound can provide a suitable method to control algal growth in small and medium laboratory scales. Scale-up beyond this point is the subject of further research but the results herein clearly demonstrate the importance of choosing the correct ultrasonic parameters in terms of frequency, power and exposure time.
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41

Moore, David. "Studies on the life cycle of the cyanobacterium Cylindrospermopsis raciborskii, focusing on akinete differentiation and germination /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18987.pdf.

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42

Tate, Rachel Shanae. "Landsat Collections Reveal Long-Term Algal Bloom Hot Spots of Utah Lake." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8585.

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Harmful algal blooms (HABs) and nuisance algal blooms (NABs) are a worldwide phenomenon with implications for human health and safety. HABs occur when algae or bacteria grow in high enough densities to harm animals and humans. A primary component of harmful algal blooms is cyanobacteria, which are aquatic, photosynthesizing microorganisms that produce toxins at high concentrations. Cyanobacterial biomass has increased worldwide in recent decades, raising concern about the future of fresh- and marine-water systems in a changing climate. Understanding the patterns and conditions of past algal blooms can provide useful insights for managing future blooms. Remote sensing can enhance our understanding of the spatiotemporal distribution of HABs and NABs. We used radiometrically corrected images from the USGS Landsat Collections available in the Google Earth Engine for cloud processing. In 2016, the USGS calibrated the sensors of Landsat 4, 5, 7, and 8 to create a continuous collection of satellite images from 1984 to present. We use this 34-year dataset to expand the historical record of algal blooms at our study site and to understand factors relating to the spatiotemporal patterns of these blooms. We applied three models, including the Floating Algae Index (FAI), the Normalized Difference Vegetation Index (NDVI), and one developed with in situ chlorophyll-a (chl-a) data, to 398 images masked for cloud cover and lake elevation taken from 34 growing seasons (April – October). We found that the Normalized Difference Water Index (NDWI) used to separate water and land pixels fails under algal bloom conditions, whereas a modified NDWI does not. We also performed an emerging hot spot analysis in ArcGIS using the chlorophyll-a, NDVI, and FAI predictions from the surface reflectance values of the images. Our analysis indicates that the Provo Bay and parts of the eastern shoreline of Utah Lake have had algal blooms for 30 out of the 34 years included in this study, rendering them enduring hot spots. The remainder of the lake is a cold spot, showing clusters of low mean chl-a, NDVI, and FAI values over time. The overall trend of mean NDVI and lake surface area over this 34-year dataset is decreasing, whereas lake water temperature is increasing. This study develops a method for analyzing algal blooms over multiple decades and provides useful information for the management and prediction of future blooms.
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43

Hampel, Justyna J. "Ammonium cycling and nitrifier community composition in eutrophic waters affected by cyanobacterial harmful algal blooms." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1558619262925446.

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44

Crafton, Elizabeth Ann. "Investigation and Management of Cyanobacteria-dominated Harmful Algal Blooms in a Drinking Water Source." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1539688257233302.

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45

Muñoz, Ramos Valentina. "Relationship between toxic cyanobacterial blooms, physico-chemical factors and multiple source excreta contamination in affected watershed." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117190.

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Missisquoi Bay (MB) is a temperate eutrophic freshwater ecosystem located in an agricultural watershed and it frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Cyanobacterial population dynamics are influenced by a plethora of factors that may differ from system to system, requiring a site-specific assessment of bloom-promoting factors to design more effective bloom prevention or remediation strategies. This is the first biomonitoring study that combined data from high-throughput 16S rRNA gene amplicon sequencing, qPCR and environmental parameters from temporal and spatial samples to identify the main bloom-promoting factors. In addition, high-throughput amplicon sequencing of mitochondrial DNA genes was performed to qualitatively identify potential external sources of nutrients originating from animal excreta. Particular emphasis was placed on 1) determining whether there was a link between nutrients from external sources and cyanobacterial blooms and 2) analyzing in situ the effect of environmental factors (particularly nitrogen (N) and phosphorus (P) concentrations) on the dynamics of cyanobacterial community composition, abundance and toxicity.The concentrations of total P (TP) and total N (TN) in MB in 2009 correlated significantly with the abundance of total cyanobacterial cells, the Microcystis 16S rRNA and mcyD genes and intracellular microcystin. The results suggest that external sources of nutrients, such as surface runoff and animal excreta, played a significant role in the load of nutrients into the bay and thus in the proliferation of toxic cyanobacterial blooms. This was indicated by the detection of non-aquatic mitochondrial DNA hosts in the bay and the relationships between the pattern of surface runoff, nutrient concentrations, E. coli counts and total cyanobacterial abundance. Potential sources of nutrients from non-aquatic animal excreta in the system comprised rodents, birds, cattle and humans, indicating that efforts are required to control pollution from animal excreta in MB. During the growing season, the major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was identified as the main mcyD-carrier and main microcystin producer, hence the most problematic taxon in the cyanobacterial bloom. The correlations observed with environmental parameters suggest that increasing nutrient concentrations and TN:TP (mass) ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic cyanobacterial blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics has been documented, this is the first time that an optimum TN:TP ratio for Microcystis dominance has been observed in the field. This observation provides further support to the theory that nutrient supply ratios are an important determinant of species composition in natural phytoplankton assemblages. Although the validity and prediction potential of this optimum ratio for Microcystis dominance has yet to be verified through longer-term studies, it may provide practical guidelines for nutrient management strategies to avoid the proliferation of this toxin producing cyanobacterial genus in MB.
La baie Missisquoi (BM) est un écosystème d'eau douce tempérée situé dans un bassin versant où les activités agricoles sont importantes. La baie est fréquemment exposée à la prolifération de Microcystis, des cyanobactéries qui ont un potentiel toxique. La dynamique des populations de cyanobactéries est influencée par une multitude de facteurs qui peuvent varier d'un site à l'autre. Une caractérisation spécifique des facteurs qui sont responsables des floraisons est donc nécessaire afin de développer des mesures préventives et des stratégies de remédiation efficaces. C'est la première fois qu'une étude de biosurveillance combine des données de séquençage d'amplicons ARN ribosomal 16S à haut débit, la PCR en temps réel et des paramètres environnementaux d'échantillons qui ont été prélevés de façon spatio-temporelle pour identifier les facteurs qui causent les floraisons. De plus, le séquençage à haut débit d'amplicons ciblant l'ADN mitochondrial a été utilisé pour identifier qualitativement les sources potentielles de nutriments qui proviennent d'excréments d'origine animale. Une insistance a été accordée plus spécifiquement à 1) l'évaluation de l'existence d'un lien entre les nutriments provenant de sources externes et les périodes de floraison de cyanobactéries et 2) l'analyse in situ des impacts des facteurs environnementaux (particulièrement les concentrations d'azote (N) et de phosphore (P)) sur la structure des communautés de cyanobactéries, leur abondance et leur toxicité.Les concentrations de P et de N à la baie Missisquoi en 2009 étaient fortement corrélées avec l'abondance des cellules de cyanobactéries, des gènes de Microcystis (ARNr 16S et mcyD) ainsi qu'avec la concentration de microcystine intracellulaire. Les résultats suggèrent que les sources externes de nutriments telles que le ruissellement de surface et les excréments d'origine animale ont contribué de manière importante à la charge d'éléments nutritifs dans la baie et ainsi à la prolifération de cyanobactéries qui produisent des toxines. Ces conclusions ont été corroborées par la présence d'ADN mitochondrial d'hôtes non aquatiques et les liens entre les types de ruissellement de surface, les concentrations de nutriments, et les dénombrements de E.coli et de cyanobactéries. Les sources potentielles de nutriments provenant des excréments animaux dans la baie incluaient les rongeurs, les oiseaux, le bétail et les humains. Ces résultats indiquent que des efforts sont requis dans la baie Missisquoi pour contrôler la pollution provenant des excréments d'origine animale.Pendant la période de floraison, la communauté de cyanobactéries était principalement composée de Chroococcales et Nostocales. Les cyanobactéries du genre Microcystis étaient à la fois les principales porteuses du gène mcyD et les principales productrices de microcystine. Ce taxon a donc été le plus problématique pendant les fleurs d'eau. Les corrélations observées entre les facteurs environnementaux suggèrent que la dominance des Microcystis a été associée à l'augmentation des concentrations en nutriments, à un ratio TN:TP (masse) d'une valeur aux environs de 11:1, combinée à une hausse de température.Même si l'importance des concentrations et des ratios de nutriments sur la dynamique des cyanobactéries et des Microcystis a déjà été documentée, c'est la première fois qu'un ratio optimum pour le genre Microcystis est observé sur le terrain. Cette observation est en accord avec la théorie voulant que les ratios de nutriments soient importants pour déterminer la composition des espèces faisant partie de la communauté phytoplanctonique. La validité et le potentiel de prédiction de ce ratio optimum pour la dominance des Microcystis devraient être vérifiés à l'aide d'études à long terme, car il pourrait devenir un critère important pour développer des stratégies de gestion de nutriments qui permettraient d'éviter la prolifération de ce genre de cyanobactéries nocives.
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46

Arthur, Karen E. "Ecotoxicology of the cyanobacterium Lyngbya majuscula and health implications for green sea turtles (Chelania mydas) /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18909.pdf.

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47

Isles, Peter D. F. "A Multiscale Analysis of the Factors Controlling Nutrient Dynamics and Cyanobacteria Blooms in Lake Champlain." ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/561.

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Cyanobacteria blooms have increased in Lake Champlain due to excessive nutrient loading, resulting in negative impacts on the local economy and environmental health. While climate warming is expected to promote increasingly severe cyanobacteria blooms globally, predicting the impacts of complex climate changes on individual lakes is complicated by the many physical, chemical, and biological processes which mediate nutrient dynamics and cyanobacteria growth across time and space. Furthermore, processes influencing bloom development operate on a variety of temporal scales (hourly, daily, seasonal, decadal, episodic), making it difficult to identify important factors controlling bloom development using traditional methods or coarse temporal resolution datasets. To resolve these inherent problems of scale, I use 4 years of high-frequency biological, hydrodynamic, and biogeochemical data from Missisquoi Bay, Lake Champlain; 23 years of lake-wide monitoring data; and integrated process-based climate-watershed-lake models driven by regional climate projections to answer the following research questions: 1) To what extent do external nutrient inputs or internal nutrient processing control nutrient concentrations and cyanobacteria blooms in Lake Champlain; 2) how do internal and external nutrient inputs interact with meteorological drivers to promote or suppress bloom development; and 3) how is climate change likely to impact these drivers and the risk of cyanobacteria blooms in the future? I find that cyanobacteria blooms are driven by specific combinations of meteorological and biogeochemical conditions in different areas of the lake, and that in the absence of strong management actions cyanobacteria blooms are likely to become more severe in the future due to climate change.
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48

Motwani, Nisha H. "Trophic complexity of zooplankton–cyanobacteria interactions in the Baltic Sea : Insights from molecular diet analysis." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116219.

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Blooms of nitrogen fixing cyanobacteria (NFC) occur in many freshwater and marine systems, including the Baltic Sea. By fixing dissolved nitrogen, they circumvent general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for non-diazotrophic primary producers and ultimately supporting secondary production. Elucidating trophic links between primary consumers and NFC is essential for understanding role of these blooms for secondary production. However, until recently, there was no reliable method to quantify individual prey species for zooplankter feeding in situ. The development of PCR-based methods to detect prey-specific DNA in the diet of consumers, including microscopic animals, allows identification and quantification of trophic linkages in the field. Using molecular diet analysis in combination with egg production measurements, biochemical markers of growth and condition; and stable isotope approach, we explored a possibility to determine (1) whether cyanobacteria are grazed and assimilated by mesozooplankters (Papers I and II), (2) which species/groups are particularly efficient consumers of cyanobacteria (Papers II and III), and (3) how feeding on cyanobacteria affects zooplankton growth and development (Paper I and III). Taken together, these laboratory and field observations, provided evidence that NFC contribute to feeding and reproduction of zooplankton during summer and create a favorable growth environment for the copepod nauplii (Paper I). The favorable growth conditions for juvenile copepods observed during NFC blooms were hypothesized to be mediated by picoplankton that take up bioavailable nitrogen exuded from cyanobacterial cells. This hypothesis found support in Paper II that provided quantitative estimates for the direct picocyanobacteria → mesozooplankton pathway, with highest weight-specific consumption observed in nauplii. Further, using field observations on zooplankton and phytoplankton development during a growth season in the northern Baltic proper, we found that NFC nitrogen is assimilated and transferred to zooplankton via both direct grazing and indirectly through grazing on small-sized phyto- and bacterioplankton (Paper III). Finally, these and other findings emphasizing the importance of NFC for Baltic Sea secondary production during growth season were synthesized to show that diazotrophic nitrogen enters food webs already at bloom initiation (Paper III) and is transferred via multiple pathways to pelagic and benthic food webs and, ultimately, to fish (Paper IV).

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Accepted.

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49

Prentice, Matthew James. "Temporal and spatial variations of cyanobacteria in Karori Reservoir, Wellington." The University of Waikato, 2008. http://hdl.handle.net/10289/2363.

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The Lower Karori Reservoir (LKR) is a small, monomictic lake of 2.34 ha situated in the Karori Wildlife Sanctuary (KWS), Wellington. Over the past decade cyanobacterial blooms have become a common occurrence in this water body. In 2005 Anabaena planktonica was detected for the first time in the LKR and this species now forms dense blooms during summer. These blooms are problematic as they reduce aesthetic appeal and have resulted in odour problems for visitors to this high profile wildlife sanctuary. The objectives of this study were to identify key physical, chemical and biological variables influencing phytoplankton dynamics in the LKR and to use ecological models to investigate plausible management options. The key parameters investigated, that may cause bloom formation were; summer stratification, high nutrient levels, and the food web effects of a large population of European perch (Perca fluviatilis). High resolution sampling was carried out every six hours over a 72 hour period during pre-bloom, bloom and post-bloom periods in 2006/7 to elucidate short term temporal and spatial variations in biological and physico-chemical parameters. Quantitative polymerase chain reaction (QPCR) was used to enumerate A. planktonica populations, allowing a large number of samples to be simultaneously evaluated. Algal densities were also estimated using conventional phytoplankton enumeration and chlorophyll a analysis. Water samples were collected for nutrient analysis at discrete depths and profiles were taken for temperature, dissolved oxygen and photosynthetic active radiation. Secchi depth and pH were also measured. Weekly or fortnightly phytoplankton and zooplankton samples and physical variables have been collected at LKR since September 2005 as part of an independent sampling program carried out by the KWS, Waikato University and Cawthron Institute. In this project the 2-year data set was used to assist with analysis of lake processes and for validation of the hydrodynamic-ecological model DYRESM-CAEDYM. Between 12 and 15 February, 2007, electric fishing was undertaken within the LKR. A total of 3,946 P. fluviatilis were removed and the effects on phytoplankton and zooplankton concentrations were investigated. To increase knowledge of the physiology of A. planktonica, laboratory experiments were undertaken using cultures subjected to a range of different light intensities and temperature regimes The phytoplankton assemblage of the LKR shows very distinct temporal variations. Summer stratification occurred in the LKR for ~4 months each summer. During these periods A. planktonica comprised up to 99.9% of the surface phytoplankton population. During isothermy chlorophytes, bacillariophytes and small flagellated dinophytes are co-dominant in the phytoplankton assemblage. The results of the QPCR showed distinct diurnal vertical movement of A. planktonica, with the highest cell concentrations occurring at 1900 hours at the surface. Ammonium (NH4-N) is the dominant species of inorganic nitrogen during periods of stratification, while nitrate (NO3-N) is generally dominant during times of isothermy. Phosphate concentrations at surface and depth remained at low levels throughout the sampling period. The large surface populations of A. planktonica, are probably responsible for the elevated total nitrogen concentrations in surface waters during stratified periods. There appeared to be some short term effects of the P. fluviatilis removal with an increase in large crustaceans (e.g., Daphnia sp.) and a reduction in A. planktonica densities observed in the months following the P. fluviatilis removal. Only a small proportion of the total P. fluviatilis population was removed and it is unlikely that the effects will be long-lasting without subsequent removal steps. However, it seems likely that P. fluviatilis is one of the factors contributing to cyanobacterial blooms and management of this fish species should be considered in future lake restoration plans. Growth experiments indicated A. planktonica grow over a wide range of light intensities and temperatures, although highest growth rates were generally associated with higher temperatures (25 C) and light intensities (60 - 140 μmol m-2 s-1). Ecological and hydrodynamic trends within the LKR over a two year period were simulated with adequate success using the model DYRESM-CAEDYM. Management scenarios simulated using DYRESM-CAEDYM suggest implementation of an artificial destratification system in the LKR may be the most practical and effective means of controlling A. planktonica blooms. The addition of an artificial aeration system emitting air at a rate of approximately 50 l-1 s-1 should result in an isothermal system. Without summer stratification some of the physiological features of A. planktonica (e.g., buoyancy regulation and nitrogen-fixation) that give it a competitive advantage over other phytoplankton species will be reduced.
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Kennedy, Matthew R. "The Role of Microzooplankton and Mesozooplankton Grazing During the Planktothrix-Dominated Cyanobacterial Blooms in Sandusky Bay, Lake Erie." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589546747826657.

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