Thursday, September 27, 2012

Mad River Basin: Physiochemical Parameters

     Any aquatic system is directly affected by the surrounding environment. The types of minerals and sediments that end up in suspension are a byproduct of the composition of the surrounding geologic features that the body of water moves through. Because of both biotic (nitrogen fixing, byproducts of life processes, weathering from plant growth, etc.) and abiotic factors (Rainfall, erosion, mechanical weathering from wind, etc.), particles in rock and soil naturally end up in waterways. Human activity is unique in that we can have a very dramatic effect on the water quality. Through mining, pollution, construction, and redirecting natural flow of waterways, we are able to make a large impact in a relatively short time.

     The parameters that we tested include pH, temperature, specific conductivity, and total alkalinity. By measuring pH, one can find the relative concentration of H+ ions dissolved in the waterway. Temperature may vary depending on season, elevation, type of runoff flowing into the system, etc.Specific conductivity measures the concentration of electrolytes (in our case, CaCO3), in suspension, and finally, total alkalinity measures a waterway's ability to neutralize acids that enter the system (commonly confused with basicity). When comparing the Mad River to other, larger aquatic systems, all of these measured values will vary more over time in the Mad River because of its smaller volume. A smaller volume is more susceptible to swings in both solvent concentration and temperature.

     A seasonal change in pH can be seen below in Figure 1:

Figure 1: The figure above, displaying the pH readings over the course of one calender year (2009)was taken from the Mad River. There is no trend that can be seen as the year progresses.

     Below in Figure 2, a seasonal trend can be seen when looking at temperature readings throughout the year:

Figure 2: The readings taken from the Mad River over the course of the year have a definite trend, increasing over the summer months when air temperatures are elevated and decreasing during the winter months when air temperatures drop.

- Evan A.

1 comment:

  1. Quick note, that conductivity doesn't measure what is in suspension, but rather what is soluble. That is probably mostly Ca ions and HCO3 (bicarbonate) weathered from CaCO3 as you mention, but could also contain ions from salts applied on roads, ions from atmospheric deposition, etc.

    Also, pH may vary more in the Mad River than in a larger mostly carbonate stream (e.g. Ohio River), but it is likely to vary less than streams in other rock types (e.g. granite from lab) that do not have acid buffering capacities.