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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Factors Affecting the Toxic Cyanobacteria Nodularia Spumigena in Farmington Bay of Great Salt Lake, Utah

McCulley, B. Eric 01 May 2014 (has links)
Farmington Bay of Great Salt Lake receives a significant amount of the nutrient-polluted runoff from Salt Lake and Davis Counties, Utah. This nutrient-laden runoff has led to seasonal blooms of blue-green algae, Nodularia spumigena, which produce a toxin called nodularin that has been shown to be toxic to aquatic organisms, birds, and mammals. Nodularia spumigena are the most common algae found in Farmington Bay. This study focused on understanding the physical and chemical factors controlling the growth of Nodularia spumigena in order to improve our knowledge about how nutrients impact algae in the Great Salt Lake. The salinity of the bay ranged from almost fresh water (less than 0.2%) to water twice as salty as the sea (7.0%). Nutrient (nitrogen and phosphorus) levels were high in the bay, and showed patterns of change from south to north. Nodularia spumigena was found in concentrations that greatly exceeded the World Health Organization’s standards for contact recreation. Laboratory studies suggest that nutrients and salinity are significantly correlated with levels of Nodularia spumigena from Farmington Bay. In combination with complex ecosystem interactions, nutrients and salinity in Farmington Bay apparently contribute to the high levels of Nodularia spumigena that we measured.
2

Removal of Microcystin-LR Using Powdered Activated Carbon: Effects of Water Quality and Activated Carbon Property

Bajracharya, Asnika, Bajracharya January 2017 (has links)
No description available.
3

Toksične cijanobakterije sa teritorije Republike Srbije / Toxic cyanobacteria from the territory of the Republic of Serbia

Tokodi Nada 28 June 2016 (has links)
<p>Ispitano je prisustvo toksičnih cijanobakterija u različitim ekosistemima sa teritorije&nbsp;Republike Srbije i analizirane su negativne posledice koje mogu da prouzrokuju ovi&nbsp;mikroorganizmi. Formirana je Baza podataka cijanobakterija u Srbiji koja prilaže veliki broj bitnih&nbsp; i korisnih informacija iz preko 70 literaturnih izvora o prostiranju i učestalosti pojave cijanobakterija i njihovih toksina u periodu od 130 godina, kao i njihovih efekata na živi svet u vodenim ekosistemima, ali i &scaron;ire. Istraživana su 64 vodena ekosistema, uključujući reke, jezera, bare, kanale, ribnjake, akumulacije za navodnjavanje, akumulacije za snabdevanje vodom za piće i akumulacije sa drugom namenom, gde je najče&scaron;će cvetalo pet vrsta cijanobakterija i to:&nbsp;<em> Microcystis aeruginosa,&nbsp; Aphanizomenon flos-aquae</em>,&nbsp; <em>Planktothrix agardhii,&nbsp; Microcystis flos-aquae</em>&nbsp; i<em>&nbsp; Planktothrix rubescens</em>&nbsp; koje ujedno i &scaron;ire svoj areal rasprostranjenja na teritoriji Republike Srbije. U brojnim vodenim telima detektovani su mikrocistini i to u visokim koncentracijama.</p><p>Istraživanje vodenog ekosistema Ludo&scaron; sa teritorije Republike Srbije vr&scaron;eno je da bi se ustanovilo prisustvo i uticaj cijanobakterija i cijanotoksina na druge biljne i životinjske organizme u prirodnim uslovima. Trofički status jezera Ludo&scaron; najče&scaron;će je eutrofan, a cvetanje cijanobakterija kontinuirano jo&scaron; od 1970. godine. Tokom 2011. i 2012. godine&nbsp; vrste<em> Limnothrix&nbsp; redekei&nbsp;</em> i&nbsp;<em> Pseudanabaena&nbsp; limnetica</em>&nbsp; nađene&nbsp; u&nbsp; cvetanju. Detektovano je i prisustvo mikrocistina/nodularina i saksitoksina u biomasi i vodi, a mikrocistini su detektovani i u tkivu vodenih biljaka (trske&nbsp;<em> Phragmites communis</em>, rogoza&nbsp; <em>Typha latifolia</em>&nbsp; i ljubičastog lokvanja<em> Nymphaea elegans</em>) i ribi (<em>Carassius gibelio</em>) iz jezera Ludo&scaron;. Histolo&scaron;kim pregledom tkiva ribe&nbsp; pronađene su naizraženije promene u jetri, bubrezima i &scaron;krgama, a primećene su i na crevima.</p><p>Testiranjem biolo&scaron;kih lesnih pokorica sa teritorije Vojvodine nisu detektovani&nbsp;mikrocistini/nodularini, a nije detektovana ni toksičnost uzoraka. Pretpostavlja se da su koncentracije cijanotoksina ispod granica detekcije ili ih nema u testiranim biolo&scaron;kim lesnim pokoricama. Razvojem novih metoda i optimizacijom postojećih za detekciju cijanotoksina u biolo&scaron;kim lesnim pokoricama i drugim terestričnim ekosistemima potrebno je proveriti dobijene rezultate.</p><p>Proučavanjem svojstva 84 soja cijanobakterija iz NSCCC, koji potiču iz terestričnih i&nbsp;vodenih ekosistema sa teritorije Republike Srbije, dobijena je intracelularna toksičnost u eksponencijalnoj i stacionarnoj fazi rasta, kao i ekstracelularna toksičnost &nbsp;kod jednog soja koji potiče sa terestričnog ekosistema. Dobijeni su i pozitivni rezultati &nbsp;na prisustvo mikrocistina, nodularina ili/i saksitoksina kod 34,1% terestričnih i 55,5% vodenih sojeva koji potiču sa teritorije Republike Srbije. Rezultati ukazuju na&nbsp; potencijalnu opasnost pojave ovih&nbsp; mikroorganizama i njihovih toksičnih metabolita u različitim ekosistemima sa teritorije Republike Srbije.</p><p>Eksperimentalno je potvrđena akumulacija mikrocistina u račiću<em>&nbsp; Daphnia pulex&nbsp; </em>usled ishrane toksičnim sojem iz NSCCC, zbog čega upotreba ove vrste račića u izvođenju biolo&scaron;kih testova za testiranje prisustva cijanotoksina treba da se preispita.&nbsp; &Scaron;tavi&scaron;e, veliki broj jedinki dafnija (92,2%) koristio je istraživane sojeve iz NSCCC za ishranu, odnosno ishrana je bila moguća sa svim vodenim i sa gotovo 90% terestričnih sojeva, &scaron;to može poslužiti kao osnov za dalja istraživanja prevencije cvetanja.</p><p>S obzirom na mogućnost ishrane račića&nbsp;<em> Daphnia&nbsp; sp</em>. cijanobakterijama, kompleks&nbsp;<br />ribnjaka sa teritorije Republike Srbije kori&scaron;ćen je za istraživanje potencijalnog načina&nbsp;<br />prevencije pojave i cvetanja cijanobakterija u zavisnosti od pravovremenog uno&scaron;enja&nbsp;<br />pomenutog račića. Na osnovu koncentracije hlorofila&nbsp; a&nbsp; i trofičkog statusa,&nbsp; kvalitativne i kvantitativne analize cijanobakterija, toksičnosti vode&nbsp; i prisustva cijanotoksina mikrocistina/nodularina i saksitoksina, potvrđeno je smanjenje cvetanja cijanobakterija i drugih negativnih efekata u eksperimentalnim jezerima u odnosu na kontrolna. Ukoliko pak dođe do cvetanja i proizvodnje toksina&nbsp; ijanobakterija u vodenim ekosistemima, zbog ozbiljnost pojave i mogućih negativnih posledica po zdravlje ljudi, neohodno je uvesti postupke eliminacije ćelija&nbsp; cijanobakterija i njihovih &nbsp;toksina u praksu pri obradi&nbsp; otpadnih voda i preči&scaron;ćavanja vode iz povr&scaron;inskih akumulacija u Republici Srbiji.</p> / <p>The presence of toxic&nbsp; cyanobacteria in different ecosystems from the territory of the Republic of Serbia was analyzed as well as the negative consequences that may be causeed by these microorganisms. Serbian Cyanobacterial Data Base was formed where great number of important and useful information from over 70 literary sources regarding the distribution and frequency of cyanobacteria and their toxins over a period of 130 years, as well as their effects on wildlife in aquatic ecosystems, and beyond was presented. The study consisted of 64 aquatic ecosystems, including rivers, lakes, ponds, canals, irrigation reservoirs, reservoirs for drinking water supply and reservoirs with other purpose, where five species of cyanobacteria <em>Microcystis aeruginosa,&nbsp; Aphanizomenon flos-aquae,&nbsp; Planktothrix agardhii,&nbsp; Microcystis flosaquae&nbsp;</em> and&nbsp; <em>Planktothrix rubescens</em>&nbsp; frequently bloomed, and also expanded their area of distribution on the territory of the Republic of Serbia. In many water bodies microcystins were detected in high concentrations.</p><p>Research into aquatic ecosystem Ludo&scaron;, located on the territory of the Republic of Serbia, was performed in order to determine the presence and effect of cyanobacteria and cyanotoxins on other plant and animal organisms in natural conditions. Trophic status of&nbsp; the lake Ludo&scaron; was usually eutrophic, and cyanobacteria bloom is constant since 1970. During 2011 and 2012, the species <em>Limnothrix&nbsp; redekei</em>&nbsp; and&nbsp; <em>Pseudanabaena&nbsp; limnetica&nbsp;</em> were found in blooming. Presence of microcystins/nodularin and saxitoxin was detected in&nbsp; biomass and water, and microcystins were detected in tissues of aquatic plants (reed <em>Phragmites communis,</em> cattail&nbsp;<em>Typha latifolia&nbsp;</em>and royalblue waterlily&nbsp; <em>Nymphaea elegans</em>) and fish (<em>Carassius gibelio</em>) from the lake Ludo&scaron;. Histological examination of tissue showed most prominent changes in liver, kidney and gills, and alterations were also observed in the intestine.</p><p>Testing of the biological loess crust from Vojvodina showed no presence of microcystins/nodularin and toxicity of samples was not detected as well. It is assumed that cyanotoxin concentrations were below detection limit or are absent from the tested biological loess crusts. The development of new methods and optimization of existing ones for detection of cyanotoxins in biological loess crustsand&nbsp; other terrestrial ecosystems is necessary in order to revise obtained results.</p><p>Research of the properties from 84 strains of cyanobacteria from NSCCC originating&nbsp;from terrestrial and aquatic ecosystems from the territory of the Republic of &nbsp;Serbia, resulte d inintracellular toxicity in exponential and stationary growth phase, as &nbsp;well as extracellular toxicity of a strain originating from terrestrial ecosystems. The obtained results were positive for the presence of microcystins, nodularin and/or saxitoxin&nbsp; for 34.1% terrestrial and 55.5% aquatic strains originating from the territory of the Republic of Serbia. These results demonstrate the potential risk of occurrence of these microorganisms and their metabolites in different ecosystems from the territory of the Republic of Serbia.</p><p>Accumulation of microcystins in shrimp <em>Daphnia pulex</em>&nbsp;after feeding with toxic strain&nbsp;from NSCCC was experimentally confirmed, indicating that the use of this species of shrimp in biological tests which determine the presence of cyanotoxins needs to be revisited. Moreover, a large number of&nbsp;<em>Daphnia&nbsp; individuals </em>(92.2%) used the investigated strains of NSCCC for food, and the feeding was possible with all &nbsp;the water strains and nearly 90% of terrestrial strains, which can serve as a basis for further research of bloom prevention.</p><p>With regard to the possibility shrimp <em>Daphnia&nbsp;</em>sp. feeding with cyanobacteria, a&nbsp;complex of ponds from the territory of the Republic of Serbia was used to explore &nbsp;potential ways of prevention the occurrence and blooming of cyanobacteria, depending on the timely introduction of the aforementioned shrimp. Based on the concentrations of chlorophyll&nbsp; a&nbsp; and trophic status, qualitative and quantitative analysis of cyanobacteria, the toxicity of water and the presence of&nbsp; cyanotoxins microcystins/nodularin and saxitoxin, reduction in blooming cyanobacteria and other negative effects in the experimental lakes when compared to the control lakes was confirmed. If the blooming regardless occurres as well as production of cyanobacterial &nbsp;toxins in aquatic ecosystems, due to the seriousness of the phenomenon and the possible negative consequences for human health, it would be necessary to introduce &nbsp;procedures for the elimination of cells of cyanobacteria and their toxins into practice in waste water treatment and purification of water from surface reservoirs in the Republic of Serbia.</p>
4

Assessment of toxic cyanobacterial abundance at Hamilton Harbour from analysis of sediment and water

Jonlija, Miroslava January 2014 (has links)
The western embayment of Lake Ontario, Hamilton Harbour, is one of the most polluted sites in the Laurentian Great Lakes and in recent years has seen a reoccurrence of cyanobacterial blooms. This study uses a multidisciplinary approach to examine the presences of toxic Cyanobacteria in the harbour in order to gain insight into these recurrent blooms. Microscopic analyses of phytoplankton samples collected during the 2009 summer-fall sampling season from two locations within the harbour showed the spatial and seasonal diversity of the contemporary cyanobacterial community. Microcystis colonies relative abundances in relation to total algal numbers were estimated. The lowest and highest relative abundances of Microcystis in the phytoplankton population were 0.6% and 9.7%, respectively, and showed seasonal variability between stations. Fourteen cyanobacterial genera comprising six families and three orders were identified and for which the most abundant filamentous genera during the summer-fall sampling season were Planktothrix, Aphanizomenon and Limnothrix. Potential microcystin producers Microcystis, Planktothrix, Aphanizomenon and Dolichospermum were also present and during the sampling period Microcystis was recorded at both stations on all dates, however, its relative abundance was below 10 % throughout the study period. The composition and abundance of filamentous cyanobacteria were observed to be positively statistically correlated to water quality environmental parameters dissolved nitrates (NO3/NO2), dissolved inorganic carbon (DIC), and conductivity. Redundancy analysis (RDA) found that 53.35% total variance of Aphanizomenon was correlated to low water column NO3/NO2 and conductivity, and higher water column DIC. 58.13% of the relative abundance of Planktothrix was correlated to high concentrations of dissolved nitrates, while 51.69% of total variance of Limnothrix was correlated to higher DIC and lower water column dissolved nitrate concentrations. Information about past cyanobacterial communities was obtained from the sediment core analysis, using paleolimnological and modern molecular methods. The age of the 100.5 cm long sediment core retrieved from the deepest part of Hamilton Harbour was established to be 140 years (1869-2009), using the Constant Rate of Supply (CRS) 210Pb age model. This age was not sufficient to provide information of harbour’s environmental conditions, presence of the blooms, and triggers for their occurrence before European settlement in the area. Results of the HPLC analysis of fossil pigments indicated that the dominant members of the algal community have not changed over the 140 years and that cyanobacteria were regular members of the phytoplankton community. The composition of the major chlorophyll pigments indicated high presence of Chlorophyta and Bacillariophyta in the harbour at all times. The main algal groups identified on the basis of marker pigments presence, besides the Chlorophyta and Bacillariophyta, were the Dinophyta and the Cryptophyta. The presence of a scytonemin derivative, compound B, indicated that cyanobacterial blooms were occurring in past, before the first officially recorded blooms in the 1960s. Cyanobacterial pigments presence indicated that Cyanobacteria have been a regular but not dominant feature of Hamilton Harbour phytoplankton in the past. To our knowledge, this study is the first one examining fossil pigments from Hamilton Harbour. Results of the PCR-DGGE molecular analysis of 16S rRNA-V3 gene fragments from sedimentary DNA revealed the presence of thirteen cyanobacterial genotypes. The temporal change in the cyanobacterial community composition was indicated by the increasing number of species over time, from the oldest to the most recent sediment layers. The deepest sediment strata showed the lowest number (two bands) and intensity of bands. The most recent sediment layer had the greatest numbers (11) and intensity of bands. This increased diversity indicated changing environmental conditions in the harbour, primarily nutrient pollution and worsening water quality. Results of the PCR-DGGE molecular analysis of mcyE-AMT gene fragments showed that Microcystis aeruginosa and Planktothrix rubescens were two microcystin producers present in Hamilton Harbour over the last 80 years. The persistent presence and resilience of these two genera indicated a more serious and longer-term issue of toxic blooms than previously recognized. Historical records show that noticeable anthropogenic impact on Lake Ontario environment has been measurable since the 1780s, the first dramatic impact on the Lake Ontario watershed was evident from the mid1880s, the earliest evidence of eutrophication in the lake occurred between 1820 and 1850, while human induced environmental changes in Hamilton Harbour date back ca. 350 years. In the 1960s, cyanobacterial blooms were first officially recognized in the harbour and the lower Great Lakes. The present research is the first report of the mcyE module and AMT domain of microcystin genes being amplified from sediment of North American lakes, and showed that toxic Cyanobacterial have been regular members of Hamilton Harbour phytoplankton community for almost a century. This research considerably deepened the knowledge of the past toxic cyanobacterial blooms in Hamilton Harbour and their possible causes. It also showed that in the absence of historical records, both the PCR-DGGE method and the mcyE-AMT gene may be used for reconstruction of the past toxic blooms not only in the Laurentian Great Lakes, but also in other aquatic regions of the world impacted by toxic cyanobacterial blooms. Also, it demonstrated the utility of the combined molecular and paleolimnological analyses, which might become a useful tool in the determination of the bloom causes factors and in the mitigation of the future production of toxic blooms.

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