Standardized Aquatic Microcosm

Benthic-Pelagic Microcosm Compartmentalized Lake Mixed Flask Culture Microcosm Pond Microcosm Sediment Core Microcosm Ecocore Microcosm Ecocore II Microcosm Standard Aquatic Microcosm Stream Microcosm Waste Treatment Microcosm... 

Conquest, L.L. and EB. Taub. 1989. Repeatability and reproducibility of the standard aquatic microcosm statistical properties. In Aquatic Toxicology and Hazard Assessment Vol. 12, ASTM STP 1027. U.M. Cowgill and L.R. Williams, Eds. American Society for Testing and Materials, Philadelphia, PA, pp. 159-177. 

The Standardized Aquatic Microcosm (SAM) was developed by Frieda Taub and colleagues (Taub et al. 1987, Conquest and Taub 1989) to examine the effects of toxicants on multispecies systems in the laboratory. Figure 4.1 illustrates the course of events over the 63 d of the experiment and Table 4.13 provides a tabular overview. The microcosms are prepared by the introduction of ten algal, four invertebrate, and one bacterial species into 3 1 of sterile defined medium. Test containers are 4-1 glass jars. An autoclaved sediment consisting of 200 g silica sand and 0.5 g ground chitin are autoclaved separately and added to the already autoclaved jar and media. 

Timeline for the standardized aquatic microcosm. The 63-d toxicity test is specific in its sampling requirements, acclimation times, and dosing. 

Summary of Test Conditions for Standardized Aquatic Microcosms Freshwater... 

ASTM E 1366-91. 1993. Standard practice for standardized aquatic microcosms Freshwater. Annual Book of ASTM Standards. American Society for Testing and Materials, Philadelphia, PA. 

The multivariate methods described above have been used to examine a series of multispecies toxicity tests. Described below are the data analyses from two published tests using methodology derived from the Standardized Aquatic Microcosm (SAM) (ASTM E1366-91). The method is described in some detail in Chapter 4. 

Community conditioning has been tested in a series of standardized aquatic microcosms using the turbine fuel JP-8 in a series of two back-to-back replicated experiments (Landis et al. 2000). The first experiment was for the typical 63-d duration of the protocol, but the second was extended to 126 d. As far as possible, the experiments were replicated with organisms taken from the same cultures, conducted in the same rooms, with the same lot of toxicant and with the same basic staff. As in previous microcosm experiments, the organisms were counted, the toxicant quantified, and the oxygen content and pH measured. Graphical methods and three multivariate clustering methods were used to follow the patterns within both experiments. 

Taub, F.B. 1988. Standardized aquatic microcosm — development and testing. Acjuatic Ecotoxicology II. 

Taub, F.B. 1989. Standardized aquatic microcosms. Environ. Sci. Technol. 23 1064-1066. 

Many multispecies tests and field studies are designed to look at only certain populations or other attributes of the ecosystem. This is not the fault of the study per se, since the funding, personnel, and physical resources are usually limited. The danger lies in the picking and choosing of secondary results from these studies. For example, the standardized aquatic microcosm contains 16 species that are initially inoculated into the system. However, in the results for publication, the dynamics and interactions of all species and the combinations are not reported. To do so would be cumbersome and expensive. Only the dynamics of the organisms and interactions which are apparently the critical components are reported. Assuming that the other components are not affected because of their omission or lack of space in the article could be erroneous. Anecdotal data from field or multispecies tests are similarly difficult to interpret. Omission or inclusion of a report may reflect more the nature of the researcher than the presence or absence of the effect. 

---