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In vivo chlorophyll fluorescence measurements : comparing the YSI 6025 sensor with the standardized NEN 6520 analyses
The aim of this study is a comparison between an in situ chlorophyll sensor (YSI 6025) and the spectrophotometric method for chlorophyll (NEN6520:2006) and to find explanations for possible deviations. The YSI 6025 sensor seems a promising tool which can be used complementary to standardized spectrophotometric analyses. To find out what the unexplained variation is between the YSI and NEN, Deltares advices to include CDOM and algal composition (and concentration) in the field monitoring program. The YSI 6025 chlorophyll sensor should be calibrated with the phytoplankton assemblage of the location of interest to obtain correct chlorophyll readings.
Derivation of dissolved background concentrations in Dutch surface water based on a 10th percentile of monitoring data
Dissolved background concentrations were derived for fresh water and marine waters. Based on an inventory of methods to derive dissolved background concentrations (Oste et al., 2012), the monitoring data approach was used to determine the dissolved background concentration. The monitoring data approach means that a 10th percentile of all monitoring data is considered as an ambient background concentration.
Eutrophication assessment using remotely sensed and in situ chlorophyll-a data : KPP efficiente monitoring 2013 : eutrophication
National marine environmental monitoring is carried out for multiple purposes. The comparison between chlorophyll-a based on remote sensing and the in situ data in the context of a typical OSPAR eutrophication assessment shows that both sources of information have their strengths and limitations. Possible biases notwithstanding, the spatial coverage of the remote sensing data is providing amore accurate way of estimating regional statistical properties of the ecosystem compared to point-based (station-wise) assessments. The ultimate recommendation for RWS is to start implementing ocean colour remote sensing as a baseline data source in its monitoring strategy from 2014 onward.
Assessment Zealand water level measurement network : creating a method for evaluating measurement networks using hydrodynamic models
There is an increasing demand for information on the state of water systems. A procedure was developed for optimizing a monitoring system that is based on data model integration (DMI) techniques. Using the optimisation procedure, a set of twelve measurement stations was expected to produce a DMI based monitoring system that satisfied an accuracy of RMSE of 3 to 5 cm at the Dutch stations.
Eelgrass restoration in the Dutch Wadden Sea : methodology and first results
Before ca. 1930, Eelgrass (Zostera marina) was widespread throughout the whole of the Wadden Sea. Infrastructural works, disease, eutrophication and other factors have contributed to its demise. In the Dutch Wadden Sea Eelgrass has virtually disappeared. Within the European Water Framework Directive targets are set to increase its occurrence. With the reduction of nutrient runoff from land, the area of suitable habitat has increased. In Germany, Eelgrass has shown a remarkable recovery in the intertidal. In the Netherlands this has not been the case, even though models indicate that there is suitable habitat available. A hypothesis, that the lack of recovery is due to a lack of sufficient seed availability, is currently tested in a large-scale recovery project. The methodology is based on a technique developed in the U.S.A., where it has been successfully used, particularly on subtidal populations. The method was adapted to be used in the intertidal in the Wadden Sea. First results are encouraging, but there is no guarantee that the meadows are able to persist and increase. The various natural and anthropogenic changes in the system preclude the return to any historical reference situation. However, increasing the occurrence of a key species, characteristic for the Wadden Sea, may be possible.
Kansenkaart Tijdelijk Anders Bestemmen Deltaprogramma : inspiratieboek
Waterveiligheid en de zoetwatervoorziening in Nederland vragen steeds meer ruimte in de toekomst vanwege klimaatverandering. De Kansenkaart laat zien wat tussentijds nog allemaal mogelijk is voor de Deltaprogramma's Kust, Rivieren en Rijnmond.
Indicatoren voor kustlijnzorg : analyse van indicatoren voor veiligheid en recreatie
Op basis van de reeds beschikbare informatie vanuit de kustdatabase, zijn twee functies van de kust in kaart gebracht functie veiligheid en de functie recreatie. Het doel van de voorliggende studie is het analyseren van de relatie tussen het historische kustgedrag en de in het verleden uitgevoerde zandsuppleties.
Monitoring vooroeververdediging Westerschelde 2010 : T1 Cluster 1 - T0 Cluster 2
De algehele conclusie is dat op de nieuw gestorte ondergrond zich nieuwe pioniersgemeenschappen hebben gevestigd.
Operationele golfmodellering Noordzee - fase 2
Effect peilvariaties op waterkwaliteit IJsselmeer
In deze verkennende studie is met een 2D oppervlaktewatermodel onderzocht hoe, bij veranderingen in het meerpeil, nutriënten en algenconcentraties en samenstelling in het oppervlaktewater veranderen ten opzichte van de uitgangssituatie. Conclusie is dat d.