Techniques were developed to study the effects of increased water temperature on certain zooplankters; specific studies were conducted on Daphnia pulex, an abundant and important zooplankter of the lower Columbia River. Study methods simulated prolonged exposure to constant high tempera· tures in thermal discharges and short exposures to increased temperatures in condensers of cooling systems. ...

Tannery wastewater contains large quantities of organic and inorganic compounds, including toxic substances such as sulfides and chromium salts. The evaluation of wastewater quality in Chile nowadays is based on chemical specific measurements and toxicity tests. The goal of this research was to characterize tannery wastewater and to relate its physical/chemical parameters with its acute toxicit...

Recent studies have indicated that nitrogen availability can be an important determinant of primary production in freshwater lakes and that herbivore growth can be limited by low dietary nitrogen availability. Furthermore, a lack of specific essential nitrogenous biochemicals (such as essential amino acids) might be another important constraint on the fitness of consumers. This might be of part...

Toxicokinetic-toxicodynamic (TKTD) models quantify the time-course of internal concentration, which is defined by uptake, elimination and biotransformation (TK), and the processes which lead to the toxic effects (TD). TKTD models show potential in predicting pesticide effects in fluctuating concentrations, but the data requirements and validity of underlying model assumptions are not known. We ...

Many prey species evolved inducible defense strategies that protect effectively against predation threats. Especially the crustacean Daphnia emerged as a model system for studying the ecology and evolution of inducible defenses. Daphnia pulex e.g. shows different phenotypic adaptations against vertebrate and invertebrate predators. In response to the invertebrate phantom midge larvae Chaoborus ...

Myrionecta rubra and Mesodinium pulex are among the most commonly encountered planktonic ciliates in coastal marine and estuarine regions throughout the world. Despite their widespread distribution, both ciliates have received little attention by taxonomists. In order to better understand the phylogenetic position of these ciliates, we determined the SSU rRNA gene sequence from cultures of M. r...

ecotoxicity of rhodium (rh) from the model of mining waste water side stream was examinedin this paper. rh was extracted from the model of the mining waste water using an emulsion liquid membrane(elm). the extractions were done at ph of 1.87 and ph 2.92 and 41.6 % and 46.2 % of rh was extractedrespectively. the side streams of ph of 1.87 and ph 2.92 after the extractions were examined for ecoto...

Ecological genomics aims to understand the functional association between environmental gradients and the genes underlying adaptive traits. Many genes that are identified by genome-wide screening in ecologically relevant species lack functional annotations. Although gene functions can be inferred from sequence homology, such approaches have limited power. Here, we introduce ecological regulator...

The origin and maintenance of sex remains one of the most debated topics in evolutionary biology. Investigations of the molecular genetic consequences of asexuality, such as direct estimation of mutation and recombination rates in asexual lineages, are critical for explaining the prevalence of sex in nature. In this study, we use long-term mutation accumulation lines of asexually propagating Da...