Title: Determine the impact of instant release fertilizer versus timed-release fertilizer in respect to eutrophication levels.
Grade level: High School - Grades 10-12
Academic Level: Ordinary
Project Type: Experimental
Awards: Second Place, Canada Wide Virtual Science Fair
Affiliation: Canada Wide Virtual Science Fair
Description: Seven containers, each being able to hold 18 litres, were each filled with 16 litres of tap water, with the chlorine content filtered out as this is toxic to the algae, and will inhibit the algal growth. Each of the containers was seeded with 15mL of chilled river water from the North Saskatchewan River (containing algae). The varying concentrations of nutrients applied simulated the intensity of the agricultural runoff. The low concentrations would simulate little agricultural runoff, and extra-high concentration, to simulate overuse of fertilizer and thus resulting in serious agricultural runoff and eutrophication. After four weeks, each of the containers was filtered through pre-weighed filter papers. The moisture content within the filter papers was evaporated, leaving only the algae particles on the filter paper.
Eutrophication is an increase in chemical nutrients - typically compounds containing nitrogen or phosphorus - in an ecosystem, and may occur on land or in water.
Eutrophication is frequently a result of nutrient pollution such as the release of sewage effluent and run-off from lawn fertilizers into natural waters although it may also occur naturally in situations where nutrients accumulate (e.g. depositional environments) or where they flow into systems on an ephemeral basis. Eutrophication generally promotes excessive plant growth and decay, favors certain weedy species over others, and is likely to cause severe reductions in water quality. In aquatic environments, enhanced growth of choking aquatic vegetation or phytoplankton (that is, an algal bloom) disrupts normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen in the water, needed for fish and shellfish to survive. The water then becomes cloudy, colored a shade of green, yellow, brown, or red. Human society is impacted as well: eutrophication decreases the resource value of rivers, lakes, and estuaries such that recreation, fishing, hunting, and aesthetic enjoyment are hindered. Health-related problems can occur where eutrophic conditions interfere with drinking
An algal bloom is a rapid increase in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells. Although there is no officially recognized threshold level, algae can be considered to be blooming at concentrations of hundreds to thousands of cells per milliliter, depending on the severity. Algal bloom concentrations may reach millions of cells per milliliter. Algal blooms are often green, but they can also be yellow-brown or red, depending on the species of algae.
Algal blooms are the result of an excess of nutrients, particularly phosphorus. Excess carbon and nitrogen have also been suspected as causes, but research has shown that this is not the case. When phosphates are introduced into water systems, higher concentrations cause increased growth of algae and plants. Algae tend to out-compete plants under these conditions, and many plant species may begin to die. This dead organic matter becomes food for bacteria that decomposes it. With more food available, the bacteria increase in number and use up the dissolved oxygen in the water. When the dissolved oxygen content decreases, many fish and aquatic insects cannot survive. This results in a dead area.
Blooms may be observed in freshwater aquariums when fish are overfed and excess nutrients are not absorbed by plants. These are not generally harmful for fish, and the situation can be corrected by changing the water in the tank and then reducing the amount of food given.
Algal blooms sometimes occur in drinking water supplies. In such cases, toxins from the bloom can survive standard water purifying treatments. Researchers at Florida International University in Miami are experimenting with using 640-kilohertz ultrasound waves that create micropressure zones as hot as 3,700 °C. This breaks some water molecules into reactive fragments that can kill algae.
Source: Wikipedia (All text is available under the terms of the Creative Commons Attribution-ShareAlike License)