Preparation & Experimentation:

Seven containers, each being able to hold 18 litres, were each filled with 16 litres of tap water, with the chlorine content filtered out. Filtered water was used in order to remove chlorine content present in tap water, as this is toxic to the algae, and will inhibit the algal growth. The two types of fertilizer used were Plant Prod All Purpose Fertilizer 20-20-20 as the instant release fertilizer, and Smart Cote Hanging Basket Food 14-14-14 as the timed release fertilizer. These two fertilizers were chosen to ensure that the same ratio of nitrogen, potassium, and phosphorus are of the same, so that given quantities of each substance can be obtained. The two types of fertilizer were kept at room temperature. To simulate agricultural runoff, three different amounts of fertilizer were applied to each bucket. The control had no fertilizer, the low concentration contained 6400µg of fertilizer (both instant release and timed release), medium concentration containers contained 12800µg of fertilizer (both instant release and timed release), high concentration containers contained 25600µg of fertilizer (both instant and timed release), and extra-high concentration containers contained 51200µg of fertilizer (both instant and timed release). The varying concentrations of nutrients simulated the intensity of the agricultural runoff. The low concentrations would simulate little agricultural runoff, and increasing continually until the extra-high concentration, to simulate overuse of fertilizer and thus resulting in serious agricultural runoff and eutrophication. These values were in accordance to the values portrayed from the University of Florida, which classified nitrogen, which was present in equal amounts as the potassium and phosphorus in the fertilizers used, in different concentrations to describe the body of water. Values of less than 400 micrograms / litre of nitrogen would be classified as oligotrophic, which describes the lack of plant nutrients. Values from 401 to 600 micrograms / litre was classified as mesotrophic, describing medium amounts of nutrients present in the water. Values from 601 to 1500 micrograms / litre was classified as eutrophic, describing a body of water which is rich in nutrient and mineral content. Finally, values greater than 1500 micrograms / litre was classified as hypereutrophic, describing the nutrient content in the body of water as to be in an excess quantity. To complete the simulation of agricultural runoff entering bodies of water to cause eutrophication, each of the containers were seeded with 15mL of chilled river water from the North Saskatchewan River. With each of the containers seeded with this river water, it would simulate the runoff entering a river or lake, which stimulates the algae particles that are already present in the water. In order to aerate each of the containers to allow oxygen to enter the water, an air pump was used, which was connected to rubber hoses with air stones at the end to allow for maximum oxygen uptake into the water. The air pump was allowed to run for 24 hours a day. Furthermore, to encourage algal growth, Sylvania Grow-lux wide spectrum lights were used in order to provide the algae with the full spectrum of light to further promote photosynthesis. The lights were activated from 7am to 11pm, to simulate an average 16 hours of sunlight in a day. All containers were maintained at room temperature, and the rate at which air was pumped was constant through each of the containers, and through the length of time the investigation took place. The investigation lasted for four weeks, to allow for adequate algae growth.

 

Collection of Data:

After the four weeks were elapsed, each of the containers was filtered through pre-weighed filter papers. As it would be a lengthy process to filter the 16 litres of water using the force of gravity to pull the solution down through the filter paper, vacuums were utilized in order to speed up the process. By utilizing a reverse air pump, connected to several flasks, and in conjunction to using the Whatman no.1 filter paper, the process of filtering all of the solution within the containers was dramatically sped up. The wet filter paper was placed into pre-weighed paper bags to be placed in the incubator at 70oC, where the moisture content within the filter paper can be evaporated, leaving only the algae particles on the filter paper. The dry weight of the paper bag plus filter paper and algae was then taken, and compared to the initial weight of the paper bag and filter paper combined, without any algae.

Definitions

 

oligotrophic

Describing a body of water that lacks plant nutrients. This type of body of water would not encourage plant and algal growth. Eutrophication would not be occuring due to the lack of nutrients

 

mesotrophic

Describing a body of water that has medium amounts of plant nutrients. This type of body of water would somewhat encourage plant and algal growth to a certain degree. There is a chance that eutrophication is occuring, but it would be to a small degree

 

eutrophic

Describing a body of water that has high amounts of plant nutrients. This type of body of water would encourage plant and algal growth. Eutrophication may be occuring

 

hypereutrophic

Describing a body of water that has very high amounts of plant nutrients, so much that the plants present would not be able to use it all, and there would be an excess. This type of body of water would greatly encourage plant and algal growth, and eutrophication would most likely be occuring

 

seeded

A sample of water, in this case, taken from the North Saskatchewan River, placed into the test environment to implant a population of algae

 

leaching

The loss and removal of the fertilizer, which can result in runoff containing nutrients

 

denitrification

The removal of nitrogen from the soil, which may occur due to the bacteria found within the soil