Title: Community Testing, Microcosm and Mesocosm Experiments: Ecotoxicological Tools with High Ecological Realism
Abstract: The aim of an ecotoxicological test is to provide information on the potential impact of a chemical on an ecosystem before it has caused any damage to this ecosystem. After a discussion of some of the shortcomings of conventional, short-term, single-species laboratory tests as predictive tools in ecotoxicology, a brief overview is given of current approaches to the design of multi-species test systems used either in short-term or in long-term studies of fate and effects of chemicals in the aquatic environment. A detailed account is given of the advantages and disadvantages of a few strategies which have been thoroughly investigated in the ESTHER Program: (a) excised natural communities of periphyton and phytoplankton, (b) laboratory-scale enclosures of marine profundal-zone benthic communities (microcosms), (c) large land-based enclosures of marine littoral-zone ecosystems (mesocosms), and (d) limnic pelagic and benthic in situ enclosures (limnocorrals). The basic idea of the model ecosystem approach is to mimic the mother system so closely that the ecosystem response to a potential stress is duplicated by and can be observed in the model system. However, a model can never be identical to the real world with regard to all significant properties (e.g., size, time scale, flow conditions, complexity, composition, prehistory) and, therefore, model ecosystems must be approximations of the mother system. Mesocosms, microcosms and excised natural communities do not differ in this respect. The crucial point in designing a model system may not be to maximize the realism, but rather to make sure that ecologically relevant information can be obtained. It is concluded that the two main approaches to model ecosystem testing are both useful but for somewhat different purposes: the "whole ecosystem" or mesocosm approach when high degree of ecological realism is needed in long-term studies of both fate and effects of a pollutant; the excised community or microcosm approach when high flexibility, simplicity and high test capacity are required, e. g., for explanatory studies of the mode of action of a pollutant.
Publication Year: 1989
Publication Date: 1989-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 19
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