Publicaties

3898 resultaten

  • High-level abundances of methanobacteriales and syntrophobacterales may help to prevent corrosion of metal sheet piles

    Auteurs: Zandt, M.H. in 't; Kip, N.; Frank, J.; Jansen, S.; Veen, J.A. van; Jetten, M.S.M.; Welte, C.U. (2019)
    Gepubliceerd in: Applied and enviromental microbiology, volume 85 (2019) nummer 20, pagina 1-15

    Iron sheet piles are widely used in flood protection, dike construction, and river bank reinforcement. Their corrosion leads to gradual deterioration and often makes replacement necessary. Natural deposit layers on these sheet piles can prevent degradation and significantly increase their life span. However, little is known about the mechanisms of natural protective layer formation. Here, we studied the microbially diverse populations of corrosion-protective deposit layers on iron sheet piles at the Gouderak pumping station in Zuid-Holland, the Netherlands. Deposit layers, surrounding sediment and top sediment samples were analyzed for soil physicochemical parameters, microbially diverse populations, and metabolic potential. Methanogens appeared to be enriched 18-fold in the deposit layers. After sequencing, metagenome assembly and binning, we obtained four nearly complete draft genomes of microorganisms (Methanobacteriales, two Coriobacteriales, and Syntrophobacterales) that were highly enriched in the deposit layers, strongly indicating a potential role in corrosion protection. Coriobacteriales and Syntrophobacterales could be part of a microbial food web degrading organic matter to supply methanogenic substrates. Methane-producing Methanobacteriales could metabolize iron, which may initially lead to mild corrosion but potentially stimulates the formation of a carbonate-rich protective deposit layer in the long term. In addition, Methanobacteriales and Coriobacteriales have the potential to interact with metal surfaces via direct interspecies or extracellular electron transfer. In conclusion, our study provides valuable insights into microbial populations involved in iron corrosion protection and potentially enables the development of novel strategies for in situ screening of iron sheet piles in order to reduce risks and develop more sustainable replacement practices.

  • Analyse van de bijdrage van verschillende emissieroutes van gewasbeschermingsmiddelen aan de waterkwaliteit

    Auteurs: Kruijne, R.; Wenneker, M.; Montforts, M.; Weert, J.P.A. de; Loon, A.F. van (2020)

    Vanuit de Delta Aanpak Waterkwaliteit is besloten tot een extra inspanning om er voor te zorgen dat de waterkwaliteitsdoelen van de Kaderrichtlijn Water (KRW) in 2027 gehaald worden. Sinds 2018 krijgt dit vorm in de Kennis Impuls Waterkwaliteit (KIWK) en één van de onderwerpen in dit programma betreft de emissieroutes van gewasbeschermingsmiddelen die problemen veroorzaken met de waterkwaliteit en met de drinkwaterfunctie van oppervlaktewater en grondwater. De doelstelling van het onderhavige project is om de belangrijkste aangrijpingspunten voor emissiereductie te identificeren. In voorliggend rapport wordt het resultaat van fase 1 van dit project beschreven. De deeldoelstelling van deze fase is het inventariseren van de beschikbare kennis en het identificeren van de kennishiaten. Dit biedt aanknopingspunten voor waterbeheerders om de KRW-doelen en de doelen van de 2e nota Duurzame Gewasbescherming te realiseren.

  • Het Landelijk Waterkwaliteitsmodel : uitbreiding van het Nationaal Water Model met waterkwaliteit ten behoeve van berekeningen voor nutriënten

    Auteurs: Bolt, F.J.E. van der; Kroon, T.; Groenendijk, P.; Renaud, L.V.; Roovaart, J.C. van den; Janssen, G.M.C.M.; Loos, S.; Cleij, P.; Linden, A.M.A. van der; Marsman, A. (2020)

    De stuurgroep Nationaal Water Model heeft de opdracht gegeven een landelijk waterkwaliteitsmodel nutriënten te ontwikkelen. Dit Landelijk WaterKwaliteitsModel (LWKM) is gebaseerd op de recentste data, gebruikt de resultaten van het Landelijk hydrologisch Model en bouwt waar mogelijk voort op of maakt gebruik van onderdelen van eerdere modelinstrumenten als STONE en het Landelijk KRW-Verkenner Model (LKM). Dit rapport beschrijft de opzet, de realisatie, de gebruikte invoergegevens, de initialisatie, de kalibratie, de toetsing en resultaten van de eerste versie van het LWKM.

  • Verschil in uitloging van PFAS uit grond en bagger

    Auteurs: Wintersen, A.; Osté, L.A.; Meiracker, R. van den; Breemen, P. van; Roskam, G.D.; Spijker, J. (2020)

    De uitloging van PFAS uit landbodem, uiterwaardebodem en waterbodem (bagger) is vergelijkbaar voor deze drie categorieën bodems. Poly- en perfluoralkylstoffen (PFAS) is een verzamel naam voor duizenden stoffen. PFOS en PFOA zijn twee veelvoorkomende PFASverbindingen die in heel Nederland verspreid kunnen worden aangetroffen in concentraties van enkele microgrammen per kilogram grond of bagger. Om te voorkomen dat deze stoffen zich verder door het milieu verspreiden, zijn er eisen gesteld aan het gebruik van grond en bagger waar PFAS in zit. Grond en bagger kunnen onder andere worden gebruikt bij het ondieper maken van plassen waaruit ooit zand en klei is gewonnen. Bij dit soort toepassingen onder oppervlaktewater zullen PFOS en PFOA in ongeveer dezelfde mate vrijkomen uit de drie soorten bodems die zijn onderzocht.

  • Uncertainties in projections of sandy beach erosion due to sea level rise : an analysis at the European scale

    Auteurs: Athanasiou, P.; Dongeren, A.R. van; Giardino, A.; Vousdoukas, M.I.; Ranasinghe, R.; Kwadijk, J.C.J. (2020)
    Gepubliceerd in: Scientific reports : an open-access multidisciplinary journal, volume 10 (2020), pagina 1-25

    Sea level rise (SLR) will cause shoreline retreat of sandy coasts in the absence of sand supply mechanisms. These coasts have high touristic and ecological value and provide protection of valuable infrastructures and buildings to storm impacts. So far, large-scale assessments of shoreline retreat use specific datasets or assumptions for the geophysical representation of the coastal system, without any quantification of the effect that these choices might have on the assessment. Here we quantify SLR driven potential shoreline retreat and consequent coastal land loss in Europe during the twenty-first century using different combinations of geophysical datasets for (a) the location and spatial extent of sandy beaches and (b) their nearshore slopes. Using data-based spatially-varying nearshore slope data, a European averaged SLR driven median shoreline retreat of 97 m (54 m) is projected under RCP 8.5 (4.5) by year 2100, relative to the baseline year 2010. This retreat would translate to 2,500 km2 (1,400 km2) of coastal land loss (in the absence of ambient shoreline changes). A variance-based global sensitivity analysis indicates that the uncertainty associated with the choice of geophysical datasets can contribute up to 45% (26%) of the variance in coastal land loss projections for Europe by 2050 (2100). This contribution can be as high as that associated with future mitigation scenarios and SLR projections.

  • Spatial variability in macrofaunal diet composition and grazing pressure on microphytobenthos in intertidal areas

    Auteurs: Daggers, T.D.; Oevelen, D. van; Herman, P.M.J.; Boschker, H.T.S.; Wal, D. van der (2020)

    Microphytobenthos forms an important part of the diet of macrofauna (macrozoobenthos) in many intertidal ecosystems. It is unclear, however, whether the dependence of macrofauna on microphytobenthos varies spatially within and among tidal systems. We aim (1) to assess the spatial variability in the importance of microphytobenthos in the diet of macrofauna (i.e., between and within two tidal basins and as function of elevation), (2) to quantify grazing pressure of the macrofaunal community on different potential food sources (microphytobenthos, phytoplankton and terrestrial organic material) for several sites in two tidal basins and (3) to compare microphytobenthic production and summer/autumn grazing of the total macrofaunal community and grazing pressure per feeding type, with potential microphytobenthic production estimated from rates in early spring, when grazing was low. Using a natural stable isotope approach, we identified microphytobenthos as a more important food source for macrofauna than phytoplankton and terrestrial organic material. Microphytobenthos dependency differed between tidal basins for the genera Bathyporeia (sand digger shrimp), Macoma (Baltic tellin), and Peringia (mudsnail) and for sampled individuals of all genera combined, and did not vary as function of elevation. We showed that macrofaunal grazing on microphytobenthos is quantitatively important and, in some cases, approached microphytobenthic production rates in early spring. No positive relation between microphytobenthic production in early spring and macrofaunal grazing in summer/autumn was observed. This suggests that the studied consumer‐resource interactions are coupled on a larger spatial scale (i.e., mesoscale, ≈10 to 100 km), rather than the fine (mm to m) scale.

  • Application au réseau du Nord-Pas de Calais

    Auteurs: Horvath, K.; Nouasse, H.; Rajaoarisoa, L.; Duviella, E.; Chuquet, K. (2016)
    Gepubliceerd in: Journal Européen des Systèmes Automatisés​ (JESA), volume 49 (2016) nummer 3, pagina 299-323

    L’étude du changement climatique et de son impact sur les fleuves et rivières, ainsi que sur les voies navigables, est au centre des préoccupations de plusieurs laboratoires de recherche en Europe. Il s’agit à partir de modèles climatiques couplés à des modèles hydrologiques de prédire l’état de la ressource sur des horizons futurs allant jusqu’à la fin du siècle, en considérant plusieurs scénarios de changement climatique. Cette démarche n’est pertinente qu’à la condition de disposer de modèles climatiques et hydrologiques fiables et de méthodes permettant de réduire l’incertitude liée à l’utilisation de chaque modèle. Dans le cas contraire, l’étude de la résilience des voies navigables peut être effectuée à partir d’un modèle volumique représentant leur dynamique. Ce type de modèle est considéré dans cet article. Il s’agit d’un modèle intégré de réseaux de voies navigables qui permet la modélisation de leur dynamique tout en considérant la possible influence des bassins versants et des nappes phréatiques. Ce modèle est basé sur le bilan journalier des volumes d’eau entrant et sortant de chaque bief du réseau. Il est utilisé afin d’étudier les conditions limites du bon fonctionnement des réseaux de voies navigables en période d’étiage. L’approche proposée est illustrée dans le cadre du réseau de navigation du Nord-Pas de Calais à partir de données réelles.

  • EnvirVis 2020 - Workshop on Visualisation in Environmental Sciences (Norrköping, Sweden, May 25-29, 2020)

  • Visual exploration of climate-related volunteered geographic information

    Auteurs: Navarra, C.; Opach, T.; Vrotsou, K.; Joling, A.; Wilk, J.; Neset, T.S. (2020)
    Gepubliceerd in: EnvirVis 2020 - Workshop on Visualisation in Environmental Sciences (Norrköping, Sweden, May 25-29, 2020) (2020), pagina 1-7

    This paper describes two approaches for visually exploring climate-related data collected within the citizen science research project, CitizenSensing. The project addresses the need of European cities and their citizens for enhanced knowledge of sitespecific conditions regarding climatic risks and adaptation measures. The visual exploration approaches discussed are: (1) a web portal enabling users to gain a low-level overview of the collected data on a map, and (2) a visual analysis tool facilitating in-depth visual data exploration in search of spatio-temporal patterns. The aim of the study is to assess and discuss the potential of such visual exploration approaches in the context of Volunteered Geographic Information.

  • Improving forecast skill of lowland hydrological models using ensemble Kalman filter and unscented Kalman filter

    Auteurs: Sun, Y.; Bao, W.; Valk, K.; Brauer, C.C.; Sumihar, J.; Weerts, A.H. (2020)
    Gepubliceerd in: Water resources research (2020), pagina 1-25

    For operational water management in lowlands and polders (for instance in the Netherlands), lowland hydrological models are used for flow prediction, often as an input for a real‐time control system to steer water with pumps and weirs to keep water levels within acceptable bounds. Therefore, proper initialization of these models is essential. The ensemble Kalman filter (EnKF) has been widely used due to its relative simplicity and robustness, while the unscented Kalman filter (UKF) has received little attention in the operational context. Here, we test both UKF and EnKF using a lowland lumped hydrological model. The results of a reforecast experiment in an operational context using an hourly time step show that when using nine ensemble members, both filters can improve the accuracy of the forecast by updating the state of a lumped hydrological model (Wageningen Lowland Runoff Simulator, WALRUS) based on the observed discharge, while UKF has achieved better performance than EnKF. Additionally, we show that an increase in the ensemble members does not necessarily mean a significant increase in performance. WALRUS model with either UKF or EnKF could be considered for hydrological forecasting for supporting water management of polders and lowlands, with UKF being the computational leaner option.

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