Mesocosm definition

Further, the validation of a model needs the definition of the criterion for establishing that a model has been validated. How well should a model predict effects precisely, and what are the bounds between which one calls a model (sufficiently) valid It also needs the definition of the context against which a model is to be considered valid. For example, validation of the SSD model has generally been based on whether the so-called hazardous concentration for 5% of the species (HC5) is a concentration that is conservative (sufficiently protective) compared to the no-effect concentration in multispecies mesocosm or field tests. In that sense, the model has performed well for both aquatic and terrestrial systems (e.g., Emans et al. 1993 Okkerman et al. 1993 Posthuma et al. 1998 Versteeg et al. 1999 van den Brink... 

Microcosms can be defined as controlled, reproducible laboratory systems that attempt to simulate the situation in a portion of the real world , while mesocosms are manmade, surrogate ecosystems that can be used to assess the fate and effects of chemicals at many different levels of biological organization . Mesocosms are bounded, and partially enclosed outdoor experimental systems that fall, in complexity, between laboratory microcosms and the real world macrocosm . The definition of a mesocosm has been refined further as a physically confined multitrophic... 

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