Aquarium experiment

Zone of groundwater stagnation. At depths below sea level all the rock systems of the continents are filled with water to their full capacity—they are saturated. Being below sea level, the water stored in these rocks is under no hydraulic potential difference, and therefore this water does not flow—it is static, or stagnant (Fig. 2.14). This situation is similar to that of water stored in a tub, it cannot flow out, and hence is stagnant. Additional water reaching the tub overflows. The same is observed in the sand-filled aquarium experiment (Fig. 2.13) after steady state is reached, all the new rainwater infiltrates down to the level of the rim and flows out, whereas the deeper water remains static. 

H. Van Ryswyk, E. W. Hall, S. J. Petesch, and A. E. Wiedeman, / Chem. Ed. 2007, 54, 306. The aquarium experiment was popularized by Prof. Kenneth Hughes at Georgia Institute of Technology (K. D. Hughes, Anal. Chem. 1993, 65, 883A). For other classroom applications of the fishtank, see F. Calascibetta, L. Campanella, and G. Favero,... 

The aquarium experiments weie designed to show the rate and extent of the radionuclide accumulations by organisms and sediments of the lake and to furnish guidelines for the field applications. The general objectives of the field experiments were (1), to measure the accumulations of the selected nuclides in organisms with access to their usual sources of nutrition and (2), to evaluate the role of the food web in the accumulation by measuring relative assimilation directly from the water in organisms held in containers. 

Figure 97. Uptake of radionuclides by biota in an aquarium and a freshwater lake, (a) Diagram of the aquarium experiment, (b) Application of radioactive nuclides to Fern Lake. The tank and distribution pipe were on a raft towed by a boat. From Short et al. (1973). (b) courtesy of L. R. >onaldson. 

This experiment describes the construction of an air sampler using an aquarium pump, a flow meter, a filter holder, and bottles that serve as traps for analytes. Applications include the determinations of SO2, NO2, HCHO, and suspended particulate matter. 

This experiment describes a semester-long project in which the concentration of several ions in a fresh water aquarium are monitored. Ions that are monitored using potentiometric electrodes include H+ (pH electrode), Gh (chloride electrode), HG03 (GO2 electrode), NH4+ (NH3 electrode), and N03 (NH3 electrode). Nitrate concentrations were determined following its conversion to ammonia. 

Figure 75 The effect of starvation and subsequent feeding on the optical density of the muscle of summer-caught cod in an aquarium. The optical density is relative to an arbitrary fixed standard. , starved fish x, controls caught from die same fishing ground as the starved fish at various times during the experiment. (After Love, 1962.)...

Fig. 4.4. This figure may be considered a window to a chemical aquarium. The core of each of the structures is carbon and most of the hemispherical structures attached to the core represent hydrogen atoms. When these molecules collide under appropriate conditions, either on the surface of a catalyst or with sufficient energy, the carbon core of two units will form covalent bonds, displacing hydrogen. The discharge chamber in the Miller-Urey experiment served to displace the hydrogen and thus to create active molecular species that would form larger covalent structures.

Fig. 2.12 A basic experiment in water flow an aquarium exposed to rain. The vessel fills up and the additional rainwater overflows. At a steady state, all the arriving rainwater flows laterally toward the bases of drainage, and the water at the bottom of the vessel is stagnant (dead volume).

Fig. 2.13 A second basic experiment in water flow an aquarium filled and heaped with sand is exposed to rain. At steady state the rain infiltrates along vertical downflow paths (free flow) until a zone of lateral flow (overflow) is reached. The water at the deeper part is stagnant. Eddies create a thin transition or mixing zone.

A second example of an activated chemical defense concerns the Indo Pacific sponge Aplysinella rhax, in which tissue damage results in the rapid enzymatic transformation of psammaplin A sulfate 63 into psammaplin A 64 exposure of 63 to tissue from other sponges does not result in any conversion. Compound 63 deters feeding by reef fish, but when offered a choice between psammaplin A and its sulfate, both foods were avoided. In aquarium assays with C. solandri, extracts of damaged tissue were more deterrent than extracts from intact tissue, but both treatments were less palatable than control foods. In choice experiments, C. solandri preferred food treated with 63 over 64.104... 

In the n-dimensional hypervolume that describes the placement and trajectory of the ecosystem, it is possible to compare the positions of systems at a specified time. This displacement can be measured by computing the distance from the systems, and this displacement vector can be regarded as the displacement of these systems in space. The displacement vectors can be easily calculated and compared. Using the data generated by Giddings et al. (1980) in a series of classic experiments comparing results of the impacts of synthetic oil on aquarium and small-pond multispecies systems, Johnson was able to plot dose-response curves using the mean separation of the replicate systems. These plots are very reminiscent of dose-response curves from typical acute and chronic toxicity tests. 

Vargula individuals were collected at Shima County (Pacific coast of Mie Prefecture, Japan) and were kept in aquariums before the incorporation experiment. Materials... 

The experiment involved two groups of tadpoles of red-legged frogs. They were placed in an aquarium partitioned by a screen that allowed water to flow but blocked communications by sight and sound. When a wooden heron (a bird that preys on tadpoles) threatened the tadpoles in the one compartment, those on the other side moved away from the partition and ducked under a shelter. The... 

---