Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Eco-engineering for clarity : clearing blue-green ponds and lakes in an urbanized area
    Waajen, Guido W.A.M. - \ 2017
    Wageningen University. Promotor(en): M. Scheffer, co-promotor(en): M.F.L.L.W. Lürling. - Wageningen : Wageningen University - ISBN 9789463431095 - 306
    ponds - lakes - ecological engineering - urban areas - cyanobacteria - eutrophication - water quality - water management - plassen - meren - natuurtechniek - stedelijke gebieden - cyanobacteriën - eutrofiëring - waterkwaliteit - waterbeheer

    Small lakes and ponds are common features in urban areas and they contribute to the quality of citizens’ life. A poor water quality, however, can easily give rise to nuisance. A major cause for a poor water quality is a high concentration of plant-nourishing nutrients, eutrophication. In (semi-)standing waters, eutrophication often results in a high biomass of blue-green algae (cyanobacteria), turbid water and the disappearance of submerged aquatic plants. The cyanobacterial blooms can be accompanied with fish kills due to anoxia, the development of unpleasant surface scums and malodors. As cyanobacteria can produce potent toxins, they impose a serious risk for citizens’ health, pets and wildlife. The cyanobacterial blooms hamper the anthropogenic use of the water and can have negative economic impacts. Water managers experience that the reduction of cyanobacterial nuisance is arduous. As long-term positive effects of management interventions are not often achieved, there is need for effective approaches.

    The objective of this study was to investigate the efficacy of promising methods to reduce cyanobacterial nuisance in city waters, targeting the clear water state and promoting the growth of aquatic plants. Various methods were tested, in the laboratory, in small and large compartments and were eventually applied in whole ponds and lakes. It is widely accepted that the reduction of nutrient inputs is essential for long-term positive effects. This study focused on the reduction of the input and the availability of the key-nutrient phosphorus. It was shown that cyanobacterial nuisance was wide spread in urban ponds and lakes in the Dutch province of North Brabant. The phosphorus inputs of four urban lakes in this province were addressed. The study lakes differed greatly in the phosphorus sources and loads, depending on site-specific characteristics. These differences affected the selection of measures. It was shown that in-lake measures were effective in realizing the long-term abatement of the cyanobacterial nuisance, provided the external phosphorus input was limited. If the external phosphorus input could not be limited sufficiently, in-lake measures did not result in the long-term reduction of cyanobacterial nuisance.

    To reduce the bioavailable phosphorus stock in the lake with in-lake measures, sediment capping with a phosphorus-binding agent (lanthanum-modified bentonite, LMB) can be effective and cheaper than sediment removal by dredging. The additional use of a flocculant may have added value and suppressed cyanobacterial blooms quickly and effectively. Aquatic plants and macroinvertebrates responded positively to the achieved improvement of the water quality. Accumulation of lanthanum was shown in aquatic plants and fish, following LMB exposure. No toxic effects of lanthanum from LMB were observed. Depending on site-specific characteristics, dredging or LMB did not suffice to limit the available phosphorus stock in the lake. For this situation, the additional capping of the sediment with sand was tested and subsequently applied in a lake. Management of the fish biomass and lake reconstruction can support rehabilitation. The results of this study underpin the importance of a site-specific diagnosis (water system analysis). The diagnosis clarifies the underlying causes of cyanobacterial nuisances and is essential for a site-specific tailored set of measures. This study showed that a site-specific set of measures reduced cyanobacterial nuisance effectively for a long term.

    As eutrophication control is not always feasible or might be effective only in the long run, curative measures are needed for symptom relief. Several curative end-of-pipe measures that are often suggested were evaluated: effective microorganisms (EM®), golden algae, plant extracts, ultrasound and artificial mixing of non-stratifying waters. No strong support for the efficacy of these measures could be shown. Next to the above mentioned application of flocculant, the use of freshwater quagga mussels is promising. The efficacy of the mussels was experimentally tested and it was shown that the introduction of mussels in a hypertrophic urban pond reduced the phytoplankton biomass, including cyanobacteria, and induced a clear water state. The quagga mussel is an invasive alien species and new introductions should be considered carefully.

    Based on the results from this study, the thesis provides a road map for water managers for the reduction of cyanobacterial nuisances in urban ponds and lakes.

    Further improvements in water quality of the Dutch Borderlakes : two types of clear states at different nutrient levels
    Noordhuis, Ruurd ; Zuidam, B.G. van; Peeters, E.T.H.M. ; Geest, G.J. van - \ 2016
    Aquatic Ecology 50 (2016)3. - ISSN 1386-2588 - p. 521 - 539.
    Abramis brama - Alternative stable states - Biomanipulation - Cyanobacteria - Dreissena - Macro-algae - Quagga Mussel - Regime shift - randmeren - mussels - algae - water quality - aquatic ecology - eutrophication - randmeren - abramis brama - mossels - cyanobacteriën - algen - waterkwaliteit - aquatische ecologie - eutrofiëring

    The Borderlakes are a chain of ten shallow, largely artificial, interconnected lakes in the Netherlands. The ecological recovery of the central Borderlakes (viz. lake Veluwe and Wolderwijd) has been well documented. These lakes shifted from a eutrophic, Planktothrix dominated state in the 1970s to a clear state in 1996. Around 2010, the formerly hypertrophic, southern Borderlake Eem also reached a clear state, but at considerably higher nutrient levels. In this paper, monitoring data are used to compare these changes and identify the differences in driving processes and their consequences. The 1996 shift in Lake Veluwe was linked to increased fishery for benthivorous Bream, followed and stabilized by increase in Zebra Mussels and charophytes. Nutrients in Lake Eem decreased as well and Planktothrix disappeared here too in 1996, despite relatively high TP concentrations which remained stable over time. The start of the change into the clear state in this case also involved a decrease in the Bream population, but with a stronger additional role for dreissenids, particularly of Quagga Mussels. Remaining blooms of cyanobacteria almost disappeared, but the current situation in Lake Eem represents a different type of clear water state than in the central Borderlakes. This type is characterized by the combination of a relatively high phosphorus load, intense dreissenid filtration and filamentous macro-algae instead of either blooms of cyanobacteria or dominance of charophytes. With the dominant role of the River Eem, the relatively short residence time and increasing difficulty to bring down nutrient loading any further, the stability of this clear state depends on high densities (and filtration rates) of dreissenids.

    Light harvesting, light adaptation and photoprotection in aquatic photosynthesis studies by time-resolved fluorescence spectroscopy
    Chukhutsina, V. - \ 2015
    Wageningen University. Promotor(en): Herbert van Amerongen. - Wageningen : Wageningen University - ISBN 9789462572454 - 190
    licht - adaptatie - bacillariophyta - cyanobacteriën - verdedigingsmechanismen - fotochemie - spectrofluorimetrie - light harvesting complexen - light - adaptation - bacillariophyta - cyanobacteria - defence mechanisms - photochemistry - spectrofluorimetry - light harvesting complexes

    Summary

    Aquatic photosynthetic organisms unavoidably experience light fluctuations that vary in amplitude, duration and origin, compromising their photosynthetic efficiency. Weather conditions and underwater flow cause continuous changes in irradiance to which the organisms have to adapt. Many light-adaptation strategies of photosynthetic organisms, such as light acclimation, photoprotection and state transitions are still not well understood. In this thesis, time-resolved fluorescence spectroscopy is used to obtain insight into the response of diatoms and cyanobacteria, both aquatic photosynthetic organisms, to changing light conditions.

    In chapter 2, photoacclimation (long-term acclimation to irradiance conditions) of the diatom Cyclotella meneghiniana is discussed. It is shown that the diatom cells fine-tune the amount of absorbed light energy by modifying their antenna size: cells grown in high light intensity have smaller antennas than those grown in low light. At the same time, the increase of growth light intensity leads to a decrease of the relative amount of photosystem I (PSI) as compared to PSII. Such a strategy might be beneficial for diatoms, since they are known to have an electron transfer cycle around PS II to release excess electrons produced in high light intensities. Besides discussing photoacclimation, we give a detailed description the fluorescence kinetics in C. meneghiniana. It is concluded that the diatom antenna, represented by light-harvesting fucoxanthin chlorophyll proteins (FCPs), transfer their excitation energy predominantly to PSII. FCPs associated with PSII are slightly richer in red-absorbing fucoxanthin than the FCPs associated with PSI, suggesting that PSII antennas (partly) constitute the antenna form FCPb (i.e. oligomeric antenna complexes).

    In chapter 3 the process of non-photochemical quenching (NPQ, thermal dissipation of excess absorbed light energy) of chlorophyll a fluorescence was studied in the same diatom species. Diatoms can rapidly switch on/off NPQ to respond to fast light-intensity changes in moving waters. They are capable to induce higher NPQ values than plants or other photosynthetic organisms. The reason for such high NPQ values, however, is not clear. We performed picosecond fluorescence measurements at 77K on cells locked in three different states: Besides using conventional unquenched and quenched states of the cells (in the absence and presence of the total NPQ component, respectively), we also performed measurements on the dark-adapted state directly following NPQ. In this state, diatoxantin (Dtx, a carotenoid related to NPQ), accumulated during the NPQ period and Dtx-related NPQ persists, while ΔpH-related NPQ has relaxed. In this way we revealed the following sequence of events during full development of NPQ. First, the pH gradient across the thylakoid membrane induces quenching of FCP trimers (FCPa complexes), while they are still part of PSII. This is followed by (partial) detachment of FCPa from PSII after which quenching persists. The pH gradient also causes the formation of Dtx, which leads to further quenching of isolated PSII cores and some aggregated FCPa. To summarize, quenching of PSII -both cores and complexes- and FCPa substantially contribute to NPQ in diatoms. The FCPb antenna form on the other hand does not contribute to the NPQ process.

    Certain aquatic photosynthetic organisms, such as cyanobacteria and green algae, can also cope with changing light conditions by dynamically varying the relative antenna size of PSI and of PSII. Consequently, a redistribution of light energy between the PSs is achieved. This phenomenon is called “state transitions”. It is known to be driven via a change in the redox status of electron carriers between PSII and PSI. In cyanobacteria, this redox change can be achieved via dark-light transitions. However, the cascade of microscopic events that lead to subsequent energy redistribution in cyanobacteria is still not completely clear. In chapter 4, a study on dark-light transitions using the cyanobacterium Synechocystis sp. PCC 6803 as a model organism is described. It is demonstrated that during dark to light transitions, there is mainly detachment of phycobilisomes (PBSs) (cyanobacterial antennas) from PSI, generally not followed by their attachment to PSII: only 15 % of the PBSs that detach from PSI actually move to PSII, while the major part remains detached from both PSs. We conclude that PSI-PSII-PBS megacomplexes, which were recently isolated using chemical cross-linking, are not involved in dark/light state transitions, suggesting that, if present, they are only transiently formed in cyanobacteria. To summarize, the findings presented in chapter 4 suggest that in cyanobacteria, unlike in green algae or higher plants, the main role of state transitions is to change the absorption cross-section of PSI, rather than that of PSII.

    In chapter 5, a study of the role of flv4-2 operon-encoded proteins in Synechocystis is described. Three genes are found in the operon: Flv4, Sll0218, and Flv2. Only recently flv4-2 operon-encoded proteins were found to constitute an additional photoprotective mechanism in a number of cyanobacteria by safeguarding PSII activity via an alternative electron chain. Its contribution becomes vital for the cells in high light and in air-level CO2, when the photosynthetic electron transport chain is over-reduced. It is demonstrated that deletion of the operon induces 20% PBS detachment. The reduced PSII dimer to monomer ratio, as a result of the absence of the small Sll0218 protein, favors a relative decrease of the PSII dimer content of about 20%, showing a direct correlation between PSII dimer destabilization and PBS detachment from reaction centers. On the other hand, the suggested binding of the Flv2/Flv4 heterodimer closely to the quinone B (QB) pocket in PSII increases the QB redox potential, thereby promoting forward electron transfer and increasing the charge separation rates in PSII. This activity of the Flv2/Flv4 heterodimer in combination with its earlier reported role as an electron acceptor in alternative electron chain provides more oxidized state of the PQ pool in high light and in air-level CO2.

    Beating the blues: Is there any music in fighting cyanobacteria with ultrasound?
    Lurling, M.F.L.L.W. ; Tolman, Y. - \ 2014
    Water Research 66 (2014). - ISSN 0043-1354 - p. 361 - 373.
    oppervlaktewater - cyanobacteriën - ultrageluid - waterkwaliteit - surface water - cyanobacteria - ultrasound - water quality - anabaena-flos-aquae - microcystis-aeruginosa - effective microorganisms - harmful cyanobacteria - growth-inhibition - climate-change - bloom control - gas vesicles - fresh-water - eutrophication
    The hypothesis that cyanobacteria can be controlled by commercially available ultrasound transducers was tested in laboratory experiments with cultures of the cyanobacteria Anabaena sp., Cylindrospermopsis raciborskii and Microcystis aeruginosa and the green alga Scenedesmus obliquus that were grown in the absence or presence of ultrasound (mix of 20, 28 and 44 kHz). The Scenedesmus experiment also included a treatment with the zooplankton grazer Daphnia magna. Chlorophyll-a and biovolume-based growth of Anabaena was significantly lower in ultrasound exposed cultures than in controls. Particle based growth rates were higher in ultrasound treatments. Filaments were significantly shorter in ultrasound exposed cultures reflecting filament breakage. Photosystem II efficiency was not affected by ultrasound. In Cylindrospermopsis chlorophyll-a based growth rates and photosystem II efficiencies were similar in controls and ultrasound treatments, but biovolume-based growth was significantly lower in ultrasound exposed cultures compared to controls. Despite biovolume growth rates of the filamentous cyanobacteria were reduced in ultrasound treatments compared to controls, growth remained positive implying still a population increase. In Microcystis and Scenedesmus growth rates were similar in controls and ultrasound treatments. Hence, no effect of ultrasound on these phytoplankton species was found. Ultrasound should not be viewed "environmental friendly" as it killed all Daphnia within 15 min, releasing Scenedesmus from grazing control in the cultures. Based on our experiments and critical literature review, we conclude that there is no music in controlling cyanobacteria in situ with the commercially available ultrasound transducers we have tested.
    Brandstof kweken biedt zicht op schone toekomst
    Klein Lankhorst, R.M. - \ 2013
    Milieu : opinieblad van de Vereniging van Milieuprofessionals 2013 (2013)sept. - ISSN 1873-5436 - p. 11 - 13.
    zonne-energie - biobrandstoffen - biobased economy - duurzame energie - fotosynthese - stralingsbenuttigingsefficiëntie - cyanobacteriën - solar energy - biofuels - biobased economy - sustainable energy - photosynthesis - radiation use efficiency - cyanobacteria
    De zon is onze perfecte duurzame energiebron die we kunnen aftappen via fotosynthese. Planten doen dit al van nature, maar lang niet efficiënt genoeg. Daarom werkt het bedrijf BioSolar Cells aan de ontwikkeling van Solar Fuels: brandstoffen die rechtstreeks, zonder eerst biomassa te maken, worden gemaakt uit zonlicht, water en CO2. Dit kan met hoge efficiëntie en ondervangt bovendien een aantal knellende problemen met het gebruik van biomassa.
    Controlling eutrophication by combined bloom precipitation and sediment phosphorus inactivation
    Lürling, M.F.L.L.W. ; Oosterhout, J.F.X. - \ 2013
    Water Research 47 (2013)17. - ISSN 0043-1354 - p. 6527 - 6537.
    meren - oppervlaktewaterkwaliteit - eutrofiëring - cyanobacteriën - sedimentatie - uitvlokking - lanthaan - bentoniet - tests - fosfor - ecologisch herstel - noord-brabant - lakes - surface water quality - eutrophication - cyanobacteria - sedimentation - flocculation - lanthanum - bentonite - tests - phosphorus - ecological restoration - noord-brabant - prymnesium-parvum haptophyceae - harmful cyanobacterial blooms - dissolved organic-matter - rare-earth-elements - of-the-art - microcystis-aeruginosa - lake restoration - local soils - polyaluminum chloride - phosphate adsorption
    The hypothesis that the combination of the flocculent polyaluminium chloride (PAC) with the lanthanum-modified bentonite Phoslock® (Flock & Lock) could sink effectively a water bloom of cyanobacteria and could shift a turbid, cyanobacteria infested lake to a clear water lake was tested in a controlled laboratory experiment and a whole lake experiment. In the laboratory, a relatively low dose of the flocculent PAC (2.2 and 4.4 mg Al l-1) was insufficient to sediment positively buoyant cyanobacteria (Microcystis aeruginosa). Similarly, the lanthanum modified clay (dosed at 390 mg l-1) was insufficient to sediment the positively buoyant cyanobacteria. However, the combination of PAC and Phoslock® effectively sedimented cyanobacteria flocks. Likewise, a combined treatment of 2 tons PAC and 18 tons Phoslock® in Lake Rauwbraken in April 2008 effectively sedimented a developing cyanobacteria bloom of Aphanizomenon flos-aquae. The average chlorophyll-a concentration in the two years prior to this Flock & Lock treatment was 19.5 (±36.5) µg l-1, while it was as low as 3.7 (±4.5) µg l-1 in the years following the treatment. The combined treatment effectively reduced the amount of total phosphorus (TP) in the water column from on average 169 (±126) µg P l-1 before the application to 14 (±15) µg P l-1 after the treatment. Based on mean summer chlorophyll-a and TP concentrations, the lake was shifted from a eutrophic/hypertrophic state to an oligo/mesotrophic state. From directly after treatment in April 2008 until and including 2013, Lake Rauwbraken remained in an oligo-mesotrophic clear water state with TP reduced to less than 10% of the pre-treatment. This result shows that eutrophication in relatively small, isolated, stratifying lakes can be restored by targeting both water column and sediment P using a combination of flocculent and solid phase P-sorbent
    Light harvesting and photoprotection in Cyanobacteria
    Tian, L. - \ 2013
    Wageningen University. Promotor(en): Herbert van Amerongen. - [S.l.] : s.n. - ISBN 9789461735294 - 167
    cyanobacteriën - fotosynthese - light harvesting complexen - fluorescentie - lichtverdeling - cyanobacteria - photosynthesis - light harvesting complexes - fluorescence - light distribution

    The process of photosynthesis has been studied for centuries, but despite a large amount of progress, there are still many aspects that are not fully understood. An important part of the progress is the fact that many structures of photosynthetic complexes have been resolved 1,2and these complexes have been studied separately in great detail, amongst other with ultrafast spectroscopic techniques. These studies allow to monitor excitation-energy transfer (EET) and charge separation (CS), the first crucial processes after the absorption of a photon. Many picosecond studies have also been performed in vivo in the past before the crystal structures were known, but due to an additional lack of knowledge about the organization and composition of the thylakoid membrane where most of the EET and CS processes take place, the obtained results were difficult to interpret. More recently, new interest has arisen in in vivo studies on photosynthetic organisms because a lot of molecular and organizational information has been obtained but also because the spectroscopic techniques have improved and mutants have become available that allow to study the effect of specific modifications in the organisms. This thesis focuses on the study of the light energy harvesting processes of photosynthetic complexes in cyanobacteria in general by using time-resolved fluorescence techniques, and with particular emphasis on the study of the in vivo protective process of non-photochemical quenching (NPQ) that is induced in the presence of high intensities of blue-green light.

    First report of (homo)anatoxin-a and dog neurotoxicosis after ingestion of benthic cyanobacteria in The Netherlands
    Faassen, E.J. ; Harkema, H. ; Begemann, L.L.J. ; Lürling, M.F.L.L.W. - \ 2012
    Toxicon 60 (2012)3. - ISSN 0041-0101 - p. 378 - 384.
    zwemwater - cyanobacteriën - toxinen - waterverontreiniging - oppervlaktewater - ijsselmeer - nederland - swimming water - cyanobacteria - toxins - water pollution - surface water - lake ijssel - netherlands - blue-green-algae - fresh-water - anatoxin-a - mass-spectrometry - homoanatoxin-a - identification - cylindrospermopsin - biosynthesis - microcystin
    In April and May 2011, three dogs died and one dog became ill after swimming in Lake IJmeer (The Netherlands). At the time, the lake was infested with the benthic cyanobacterial species Phormidium. A Eurasian Coot (Fulica atra) and a Black-headed Gull (Chroicocephalus ridibundus) also died near Lake IJmeer in the same period. One of the dogs and both birds were subjected to a pathological investigation. Furthermore, the Phormidium mat; algal samples from the dikes; contents of the animals' digestive systems and organ tissues were analysed for the following cyanobacterial toxins: (homo)anatoxin-a; (7-deoxy-)cylindrospermopsin; saxitoxins and gonyautoxins by LC-MS/MS. Samples were also analysed for the nontoxic (homo)anatoxin-a metabolites dihydro(homo)anatoxin-a and epoxy( homo) anatoxin-a. The dog necropsy results indicated neurotoxicosis and its stomach contained Phormidium filaments. Anatoxin-a was detected in the Phormidium mat (272 mu g g(-1) dry weight, stdev 65, n = 3) and in the dog's stomach contents (9.5 mu g g(-1) dry weight, stdev 2.4, n = 3). Both samples also contained the anatoxin-a metabolite dihydroanatoxin-a, and a trace of homoanatoxin-a was detected in the Phormidium mat. The birds were in bad nutritive condition at the time of necropsy and their stomachs and intestines did not contain any cyanobacterial material. Furthermore, no cyanobacterial toxins were detected in their stomachs, intestines and organs and they both had lesions that are not associated with cyanobacterial intoxication. This is the first report of anatoxin-a and homoanatoxina occurrence in The Netherlands, these toxins have likely caused the deaths of three dogs. The birds probably died of other causes. Dutch recreational waters are at this moment only screened for pelagic cyanobacterial species, the current bathing water protocol therefore does not protect humans and animals from negative effects of blooms of benthic cyanobacteria.
    Bestrijding blauwalgenoverlast : eindrapportage praktijkonderzoek
    Lürling, M.F.L.L.W. ; Engels, B. ; Waajen, G. ; Zanten, H. van; Turlings, L. - \ 2012
    Amersfoort : Stowa (Rapport / STOWA 2012-42) - ISBN 9789057735752 - 169
    oppervlaktewaterkwaliteit - eutrofiëring - cyanobacteriën - fosfaat - aquatische ecologie - zwemwater - plassen - visbestand - stedelijke gebieden - noord-brabant - biologische behandeling - surface water quality - eutrophication - cyanobacteria - phosphate - aquatic ecology - swimming water - ponds - fishery resources - urban areas - noord-brabant - biological treatment
    Wat zijn de aanpak en maatregelen of combinaties van maatregelen, die bijdragen aan het structureel bestrijden van overlast door blauwalgen? Dat is binnen het onderzoeksproject Kansrijke Innovatieve Maatregelen Bestrijding Blauwalgenoverlast onderzocht. Dit project heeft als belangrijkste doel om meer inzicht te krijgen in de kosteneffectiviteit van veelbelovende maatregelen om interne nalevering te beteugelen. Hiertoe zijn een aantal structurele, kansrijke maatregelen voor verbetering van de oppervlaktewaterkwaliteit in plassen en stedelijk water op praktijkschaal getest, zoals in zwemplas De Kuil (Prinsenbeek) met regelmatig blauwalgenoverlast, en in twee vijvers te Dongen en Eindhoven waarin verschillende compartimenten zijn aangelegd. Hierin zijn actief biologisch beheer (visstandbeheer, waterplanten uitzetten), baggeren (al dan niet met een vlokmiddel) en chemisch P-fixatie met lanthaan gemodificeerde klei (met en zonder vlokmiddel) onderzocht.
    Controlling toxic cyanobacteria: effects of dredging and phosphorus-binding clay on cyanobacteria and microcystins
    Lürling, M.F.L.L.W. ; Faassen, E.J. - \ 2012
    Water Research 46 (2012)5. - ISSN 0043-1354 - p. 1447 - 1459.
    oppervlaktewaterkwaliteit - meren - herstelbeheer - eutrofiëring - cyanobacteriën - lanthaan - klei - vergelijkend onderzoek - aquatische ecologie - surface water quality - lakes - restoration management - eutrophication - cyanobacteria - lanthanum - clay - comparative research - aquatic ecology - rare-earth-elements - lake restoration - organic-matter - shallow lakes - sediment removal - northern poland - urban lake - blooms - water - fresh
    Sediment dredging and Phoslock(®) addition were applied individually and in combination in an enclosure experiment in a Dutch hypertrophic urban pond. These measures were applied to control eutrophication and reduce the risk of exposure to cyanobacterial toxins. Over the 58 days course of the experiment, cyanobacteria (predominantly Microcystis aeruginosa) gradually decreased until they dropped below the level of detection in the combined treated enclosures, they were reduced in dredged enclosures, but remained flourishing in controls and Phoslock(®) treated enclosures. Cyanobacteria were, however, less abundant in the enclosures (medians chlorophyll-a 30-87 µg l(-1)) than in the pond (median chlorophyll-a 162 µg l(-1)), where also a thick surface scum covered one-third of the pond for many weeks. Soluble reactive phosphorus (SRP), total phosphorus and total nitrogen concentrations were significantly lower in the combined dredged and Phoslock(®) treated enclosures than in controls. Median SRP concentrations were 24 µg P l(-1) in the combined treatment, 58 µg P l(-1) in dredged enclosures, and 90 µg P l(-1) in controls and 95 µg P l(-1) in Phoslock(®) treated enclosures. Hence, the combined treatment was most effective in decreasing SRP and TP, and in lowering cyanobacterial biomass. Microcystin (MC) concentrations were analyzed by LC-MS/MS. MC concentrations and cyanobacterial biomass were positively correlated in all treatments. Mean MC concentrations in controls (71 µg l(-1)), Phoslock(®) treated enclosures (37 µg l(-1)) and dredged enclosures (25 µg l(-1)) exceeded the provisional guideline of 20 µg l(-1), whereas mean MC concentrations were 13 µg l(-1) in the combined treated enclosures. All samples contained the MC variants dmMC-RR, MC-RR, MC-YR, dmMC-LR and MC-LR; traces of MC-LY and nodularin were detected in few samples. The different treatments did not change the relative contribution of the variants to the MC pool; MC profiles in all treatments and the pond showed dominance of MC-RR followed by MC-LR. In the surface scum of the pond, total MC concentration was extremely high (64000 µg l(-1) or 1300 µg g(-1) DW), which poses a serious health hazard to children playing on the banks of the pond. Based on our results and pond characteristics, we propose combined sediment dredging and Phoslock(®) addition, fish removal and strong reduction of duck feeding by the neighborhood as most promising measures controlling cyanobacterial hazards in this pond.
    Warmer climates boost cyanobacterial dominance in shallow lakes
    Kosten, S. ; Huszar, V.M. ; Bécares, E. ; Costa, S. ; Donk, E. van; Hansson, L. ; Lurling, M.F.L.L.W. - \ 2012
    Global Change Biology 18 (2012)1. - ISSN 1354-1013 - p. 118 - 126.
    fytoplankton - klimatologie - cyanobacteriën - temperatuur - meren - oppervlaktewaterkwaliteit - phytoplankton - climatology - cyanobacteria - temperature - lakes - surface water quality - fish community structure - trophic state - phytoplankton community - mesocosm experiments - blooms - nitrogen - nutrient - phosphorus - eutrophication
    Dominance by cyanobacteria hampers human use of lakes and reservoirs worldwide. Previous studies indicate that excessive nutrient loading and warmer conditions promote dominance by cyanobacteria, but evidence from global scale field data has so far been scarce. Our analysis, based on a study of 143 lakes along a latitudinal transect ranging from subarctic Europe to southern South America, shows that although warmer climates do not result in higher overall phytoplankton biomass, the percentage of the total phytoplankton biovolume attributable to cyanobacteria increases steeply with temperature.
    Klimaat & waterkwaliteit : klimaatinvloed op waterkwaliteit en het voorkomen van cyanobacteriële toxines
    Kosten, S. ; Kardinaal, E. ; Faassen, E. ; Netten, J.J.C. ; Lürling, M.F.L.L.W. - \ 2011
    Utrecht : Programmabureau Kennis voor Klimaat - 110
    waterverontreiniging - eutrofiëring - cyanobacteriën - klimaatverandering - ecotoxicologie - inventarisaties - water pollution - eutrophication - cyanobacteria - climatic change - ecotoxicology - inventories
    Zowel de fysische als de chemische en biologische toestand van oppervlaktewateren worden door klimaatverandering beïnvloed. Doordat verschillende klimaatfactoren verschillende effecten hebben, is de invloed van klimaatverandering op aquatische ecosystemen niet altijd eenduidig. Wat echter wel duidelijk is, is dat klimaatverandering eutrofiëring versterkt. Om deze negatieve effecten van klimaatverandering tegen te gaan zijn extra reducties in nutriëntenbelasting nodig. Ook is duidelijk dat hogere temperaturen leiden tot meer cyanobacteriën, met name in eutrofe wateren. Cyanobacteriën kunnen toxische stoffen produceren. De resultaten van onze studie bevestigen de aanwezigheid van een groot aantal eerder aangetroffen cyanobacteriële toxines in Nederlandse oppervlaktewateren.
    Praktijkproeven blauwalgenbestrijding in Noord-Brabant
    Waajen, G. ; Lurling, M.F.L.L.W. ; Engels, B. ; Zanten, H. van - \ 2010
    H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 43 (2010)5. - ISSN 0166-8439 - p. 60 - 63.
    waterkwaliteit - eutrofiëring - cyanobacteriën - fosfaten - onderzoeksprojecten - stedelijke gebieden - oppervlaktewaterkwaliteit - waterschappen - maatregelen - zwemwater - noord-brabant - water quality - eutrophication - cyanobacteria - phosphates - research projects - urban areas - surface water quality - polder boards - measures - swimming water - noord-brabant
    Overlast door blauwalgenbloei is een hardnekkig en veel voorkomend waterkwaliteitsprobleem. Het is niet alleen hinderlijk omdat het vaak in de woonomgeving of in zwemplassen voorkomt, maar er zijn ook risico’s voor dier- en volksgezondheid aan verbonden. Structurele bestrijding van blauwalgen blijkt in de praktijk een lastige opgave. Veel van de uitgevoerde bestrijdingsmaatregelen blijken onvoldoende effect te sorteren. Om de kennis van de effectiviteit, mogelijke neveneffecten en kosten van kansrijke maatregelen te vergroten, worden in Noord-Brabant praktijkproeven uitgevoerd. Maatregelen die worden onderzocht, zijn onder andere de recent beschikbaar gekomen Flock en Lock-methodiek, baggeren en actief biologisch beheer. De maatregelen worden in verschillende combinaties toegepast. De uitvoering van de eerste maatregelen begon in mei 2009. Het project loopt dit jaar in ieder geval door. In het onderzoek werken de Wageningen Universiteit, de waterschappen Brabantse Delta, Aa en Maas en De Dommel en STOWA samen
    Verkennend onderzoek naar blauwalgengroei in de woonomgeving : blauwalgen in stadswater
    Lürling, M.F.L.L.W. ; Oosterhout, J.F.X. ; Beekman-Lukassen, W.D. ; Dam, H. van - \ 2010
    Amersfoort : Stowa (Rapport / STOWA 2010 20) - ISBN 9789057734830 - 57
    oppervlaktewater - plassen - stedelijke gebieden - aquatisch milieu - cyanobacteriën - monitoring - inventarisaties - kwantitatieve analyse - fluorescentie - oppervlaktewaterkwaliteit - noord-brabant - gelderland - surface water - ponds - urban areas - aquatic environment - cyanobacteria - monitoring - inventories - quantitative analysis - fluorescence - surface water quality - noord-brabant - gelderland
    De leerstoelgroep Aquatische Ecologie en Waterkwaliteitsbeheer van Wageningen University is in 2006 begonnen met een inventarisatie van cyanobacteriënbloei in stedelijk water. De hoeveelheid cyanobacteriën, de soortensamenstelling, het voorkomen van drijflagen, de hoeveelheid gifstoffen en een aantal milieuvariabelen werden in kaart gebracht. Om een eerste indruk te verkrijgen van de cyanobacteriënbloei in oppervlaktewater in de woonomgeving, is in de zomer van 2006 (juli, augustus) een kleine selectie van 50 verschillende stadswateren in Noord-Brabant en Gelderland bemonsterd. Twee vijvers zijn gedurende 2006 intensiever bemonsterd om een indruk te verkrijgen van het verloop van de cyanobacteriënbloei in deze vijvers. De cyanobacteriën werden gekwantificeerd en onderscheiden van eukaryote algen met behulp van in vivo chlorofyl-a fluorescentie.
    Blauwalgen binnen het Kennis voor Klimaat programma
    Kosten, S. ; Faassen, E. ; Lurling, M. - \ 2009
    Cyano Nieuws : nieuwsbrief van de werkgroep Cyanobacteriën (2009)10. - p. 10 - 11.
    cyanobacteriën - toxinen - inventarisaties - oppervlaktewater - ecotoxicologie - cyanobacteria - toxins - inventories - surface water - ecotoxicology
    Korte beschrijving van de inventarisatie van cyanotoxines die binnen het Kennis voor Klimaat Programma uitgevoerd gaat worden in Nederlandse oppervlaktewateren, om een indruk te krijgen welke toxines waar en onder welke omstandigheden voorkomen.
    HSOV01B : Invloed van klimaat op waterkwaliteit: welke trends zijn al zichtbaar?
    Kosten, S. - \ 2009
    klimaatverandering - waterkwaliteit - oppervlaktewater - cyanobacteriën - onderzoeksprojecten - climatic change - water quality - surface water - cyanobacteria - research projects
    Poster gepresenteerd op de projectendag KvK (sptember 2009) over project HSOV01b (onderdeel van het programma Kennis voor Klimaat) dat onderzoekt welke effecten ten gevolge van klimaatsverandering al zichtbaar zijn in oppervlakte wateren en welke implicaties dit heeft voor het behalen van verschillende ecologische en gebruiksdoelen. Tevens worden de verspreiding en concentraties van verschillende typen blauwalgentoxines onderzocht.
    Flock & Lock in De Rauwbraken : strandbad en onderwaterpark : een innovatief experiment om blauwalgenbloei te voorkomen door vastleggen van fosfaat
    Lürling, M.F.L.L.W. ; Oosterhout, J.F.X. - \ 2009
    Wageningen : Wageningen UR, Lsg Aquatische Ecologie & Waterkwaliteitsbeheer (Rapport M347) - 42
    eutrofiëring - verontreinigingsbeheersing - cyanobacteriën - algen - waterkwaliteit - zwemmen - waterrecreatie - openluchtrecreatie - fosfaten - uitvlokking - uitvlokkingsmiddelen - stedelijke gebieden - oppervlaktewaterkwaliteit - zwemwater - noord-brabant - eutrophication - pollution control - cyanobacteria - algae - water quality - swimming - water recreation - outdoor recreation - phosphates - flocculation - flocculants - urban areas - surface water quality - swimming water - noord-brabant
    Na twee jaar intensieve voorbereiding, is in april 2008 strandbad De Rauwbraken bij Tilburg behandeld met een vlokmiddel en een gemodificeerde klei om een einde te maken aan de toenemende blauwalgenoverlast. Sinds 2000 wordt in de Rauwbraken een toenemende bloei van blauwalgen waargenomen. Door deze bloei treedt een overschrijding van de zwemwaterkwaliteitsnorm op. De behandeling was gericht op een sterke reductie van de hoeveelheid blauwalgen door het wegvangen van de belangrijkste voedselbron fosfaat.
    Lake and watershed characteristics rather than climate influence nutrient limitation in shallow lakes
    Kosten, S. ; Huszar, V.M. ; Mazzeo, N. ; Scheffer, M. ; Sternberg, L.S.L. ; Jeppesen, E. - \ 2009
    Ecological Applications 19 (2009)7. - ISSN 1051-0761 - p. 1791 - 1804.
    waterkwaliteit - voedingsstoffen - meren - stikstof - fosfor - cyanobacteriën - eutrofiëring - herstel - klimaat - zuid-amerika - primaire productie - water quality - nutrients - lakes - nitrogen - phosphorus - cyanobacteria - eutrophication - rehabilitation - climate - south america - primary production - phytoplankton community structure - fresh-water - meteoric precipitation - nitrogen-retention - subtropical lakes - trophic state - danish lakes - n-p - denitrification
    Both nitrogen (N) and phosphorus (P) can limit primary production in shallow lakes, but it is still debated how the importance of N and P varies in time and space. We sampled 83 shallow lakes along a latitudinal gradient (5°–55° S) in South America and assessed the potential nutrient limitation using different methods including nutrient ratios in sediment, water, and seston, dissolved nutrient concentrations, and occurrence of N-fixing cyanobacteria. We found that local characteristics such as soil type and associated land use in the catchment, hydrology, and also the presence of abundant submerged macrophyte growth influenced N and P limitation. We found neither a consistent variation in nutrient limitation nor indications for a steady change in denitrification along the latitudinal gradient. Contrary to findings in other regions, we did not find a relationship between the occurrence of (N-fixing and non-N-fixing) cyanobacteria and the TN:TP ratio. We found N-fixing cyanobacteria (those with heterocysts) exclusively in lakes with dissolved inorganic nitrogen (DIN) concentrations of
    Analyse van monsters uit Almere op aanwezigheid cyanotoxines
    Lürling, M.F.L.L.W. - \ 2009
    Wageningen : WUR Aquatische Ecologie en Waterkwaliteitsbeheer - 6
    cyanobacteriën - toxinen - neurotoxinen - cytotoxinen - microcystis - hepatotoxinen - monsters - slib - havens - analyse - flevoland - cyanobacteria - toxins - neurotoxins - cytotoxins - microcystis - hepatotoxins - samples - sludges - harbours - analysis - flevoland
    Er worden verschillende groepen van cyanotoxines onderscheiden, waarvan op basis van de werking de neurotoxines, cytotoxines en hepatotoxines de belangrijkste zijn. Dit document beschrijft de resultaten van een spoedanalyse van twee potten met drijflaagmateriaal uit de omgeving van Almere-Haven, met cyanobacteriënmateriaal op aanwezigheid van cyanotoxines. In opdracht van RWS en de gemeente Almere is het aangeleverde materiaal geanalyseerd op microcystines, saxitoxine en cylindrospermopsine.
    Laboratory experiments testing the effectiveness of the commercially available product PoCo in mitigating cyanobacterial blooms and decomposing organic matter
    Lürling, M.F.L.L.W. ; Kosten, S. - \ 2009
    Wageningen : Wageningen University (Aquatic Ecology Memo reports M349) - 17
    waterverontreiniging - cyanobacteriën - meren - katalysatoren - tests - eutrofiëring - mineralisatie - daphnia - paraguay - waterzuivering - biokatalyse - ecologisch herstel - water pollution - cyanobacteria - lakes - catalysts - tests - eutrophication - mineralization - daphnia - paraguay - water treatment - biocatalysis - ecological restoration
    The Dutch company WiseUse International BV has proposed using a so-called bio stimulator “PoCo” (Pollution Control) in ecological restoration of Lake Ypacarai (Paraguay). In this study results of laboratory assays are reported testing the performance of PoCo regarding the alleged enhanced mineralization of organic matter in the water phase and sediment, the inhibition of cyanobacterial growth (as a clear measure counter acting the symptoms of eutrophication) and effects on survival of the waterflea Daphnia.
    Blauwalgen: giftig groen
    Lürling, M.F.L.L.W. ; Dam, H. van; Wal, B. van der - \ 2009
    Utrecht : Stowa (Rapport / STOWA 2009 43) - ISBN 9789057734663 - 48
    cyanobacteriën - waterkwaliteit - oppervlaktewater - toxinen - effecten - volksgezondheid - klimaatverandering - temperatuur - oppervlaktewaterkwaliteit - cyanobacteria - water quality - surface water - toxins - effects - public health - climatic change - temperature - surface water quality
    De laatste paar jaar waren de zomers niet zo heet, maar in de recordwarme zomers van 2003 en 2006 waren de signalen overduidelijk: op veel plaatsen werd intensieve bloei van cyanobacteriën (‘blauwalgen’) gesignaleerd. De laatste decennia is de temperatuur van het Nederlandse oppervlaktewater al een paar graden toegenomen en volgens de gangbare klimaatscenario’s zal de temperatuurstijging nog wel even doorgaan; ten gunste van de cyanobacteriën. Behalve visuele, geur- en stankoverlast zijn cyanobacteriën bekend om de productie van gifstoffen, die schadelijk zijn voor de gezondheid van mens en dier. Maar ook blijken de cyanobacteriën aan de basis van de evolutie van het leven op aarde te staan, met een voor zulke primitieve organismen opvallen rijkdom aan vormen. De verschillende soorten zijn aangepast aan het leven in een groot aantal, soms zeer verschillende milieus, van droge woestijnbodems tot in hete bronnen. In deze brochure wordt de achtergrondkennis over cyanobacteriën op een rijtje gezet, niet alleen ten behoeve van de bestuurders, de makers van het waterbeleid en de waterbeheerders, maar ook voor de onderzoekers. Gezamenlijk spannen deze groeperingen zich in diverse verbanden in om vat te krijgen op de precieze mechanismen die de bloei van cyanobacteriën veroorzaken, om de aard en werking van de gifstoffen te achterhalen en om voorspellingsmodellen voor cyanobacteriën te ontwikkelen. Dat om de gezondheidsrisico’s van de cyanobacteriën zoveel mogelijk het hoofd te bieden.
    Complexiteit van nutriëntenlimitaties in oppervlaktewateren
    Loeb, R. ; Verdonschot, P.F.M. - \ 2009
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 128)
    eutrofiëring - voedingsstoffen - oppervlaktewater - ecohydrologie - beperkende factoren - koolstof - fosfor - stikstof - silicium - fytoplankton - algen - cyanobacteriën - kwaliteitscontroles - kaderrichtlijn water - aquatische ecosystemen - eutrophication - nutrients - surface water - ecohydrology - limiting factors - carbon - phosphorus - nitrogen - silicon - phytoplankton - algae - cyanobacteria - quality controls - water framework directive - aquatic ecosystems
    Voor het oplossen van eutrofiëringsproblemen is het van belang te weten welk nutriënt er sturend is voor het optreden van deze effecten. In aquatische systemen is de bepaling van het groeilimiterende (sturende) nutriënt lastig, doordat toename van dit nutriënt niet noodzakelijkerwijs gepaard gaat met biomassatoename vanwege interacties met lichtlimitatie. Uit literatuur blijkt dat fosfor, zoals werd aangenomen, het nutriënt is dat het vaakst limiterend is voor algenbloei. Ook limitering door stikstof, koolstof en silicium komen echter voor. Voor het behoud van karakteristieke soorten water- en oeverplanten en van de biodiveristeit, zoals wordt vereist door de Kaderrichtlijn Water, is stikstof echter ook van groot belang.
    Eco-hydrodynamic modelling of primary production in coastal waters and lakes using BLOOM
    Los, F.J. - \ 2009
    Wageningen University. Promotor(en): Marten Scheffer. - S.l. : S.n. - ISBN 9789085853299 - 276
    ecologie - wiskundige modellen - simulatiemodellen - kustwateren - meren - algen - cyanobacteriën - aquatische ecologie - aquatische ecosystemen - volkerak-zoommeer - voordelta - ecology - mathematical models - simulation models - coastal water - lakes - algae - cyanobacteria - aquatic ecology - aquatic ecosystems - volkerak-zoommeer - voordelta
    Met BLOOM wordt de hoeveelheid en samenstelling van algen uitgerekend in relatie tot de beschikbaarheid van voedingsstoffen, de hoeveelheid licht in het water en begrazing. In vergelijking tot de meeste andere operationele modellen beschouwt BLOOM een relatief groot aantal algensoorten en werkt het volgens een alternatief competitieprincipe. De rekentijd van het model is relatief kort, wat ervoor zorgt dat kan worden ingezet voor complexe systemen en langjarige berekeningen. BLOOM wordt wereldwijd toegepast op meren, stelsels van kanalen, zeearmen, lagunes en kustzeeën. Recente toepassingen betreffen de aanleg van de tweede Maasvlakte, analyse van de gevolgen van de stormvloedkering op de Lagune van Venetië en de milieu-effectrapportage van het Volkerak Zoommeer, waar het gaat om de vraag of dit zoet moet blijven of weer zout moet worden. Hoewel het model maar een deel van het aquatische ecosysteem nabootst, blijken de resultaten toch nauwkeurig genoeg om managers van waardevolle informatie te voorzien
    De beleving van grote wateren : de invloed van een aaantal man-made elementen onderzocht
    Vries, S. de; Boer, T.A. de; Goossen, C.M. ; Wulp, N.Y. van der - \ 2008
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-rapport 64) - 98
    mariene gebieden - meren - perceptie - gebouwen - jachthavens - turbines - cyanobacteriën - kustgebieden - omgevingspsychologie - menselijke invloed - marine areas - lakes - perception - buildings - marinas - turbines - cyanobacteria - coastal areas - environmental psychology - human impact
    De invloed van boorplatforms, windturbines, hoogbouw aan de kust, jachthavens en vooroevers op de beleving van grote wateren is onderzocht. Als enige niet man-made element is blauwalg meegenomen. De beleving beperkt zich hier tot de waardering voor de visuele component. Door middel van (gemonteerde) foto’s kreeg de ene groep de situatie met het element voorgelegd, een andere zonder. Ongeveer 2300 leden van een consumentenpanel, verdeeld over vier groepen, namen via het internet deel aan het onderzoek. Elke groep beoordeelde 30 foto’s. Boorplatforms hebben de grootste negatieve impact, gevolgd door windturbines en daarna hoogbouw. Vooroevers hebben als enige gemiddeld een (licht) positieve impact. De negatieve impact bleek groter naarmate de situatie zonder element aantrekkelijker werd gevonden. Systematische variaties van de verschijningsvorm van een element lieten zien dat de ‘stap’ van niet naar wel aanwezig zijn het grootste effect opleverde: de negatieve impact nam slechts gering toe met de variabelen nabijheid, grootte en aantal van het element. Trefwoorden: belevingswaarde, grote wateren, boorplatforms, windturbines, hoogbouw, jachthavens, vooroevers, blauwalg
    Climate change and bathing water quality
    Roijackers, R.M.M. ; Lürling, M.F.L.L.W. - \ 2007
    Wageningen : Wageningen UR - 39
    waterkwaliteit - oppervlaktewater - zwemmen - waterrecreatie - volksgezondheid - eu regelingen - richtlijnen (directives) - pathogenen - cyanobacteriën - klimaatverandering - algen - nederland - kaderrichtlijn water - oppervlaktewaterkwaliteit - zwemwater - water quality - surface water - swimming - water recreation - public health - eu regulations - directives - pathogens - cyanobacteria - climatic change - algae - netherlands - water framework directive - surface water quality - swimming water
    In the new European bathing water directive, 2006/7/EG, two microbiological indicators, i.e. intestinal enterococci and Escherichia coli, are used to assess the state of the official outdoor bathing waters. In this directive also cyanobacteria are included, being a cause of insufficient bathing water quality. Climate change will affect bathing water quality with respect to both the number of pathogens and cyanobacteria, as well as their impact on human health. It is to be expected that by 2050, compared to 1990, the winters in The Netherlands will be milder and wetter, the summers will be warmer, with less frequent, but more intensive showers, thus increasing the chance for flooding and the growing season will be longer. It is most probable that these changes in climate will have effects on the health risk for bathing in surface waters. Therefore, a literature study was made to investigate the impact of climate change on bathing water quality and the applicability of the new European bathing water directive for The Netherlands
    Onderzoek naar bestrijding van blauwalgen door middel van 'Effectieve micro-organismen'
    Lürling, M.F.L.L.W. ; Euwe, M. ; Tolman, Y. - \ 2007
    Wageningen : WUR (Rapport / Wageningen UR, Leerstoelgroep Aquatische Ecologie & Waterkwaliteitsbeheer M342) - 71
    cyanobacteriën - waterkwaliteit - verontreinigingsbeheersing - preventie - stedelijke gebieden - randmeren - zuidelijk flevoland - cyanobacteria - water quality - pollution control - prevention - urban areas - randmeren - zuidelijk flevoland
    Door uitwisseling van nutriënten en deeltjes beïnvloedt het Gooimeer in grote mate de waterkwaliteit in Almere-Haven. Doordat de totale biomassa van ‘s zomers in het Gooimeer drijvende blauwalgen hoog is, kan er opeenhoping van grote hoeveelheden blauwalgen in de havenkom van Almere-Haven plaatsvinden. Dit gebeurde in 2006 en in mindere mate in 2007, ondanks allerlei in 2007 getroffen effectgerichte maatregelen. De opeenhopingen van blauwalgen zijn onwenselijk vanwege de mogelijke overlast (stank) en gezondheidsrisico’s. Aanvullende maatregelen lijken gewenst. Om inzicht te krijgen in de effectiviteit, het werkingsmechanisme en eventuele neveneffecten van één van de in 2007 vooralsnog afgevallen mogelijke bestrijdingsmethodes van overmatige blauwalgenbloei, de Effectieve Micro-organismen (EM) modderballen is gericht onderzoek gedaan door middel van laboratoriumexperimenten met de EM-modderballen
    Long-term bioconcentration kinetics of hydrophobic chemicals in Selenastrum capricornutum and Microcystis aeruginosa
    Koelmans, A.A. ; Woude, H. van der; Hattink, J. ; Niesten, D.J.M. - \ 1999
    Environmental Toxicology and Chemistry 18 (1999). - ISSN 0730-7268 - p. 1164 - 1172.
    benzeen - chloride - polychloorbifenylen - hydrofobiciteit - waterverontreiniging - microcystis aeruginosa - algen - cyanobacteriën - ecotoxicologie - bioaccumulatie - aquatische ecosystemen - benzene - chloride - polychlorinated biphenyls - hydrophobicity - water pollution - microcystis aeruginosa - algae - cyanobacteria - ecotoxicology - bioaccumulation - aquatic ecosystems
    Sediment transport, light and algal growth in the Markermeer : a two-dimensional water quality model for a shallow lake
    Duin, E.H.S. van - \ 1992
    Agricultural University. Promotor(en): L. Lijklema. - Lelystad : Directoraat-Generaal Rijkswaterstaat, Directie Flevoland - ISBN 9789036910965 - 274
    meren - reservoirs - plassen - water - sediment - cyanobacteriën - algen - hydrologie - limnologie - fysische eigenschappen - waterkwaliteit - waterbeheer - straling - licht - lichtdoorlating - reflectie - refractie - absorptie - emissie - groei - plantenontwikkeling - modellen - onderzoek - oscillatoria agardhii - nederland - schizophyceae - optica - biologische eigenschappen - flevoland - waterbodems - lakes - reservoirs - ponds - water - sediment - cyanobacteria - algae - hydrology - limnology - physical properties - water quality - water management - radiation - light - light transmission - reflection - refraction - absorption - emission - growth - plant development - models - research - oscillatoria agardhii - netherlands - schizophyceae - optics - biological properties - water bottoms - flevoland

    This thesis reports on a study of the water quality in the Markermeer, focusing on the relationships between sediment transport, the light field and the growth of Oscillatoria agardhii . The study comprises two aspects: an extensive data collection program with the data analysis, and the development, calibration and application of a set of dynamic models, in order to assess the effect of management measures on these water quality aspects.

    The data collection program contained weekly and hourly monitoring of water quality variables. Characteristics of the sediment and characteristics of the light field were measured in fall velocity experiments with various sediment samples. Experiments were conducted with light and dark bottles and with a large perspex cylinder filled with Oscillatoria agardhii and placed in the lake. These experiments produced information on the growth characteristics of Oscillatoria agardhii in the Markermeer and on different kinds of adaptation of growth parameters to the light conditions.

    The model that has been developed to simulate the effect of management measures on the water quality of the Markermeer focusing on the effect of Oscillatoria agardhii , combines a sediment transport model (STRESS-2d), a light attenuation routine (CLEAR) and a growth model for Oscillatoria agardhii (ALGA). With the integrated model the effect of two management scenarios has been evaluated: the construction of the Markerwaard and increased flushing with water from the IJsselmeer.

    Modelling photosynthesis and oxygen in a shallow hypertrophic lake.
    Duin, E.H.S. van; Lijklema, L. - \ 1989
    Ecological Modelling 45 (1989). - ISSN 0304-3800 - p. 243 - 260.
    algen - computersimulatie - cyanobacteriën - eutrofiëring - hydrobiologie - meren - modellen - nederland - voedingsstoffen - fotosynthese - plassen - onderzoek - reservoirs - simulatie - simulatiemodellen - trofische graden - water - waterverontreiniging - waterkwaliteit - schizophyceae - algae - computer simulation - cyanobacteria - eutrophication - hydrobiology - lakes - models - netherlands - nutrients - photosynthesis - ponds - research - reservoirs - simulation - simulation models - trophic levels - water - water pollution - water quality - schizophyceae
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