Mesocosms

Schief J, Mutz M (2009) Effects of sudden flow reduction on the decomposition of alder leaves (Alnus glutinosa L (Gaertn.)) in a temperate lowland stream. A mesocosm study. Hydrobiologia 624 205-217... 

Genter RB, Cherry DS, Smith EP, Cairns J Jr (1987) Algal-periphyton population and community changes from zinc stress in stream mesocosms. Hydrobiologia 153 261... 

In the quest for better methods of establishing the environmental safety (or otherwise) of chemicals, interest has grown in the use of microcosms and meso-cosms—artificial systems in which the effects of chemicals on populations and communities can be tested in a controlled way, with replication of treatments. Mesocosms have been defined as bounded and partially enclosed outdoor units that closely resemble the natural environment, especially the aquatic environment (Crossland 1994). Microcosms are smaller and less complex multispecies systems. They are less comparable with the real world than are mesocosms. Experimental ponds and model streams are examples of mesocosms (for examples, see Caquet et al. 2000, Giddings et al. 2001, and Solomon et al. 2001). The effects of chemicals at the levels of population and community can be tested in mesocosms, although the extent to which such effects can be related to events in the natural environment is questionable. Although mesocosms have been developed by both industrial... 

Another issue is the development and refinement of the testing protocols used in mesocosms. Mesocosms could have a more important role in environmental risk assessment if the data coming from them could be better interpreted. The use of biomarker assays to establish toxic effects and, where necessary, relate them to effects produced by chemicals in the field, might be a way forward. The issues raised in this section will be returned to in Chapter 17, after consideration of the individual examples given in Part 2. 

FIGURE 9.4 Relationship between scope for growth and whole tissue concentration of 2-and 3-ring aromatic hydrocarbons in Mytilus edulis (mean 95% confidence limits). A, Data from Solbergstrand mesocosm experiment, Oslo Fjord, Norway. , Data from Sullom Voe. Shetland Islands (Moore et al. 1987). 

Considering evidence from both field and mesocosm studies, it may be concluded that certain groups of aquatic macroinvertebrates are sensitive to pyrethroids and that there can be changes, in the short term, at the population level and above with exposure to environmentally realistic concentrations of them. It should be possible to pick up effects of this kind in natural waters using ecological profiling, for example, the River Invertebrate Prediction and Classification System (RIVPACS). There is... 

In a similar way, an integrated biomarker approach has a role when carrying out experiments in mesocosms. Under these controlled conditions, behavioral effects of neurotoxic pollutants, acting singly or in combination, can be monitored and compared with data on predator-prey relationships and effects at the population level. The employment of mechanistic biomarker assays can facilitate comparisons between results obtained in mesocosms and other data obtained in the field or in laboratory tests. Here is one way of attempting to answer the difficult question— how comparable are mesocosms to the real world ... 

The relationship between biomarker responses and effects at the population level can be tested in both field experiments and more controlled experiments in mesocosms. It may be possible to define thresholds for biomarker assays performed on indicator species, above which population effects have been shown to occur. Indicator species may be either free living or deployed. The advantage of the latter is... 

Apart from the use of this approach to study the ecotoxicology of neurotoxic pollutants in the field, it also has potential for use during the course of environmental risk assessment. An understanding of the relationship between biomarker responses to neurotoxic compounds and effects at the population level can be gained from both field studies and the use of mesocosms and other model systems. From these it may be possible to define critical thresholds in biomarker responses of indicator species above which population effects begin to appear. In the longer term, this approach... 

An approach that has gained attention recently is the use of model ecosystems microcosms, mesocosms, and macrocosms for testing chemicals (Chapter 4,... 

Section 4.5). Of these, mesocosms have stimulated the greatest interest. In these, replicated and controlled tests can be carried out to establish the effects of chemicals upon the structure and function of the (artihcial) communities they contain. The major problem is relating effects produced in mesocosms to events in the real world (see Crossland 1994). Nevertheless, it can be argued that mesocosms do incorporate certain relationships (e.g., predator/prey) and processes (e.g., carbon cycle) that are found in the outside world, and they test the effects of chemicals on these. Once again, the judicious use of biomarker assays during the course of mesocosm studies may help to relate effects of chemicals measured by them with similar effects in the natural environment. 

Microcosm, mesocosm, and macrocosm Small, medium, or large multispecies system in which effects of chemicals can be studied. 

Caquet, T., Lagadic, L., and Sheffield, S.R. (2000). Mesocosms in ecotoxicology (1) Outdoor aquatic systems. Reviews in Environmental Contamination and Toxicology 165, 1-38. 

Crossland, N.O. (1994). Extrapolation from mesocosms to the real world. Toxicology and Ecotoxicology News 1, 15-22. 

Giddings, J.M., Solomon, K.R., and Maund, S.J. (2001). Probabilistic risk assessment of cotton pyrethroids.il Aquatic mesocosm and held studies. Environmental Toxicology and Chemistry 20, 660-668. 

Mathematical modeling of trichloroethylene volatilization from a rapidly moving, shallow river (1 meter deep, flowing 1 meter per second, with a wind velocity of 3 meters per second) has estimated its half-life at 3.4 hours (Thomas 1982). Measured volatilization half-lives in a mesocosm, which simulated the Narragansett... 

Mesocosms placed in shallow Finnish lakes were used to evaluate changes brought about by extended incubation of biologically treated bleachery effluent from mills that used chloride dioxide. The mesocosms had a volume of ca. 2 m and were constructed of translucent polyethere or black polyethene to simulate dark reactions. The experiments were carried out at ambient temperatures throughout the year, and sum parameters were used to trace the fate of the organically bound chlorine. In view of previous studies on the molecular mass distribution of effluents (Jokela and Salkinoja-Salonen 1992), this was measured as an additional marker. Important featmes were that (a) sedimentation occurred exclusively within the water mass within the mesocosm, (b) the atmospheric input could be estimated... 

Hendricks B, and 11 coauthors (2005) Dynamics of an oligotrophic bacterial aquifer community during contact with a groundwater plume contaminated with benzene, toluene, ethylbenzene, and xylenes an in situ mesocosm study. Appl Environ Microbiol 71 3815-3823. 

Saski EK, A Vahatalo, K Salonen, MS Salkinoja-Salonen (1996b) Mesocosm simulation on sediment formation indnced by biologically treated bleached kraft pulp mill wastewater in freshwater recipients. In Environmental Fate and Effects of Pulp and Paper Mill Effluents (Eds MR Servos, KR Munlittrick, JH Carey, and GJ van der Kraak), pp. 261-270. St Lucie Press, Delray Beach, FL. 

FIGURE 3.4 Results from the May 2000 dose-response experiment conducted in situ within mesocosms installed at 4 sites in the Florida Everglades and using isotopically labeled Hg. Experimental conditions called for dosing at 0.5, 1.0, and 2.0 times the ambient loading rate... 

Krabbeiihoft DP, Orem W, Aiken G, Gilmour CG. 2004. Unraveling the complexities of mercury methylation in the Everglades the use of mesocosms to test the effects of new mercury, sulfate, and organic carbon. Proc 7th Int Conf Mercury Pollut, RMZ-MG, 51(l-3) June2004. 

Britson CA, Threlkeld ST. 1998. Abundance, metamorphosis, developmental, and behavioral abnormalities mHyla chrysoscelis tadpoles following exposure to three agrichemicals and methyl mercury in outdoor mesocosms. Bull Environ Contam Toxicol 61 154-161. 

Goulet, R.R., Lalonde, J.D., Munger, C., Dupuis, S., Dumont-Frenette, G., Premont, S., and Campbell, P.G.C., Phytoremediation of effluents from aluminum smelters A study of A1 retention in mesocosms containing aquatic plants, Water Research, 39, 2291-2300, 2005. 

Grosskopf R, Stubner S, Liesack W. Novel euryarchaeotal lineages detected on rice roots and in the anoxic bulk soil of flooded rice mesocosms. Appl. Environ. Microbiol. 1998 64 4983-4989. 

Van Winden JF, Reichart GJ, McNamara NP, Benthien A, Sinninghe Damste JS. Temperature-induced increase in methane release from peat bogs a mesocosm experiment. PLOS One. 2012 7 e39614. 

Thompson A., Parker D.R., Amrhein C. Selenate partitioning in field-situated constructed wetland mesocosms. Ecol Eng 2003 20 17-30. 

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