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
University. Promotor(en): Marten Scheffer, co-promotor(en): Miguel Lurling. - 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.

Optimaliseren herinrichting van diepe plassen : Technisch achtergronddocument bij de MCA Verondiepen, een multicriteria-instrument om locatiekeuze en inrichtingsvariant te optimaliseren
Lange, H.J. de; Gylstra, R. ; Huijsmans, T. ; Huijsmans, T. ; Sluiter, H. ; Timmermans, F. ; Besse-Lototskaya, A.A. ; Brink, N.W. van den - \ 2015
Alterra, Wageningen-UR (Stowa rapport 2015-40) - 48 p.
plassen - zandafgravingen - publieke participatie - baggerspeciedepots - natuurontwikkeling - waterkwaliteit - ponds - sand pits - public participation - spoil banks - nature development - water quality
Het nuttig toepassen van grond of baggerspecie kan als kans worden gezien in gebiedsontwikkeling of natuurontwikkeling in en rond een diepe plas. Om een optimale keuze voor inrichting en functie te kunnen maken, moeten verschillende aspecten worden afgewogen. Hiervoor is de MCA Verondiepen ontwikkeld, een multicriteria-instrument om stakeholders op een gestructureerde wijze een analyse te kunnen doen van de huidige functie en kwaliteit, impact van herinrichting, en mogelijke nieuwe functie en kwaliteit. De toepassing van de MCA Verondiepen wordt geïllustreerd aan de hand van verschillende praktijkvoorbeelden. Dit document bevat achtergrondinformatie bij een excelinstrument.
Microalgae diets for landbased aquaculture of the cockle Cerastoderma edule: impacts of dietary fatty acids on growth
Reis Batista, I.C. dos - \ 2015
University. Promotor(en): Aad Smaal, co-promotor(en): Johan Kamermans; Rene Wijffels. - Wageningen : Wageningen University - ISBN 9789462575875 - 132
schaaldieren - schaal- en schelpdierenteelt - algen - voedering - voersamenstelling - diëten - vetzuren - groei - tanks - plassen - aquacultuur - shellfish - shellfish culture - algae - feeding - feed formulation - diets - fatty acids - growth - ponds - aquaculture

Land-based shellfish culture as a part of a multi-trophic aquaculture systems has yet to be implemented in Europe. Recently the pilot project Zeeuwse Tong (The Netherlands) evaluated the feasibility of a system of fish (Dover sole), ragworms, phytoplankton and bivalves. This thesis focused on the dietary fatty acids impact on growth, survival and fatty acid composition of juveniles (shell length >5mm) of the common cockle Cerastoderma edule, for land-based culture.

Dietary fatty acids were chosen as the main nutritional research subject given the existing literature indicating their importance for reproduction, and growth and survival of larvae, post-larvae, spat and seed of most bivalves. However, since grow-out of juvenile cockles in land-based aquaculture is not common, no information is available on the dietary fatty acid requirements of juveniles. To determine if the presence of specific fatty acids is more important for growth and survival of juvenile cockles than the total amount of dietary fatty acids supplied, least cost linear programming was used to design live microalgae diets. Monocultures of indigenous algae were grown under controlled conditions and sampled to determine their quality in terms of dry weight, organic matter, lipid and fatty acids composition. These differences in biochemical composition of the microalgae were used in a least-cost programming software, and allowed the formulation of three diets with different fatty acid contents, but similar dry weight, organic matter, lipid and total fatty acid content. The formulated diets were then used to determine the importance of dietary fatty acids for growth, survival and fatty acid composition of juvenile cockles (Cerastoderma edule). Juvenile cockles (6.24±0.04 mm) were constantly fed live microalgal diets with similar lipid, organic matter and total fatty acid contents but different individual fatty acid concentrations: high-EPA, no-DHA and low-ARA diets. Growth was positively affected by high-EPA and low-ARA diets, whereas no significant growth was observed for the no-DHA diet. However, high mortality of cockles fed no-DHA diet and the low absorption efficiency and clearance rate of this diet indicate that this diet is unsuitable for juvenile cockles. In balanced diets with EPA and DHA, lower concentrations of ARA did not limit growth. The combination of EPA and DHA in a live microalgae diet was beneficial for the growth and survival of juvenile cockles, but no conclusion on the importance of supplying only EPA could be made. To address this, an additional growth experiment was designed. Growth and fatty acid profiles of juveniles cockles were determined after 28 days of feeding diets:1) with EPA 2) with DHA; 3) with EPA and DHA from a mixture of a diatom with a green algae; 4) with EPA and DHA from a mixture of the two green algae and 5) without long-chain (>C20) fatty acids. Significantly higher growth rate was observed with the treatment rich in EPA, while the lowest growth rates were found in without EPA. These results indicate that EPA is necessary for the short-term growth of cockles. Moreover, the fatty acid profile of the polar lipids confirmed that, like most marine invertebrates, juvenile C. edule are not able to biosynthesize EPA and DHA from 18:3n-3 but are capable of biosynthesizing diene and triene NMI fatty acids. The occurrence of the NMI fatty acids was diet related, thus refuting the possibility of production of NMI as replacement for EPA and DHA.

Furthermore, in order to develop land-based culture of cockles it is crucial to have a supply of high quality live microalgal diets produced with minimum effort. Therefore, the use of simplified microalgae media, with different nitrogen sources (nitrate or ammonium) and molar N:P ratio, phosphorus, silica, iron, manganese and vitamins were also investigated. Chaetoceros muelleri, a marine diatom that was chosen given its robustness and quality as food for juvenile cockles, reacted positively to all simplified media. At the exponential phase, all cultures had reached similar cellular concentrations and dry weight productions. Cultures grown on ammonium media had a longer cultivation period, 20 days. Considering dry-weight production, culture duration, nutrient efficiency and lipid composition, the simplified media containing ammonium, phosphorus, silica, iron, manganese and vitamins proved to be a viable choice for batch culture of C. muelleri. The choice between these two media depends on the final purpose of the microalgae cultures and whether lipid contents (NH49:1), dry weight biomass (NH425:1) or nitrogen input and output (NH49:1) are more important.

In this thesis it was demonstrated that mono-algal diets with high EPA, as well as mixed live microalgae diets with high EPA and DHA contents proved to be suitable diets for C. edule juveniles. In addition, a positive relation between growth and the amount fed was found. The growth rates of the cultured cockles in this thesis are in accordance with the rates observed under natural conditions. The use of the simplified microalgae culture medium tested represents a significant decrease in the cost and preparation of the medium, as well as longer production and harvest periods, while maintaining microalgae quality. These results indicate that land-based aquaculture of cockles and microalgae is therefore a promising venture, with potential for expansion.

Eerste gekweekte rivierkreeften uitgezet
Ramaker, R. ; Ottburg, F.G.W.A. - \ 2015
Resource: weekblad voor Wageningen UR 9 (2015)18. - ISSN 1874-3625 - p. 9 - 9.
rivierkreeft - aquatische ecologie - herintroductie van soorten - bedreigde soorten - habitats - plassen - veluwe - crayfish - aquatic ecology - reintroduction of species - endangered species - ponds
Voor het eerst zijn gekweekte Europese rivierkreeften uitgezet in de Nederlandse natuur. De Europese rivierkreeft kwam tot voor kort nog slechts voor in één Nederlandse vijver en het leek slechts een kwestie van tijd tot de soort uit ons land zou verdwijnen. Een kweekprogramma moet nu de Europese rivierkreeft behouden voor Nederland. Sommige oorzaken van de teruggang in Europese rivierkreeften zijn inmiddels weggenomen, maar de kreeftenpest vormt nog steeds een grote bedreiging.
Een peilbuis in de voortuin: monitoren doe je samen
Breman, B.C. ; Groot, M. de; Ottow, B. ; Rip, W. - \ 2015
H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 47 (2015)7/8. - ISSN 0166-8439 - p. 46 - 47.
waterstand - plassen - monitoring - maatschappelijke betrokkenheid - bewonersparticipatie - utrecht - water level - ponds - community involvement - community participation
In 2008 wekte de invoering van flexibel peilbeheer in de Loosdrechtse Plassen veel wantrouwen. Om het draagvlak en de relaties te verbeteren gingen de waterbeheerders samen met mensen uit het gebied uitgebreid monitoren. Dat ging zo ver dat particulieren peilbuizen in de tuin kregen, en metingen verzorgden.
MCA Verondiepen: multicriteria-instrument voor locatiekeuze en inrichting bij het verondiepen van diepe plassen
Lange, H.J. de; Gylstra, R. ; Huijsmans, T. ; Nusselein, T. ; Verbeek, S. - \ 2014
veengebieden - plassen - stort - grondverzet - baggerspeciedepots - beslissingsondersteunende systemen - peatlands - ponds - spoil - earth moving - spoil banks - decision support systems
Het nuttig toepassen van grond of baggerspecie kan als kans worden gezien in gebiedsontwikkeling of natuurontwikkeling in en rond een diepe plas. Om een optimale keuze voor inrichting en functie te kunnen maken, moeten verschillende aspecten worden afgewogen. Hiervoor is de MCA Verondiepen ontwikkeld, een multicriteria-instrument om stakeholders op een gestructureerde wijze mee te laten denken over de huidige functie en kwaliteit, impact van herinrichting, en mogelijke nieuwe functie en kwaliteit. De toepassing van de MCA Verondiepen wordt geïllustreerd aan de hand van vijf praktijkvoorbeelden.
FOCUS_TOXSWA manual 4.4.2 : User’s Guide version 4
Beltman, W.H.J. ; Horst, M.M.S. ter; Adriaanse, P.I. ; Jong, A. de; Deneer, J.W. - \ 2014
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 14) - 130
toxicologie - waterverontreiniging - waterbodems - pesticiden - waterlopen - plassen - modellen - toxicology - water pollution - water bottoms - pesticides - streams - ponds - models
The FOCUS_TOXSWA model calculates exposure concentrations of pesticides and their metabolites in watercourses and ponds. These concentrations are used in the pesticide registration procedure at EU level. The model concepts of TOXSWA are described briefly. The input files, output files, and the use of the graphical user interface to access the input and output are described. Input data are stored in a database. Pesticide entries resulting from drainage or runoff/erosion are accessed from separate files generated by FOCUS_MACRO and FOCUS_PRZM. Substance properties are accessed from the SPIN tool/database. Instructions for simulating a water-sediment study and a multi-year run are given
Scenario studies for algae production
Slegers, P.M. - \ 2014
University. Promotor(en): Gerrit van Straten; Rene Wijffels, co-promotor(en): Ton van Boxtel. - Wageningen : Wageningen University - ISBN 9789461738448 - 221
algen - algenteelt - ontwerp - fotobioreactoren - plassen - biomassa productie - biomassa - energiegebruik - bioproceskunde - algae - algae culture - design - photobioreactors - ponds - biomass production - biomass - energy consumption - bioprocess engineering

Microalgae are a promising biomass for the biobased economy to produce food, feed, fuel, chemicals and materials. So far, large-scale production of algae is limited and as a result estimates on the performance of such large systems are scarce. There is a need to estimate large-scale biomass productivity and energy consumption, while considering the uncertainty and complexity in such large-scale systems.

In this thesis frameworks are developed to assess 1) the productivity during algae cultivation, 2) energy consumption during the transport of resources and processing biomass to biodiesel, and 3) the frameworks are applied to estimate the impact of algae cultivation in the production of algae-based food commodities. Design, location and future scenario are applied to deal with the complexity and uncertainty arising in the various data and models used.

The first part of this thesis focuses on the development of a productivity framework for biomass production for flat panels (Chapter 2), horizontal and vertical tubular photobioreactors (Chapter 3) and raceway ponds (Chapter 4). The framework uses bio-physics-based models to simulate the light input on the reactor surface and the light gradient inside the reactor systems. The internal light gradient depends on the reactor geometry and dimensions, and the penetration of diffuse light between parallel reactors, which includes the canyon effect, and the reflection of light from the ground surface to the reactors are incorporated as well. Specific growth rates are derived from this internal light gradient based on species-specific growth characteristics. In raceway ponds the effect of the dynamic water temperature on the specific growth rate is included.

The productivity framework enables to study cultivation under a wide range of process conditions and reactor designs, even those which have not been yet developed or tested under outdoor conditions. The results show that regional weather conditions, solar angles and algae species are key factors in making the best choice for the specific reactor design. The productivity framework allows to optimise the reactor design (e.g. geometry, light path, distances between parallel units and height) to the regional light conditions and growth characteristics of the algae species of interest. The best biomass concentration for cultivation varies between the reactor design, location and algae species. We recommend to select species suited to growth well at the regional light angles and weather conditions. An initial global sensitivity analysis shows that the absorption coefficient, maximum specific growth rate and functional cross section of the photosynthetic apparatus are the essential parameters of the model for single flat panels. An important next step is to validate and calibrate the productivity framework using data from outdoor experiments in various reactor designs, at different locations and with several algae species.

Algae production is strongly connected to regional weather conditions, but also to the infrastructure for resource supply and to the processing of biomass. The energy consumption for resource supply has not been quantified yet and the energy consumption of biomass processing is mostly based on fixed values. These elements are tackled in part 2 of this thesis.

In Chapter 5the productivity framework is combined with logistic models to optimise the supply network for algae cultivation. The results show that the availability, supply and demand of resources has a dominant effect on the feasibility of regions for algae cultivation. Not all locations achieve a positive energy balance for transport and the supply logistics is essential for planning algae cultivation locations. In the Benelux many locations are feasible for algae production due to the availability of large amounts of resources, while the limited supply of CO2in southern France and the Sahara demands for plants which are scattered over the regions. For the Sahara the distance for water transport should be minimal. Still, the average transport distances are higher than commonly assumed and algae cultivation does not necessarily need to take place in proximity of CO2supply. The transport energy consumption is found to be low compared to the energy contained in algae biomass (mostly below 3%).

Chapter 6 describesa model-based combinatorial optimisation approach for the energy-efficientprocessing of algae biomass. In this approach, mass and energy balances and additional relations are used to relate the product yield and energy consumption of process units and process routes to the processing conditions. Process routes with the highest net energy ratios are derived by optimising the process conditions of each process unit in a given superstructure. This optimisation leads to 5-38% improvement of the net energy ratio compared to fixed process conditions. The approach moreover allows a bottleneck analysis for each process route. The results show that process design should be tailor-made. The model-based approach proves to be a versatile tool for the design of efficient microalgae processing systems.

The developed frameworks combined with scenario studies are a powerful tool to assess algae production. The presented approaches help to reduce the uncertainty in the interpretation of data and are thereby an appropriate basis to use in impact analysis. In Chapter 7this is illustrated for the production of algae protein and oil as food commodities. The design scenarios show the implications of various reactor designs, two algae species and at two locations on biomass productivity, production cost and environmental life cycle indicators.

The achievements of this work and the new horizons from this work are discussed in Chapter 8. The results of the developed frameworks demonstrate the power of the scenario approach and show that sensible predictions and projections of biomass productivity and energy consumption for logistics and biomass processing follow from the models.

Huidige wijze van monitoren van fecale bacteriën in zwemwater geeft geen betrouwbaar beeld van actueel gezondheidsrisico zwemmers
Lange, H.J. de; Haan, M. de; Gylstra, R. - \ 2013
H2O online 2013 (2013)31 okt.
zwemwater - waterkwaliteit - plassen - oppervlaktewater - eu regelingen - coliformbacteriën - fecale coliformen - monitoring - swimming water - water quality - ponds - surface water - eu regulations - coliform bacteria - faecal coliforms
De Europese Zwemwaterrichtlijn schrijft voor dat elke zwemplas minimaal eens per maand wordt bemonsterd op één vast meetpunt. In Nederland wordt op de meeste locaties tweewekelijks bemonsterd. Waterschap Rivierenland heeft onderzoek laten doen naar de spreiding in ruimte en tijd van de metingen. Hieruit blijkt dat de hoogste concentraties E. coli zijn gemeten in de zone het dichtst bij het strand. Het vaste meetpunt is onvoldoende representatief voor deze zone. De dagelijkse variatie in E. coli-concentratie is groot. Dit bevestigt het beeld dat de huidige wijze van monitoren niet geschikt is voor het bepalen van een actueel gezondheidsrisico. Daarvoor is een andere aanpak nodig.
Watervogels en zwemwaterkwaliteit : hoe kan het beter?
Lange, H.J. de; Lammertsma, D.R. ; Keizer-Vlek, H.E. ; Haan, M. de - \ 2013
H2O online 2013 (2013)31 okt.
zwemwater - waterkwaliteit - plassen - oppervlaktewater - coliformbacteriën - fecale coliformen - watervogels - inventarisaties - swimming water - water quality - ponds - surface water - coliform bacteria - faecal coliforms - waterfowl - inventories
Veel zwemplassen zijn vervuild met bacteriën uit uitwerpselen. Mogelijke bronnen zijn mensen, honden, paarden en watervogels. De herkomst van fecale bacteriën is echter nog niet traceerbaar. Om toch vast te stellen of vogelpoep belangrijk is voor de zwemwaterkwaliteit, verzamelde Alterra gegevens van 20 zwemplassen verspreid over Nederland. Het statistische verband tussen aantallen watervogels en concentraties van fecale bacteriën bleek significant. Bovendien waren in helder, plantenrijk water de aantallen bacteriën duidelijk lager dan in troebel water zonder waterplanten.
Replication of white spot syndrome virus (WSSV) in the polychaete Dendronereis spp
Desrina, H. ; Verreth, J.A.J. ; Prayitno, S.B. ; Rombout, J.H.W.M. ; Vlak, J.M. ; Verdegem, M.C.J. - \ 2013
Journal of Invertebrate Pathology 114 (2013)1. - ISSN 0022-2011 - p. 7 - 10.
morphogenesis - community - thailand - water - ponds - dna
This study investigated whether WSSV replicates in naturally infected Dendronereis spp., a common polychaete (Nereididae) species in shrimp ponds in Indonesia. To detect WSSV replication, (i) immunohistochemistry (IHC) using a monoclonal antibody against WSSV VP28 protein and (ii) nested RT-PCR using specific primers set for the vp28 gene to detect WSSV-specific mRNA were applied. WSSV immunoreactive-nuclei were detected in the gut epithelium of the polychaete and WSSV mRNA was detected with nested RT-PCR. This, together with the IHC results, confirmed that WSSV could replicate in Dendronereis spp. This is the first report showing that WSSV replicated in a naturally infected non-crustacean host.
Natuurkwaliteit Drentse vennen opnieuw gemeten : bijna een eeuw ecologische veranderingen
Dam, H. van; Arts, G.H.P. ; Bijkerk, R. ; Boonstra, H. ; Belgers, J.D.M. ; Mertens, A. - \ 2013
Amsterdam [etc.] : Herman van Dam Adviseur Water en Natuur [etc.] (Alterra-rapport 2351) - 286
stilstaand water - plassen - zoetwaterecologie - biochemie - macrofauna - aquatische ecologie - ecologisch herstel - zure regen - verdroging - drenthe - standing water - ponds - freshwater ecology - biochemistry - aquatic ecology - ecological restoration - acid rain - desiccation
In 2010-2011 zijn in 18 Drentse vennen inventarisaties uitgevoerd van beïnvloeding en beheer, waterstandsfluctuaties, waterchemie, vegetatie, kiezelwieren, sieralgen en macrofauna. De resultaten worden vergeleken met die van vergelijkbare inventarisaties in 1990 – 1994 en 2003. In de afgelopen dertig jaar is de kwaliteit van de onderzochte vennen aanzienlijk toegenomen, vooral door de afname van verzurende atmosferische depositie, maar ook door maatregelen tegen eutrofiëring zoals het uitbaggeren van vennen en het bestrijden van meeuwenkolonies. Ook anti-verdrogingsmaatregelen hebben rendement opgeleverd. Gemiddeld is de kwaliteit van de vegetatie, sieralgen en kiezelwieren nu even goed als of zelfs beter dan in de eerste helft van de twintigste eeuw. In de meeste vennen is de kwaliteit van de macrofauna sinds begin jaren negentig niet vooruitgegaan, mogelijk door het slechte koloniserende vermogen van veel macrofaunasoorten, de zuurstofarme waterbodem met toxische zwavelverbindingen en een eventuele ontoereikende omgevingskwaliteit van de vennen. In sommige vennen draagt externe belasting door overnachtende ganzen bij tot eutrofiëring. In vennen waar dat niet het geval is treedt soms interne eutrofiëring op. Door stijging van de pH door afname van verzuring wordt organische stof uit het sediment gemineraliseerd en komen voedingsstoffen vrij in de waterlaag. Vooral in de laatste vijf jaar heeft dat tot achteruitgang van de kwaliteit van algen en macrofauna geleid. Er worden aanbevelingen voor beheer en onderzoek gedaan, zoals het continueren van het huidige beheer, aangevuld met het opnieuw graven van veenputten in dichtgroeiende vennen, het beperken van de invloed van ganzen en grazende runderen en het voorkómen van invasies van exoten. Om de effecten van beleidsmaatregelen en beheer in de toekomst te blijven volgen wordt aanbevolen het onderzoek in alle vennen elke 10-12 jaar te herhalen, aangevuld met frequentere monitoring in een klein aantal vennen.
Verspreiding van de Bittervoorn langs de Maas in Noord-Limburg: Incidaties voor een regionale metapopulatiestructuur.
Pollux, B.J.A. ; Korosi, A. ; Pollux, P.M.J. - \ 2012
Natuurhistorisch Maandblad 101 (2012). - ISSN 0028-1107 - p. 116 - 121.
vissen - plassen - uiterwaarden - inventarisaties - noord-limburg - fishes - ponds - river forelands - inventories
In dit artikel wordt de verspreiding van de Bittervoorn (Rhodeus sericeus amarus Bloch 1782) in 15 uiterwaardplassen langs de Maas in Noord-Limburg beschreven. Deze werden gedurende de jaren 2010 en 2011 vijfmaal bemonsterd. De Bittervoorn is in tien van de 15 plassen aangetroffen. In negen ervan zijn tijdens schepnetbemonsteringen ook grote zoetwatermosselen opgeschept, wat doet vermoeden dat deze algemeen in de uiterwaarden voorkomen. De aanwezigheid van zoetwatermosselen is, door de unieke paarsymbiose tussen beide soorten, een voorwaarde voor succesvolle voortplanting van de Bittervoorn. Op basis van vangsten van kleine pas uit het ei gekomen vissen blijkt dat de Bittervoorn zich in 2011 in vijf uiterwaardplassen heeft voortgeplant. Tot slot wordt inzichtelijk gemaakt dat de Bittervoornpopulaties in de uiterwaarden een aantal kenmerken vertonen die karakteristiek zijn voor een metapopulatie.
Environmental comparison of intensive and integrated agriculture-aquaculture systems for striped catfish production in the Mekong Delta, Vietnam, based on two existing case studies using life cycle assessment
Kluts, I.N. ; Potting, J.M.B. ; Bosma, R.H. ; Phong, L.T. ; Udo, H.M.J. - \ 2012
Reviews in Aquaculture 4 (2012)4. - ISSN 1753-5123 - p. 195 - 208.
impact - water - ponds
Vietnam is the largest producer for the export of striped catfish. Traditionally striped catfish production in the Mekong Delta took place in integrated agriculture–aquaculture systems, but has shifted recently to intensive systems to meet increasing export demands. A recent study quantified the environmental impact of intensive striped catfish production in Vietnam. Another did the same for integrated systems. Both studies used life cycle assessment, covered similar environmental impact categories, and were roughly matched in the production stages included. However, an environmental comparison of both systems has not been made so far. The objective of this paper is to make a comparative life cycle assessment of striped catfish production in intensive and integrated systems. The comparison was based on existing life cycle assessments on these systems, but their methodological choices and data had to be aligned. The results show that striped catfish production in intensive systems contributes considerably more to seven of the nine assessed impact categories (global warming, ozone depletion, acidification, eutrophication, photochemical oxidation, human toxicity, freshwater ecotoxicity, marine aquatic ecotoxicity, fossil depletion). Only contributions to eutrophication and freshwater ecotoxicity were higher for the integrated systems than for the intensive systems. In both systems, grow-out fish farming contributes most to eutrophication and freshwater ecotoxicity, whereas feed production contributes most to all other impact categories. The environmental performance of integrated striped catfish production is convincingly better in most impact categories. This raises questions about whether (elements of) these systems can be used to mitigate the environmental impact of intensive striped catfish production.
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 - 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.
Plan voor behoud rivierkreeft
Ottburg, Fabrice - \ 2012
crayfish - biodiversity - nature conservation policy - habitats - ponds
Het storten van bagger in diepe zandwinputten is nadelig voor de visstand
Harmsen, J. ; Bierman, H. ; Zoetemeyer, B. - \ 2012
Visionair : het vakblad van sportvisserij Nederland 15 (2012). - ISSN 1569-7533 - p. 36 - 38.
zandafgravingen - plassen - bagger - baggerspeciedepots - ecologische verstoring - dierenwelzijn - opinies - visstand - aquatische ecologie - mens-dier relaties - sand pits - ponds - dredgings - spoil banks - ecological disturbance - animal welfare - opinions - fish stocks - aquatic ecology - human-animal relationships
Het storten van bagger in diepe zandwinputten lijkt een eenvoudige en goedkope oplossing voor het baggerprobleem. Deze zandwinputten zijn echter ook onderdeel van het leefmilieu voor vissen. Kun je dan zo maar bagger gaan storten? De deskundigen verschillen van mening
Europese rivierkreeften in Nederland : vaststellen, veiligstellen, versterken en veilige leefgebieden
Ottburg, F.G.W.A. ; Roessink, I. - \ 2012
Wageningen : Alterra (Alterra-rapport 2341) - 41
rivierkreeft - biodiversiteit - natuurbeleid - natuurbescherming - habitats - plassen - waterlopen - nederland - crayfish - biodiversity - nature conservation policy - nature conservation - ponds - streams - netherlands
De Europese rivierkreeft is een bedreigde diersoort in Nederland waarvoor men maatregelen moet nemen in het kader van internationale afspraken voor behoud van biodiversiteit. Het voorliggende rapport geeft antwoord op de vraag wat de slagingskans is voor het voortbestaan van de Europese rivierkreeft in Nederland en welke inzet hiervoor nodig is. Dit rapport geeft ook een visie om te kunnen komen tot duurzame populaties van Europese rivierkreeften in Nederland. Deze visie bestaat uit de vier V’s, namelijk Vaststellen, Veiligstellen, Versterken en Veilige leefgebieden. Een eerste kleine inventarisatie onder verschillende instanties, zoals provincies, waterschappen, terreinbeherende organisaties en (particuliere)gebiedseigenaren maakte inzichtelijk dat er voldoende commitment is om zich actief te willen inzetten voor het behoud van de Europese rivierkreeft.
Growth and nutrient budgets (C-N-P) of the manila clam Venerupsis philippinarum in a commercial pond system
Brinke, N. ten; Jansen, H.M. ; Verdegem, M.C.J. - \ 2012
Yerseke : IMARES (Report / IMARES Wageningen UR 12.017) - 25
venerupis philippinarum - clams - growth - nutrients - ecophysiology - ponds - zeeland - kokkels - groei - voedingsstoffen - ecofysiologie - plassen
To study potential mechanism(s) causing the reduced growth of the clam Venerupis philippinarum at the end of the production cycle, observed in the culture ponds at Zeeland Aquaculture in 2011, specific studies on eco-physiology and nutrient dynamics of individual clams were performed in the culture ponds during the production period in 2012. The study was divided in two sub-projects: Sub-project I: which focused on the uptake of the clam in terms of clearance rates and absorption efficiencies, Sub-Project II: focused on the internal nutrient fluxes of carbon, nitrogen and phosphorus, of the clams in the culture ponds in relation to food availability and environmental conditions, described in this report.
Development of a multimetric index based on macroinvertebrates for drainage ditch networks in agricultural areas.
Verdonschot, R.C.M. ; Keizer-Vlek, H.E. ; Verdonschot, P.F.M. - \ 2012
Ecological Indicators 13 (2012)1. - ISSN 1470-160X - p. 232 - 242.
benthic macroinvertebrates - community - biodiversity - integrity - streams - ponds - conservation - macrophytes - diversity - eutrophication
Drainage ditches are a prominent feature of many intensively managed agricultural areas. These small, shallow, line-shaped waterbodies could harbor a rich macroinvertebrate community, resembling that of natural small lentic ecosystems. Despite their high biodiversity potential, many ditch ecosystems are degraded due to nutrient enrichment, resulting in a shift from a mesotrophic system characterized by a diverse vegetation of emergent-, submerged-, and floating macrophytes to a hypertrophic state dominated by Lemnaceae or phytoplankton. Tools to assess the ecological quality of drainage ditches are currently lacking. Therefore, a multimetric index based on macroinvertebrates was developed to assess the ecological quality of drainage ditch systems in The Netherlands. Based on a large dataset from regional water district managers, who conduct routine sampling of macroinvertebrates in drainage ditches, a degradation gradient composed of 223 samples was derived, which represented the combined stressors eutrophication, organic pollution and salinity. We used a stepwise process to evaluate the discriminatory efficiency of a variety of diversity, abundance/composition, tolerance/sensitivity, and functional metrics for assessing ecological degradation in drainage ditches. After evaluating metric range, strength of correlation to the stressor gradient, degree of redundancy, and sample- and seasonal repeatability, five metrics were selected for the drainage ditch multimetric index: number of Trichoptera families, percentage of Gastropoda families, percentage of taxa preferring fresh water (Cl- <300 mg L-1), Dutch Saprobic index, and the percentage of predator taxa. The relationship of these single metrics with the stressor gradient is discussed.
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