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What does AQUATOX do?
Table of Contents
AQUATOX simulates the transfer of biomass, energy and chemicals from one compartment of the ecosystem to another. It does this by simultaneously computing each of the most important chemical or biological processes for each day of the simulation period; therefore it is known as a process-based or mechanistic model. AQUATOX can predict not only the environmental fate of chemicals in aquatic ecosystems, but also their direct and indirect effects on the resident organisms. Therefore it has the potential to establish causal links between chemical water quality and biological response and aquatic life uses.
AQUATOX differs from most water quality models in several ways. Most models include few if any biological components, whereas AQUATOX is an ecosystem model. It includes not only numerous types of plants, invertebrates and fish, it also treats the biota as interacting with the chemical/physical system. As mentioned above, AQUATOX is a process-based model, as opposed to an empirical model, which are often based on statistical relationships. Empirical models may establish that correlations between variables exist, but do not explain why, or explain the mechanisms of the relationship.
Ecological components simulated by AQUATOX
AQUATOX State Variables
AQUATOX can model numerous inter-related components in aquatic ecosystems, known as the state variables.
- phytoplankton (multiple species)
- periphyton and submerged aquatic vegetation (multiple species)
- planktonic and benthic invertebrates (multiple species)
- forage, game, and bottom fish (multiple species)
- nutrients and dissolved oxygen
- organic and inorganic sediments
- toxic organic chemicals (up to 20 different chemicals simultaneously)
AQUATOX is not intended to include every species of plant or animal that can exist in an aquatic habitat or every ecological process, but attempts to characterize the significant factors that determine the functioning of the ecosystem.
Aquatic ecosystems represented by AQUATOX
- vertically stratified lakes, reservoirs and ponds
- rivers and streams
- experimental ponds ("mesocosms")
As in many water quality models, AQUATOX assumes that the water body is uniformly mixed, except where vertical stratification occurs in lakes and reservoirs.
Ecological processes simulated by AQUATOX
AQUATOX is a process-based model, meaning that it explicitly simulates the numerous biological and ecological processes that operate to link the ecosystem together. In this way it predicts the environmental fate and ecological effects of the various environmental stressors.
Biological effects
- food consumption
- growth and reproduction
- natural mortality
- acute and chronic toxicity
- trophic interactions
Environmental fate
- nutrient cycling and oxygen dynamics
- partitioning of organic toxicants to water, biota and sediments
- toxic organic chemical transformations
- bioaccumulation through gills and diet