Water is a good habitat for many organisms. The pureness of water has strong effect on aquatic organism (Walter, 2008). The altering of water condition could favor for the growth of one certain organism, but less favor for other organisms that leads to the competing out other organism by abundance of favor one . So, the result goes to decreasing of water biodiversity. Water ecology, which studies on the interaction between of biotic and abiotic factors to the growth of organism in water, is too important in order to keep the ecosystem balance. In our study, we focused on how the fertilize (nitro, phosphorus) effects on the populations of water organisms. Euglena is the mixotrophic which could synthesis energy from photosynthesis, but also could consume the food to make energy (Robert.et al, 2012). From the trophic characteristic of Euglena, my hypothesis for this study was the population of Euglena would increase in the rich fertilize environment. The rationale for my hypothesis was Euglena could consume the food to have energy, so the rich fertilize environment was a good source for growth and reproduction of Euglena, that’s why their population would increase by time.
The water from American river was collected for our sample. We set up three different ecosystems for organisms in three different jars: control, low fertilize and high fertilize environment. First river water was added to the jar, then organisms was added and the different amount of fertilize was put last to appropriate jar. We were helped to identify each organism under microscope. Before adding organism to ecosystems, counting sample had been done. The sampling was done every week through 3 weeks. After 3 weeks, the number of organisms of Euglena and other heterotrophic in each ecosystem was used to plot graphs and analysis.
The population of Euglena in control condition increased in first two weeks, and then it decreased. In the low and high
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