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Biocomplexity - Ecosystem Report

Course

Biocomplexity (091123 )

304 Documents
Students shared 304 documents in this course
Academic year: 2016/2017
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University of Technology Sydney

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  • VV
    Well done- very helpful thank you :-)

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Construction of a stable and ecosystem in a bottle Abstract The stability of an aquatic ecosystem depends on the interaction between organisms and the biotic and abiotic factors within a community. A sustainable aquatic ecosystem consisting of varying components was monitored over the visual changes were noted, and measurements were recorded. The direction of the flow of energy between trophic levels was presented in a food web that was proposed during the construction of the ecosystem. With the appropriate components, organisms can benefit from the transfer of energy to increase their biomass. An increase in biomass can be defined as the growth of the individuals in an ecosystem, and ultimately a stable ecosystem where individuals are healthy in optimal environmental conditions. These conditions which consist of biotic and abiotic factors were measured, the biotic variables were recorded at the start and end of the experiment to avoid disturbing the ecosystem, while the abiotic factors were measured using multiple probes, and phosphate and nitrate water test kits. Through this study, it was found that there any large changes in the variables, and there was an increase in the biomass of organisms such as duckweeds and aquatic snails. Overall, the ecosystem can be considered stable and wellbalanced. Introduction An aquatic ecosystem is a group of living organisms interacting with one another in combination with the elements of their watery environment. Aquatic ecosystems can be classified into two major types, freshwater and marine. Freshwater ecosystems include lakes, ponds, rivers and streams and wetlands. Freshwater ecosystems cover a tiny portion of Earth whereas Marine ecosystems cover a much larger surface area of approximately Both ecosystems are this is due to their physical and chemical characteristics, for example, freshwater biomes contain water whereas marine biomes have higher salt concentrations that average (Clout, 2015). Freshwater ecosystems include a diverse community of plants and animals that have adapted to the freshwater biome. In lakes, most aquatic plants are found in the shallow water layer known as the littoral zone, where light penetrates and supports the plants to grow. The limnetic zone which is and close to the surface contains a variety of species such as fish, zooplankton and phytoplankton. The benthic zone is the lowest level and is made up of inorganic matter such as sand, rocks and mud (Clout, 2015). Benthic species are essential for the functioning of an ecosystem as they perform a range of functions such as the decomposition of organic matter and providing food for aquatic and vertebrate consumers (Covich, Palmer Crowl, Biotic and abiotic factors are also necessary for the functioning of an ecosystem as they affect how organisms survive and reproduce. Ecosystem functioning depends on the biotic and abiotic factors and the relationships between organisms (Humbert and Dorigo, 2005). The health of an aquatic ecosystem is at risk if there is an imbalance in the biotic (such as biomass of organisms) and abiotic characteristics (such as pH, temperature, salinity, and dissolved oxygen, nitrate and phosphate levels). For example, a decrease in pH will make the water more this will have detrimental effects on the living organisms and hinder their ability to survive. Similarly, high levels of phosphates and nitrates also make it difficult for organisms to survive as they contribute to algal blooms which can block off sunlight needed for plants to photosynthesize. Furthermore, a substantial increase in the biomass of predators will decrease the population size of prey, the ecosystem would be stable and if there any large changes in the variables and if there was an increase in the biomass of the organisms. Duckweed Vallisneria Worm Snail Shrimp Detritus Figure 1: The predicted food web for the ecosystem in a bottle Materials and methods 1. Construction of the aquatic in a An aquatic in a was set up placing half a kilogram of gravel into a 2L glass jar. The jar was then filled with 1 of freshwater from Manly Dam. Before adding the organisms, they were weighed and measured (if possible) to compare the results. Different species including two aquatic snails, two shrimps, and one worm were carefully added to the jar. After that, the rooted plant Vallisneria was firmly planted in the gravel and 0 of duckweed was added using a spatula. Finally, the glass jar was covered with a net and was given a unique group name to identify our jar from the rest that were placed in the glasshouse as well. 2. Biotic components of the ecosystem worm were measured using a ruler while the shrimps were too small to be measured or weighed. These steps were carried out once more at the end of the experiment to analyse and interpret the results. 3. Abiotic components of the ecosystem The jar was monitored weekly to assess the changes in the abiotic variables of the ecosystem. Firstly, the water clarity was observed as this indicates how well light penetrates through the water for algae and aquatic growth. After that, a rinsed beforehand with deionized water was used to measure pH, salinity, dissolved oxygen and temperature of the water. Tests kits were also used to measure the concentration of phosphate and nitrate levels which involved adding a few drops from phosphate bottles into a sample of water from the jar into a test tube. The observed colour was then compared with a phosphate colour chart, which indicates the concentration of phosphate. A similar method was used in measuring the concentration of nitrates, however, instead of phosphate bottles, nitrates bottles were used, and the observed colour was compared to a nitrate colour chart. It is important to measure and record all of the abiotic variables to determine the significance of each variable and maintain the overall health of the ecosystem. Finally, the changes in the abiotic variables were graphed to understand the differences in the trends. Results 1. Abiotic components 30 Temperature 25 20 15 10 5 0 1 2 3 4 Week Figure 2: Temperature of water over four weeks The temperature of water initially started at and slightly decreased to The temperature then began to increase with a change of reaching In the final week, the temperature was steadily reaching The location of the jar has an important effect on the temperature, for example, the increase of temperature in weeks 3 and 4 could be explained due to the sunny weather during that period. The average temperature over four weeks was 16 Dissolved Oxygen 14 12 10 8 6 4 2 0 1 2 3 4 Week Figure 4: Amount of oxygen dissolved in water over four weeks The levels of dissolved oxygen in water initially started at a concentration of and decreased in week 2. During weeks 3 and 4 dissolved oxygen levels begin to Phopshate and nitrate concentration increase reaching a concentration of during the last week. 0 0 0 0 Phosphate Nitrate 0 0 0 1 2 3 4 Week Figure 5: Phosphate and nitrate content over four weeks. Initial levels of both contents were Phosphate levels increased whereas nitrate content remained constant at 2. Biotic components 3 3 Mass (g) 2 2 1 1 0 0 1 4 Week Figure 6: Change in mass of duckweed between week 1 and week 4. The increase in mass 2 demonstrates the rapid reproduction of duckweed over time. 2 Mass (g) 2 1 1 0 0 Mass of snail Week 1 Mass of dark snail Week 4 Figure 7: Change in mass of two aquatic snails between week 1 and week 4. The graph depicts the overall increase in biomass of both snails. increase in weeks three and four due to the reduced content of organic matter which was decomposed the worm. The oxygen levels probably would have decreased after week 4 due to the death of the second shrimp. However, a limitation of this experiment is that the duration is for a short period. This can be improved increasing the length of the experiment, as this would allow for a more accurate interpretation of the results rather than predicting whether or not variables such as biomass would increase or decrease in the future. Nonetheless, the results obtained for the biomass of organisms can determine the functionality of an ecosystem. The overall increase in the biomass of plants such as algae and duckweed indicates the stability of the ecosystem. The ability to reproduce rapidly was observed in weeks 3 and 4 when the temperature increased reaching the optimum growth range between 20 and (Lasfar et al. 2007). The height of the Vallisneria decreased over however new shoots were observed, indicating that it was obtaining sufficient nutrients while being eaten other organisms. The experiment did have its limitations such as the duration and the size of the in a A typical aquatic freshwater ecosystem is much larger in size and experiences many different environmental conditions such as pollution, acid rain, depth of water, water flow rate and so on. This experiment can be improved studying the ecosystem over a longer period, and recording measurements daily rather than weekly to improve the accuracy of the experiment. Also, most of the predicted food web was observed however the shrimps able to eat the worm as the worm was able to hide away from its predators. Nonetheless, the results of this experiment support the hypothesis that an ecosystem can be considered stable if there is an increase in the biomass of the organisms provided that there are no large changes in the variables. References Clout, M. (2015). An Introduction to Ecology and the Biosphere. In (Eds Reece, J., Meyers, N., Urry, L., Cain, M., Wasserman, S., Minorsky, P., Jackson, R. Cooke, B.) pp. 1200. (Pearson Australia Group: Australia.) Covich, A., Palmer, M. Crowl, T. The Role of Benthic Invertebrate Species in Freshwater Ecosystems. BioScience 49, 119. Humbert, J. Dorigo, U. (2005). Biodiversity and aquatic ecosystem functioning: A minireview. Aquatic Ecosystem Health Management 8, Abrams, P. (1992). Why predators have positive effects on prey populations?. Evolutionary Ecology 6, Spencer, M. Warren, P. (1996). The Effects of Habitat Size and Productivity on Food Web Structure in Small Aquatic Microcosms. Oikos 75, 419. Yang, X., Wu, X., Hao, H. He, Z. (2008). Mechanisms and assessment of water eutrophication. Journal of Zhejiang University SCIENCE B 9, So it took me a while to do this report, references were really hard as there many things on shrimps, algae, snails, etc. The advice I would give for doing this report is start late, otherwise going to be stressing for the report when you can actually get really good.. It did pay off in the what I got: So I bet happy because got your hands on a HD report that will help you when writing yours. A few tips I would give for this subject is that stress about how much content you have to study for this subject. In this subject the only assignments be doing are the prac quizzes, and the report about your ecosystem in a bottle (which is this report). I done bad in the first two quizzes (which are open book the way) because I overestimated how much information is in the prac manual. JUST RELY ON THE PRAC MANUAL. the real tip: Make your prac manual your notebook, write the key points of the lectures in your prac manual. Because that is where they assess you on. They make it seem they will quiz you on the previous prac when actually quizzing you on the previous lectures. Also worry about skipping lectures, skip as much as you want but make sure you have read the content and summarised the key points. Trust me, if you skip lectures and read the notes you realise they are quizzing you about the lectures. The quizzes are really easy if you write down notes about the lectures in your prac manual. pretty much all I could say for the prac quizzes because I want you doing bad when they are really easy marks and they make up about of your final mark.

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Biocomplexity - Ecosystem Report

Course: Biocomplexity (091123 )

304 Documents
Students shared 304 documents in this course

University: University of Technology Sydney

Was this document helpful?
Construction of a stable and well-balanced
ecosystem in a bottle
Abstract
The stability of an aquatic ecosystem depends on the interaction between organisms and the
biotic and abiotic factors within a community. A sustainable aquatic ecosystem consisting of
varying components was monitored over time; the visual changes were noted, and
measurements were recorded. The direction of the flow of energy between trophic levels was
presented in a food web that was proposed during the construction of the ecosystem. With the
appropriate components, organisms can benefit from the transfer of energy to increase their
biomass. An increase in biomass can be defined as the growth of the individuals in an
ecosystem, and ultimately a stable ecosystem where individuals are healthy in optimal
environmental conditions. These conditions which consist of biotic and abiotic factors were
measured, the biotic variables were recorded at the start and end of the experiment to avoid
disturbing the ecosystem, while the abiotic factors were measured using multiple probes, and
phosphate and nitrate water test kits. Through this study, it was found that there weren’t any
large changes in the variables, and there was an increase in the biomass of organisms such as
duckweeds and aquatic snails. Overall, the ecosystem can be considered stable and well-
balanced.
Introduction
An aquatic ecosystem is a group of living organisms interacting with one another in
combination with the non-living elements of their watery environment. Aquatic ecosystems
can be classified into two major types, freshwater and marine. Freshwater ecosystems include
lakes, ponds, rivers and streams and wetlands. Freshwater ecosystems cover a tiny portion

Students also viewed

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