This paper presents an ecological–economic model for a lake and its watershed systems. We describe the linkage between the watershed system and the lake aquatic ecosystem and the modeling process. The lake–watershed system was divided into six subsystems: social system, economic system, terrestrial ecosystem, lake water system, pollutant system, and lake aquatic ecosystem. The model equations w...

Many regulatory authorities set water quality objectives or thresholds based on nutrient concentrations to safeguard aquatic ecosystem health. But do these criteria adequately assess the biological and ecological status? Our research has been focussing on the performance of constructed wetlands for water quality improvement and ecosystem health. In this paper we present data on macroinvertebrat...

A model aquatic ecosystem is devised for studying relatively volatile organic compounds and simulating direct discharge of chemical wastes into aquatic ecosystems. Six simple benzene derivatives (aniline, anisole, benzoic acid, chlorobenzene, nitrobenzene, and phthalic anhydride) and other important specialty chemicals: hexachlorobenzene, pentachlorophenol, 2,6-diethylaniline, and 3,5,6-trichlo...

The need for scientific advice to manage the aquatic environment in an ecosystem context has never been greater. Many assessments of ecosystem state and change use inadequate data on non-conspicuous, non-target organisms. These include meiofauna, a diverse group of small-sized organisms (<1 mm) that live in a range of terrestrial and aquatic environments. Meiobenthic research published between ...

The insecticides mirex and chlordecone and the mirex photodegradation product, photomirex, were evaluated in a terrestrial aquatic laboratory model ecosystem. Although chlordecone was to some extent degraded during the 33 days, neither mirex nor photomirex produced identifiable levels of decomposition products in the water or in any of the organisms of the model ecosystem. All three compounds a...

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosys...

Exergy is demonstrated to be a useful measurable parameter reflecting the state of the ecosystem, and allowing estimation of the severity of its anthropogenous damage. Exergy is shown to have advantages such as good theoretical basis in thermodynamics, close relation to information theory, rather high correlation with others ecosystem goal functions and relative ease of computation. Nowadays ex...

This document outlines a strategy for integrated mercury investigations linked to restoration and adaptive management of the San Francisco Bay and Sacramento-San Joaquin Delta ecosystem (termed the Bay-Delta ecosystem and defined as the combined watershed, Delta, and Bay). Ecosystem restoration and management of the Bay-Delta ecosystem are complicated by mercury contamination from historic mini...

Certain chemicals are persistent in aquatic systems and tend to accumulate in the tissue of fish and other aquatic organisms, sometimes to levels that make them unsafe for human or wildlife consumption. The “bioaccumulative” compounds, such as polychlorinated biphenyls (PCBs), are the cause of a significant number of advisories against fish consumption throughout the U.S. Exposure to bioaccumul...