DOCUMENTATION OF SELECTED CONSTRUCTS AND PARAMETER VALUES IN THE AQUATIC MODEL CLEANER t

Scavia, D. and Park, R.A., 1976. Documentat ion of selected constructs and parameter values in the aquatic model CLEANER. Ecol. Modelling, 2: 33--58. Process representations critical to the phytoplankton and zooplankton submodels are described. These include constructs for: lightand nutrient-limitations and their interaction, temperature, consumption, and population-age structure. Values for key parameters are documented with reference to the literature on aquatic ecology and ecological modelling. Time-course relationships of the processes affecting the phytoplankton, zooplankton, phosphorus and nitrogen compartments are presented and discussed. These serve as additional documentat ion and are an important result of modelling synthesis. INTRODUCTION The aquatic model CLEAN was formulated by approximately 25 investigators in the Eastern Deciduous Forest Biome, U.S. International Biological Program (Park et al., 1974). It incorporates a number of submodels for ecologic and physiologic processes (Bloomfield et al., 1973) based on detailed studies by Biome participants at the Lake Wingra, Wisconsin, and Lake George, New York sites. Implementation of the generalized Biome version was effected at Rensselaer Polytechnic Institute (Scavia et al., 1974). More recently the basic model has been improved with the incorporation of phosphorus and nitrogen cycling, the addition of compartments for bluegreen algae and dissolved oxygen, the reformulation of the decomposition * Present address: Great Lakes Environmental Research Laboratory, 2300 Washtenaw Avenue, Ann Arbor, Mich. (U.S.A.) t Contribution No. 235 of the Eastern Deciduous Forest Biome, U.S. International Biological Program. Research supported in part by IBP-EDFB funded by the National Science Foundation under Interagency Agreement AG-199, BMS69-01147 A09 with the Energy Research and Development Administration, Oak Ridge National Laboratory and in part pursuant to Contract No. 68-03-2142 with the Environmental Protection Agency. 34 submodels, and refinement of various process terms. A subroutine has also been included to transform biomass values into environmental-perception characteristics such as predicted secchi disc readings, fish catch, algal ratios, and concentrations of noxious algae. The result is CLEANER, the Comprehensive Lake Ecosystem ANalyzer for Environmental Resources (Scavia, 1974; Park et al., 1975; Bloomfield et al., 1975). Development of CLEAN and CLEANER has been guided by a concern for biologic realism at the process level balanced against the realization that simplifications are necessary if all the principal elements of the aquatic food web are to be modelled simultaneously. Nowhere is this illustrated bet ter than in the phytoplankton, zooplankton, decomposer, and nutrient submodels (Tables I--IV). The objectives of this paper are (1) to describe the mathematical constructs (process representations) critical to the phytoplankton and zooplankton submodels in CLEANER, (2) to document the parameterizations of the phytoplankton, zooplankton, and nutrient submodels, and (3) to illustrate the behavior of these through simulation of a typical year. TABLE I Phy top lank ton 1.0 ! .1