Sunday, November 18, 2012

Nitrate Behavior - A Scalar Comparison

Mississippi River Watershed ( 
Nitrites are produced by a number of species of nitrifying bacteria in the absence of mineral nitrate sources, by means of various fermentation processes using urine and dung. Nitrates are mainly produced for use as fertilizers in agriculture because of their high solubility and biodegradability. The most prevalent nitrates are ammonium, sodium, potassium, and calcium salts. Several million kilograms are produced annually for the purpose of agricultural fertilization.

In most cases of excess nitrate concentrations in aquatic systems, the primary source is surface runoff from agricultural or landscaped areas that have received excess nitrate fertilizer. This process of excess fertilizer accumulating in aquatic ecosystems is called eutrophication and can lead to the sudden appearance of algal blooms. Because of the quick onset of floral growth, the ecosystem can develop water anoxia and dead zones, as well as the blooms causing other changes to ecosystem function, favoring groups of organisms better suited for the low oxygen content. Effectively, the excess of nitrate can change the makeup of aquatic biodiversity.
Upper Great Miami Watershed (
Fluctuations in dissolved nitrate present in waterways can vary depending on the scale of comparison. Within the small streams and rivers of Ohio,fluctuations in nitrate concentration may not be the most extreme. When looking at the data provided by the USGS concerning the Upper Great Miami watershed, we observed a small fluctuation in the minimum and maximum levels of nitrate being transported downstream (measured in g/km/hr). Below is a graph of the range (lowest to highest) and average hourly-area normalized yield of total N and total P for the Ohio River during the month of September based on all September averages:
When observing the fluctuations in the levels of dissolved nitrate transport in the waterways that the Upper Great Miami drain into, like the Ohio and Mississippi river, differences in the maximum and the minimum measurements differ much more drastically. The measurement of these waterways differ in this way because these large aquatic systems move water that had ran off of a much greater area of land. The amount of dissolved nitrate present is a result of many watersheds' water output compounding to create a highly concentrated volume when finally reaching the Mississippi River Delta and dumping into the Gulf of Mexico.
- Evan Amstutz

1 comment:

  1. The yield graphs show the appropriate magnitude of difference between sites, but the units are off. The information is well-stated!