Research Question: Why and to what effect, do the different water composition and properties change from the docks to Marinna?
Hypothesis: The water at the Marinna has higher carbon dioxide content, less transparency, less oxygen content and higher salinity.
Content:
introduction
methodology
apparatus needed
Introduction:
The aim of our project was to see the variation in the different water at the Docks and at the Marina. We were curious about the difference affected by pollution at the Marina since threre are more boats parking and passing by. Ultimately, this will affect the aqua life in the area and help us to conclude the best way to conserve and protect our ocean.
Properties of water that we looked at:
Temperature, salinity, transparency, dissolved oxygen and dissolved carbon dioxide content in water.
Experiement:
1)Surface temperature(degree C)
In order to obtain the temperature of the water in both the Marina and the docks, we connect the thermometer to logger pro and find the average temperature within 30 seconds(however, temperature will drop due to the loss of kinetic energy over time).
Results:
Docks: 10.7
Marina: 12
Source of error:We took the temperature of the water at the docks, how ever, the Marina water was transferred back to the Lab, therefore allowing for time for the temperature to fall.
2)Salinity (ppt)
Again we connect the Salinity Sensor to the logger pro and measure the salinity over a certain period of time until it stabalized.
Results(at the surface):
Docks: 30.7
Marina: 30.2
Source of Error: The measurements were only taken at the surface of the water.
3)transparency (m)
We lowered the Secci Disk into the water at the docks until it dissapeared and then we raised it again until we could see it. At the exact point that we saw the disk again, we marked the rope and measured it. The same was done at the Marina in between the boats.
Results (m)
Docks: 2.5
Marina: 1.3
Source of Error: Some people can see more than others so there was a variation in what was the actual transparency. Also, there is the uncertainty of the measuring instrument used to measure the length of the rope that was under water.
4)Dissolved oxygen content
By connecting the oxymeter to logger pro, we can see the amount of dissolved oxygen in water.
results(mg/L)
Docks:10.8
Marina:13
5) Dissolved CO2 (mg/L)
Using 25ml of sample water, we did a titration of the solution HI 3818-0 against water. The colour chagne from colourless to pink determine the end point of the titration and thus the CO2 content.The remaining solution times a certain ratio will give us the amount of dissolved CO2 in water.
Results:
Sea Table: 10.7 (+/-0.5)
Marina:6.3 (+/-0.5)
Source of error: The end point is difficult to determine due to the minor change of colour. Moreover, the water sample taken for docks is from sea table. Therefore, it is not a completely arrurate representation. Another source of error would be the transportation of the water back to the Lab, and in the process some of the CO2 would have been converted to carbonic acid. As for other discrepincies, please refer to the previous entries.
Analysis:
The average temperature at the two stations were relatively similar where as the salinity at the Marina was less than that measured at the Docks. Also, the transparency at the Marina was significantly less than that at the Docks. The level of CO2 at the docks was significantly more than that at the Marina. The level of O2 is higher in the Marina than that of the Docks.
**We must keep in mind that the Docks results and the Marina Results were taken on different days.
Interpretation:
We believe that the salinity was less at the Marina because of the rainfall the previous night. The transparency at the Marina was less than at the docks possibly because of pollution from the boats and the sewage drained. CO2 content at the docks was more because circulation and the possibility of more aquatic plants utalizing the CO2 for photosynthesis. Dissolved CO2 level and O2 oppose each other in the different locations. The higher O2 level in the Marina further proves that there are more aquatic plants in the Marina that release the oxygen. This is supported by the smaller amount of CO2 found at the Marina. The opposite is true of the Docks, implying there is less aqutic plants.
Conclusion:
Through the information gathered, we have come to reject our initial hypothesis. There seems to be more aquatic plants at the Marina than there is at the Docks because of the higher oxygen content. We believe that the sewage that is drained into the water at the docks aids the aquatic plants to grow and thus there is higher production of O2.
