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Extrapolation of Effects Measures across Levels of Biological Organization in Ecological Risk Assessment
Published in Keith R. Solomon, Theo C.M. Brock, Dick de Zwart, Scott D. Dyer, Leo Posthuma, Sean M. Richards, Hans Sanderson, Paul K. Sibley, Paul J. van den Brink, Extrapolation Practice for Ecotoxicological Effect Characterization of Chemicals, 2008
Paul J. van den Brink, Paul K. Sibley, Hans Toni Ratte, Donald J. Baird, J. Vincent Nabholz, Hans Sanderson
Community and ecosystem models are mathematical expressions that are intended to describe ecological systems composed of interacting species. Such models are typically spatially aggregated (include a minimum number of large habitat components within which the model assumes a homogeneous distribution of state variables) and represent biotic and abiotic structures in combination with physical, chemical, and ecological processes in aquatic or terrestrial systems (Bartell 2002). In ecotoxicology, they are often used to model bioaccumulation in food chains and to estimate the consequences of chemical stress on food webs, including indirect effects (Koelmans et al. 2001; Carroll 2002b). The advantage of these models over simpler ones is that they enable the integration of fate, bioaccumulation, and effects of chemicals at the ecosystem level in conjunction with information on food-web characteristics such as biomass, abundance and richness of component species, trophic structure, species interactions, and nutrient cycling. In this way, it is possible to extrapolate effects observed on populations to the community or ecosystem level.
EPA and OSHA Guidelines
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
Two major types of models are single-species population models and multispecies community and ecosystem models. Population models describe the dynamics of a finite group of individuals through time and have been used extensively in ecology and fisheries management and to assess the impacts of power plants and toxicants on specific fish populations. Population models are useful in answering questions related to short- or long-term changes of population size and structure and can be used to estimate the probability that a population will decline below or grow above a specified abundance.
A compartment model and numerical analysis of circulatory economy
Published in Journal of Management Analytics, 2019
Zhongzhi Yang, Pengzhi Kong, Boying Li, Bo Chao
A Compartment Model which is also called a conceptual model at the initial time is an ecosystem model that consists of flow charts to show interactions of different compartments of the living and nonliving components of the ecosystem. This model views each state variable of natural ecosystem as a compartment and describes the transfer relations of energy and materials between the compartments. The basic temporal laws of the natural ecosystem are reflected by the behavior of state dynamics of the compartmental model, which is one of the basic methods for analyzing the dynamic behaviors of energy flow, material flow and information flow in the natural ecosystem. A compartment model not only describes ecosystem structure and dynamics but can also show how environmental disturbances affect the ecosystem. However, its ability to predict the effects of these disturbances is limited. In addition to the applications in the ecosystem, compartment models are also used extensively in medicine, biology, physics, chemistry and economics, etc. With this kind of visualized method, the dynamic behavior of circular economy can be simulated numerically by means of a Compartment Model Theory.
Coupling flow with nutrient dynamics via BioChemFOAM in the Mississippi River
Published in Journal of Applied Water Engineering and Research, 2018
Oscar E. Hernandez Murcia, Douglas J. Schnoebelen, Athanasios N. Papanicolaou, Benjamin Abban
The optimization of nutrient removal in backwaters and designed aquatic ecosystems in complex river systems such as the Mississippi River require careful consideration of project-scale processes (Kadlec & Wallace 2008). In this context, computational fluid dynamics (CFD) modeling is a valuable analytical tool used by engineers and scientists to predict system responses to various stressors. The construction of ecosystem models of rivers, wetlands or lakes allows designers and managers to simulate various scenarios in order to improve decision-making abilities and optimize benefits to the overall ecosystem in restoration efforts (i.e. island construction, constructed wetlands and flow diversions).