Effecten van verschuivingen van nutriëntenconcentraties op biota in de Nederlandse kustwateren: fluctuaties in nutriënten en organismen in de Nederlandse kustwateren
Philippart, C.J.M. (1994). Effecten van verschuivingen van nutriëntenconcentraties op biota in de Nederlandse kustwateren: fluctuaties in nutriënten en organismen in de Nederlandse kustwateren. BEON Rapport = BEON-report(1). [S.n.]: [s.l.]. 105 pp.
Part of: BEON Rapport = BEON-report. Programma Bureau BEON: Den Haag. ISSN 0924-6576, more
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| Abstract |
In the Dutch coastal waters, the supply of nutrients fluctuated, resulting in changes of concentrations of these nutrients. In the period in which nutrients increased, simultaneous changes in number and biomass of a diversity species of organisms of different trophic levels were observed. The present government policy aims at a division in halves of the anthropogenic input of nutrients. The project is aimed to answer the question to what extend the, by the government induced changes in nutrients, will lead to the desired changes in organisms, and what the uncertainties are. An overview of the long term fluctuations in nutrients, phytoplankton, zooplankton, fish, birds and mammals in the Dutch coastal waters, is given in the following report. BY a first comparison of these series, no non-ambiguous relations between changes in nutrients and these organisms seemed to exist. Some observed changes are certainly influenced by other forms of human impact, such as fishery and micro pollution. Apart from that some changes seemed to indicate the fluctuations in large-scale processes, such as climatologic conditions, rather than local changes, such as eutrofication. It is, therefore, not easy to indicate to what extent the observed changes in marine organisms are caused by changes in nutrients or by changes in other environmental factors. When predicting the effects of the assumed reduction of nutrients on the Dutch coastal ecosytems, one ought to take into consideration the natural fluctuations in climatologic conditions and the effects of other forms of human impact (fishery, micro-pollution). Inventarisation of integrated research on the effects of changes in nutrients on marine ecosystems shows that it is possible to use the research in marine model ecosystems, to quantify the trophic interactions between nutrients, phytoplankton, zooplankton, macro fauna and fish. From this research one could also deduce that the influence of nutrient supply on the structure of the trophic web in coastal ecosystems, is determined for a great deal by the coupling between the pelagic and the benthic part of the coastal ecosystem. The problems of the relation between the changes in nutrients and organisms in the Dutch coastal waters, requires an integrated approach, meaning, taking into consideration the amount and the mutual relationship of the nutrients, the effects on the primary production and the feedback in the ecosystem by regeneration of the nutrients. Essential research is required to answer the question to what extent the by the government induced changes in nutrients will lead to the desired changes in organisms and which are the uncertainties involved. |
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