Credit River Abiotic Feature Study

Variables

There are both independent and controlled variables in this lab. The controlled variables in the experiment encompasses the method, amount of intersects, the height of transect/measurements, size of quadrant, transects, location of site, time of year and day and the place of data collection. The independent variable is amount of sunlight.  Lastly, the dependent variables are the temperature, velocity, depth and oxygen reduction potential in the Credit River.

Data Processing and Presentation

* The compiled raw data will be placed in the appendix for viewing.

Figure 1

 

Figure 2

 

Figure 3

 

Figure 4

 

*Figures 3 and 4 discount one velocity measurement. This measurement was an anomaly at 0m/s, a significant difference from any velocity data. Not shown here, the anomaly changes the graph’s contents and makes statistical analysis much more difficult since the Microsoft Excel spreadsheet program cannot render a trend line for the point with the velocity of zero. By including this point, the relationship between velocity and temperature as well as depth would be harder to understand. Reasons for the statistical anomaly can only be speculated as human error (data collection mistake) in this situation since the depth was listed as 32cm and velocity as 0m/s while all other data had a velocity greater than 0. Therefore, the exclusion of this velocity measurement enables a more accurate interpretation of the velocity data in respect to its comparisons to other values of temperature and depth.  On a wider spectrum of analysis, the temperature readings were taken with an analog thermometer, therefore a person’s interpretation of the visual reading may vary depending on the perception of the visual data, which may vary from the true value by up to ±.5 degrees Celsius.  The uncertainty and possible error in the velocity measurements is that the method used to collect data involved sending a foam ball from one point upstream one meter downstream, this lead to human errors in timing of recording the data, and natural error of there not being a straight course of travel for the ball, resulting in an decreased velocity measurement; this was solved by taking the measurement three times for each quadrat and averaging the result.  Water depth was possible to have an error of ±.5cm because of bending in the metre stick used to collect data from water pressure, the inadequate placing of the measurement device, and the water level deviating within a small range of uncertainty.

Conclusion and Evaluation

In conclusion, abiotic factors influences are interrelated within the Credit River, and are dependent upon each other. There is been a positive correlation between increased oxygen reduction potential and temperature, which was unexpected, and therefore out of sync with the hypothesis. This could be due to an increase in the water volume in the river, and the lack of protruding rocks upstream or turbulence to further oxygenate water in certain quadrats; the rationale for this is that turbulence of the water increases the dissolved oxygen present in the water and that tree coverage or other moderately tall riverside vegetation may hamper temperature levels in the river as compared to other quadrats thereby skewing the results. Also, the temperature was negatively related to the increase in water depth, proving that according to the hypothesis, the cooler water will be situated at the bottom, and the top-water has an increased temperature, due to increased exposure to solar radiation resulting in conduction of radiation to the water.  To confirm the results further, the result of comparing water velocity to temperature reflected confirmed that its correlation is positive; this can be explained through examining the relation between water depth and velocity comparison in which as the depth decreases, the velocity of the water increases. The nature of the depth, temperature and velocity is that as depth decreases, a higher volume of water flows in a compressed space, therefore making the surface flow faster, and since a more shallow depth occurs when velocity is high, the average temperature for a quadrat will be greater. Therefore, all the abiotic factors can be linked cohesively; being intertwined within the effects of another, minus the oxygen reduction potential, which defied the hypothesis, and cannot be fully judged accordingly.

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