Download or read book Spatial and Temporal Variation in Cyanobacterial Population Dynamics and Microcystin Production in Eutrophic Lakes written by and published by . This book was released on 2013 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Toxic cyanobacterial blooms threaten freshwaters worldwide. We have learned much about the environmental factors promoting cyanobacterial success: high growth rates in increased water temperatures, predator avoidance, an ability to store nitrogen (N) and phosphorus (P), positive buoyancy, high affinity for inorganic carbon (C) and efficiency for converting bicarbonate to carbon dioxide (CO2), and the ability of some to fix dinitrogen (N2). However, the physiological and ecological role of cyanotoxins eludes us. Furthermore, complex population dynamics of toxic and non-toxic cyanobacterial strains confounds many ecosystem-based studies. Thus, our research has focused on describing spatial and temporal cyanobacterial population dynamics and cyanotoxin production in eutrophic lakes. Our results indicate that vertical heterogeneity in lakes is important for partitioning individual cyanobacterial taxa within the photic zone on short time scales (hourly-daily). However, on the time-scales that toxic blooms occur (days-weeks), physics likely plays a larger role in distributing cyanobacterial biomass and toxins throughout the epilimnion. Similarly, horizontal heterogeneity in lakes can be extremely patchy. We observed on daily time-scales, cyanotoxins could vary by orders of magnitude in different parts of the lake. Thus, toxic blooms are not evenly distributed horizontally or vertically in lakes on short time scales, but were also not significantly different beyond several days. Conversely, cyanobacterial communities and toxin concentrations changed significantly over the course of the open water season. Intra-annual changes in temperature, lake stratification, and nutrient concentrations had a profound impact on cyanobacterial community composition and measured toxin concentrations. In particular, inorganic nitrogen drawdown during stratification resulted in large N2 fixing Aphanizomenon blooms. Shortly thereafter, Microcystis abundance and microcystin concentrations increased significantly. Aphanizomenon and Microcystis were both abundant in the fall, but toxin concentrations decreased. Three Microcystis genotypes were abundant at different times of the year, suggesting they occupy different niches. We proposed that microcystin production was caused by N stress, particularly the rapid drawdown of ammonium, and present a metabolic model for regulation of microcystin synthesis in Microcystis. Together, these results have implications for lake management, public health, and modeling toxin production in eutrophic lakes.
Download or read book Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake Oregon 2007 09 written by Sara L. Caldwell Eldridge and published by CreateSpace. This book was released on 2014-07-11 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phytoplankton blooms dominated by cyanobacteria that occur annually in hypereutrophic Upper Klamath Lake, Oregon, produce microcystins at concentrations that may contribute to the decline in populations of endangered Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers. During 2007–09, water samples were collected from Upper Klamath Lake to determine the presence and concentrations of microcystins and cylindrospermopsins and to relate the spatial and temporal occurrences of microcystins to water quality and other environmental variables.
Download or read book Spatial and Temporal Dynamics of Cyanobacteria and Microcystins in Freshwater Systems written by Som Cit Si Nang and published by . This book was released on 2012 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] Excessive growth of cyanobacteria, commonly known as cyanobacterial blooms, appear to be increasing in magnitude and frequency worldwide, thus posing a serious threat to the safety and security of water resources. With the increasing global water stress, there is a need for effective management of cyanobacterial blooms in water bodies. So far, it has been a great challenge to mitigate and assess public health risks associated with cyanobacterial blooms due to difficulty in predicting the level of cyanobacterial biomass and microcystin concentrations in water bodies. Moreover, the effectiveness of the current bloom prevention and risk assessment strategies depend upon the understanding of the dynamics of cyanobacteria and microcystin under natural conditions. Thus, this research aims to: i) assess the variability of the relationship between cyanobacterial biomass and microcystin concentration, which is currently used to assess the risk to human and ecosystems health; ii) determine the environmental drivers of the dynamics of cyanobacterial dominance and microcystin concentration and assess site specificity of the environmental drivers; and iii) investigate how changes in the structure of phytoplankton community and cyanobacterial composition in response to nutrient concentration affect the dynamics of microcystin concentration. The results contained in this thesis revealed that the biomass-toxin relationship is a function of spatiotemporal patterns that affect cyanobacterial and microcystin dynamics. The correlation between the biomass and toxin is weak and site-specific, and large changes in total microcystin concentrations occur even at stable cyanobacterial biomass concentrations. This could pose a significant threat to the risk assessment associated with microcystin contamination in water bodies...
Download or read book Temporal and Spatial Trends in Toxic Cyanobacteria as Identified Through Lake Sediment DNA written by Shinjini Pal and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physiological and molecular ecology of aquatic cyanobacteria written by Anton F Post and published by Frontiers Media SA. This book was released on 2015-03-26 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cyanobacteria inhabit every illuminated environment on Earth, from polar lakes to desert crusts and through their phototrophic metabolism play essential roles in global geochemical cycles. With the discovery of marine Synechococcus and Prochlorococcus almost 30 years ago, cyanobacteria have now earned their place as dominant primary producers contributing over 25 percent of global photosynthesis. Their global abundance is now explained from the coexistence of ecotypes that occupy different niches along spatial and temporal gradients. New ecotypes of Synechococcus have been identified as abundant components of microbial communities in freshwater environments and marginal seas. Extensive comparative genomics of marine and freshwater picocyanobacteria have begun to unmask adaptations to light and nutrient (N, P, Fe) limitation that these diverse environments present. Novel types of cyanobacterial diazotrophy input new N and structure microbial communities in the open sea. Current challenges include the understanding of the interactions between marine cyanobacteria and other microbes in their immediate community. In contrast, mesotrophic and eutrophic environments such as the Laurentian Great Lakes have been increasingly affected by nuisance and toxic cyanobacterial blooms that have yielded severe declines in water quality. Factors promoting bloom formation and the functional roles of toxins are important issues being addressed today.
Download or read book Handbook of Cyanobacterial Monitoring and Cyanotoxin Analysis written by Jussi Meriluoto and published by John Wiley & Sons. This book was released on 2017-01-30 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: A valuable handbook containing reviews, practical methods and standard operating procedures. A valuable and practical working handbook containing introductory and specialist content that tackles a major and growing field of environmental, microbiological and ecotoxicological monitoring and analysis Includes introductory reviews, practical analytical chapters and a comprehensive listing of almost thirty Standard Operating Procedures (SOPs) For use in the laboratory, in academic and government institutions and industrial settings Those readers will appreciate the research that validates and updates cyanotoxin monitoring and analysis plus adding to approaches for setting standard methods that can be applied worldwide. Wayne Carmichael, Analytical and Bioanalytical Chemistry (2018).
Download or read book Climate Change and Marine and Freshwater Toxins written by Luis M. Botana and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-12-16 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasingly widespread production of toxins by marine and freshwater microalgae raises serious concerns regarding seafood and drinking water safety. This book compiles studies on the influence of climate change on the spreading of toxin-producing species in aquatic systems. The chemistry and biology of toxin production is revised and an outlook on control and prevention of the toxins' impact on human and animal health is given.
Download or read book Harmful Cyanobacteria written by Jef Huisman and published by Springer Science & Business Media. This book was released on 2005-06-15 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This outstanding volume provides an up-to-date overview of the advances in our knowledge of harmful cyanobacteria. An essential reference for all scientists and environmental professionals interested in cyanobacterial ecology and water management.
Download or read book Cyanobacterial Harmful Algal Blooms State of the Science and Research Needs written by H. Kenneth Hudnell and published by Springer Science & Business Media. This book was released on 2008-03-13 with total page 955 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the ever-increasing incidence of harmful cyanobacterial algal blooms, this monograph has added urgency and will be essential reading for all sorts of researchers, from neuroscientists to cancer research specialists. The volume contains the proceedings of the 2005 International Symposium on Cyanobacterial Harmful Algal Blooms, and has been edited by H. Kenneth Hudnell, of the US Environmental Protection Agency. It contains much of the most recent research into the subject.
Download or read book Scientific Investigations Report written by Sharon E. Kroening and published by . This book was released on 2004 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecology of Cyanobacteria II written by Brian A. Whitton and published by Springer Science & Business Media. This book was released on 2012-07-05 with total page 753 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyanobacteria have existed for 3.5 billion years, yet they are still the most important photosynthetic organisms on the planet for cycling carbon and nitrogen. The ecosystems where they have key roles range from the warmer oceans to many Antarctic sites. They also include dense nuisance growths in nutrient-rich lakes and nitrogen-fixers which aid the fertility of rice-fields and many soils, especially the biological soil crusts of arid regions. Molecular biology has in recent years provided major advances in our understanding of cyanobacterial ecology. Perhaps for more than any other group of organisms, it is possible to see how the ecology, physiology, biochemistry, ultrastructure and molecular biology interact. This all helps to deal with practical problems such as the control of nuisance blooms and the use of cyanobacterial inocula to manage semi-desert soils. Large-scale culture of several organisms, especially "Spirulina" (Arthrospira), for health food and specialist products is increasingly being expanded for a much wider range of uses. In view of their probable contribution to past oil deposits, much attention is currently focused on their potential as a source of biofuel. Please visit http://extras.springer.com/ to view Extra Materials belonging to this volume. This book complements the highly successful Ecology of Cyanobacteria and integrates the discoveries of the past twelve years with the older literature.
Download or read book Environmental Fluid Dynamics written by Jorg Imberger and published by Academic Press. This book was released on 2012-09-06 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: A broad cross-section of scientists working in aquatic environments will enjoy this treatment of environmental fluid dynamics, a foundation for elucidating the importance of hydrodynamics and hydrology in the regulation of energy.
Download or read book Environmental Spatial and Temporal Effects on Microbial Composition in Lake Erie written by Anna Kathleen Ormiston and published by . This book was released on 2016 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through close interactions with biotic and abiotic environments, microbial communities in lakes mediate numerous biogeochemical processes that are essential in regional and global cycles of C, N and P. However, the relationship between bacterial community compositions and environmental conditions is still unclear. Lake Erie's natural gradient of nutrient supply and many other environmental parameters from the Sandusky Bay to the Central Basin provides an ideal experiment to examine how well bacterial community composition tracks environmental changes spatially and temporally. Surface water samples were collected along a transect that ran from the Sandusky Bay (hypereutrophic) via Sandusky Sub-basin (mesoeutrophic) to the Central Basin (oligotrophic) in June, July and August 2012. Zooplankton sample were also collected at each basin in June, July and August to see whether they respond to environmental conditions and to the changing bacterioplankton communities. Physico-chemical parameters were measured in situ. Bacterioplankton was collected on filters and filtrates were used for nutrient analyses, including ammonium, dissolved organic carbon, total dissolved nitrogen, nitrate, nitrite and soluble reactive phosphorus. Chlorophyll a concentration measurements confirmed the expected gradient of primary productivity among sites. Terminal restriction fragment length polymorphism (T-RFLP) analysis was conducted to compare of the microbial community structure and diversity along this natural gradient from the Sandusky Bay to the Central Basin. Additionally, zooplankton community structure and diversity was compared along the transect. Results showed that the free-living bacterioplankton structure differed significantly among sampling time, which was likely contributed by temporal variations in nutrient concentrations. As for the zooplankton community, Cyclopidae, Branchionidae and Synchaetidae were identified as major families (>78.4% of total zooplankton) in all samples. Zooplankton family structure had no clear separation based on site location on site location or sampling time. In addition, no significant correlation was identified between zooplankton community structure and environmental parameters or with zooplankton community structure and bacterioplankton community structure. Zooplankton diversity tests revealed significant differences in zooplankton diversity among sites and months. This research contributes a better understanding of the zooplankton and bacteria community structure found in Lake Erie. Along with this natural nutrient gradient found in Lake Erie, harmful cyanobacterial blooms (cyanoHABS) is also a serious issue that affects wildlife, human health, recreation and local economics. CyanoHABs produce cyanotoxins, such as microcystins that lead to skin irritation, illness and liver tumors. Natural bacterial degradation of these microcystins play a key role in lakes by transforming these harmful toxins to less harmful metabolites that can be consumed by other organisms without a detrimental affect on their health and ecosystem health. Microcystin-LR is a toxin produced in harmful cyanobacteria blooms in Lake Erie and in Grand Lake St. Marys. This experiment specifically compared bacterial community structure and diversity from lakes with previous CyanoHAB exposure and their response to amended Microcystin-LR levels. Water samples were collected in June 2012 in the western basin, Sandusky sub-basin and central basin of Lake Erie and three recreational sites in Grand Lake St. Mary’s. Particulate-associated bacterioplankton was filtered out of the water samples, and the remaining filtrate was starved of all carbon and incubated in the dark for 1 week. After incubation, water samples were divided into triplicate microcosms. Microcystin-LR additions were added to the water samples as the sole carbon source for the naturally existing bacterioplankton community. After the microcystin-LR addition cell counts and microcystin concentrations were measure every 24 hours for two days. T-RFLP analysis was conducted to compare original bacterial community structure and diversity for each site to the Microcystin-LR amended bacterial community structure and diversity. Significant differences between start and end MC-LR concentrations (p 0.05) measured in the incubation experiment indicated MC-LR degradation. Shannon diversity indices for bacterioplankton T-RF percent abundances were not significantly different between treatments for both lakes (ANOVA, p 0.05). T-RFLP results showed that bacterioplankton community structures were significantly different between microcystin amended and original free-living bacterioplankton communities for Grand Lake St. Mary samples, but there was no significant difference between community structure for MC-amended treatments and non amended controls. In contrast, Lake Erie’s MC-amended communities experienced no shift in community structure. Non-amended controls had natural occurring MC-concentration, which suggests that there is a large subset of bacterioplankton that could degrade MC-LR before the treatments were administered. The extensive CyanoHAB history found in both lakes can explain these results. There are two dominating cyanobacterial species in Grand Lake St. Mary’s and four in Lake Erie, which suggests that these differences may affect the differences in MC degraders found in both lakes and the overall bacterioplankton community structure. Evidence of MC-degradation could be explained by bacterioplankton using MC-LR as an energy source.
Download or read book A Manual of Chemical Biological Methods for Seawater Analysis written by Timothy R. Parsons and published by Elsevier. This book was released on 2013-10-22 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to the quantitative analysis of seawater, describing in detail biological and chemical techniques, which are considered to be amongst those most often used by biological oceanographers. The manual provides complete instructions for the addition of reagents and calculation of results with reference material for each method so that the original texts can be consulted if necessary. In general, the techniques require a minimum of prior professional training and methods needing very expensive equipment have been avoided.
Download or read book Microcystin Production and the Dominance of Toxigenic Strains of Cyanobacteria in Lake and Culture Studies written by Susan LeBlanc Renaud and published by . This book was released on 2009 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microcystin in Ugandan Lakes written by Amanda Elizabeth Poste and published by . This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eutrophication of freshwater lakes has led to an increase in the occurrence of harmful cyanobacterial blooms, and it is expected that a warming climate will further exacerbate the frequency and duration of such blooms. Microcystin is a cyanobacterial hepatotoxin that is found worldwide, and poses a serious threat to the ecological communities in which it is found as well as to those who use these waters for drinking, recreation, or as a food source. Although microcystin is known to accumulate in fish and other aquatic biota, the prevalence of microcystin in fish tissue and the human health risks posed by microcystin exposure through fish consumption remain poorly resolved. Very few studies have quantified microcystin (a broadly present cyanotoxin) in water from East African lakes, despite the large human and animal populations that rely on these lakes for both water and food, and to date there is very little information available on the accumulation of microcystin in fish from these lakes. A comprehensive set of water and fish samples was collected on a monthly basis between September 2008 and February 2009 from several lakes in Uganda. The study sites included two embayments in northern Lake Victoria (Murchison Bay and Napoleon Gulf), Lake Edward, Lake George, Lake Mburo, and the crater lakes Saka and Nkuruba. The large lakes sampled all support substantial commercially important fisheries, while the smaller lakes support subsistence fisheries that provide a critically important source of protein and income for riparian communities. Microcystin concentrations in water were determined in addition to chlorophyll and nutrient concentrations, phytoplankton community composition, mixing dynamics and light conditions. At all study sites except Lake Nkuruba, microcystin concentrations in water regularly exceeded the WHO guideline for microcystin in drinking water of 1.0 [mu]g/L. Microcystis spp. emerged as the cyanobacterial taxa that is primarily responsible for microcystin production in these lakes, and as such, microcystin concentrations were closely linked to environmental factors that favour the development of high Microcystis biomass, including high nutrient concentrations, as well as shallow mixing depth which acts to increase mean mixed layer light intensity. Because of the importance of understanding the underlying food web when considering the accumulation and trophic transfer of a compound, stable carbon and nitrogen isotope analysis was used to characterize the food webs at the previously mentioned Ugandan study sites as well as in the East African great lake Albert. Omnivory was found to be common at all study sites, and based on [delta]13C values, the food webs in these lakes were strongly based on pelagic primary production, with no strong evidence of substantial benthic contribution to these food webs, likely as a result of reduced benthic primary productivity in these generally low-transparency eutrophic lakes. The distribution and trophic transfer of mercury was also characterized in the Ugandan study lakes (including Lake Albert) in order to provide a contrast for the trophic transfer of microcystin in the same lakes. Furthermore, relatively little is known about the behaviour of mercury in tropical hypereutrophic lakes, and the study sites included in the current study provided an opportunity for the exploration of this topic. Consistent biomagnification of mercury was observed at all study sites; however, mercury concentrations in fish were generally low, and would not be expected to pose a risk to consumers. Mercury dynamics were strongly linked to lake trophic status, with biomagnification rates significantly lower at the hypereutrophic study sites than at the mesotrophic and eutrophic study sites. I found evidence that growth and possibly biomass dilution can reduce mercury concentrations at the base of the food web, while growth dilution of mercury at consumer trophic levels might effectively reduce the biomagnification rate of mercury in these hypereutrophic lakes. Microcystin was prevalent in fish muscle tissue from all study sites and at all trophic levels. In contrast to mercury, for which consistent biomagnification was observed, neither biomagnification nor biodilution was observed for microcystin; and concentrations were relatively consistent throughout the fish food web, including in top predators, indicating that efficient trophic transfer of microcystin is occurring in these lakes. Microcystin concentrations in fish from several study sites followed seasonal trends that were similar to those observed for microcystin concentrations in water at these sites, suggesting that fish can rapidly respond to changes in microcystin concentrations in water through accumulation and depuration of this toxin. Microcystin concentrations in water and fish from all Ugandan study sites (including Lake Albert) in addition to data from two temperate eutrophic embayments (Maumee Bay in Lake Erie, and the Bay of Quinte in Lake Ontario) were compiled and used to estimate potential microcystin exposure to human consumers of both water and fish from these study sites. Microcystin was pervasive in water and fish from both the tropical and temperate study sites. Also, these results establish that fish consumption can be an important and even dominant source of microcystin to humans, and can cause consumers to exceed recommended total daily intake guidelines for microcystin. These results highlight the need to consider potential exposure to microcystin through fish consumption in addition to water consumption in order to adequately assess human exposure and risk.
Download or read book Spatial and Temporal Variability of Cyanobacteria Toxicity in Rhode Island Urban Ponds written by Amie L. Parris and published by . This book was released on 2015 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is the first to identify variations in cyanobacteria concentrations over space and time in Rhode Island urban lakes. Two small lakes were sampled weekly throughout August and September 2014 at three separate locations. For Mashapaug Pond, but not Slacks Reservoir, a visible bloom was present for most of this sampling period. 100 mL samples were obtained, frozen, and analyzed using a direct-injection tandem quadrupole MS/MS detector for the presence of 10 microcystin variants and anatoxin-a in Mashapaug Pond and six microcystin variants in Slacks Reservoir. Samples at both lakes exceeded RI recreational criteria for microystin. The southern sampling station in Mashapaug Pond presented the highest concentrations of toxins followed by the northern pond while the western pond presented only minor concentrations. The current RI protocol for assessing cyanobacteria, performed only in response to visible blooms and only at one location, would not have reliably identified microcystin hazards found in this study.
