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C E Goulden

Publications and source records attributed to C E Goulden.

5 recordsLinked to original sources
PubMed1999

Culturing and bioassay testing of Daphnia magna using Elendt M4, Elendt M7, and COMBO media.

A performance-based, tiered approach was used to evaluate survival, growth, and reproduction of Daphnia magna in three selected synthetic media: Elendt M4, Elendt M7, and COMBO. Both Elendt M4 and Elendt M7 are high-hardness media currently recommended for Organization for Economic Cooperation and Development (OECD) testing. COMBO is a softer medium similar in total hardness to natural water found in the environment. Tier I consistent of an acclimation phase; Tier II involved a 21-day evaluation of survival, growth, and reproduction; and Tier III used each medium in a 21-day chronic study using a reference toxicant, 3,4-dichloroaniline (3,4-DCA). The evaluation of the performance of each medium was based on acceptance criteria similar to those used by the U.S. Environmental Protection Agency and the European Commission. Tests were run concurrently at three laboratories to assess interlaboratory variability. Daphnids were acclimated to the media for less than 1 month. Daphnid performance in all media exceeded the European Economic Community (EEC) validity criteria; however, reproductive performance and growth were significantly greater in the Elendt media than in COMBO. 3,4-DCA exerted more toxicity to daphnids in COMBO medium [no-observed-effect concentration (NOEC), <3.1microg/liter] compared with those in the Elendt media (NOEC, </=8.8 microg/liter). Elendt M7 medium provided the most consistent NOECs between laboratories (3. 1-8.8 microg/liter). However, results from two of three laboratories indicated decreases in fecundity over time in all media. The use of synthetic media for long-term culturing and bioassay testing of D. magna is still in question.

Animals↗
PubMed1998

Evaluation of a high-hardness COMBO medium and frozen algae for Daphnia magna.

A new high-hardness (H-H) COMBO medium for long-term culturing and bioassay testing of Daphnia magna was evaluated in 21-day survival, growth, and reproduction studies. The COMBO medium originally designed for softwater daphnid species (i.e., D. pulicaria) was modified for the hardwater species D. magna. This medium also allowed continuous culturing of a green algal food source for daphnids, Ankistrodesmus falcatus. After 12 generations of culturing in H-H COMBO medium, the mean fecundity was 128 +/- 12 (coefficient of variation = 9.4%). No significant observations of dead young, aborted eggs, or reduced antennas were made during the 6 months of continuous culturing. The no-observable-effect concentration (NOEC) for a reference toxicant standard, 3,4-dichloroaniline (3,4-DCA), was 8.3 micrograms/liter, which is similar to published values. These studies demonstrate that H-H COMBO is an acceptable medium for use for culturing and bioassay testing with D. magna. Additional experiments using frozen aliquots of A. falcatus were conducted. Although mean fecundity (64 +/- 7) and adult length were significantly decreased from the values for daphnids fed fresh algae, the NOEC for 3,4-DCA was > 25 micrograms/liter. The use of this alternative food source in bioassay testing appears promising, but further optimization of feeding rates is warranted.

Aniline Compounds↗
PubMed1980

Population oscillations and energy reserves in planktonic cladocera and their consequences to competition.

Time lags in an individual's response to decreased food densities are responsible for oscillations in laboratory populations of Daphnia galeata mendotae. Visible energy reserves of triacylglycerols accumulate in the body of animals at low population densities when food is abundant and are later metabolized at high population densities when food is scarce to temporarily sustain activity and reproduction. After these energy reserves are metabolized many individuals, primarily juveniles, starve and die. The length of the time lags is a function of the amount of energy reserve accumulated in the individual. Because this sustained activity and reproduction further decreases food concentrations to very low levels, individuals of a second smaller-body-sized species, Bosmina longirostris, that do not have sufficient energy reserves quickly starve and die. Thus the accumulation of energy reserves in individuals underlies the time lags important in causing population oscillations and has consequences to interspecific competition.

Journal Article↗
PubMed1969

Developmental phases of the biocoenosis.

Species number and diversity increase log-linearly with time during the early development of a biocoenosis. This period may be divided into three phases. In the first phase, diversity increases with the rapid immigration of species into the newly established habitat. In the second phase, diversity increases as common species become less common and rare species less rare. This period ends with the attainment of a maximum diversity pattern. In the third phase, rare species continue to invade the habitat until it is saturated. In each phase there is a maximal number of species that can invade the habitat.

Journal Article↗