The ecology of algal biodiesel production.

Sustainable energy production represents one of the most formidable problems of the 21st century, and plant-based biofuels offer significant promise. We summarize the potential advantages of using pond-grown microalgae as feedstocks relative to conventional terrestrial biofuel crop production. We show how pond-based algal biofuel production, which requires significantly less land area than agricultural crop-based biofuel systems, can offer additional ecological benefits by reducing anthropogenic pollutant releases to the environment and by requiring much lower water subsidies.

Development of predictive models for geosmin-related taste and odor in Kansas, USA, drinking water reservoirs.

The presence of taste and odor compounds can greatly reduce the quality of drinking water supplies. Because the monetary costs associated with the removal of these compounds can be high, it is impractical for most facilities to continuously treat their raw water. Instead, new tools are needed to help predict when taste and odor events may be most likely to occur.

Effects of eutrophication on vitellogenin gene expression in male fathead minnows (Pimephales promelas) exposed to 17alpha-ethynylestradiol in field mesocosms.

This study evaluated the effect of aquatic secondary nutrient supply levels (nitrogen and phosphorus) on the subcellular response of adult male fathead minnows (Pimephales promelas) exposed to a single nominal concentration of 17alpha-ethynylestradiol (EE2), a potent synthetic estrogen, under quasi-natural field conditions. Outdoor mesocosms were maintained under low, medium, and high nutrient supply conditions as categorized by total phosphorus (TP) level (nominal 0.012, 0.

Phytoplankton species richness scales consistently from laboratory microcosms to the world's oceans.

Species-area relationships have been observed for virtually all major groups of macroorganisms that have been studied to date but have not been explored for microscopic phytoplankton algae, which are the dominant producers in many freshwater and marine ecosystems. Our analyses of data from 142 different natural ponds, lakes, and oceans and 239 experimental ecosystems reveal a strong species-area relationship with an exponent that is invariant across ecosystems that span >15 orders of magnitude in spatial extent. A striking result is that the species-area relationship derived from small-scale experimental studies correctly scales up to natural aquatic ecosystems.

Responses of molecular indicators of exposure in mesocosms: common carp (Cyprinus carpio) exposed to the herbicides alachlor and atrazine.

Common carp (Cyprinus carpio) were treated in aquatic mesocosms with a single pulse of the herbicides atrazine or alachlor to study the bioavailability and biological activity of these herbicides using molecular indicators: Liver vitellogenin gene expression in male fish for estrogenic activity, liver cytochrome P4501A1 gene expression, and DNA damage in blood cells using the single-cell gel electrophoresis method. Both alachlor and atrazine showed dose-related increases in DNA strand breaks at environmentally relevant concentrations (<100 ppb). Gene expression indicators showed that neither herbicide had estrogenic activity in the carp, whereas atrazine at concentrations as low as 7 ppb induced cytochrome P4501A1.

Nutrient level, microbial activity, and alachlor transformation in aerobic aquatic systems.

Alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide) is a moderately toxic herbicide that is frequently found in agriculturally impacted surface waters. To assess primary mechanism(s) that affect its fate in aquatic systems, two field experiments were performed using large mesocosms (n=39) and smaller microcosms with and without microbial inhibitors (n=16). The mesocosm experiment tested the effect of fertility conditions on alachlor fate, assessing alachlor disappearance over time under oligotrophic (total phosphorus (TP) <12 microg/L) through hypereutrophic (TP>80 microg/L) water conditions.

Effects of three pharmaceutical and personal care products on natural freshwater algal assemblages.

Treated wastewaters in the United States contain detectable quantities of surfactants, antibiotics, and other types of antimicrobial chemicals contained in pharmaceutical and personal-care products (PPCPs) that are released into stream ecosystems. The degradation characteristics of many of these chemicals are not yet known, nor are the chemical properties of their byproducts. They also are not currently mandated for removal under the U.

Ecosystem Modeling with Lisrel: A New Approach for Measuring Direct and Indirect Effects.

Evaluating the effects of toxicants in ecosystems is difficult despite numerous attempts to develop field and laboratory tests. The problem appears to be the lack of an analytical methodology capable of taking advantage of the available experimental designs. Therefore, we propose a technique for modeling ecosystems-linear structural modeling with LISREL.

FACTORS AFFECTING PHYTOPLANKTON DISTRIBUTION IN A DOUBLE-CELL SEWAGE LAGOON (1) (2).

The distribution of phyioplankton in a double-cell sewage lagoon at Hallam, Nebraska, was studied in relation to physical, chemical, and biological factors during the summer and fall of 1965. Sixteen species of algae were recorded in the first and more organically rich of the two physically similar ponds, with 28 species recorded in the second pond. Population sizes were always greater in the first pond due to reduced grazing during the summer and large quantities of ammonia-nitrogen during the fall.