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Constructing a self-sustaining freshwater aquatic ecosystemAbstractThis paper summarises the general interactions of the abiotic and biotic factors in a freshwateraquatic ecosystem in a jar. The shrimp, snail, Ribbon weed and Duckweed were placed in a jar ofManly Dam water and monitored over four weeks. Results gained from this experiment allows forconclusions to be drawn on what affects the equilibrium of an ecosystem. From the results,implications were made that abiotic factors were uncontrollable, and could possibly influence thesustainability of an artificial freshwater ecosystem. Moreover, the community structure and the nutrientcycles are indicative of the health of the ecosystem as supported by the outcomes obtained. At theend of the experiment, the death of the shrimp showed that the expected food web did not take placedue to the imbalance of biotic and abiotic variables in the system. Overall the experimentdemonstrated that if the levels of salinity, dissolved oxygen (DO), nutrients and pH are too high or toolow can cause great changes to the ecosystem’s food web. IntroductionAn ecosystem is the community of organisms in an area and the physical factors that thoseorganisms interact with (Reece et al. 2011). There are various types of ecosystems, and the onestudied is the freshwater aquatic ecosystem. Aquatic biomes are characterised mainly by theirphysical environment instead of its climate (Reece et al, 2011). The local circumstances that influencethe features of an aquatic freshwater ecosystem include the level of nutrients; suspensions of solids;and bottom floor features such as sand or rock (Reece et al, 2011).Moreover, a freshwater ecosystem contains shrimps, snails, algae, macrophytes and othermicroorganisms. All these elements are linked in a complex food web by developing interactions (Cury,Shannon & Shin, 2001). A supposed food web has been derived for this ecosystem given in Diagram1. There are two trophic levels in this food web, with the snail and shrimp as the primary consumersthat depend on the Duckweed, Ribbon weed and algae for food in order to grow. If there is a decreasein one single species, it can direct to a substantial change in the overall community structure (Bader,1999).
The main objective of this experiment is to build an enclosed maintainable freshwater ecosystemfor four weeks. It is predicted that this will be a steady ecosystem due to the suitable abiotic and bioticcomponents placed in the jar. For this ecosystem to be functional there has to be a dynamicequilibrium between the primary producers, consumers and decomposers to recycle the nutrients. Diagram 1. The expected food web that is possible to take place in this ecosystem.Materials & MethodsThe biotic characteristics of the ecosystem chosen are summarised in Table 1. All materials wereplaced in a jar filled with Manly Dam water; the container is then covered with a soft mesh. Throughoutthis experiment, the abiotic factors to be measured were phosphate, nitrate, DO, salinity and pH.