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dc.contributor.authorJanse JH
dc.contributor.authorAldenberg T
dc.date.accessioned2013-09-17T23:01:36
dc.date.issued1990-01-31
dc.identifier714502001
dc.description.abstractA dynamic, deterministic model is presented to simulate the phosphorus cycle and plankton growth in the shallow, hypertrophic Loosdrecht Lakes (The Netherlands) before and after restoration measures. Both the water and the upper sediment layer are modelled. The model comprises three algal groups, zooplankton, fish detritus, zoobenthos and upper sediment (all modelled both in carbon and in phosphorus) besides inorganic phosphorus (SRP) in both the surface water and the interstitial water. Within the model system, the phosphorus cycle is completely closed. Carbon and phosphorus are described independently, so that dynamics of P/C ratios can be modelled. Sediment processes are described in a simplified form. Simulated values are largely within the range of observed ones. De detrital fraction of the seston (= phytoplankton + detritus) varies from 50-60 % in summer to about 90% in winter. SRP in the surface water is very low during most of the year. The sensitivity for external phosphorus input is larger for algal and detrital P than for algal and detritial C and chlorophyll-a. So the P/C ratio of the seston descreases following restorations measures, as is observed in the lakes, while the P/C ratios of zooplankton and fish remain constant and much higher. Phosphorus mobilisation from the sediment decreases with decreasing external input. Adaption of the model system to the reduced loading takes place in about two years. This means that without additional measures no further changes in the system are to be expected. Further reduction of phosphorus loading will lead to an improvement of water quality. Sources of uncertainty in the model include the limited knowledge on selective grazing as well as on mortality and mineralisation processes.<br>
dc.description.sponsorshipDGM/DWB-W Otterloo HA van
dc.formatapplication/pdf
dc.format.extent99 p
dc.format.extent3838 kb
dc.language.isoen
dc.publisherRijksinstituut voor Volksgezondheid en Milieu RIVM
dc.relation.ispartofRIVM Rapport 714502001
dc.relation.urlhttp://www.rivm.nl/bibliotheek/rapporten/714502001.html
dc.relation.urlhttp://www.rivm.nl/bibliotheek/rapporten/714502001.pdf
dc.subject14nl
dc.subjectmodelnl
dc.subjecteutrofieringnl
dc.subjectfosfaatnl
dc.subjectp/c rationl
dc.subjectmerennl
dc.subjectaquatisch ecosysteemnl
dc.subjectmodelnl
dc.subjecteutrophicationnl
dc.subjectphosphorusnl
dc.subjectp/c ratio lakesnl
dc.subjectaquatic ecosystemnl
dc.titlePCLoos: a eutrophication model of the Loosdrecht Lakesen
dc.title.alternativePCLoos: een eutrofieringsmodel van de Loosdrechtse Plassennl
dc.typeReport
dc.date.updated2013-09-17T21:01:42Z
html.description.abstractA dynamic, deterministic model is presented to simulate the phosphorus cycle and plankton growth in the shallow, hypertrophic Loosdrecht Lakes (The Netherlands) before and after restoration measures. Both the water and the upper sediment layer are modelled. The model comprises three algal groups, zooplankton, fish detritus, zoobenthos and upper sediment (all modelled both in carbon and in phosphorus) besides inorganic phosphorus (SRP) in both the surface water and the interstitial water. Within the model system, the phosphorus cycle is completely closed. Carbon and phosphorus are described independently, so that dynamics of P/C ratios can be modelled. Sediment processes are described in a simplified form. Simulated values are largely within the range of observed ones. De detrital fraction of the seston (= phytoplankton + detritus) varies from 50-60 % in summer to about 90% in winter. SRP in the surface water is very low during most of the year. The sensitivity for external phosphorus input is larger for algal and detrital P than for algal and detritial C and chlorophyll-a. So the P/C ratio of the seston descreases following restorations measures, as is observed in the lakes, while the P/C ratios of zooplankton and fish remain constant and much higher. Phosphorus mobilisation from the sediment decreases with decreasing external input. Adaption of the model system to the reduced loading takes place in about two years. This means that without additional measures no further changes in the system are to be expected. Further reduction of phosphorus loading will lead to an improvement of water quality. Sources of uncertainty in the model include the limited knowledge on selective grazing as well as on mortality and mineralisation processes.&lt;br&gt;


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