The Effects of Phytoremediation on Anthropogenic Nutrient Input

The Effects of Phytoremediation on Anthropogenic Nutrient Input

Logan Douglas Porter

Section 2

Group #6

Abstract

        As the human population continues to grow, human impact on the environment will also continue to increase. With pollution rates rising, ecologists must observe separate ecosystems in order to determine what type of impact humans are making and the severity of those impacts. Lake ecosystems are ideal ecosystems to observe because they can be so diverse and there are many different characteristics about them that can be studied. Some characteristics that can be studied are eutrophication, stratification, succession, turn over, and many other concepts. In this study, I examined the effects of nutrient runoff on eutrophication and how eutrophication can be controlled by phytoremediation. Data was collected, analyzed and used to observe certain characteristics about eutrophication, such as pH, nutrient levels, and dissolved oxygen, in order to determine whether the addition of the lotus plants would minimize the effects of nutrient runoff or not. It was found that through the use of phytoremediation, the negative impacts that humans have had on this lake have been minimized and this ecosystem is currently healthy.  This is important because as humans impact more and more ecosystems, ecologists must find ways to counteract the negative impacts observed and create solutions to improve the situation.

Introduction

        Today, the human population grows at a rate of 1.1% annually. This growth rate introduces approximately 70 to 80 million people to earth, per year (Nix 2012). As the human population continues to grow and more individuals are introduced to earth, the impact that humans can have on their ecosystem is becoming more and more of a concern to many people in the scientific field. These humans don’t only affect the ecosystem they live in, but they also affect those ecosystems that surround them. Even though almost every ecosystem on earth is different, the way they respond, the way nutrients cycle through them, and many other characteristics about them are similar. With the similarities between the different ecosystems, the impact of the actions taken by humans will affect many ecosystems in similar ways.  

        In lake ecosystems, changes in the temperature, pH, visibility, and nutrient content are some of the many things that humans can have an effect on. Man-made and managed areas, such as golf courses and farms, surround or border many lake ecosystems. Most of those man-made or managed areas use pesticides or fertilizers that can be harmful to lake ecosystems through nutrient runoff. Nutrient runoff is where excess amounts of nitrogen and phosphorous are added to lakes, creeks, or other bodies of water and results in an excessive growth of algae (Paerl 2009). Phosphorous and nitrogen are limiting factors for phytoplankton productivity and algal blooms. When there are excess amounts of nutrients added to the water, it increases the phytoplankton’s productivity thus leading to an increase in growth of algae. The growth of the algae negatively affects the rest of the life in and around the body of water. As the algae die and decompose, the organic matter decreases the amount of dissolved oxygen in the water that is available for use (Chislock et al. 2013). This process is called eutrophication and it will significantly change the temperature, pH, visibility, and nutrient content of the lake ecosystem.  

        Eutrophication is the number one cause of damage to freshwater ecosystems in the world. There are three main consequences that come from it. The first is that the growth of the algae on the surface of the water limits the penetration of light. This directly affects the growth of plants under the surface and the predators that use light to find their prey. Secondly, eutrophication is powered by photosynthesis. Photosynthesis lowers the amount of dissolved carbon in the water, thus causing the pH to rise to dangerous levels.  Lastly, like all life, eventually algae must die. When algae dies, the decomposition of them lowers the dissolved oxygen count in the water. This directly affects all aquatic life that uses the dissolved oxygen in the water to function on a daily basis (Boesch et al. 2009).  Though eutrophication is a potentially disastrous event for lake ecosystems, it can be managed through phytoremediation. Phytoremediation uses plants, such as the lotus plant, to remove or control certain contaminants, excess nutrients, or chemicals in ground water. Through this process, the plants use the potentially negative excess amounts of nutrients coming from runoff for their own benefit (Saier and Trevors 2010).

        I hypothesize that the shallow site will have a lower nutrient content and a more basic pH than the harbor site as a direct result of phytoremediation. If this hypothesis is true, the harbor site should have a higher nutrient content and a more acidic pH level. The purpose of this experiment is to establish the correlation between the amounts of nutrients in the water to the productivity of the algae. This is important because when the algae are going through photosynthesis, the level of dissolved carbon is being depleted, thus lowering the pH and making it more acidic. This correlation will provide information of the significance of phytoremediation and why it is such an important process for our world today.         

 Methods

        The sampling for this lab was performed on a lake within the Miami Whitewater Forest in Hamilton County, Ohio. The forest is currently operated, monitored, and managed by the Great Parks of Hamilton County.  This forest is located in a temperate region and displays an average temperature of 13 degrees Celsius and an average precipitation of 42 inches per year. This weather pattern is what is normally seen in temperate regions such as Ohio. The lake that way surveyed is man-made and managed. It shares many similarities with regular lakes such as shallow and deep areas, animals, vegetation on the shoreline, and many other characteristics. The lake has two distinct regions with different features. The first distinct region is the shallow side. This side is around 1 to 2 meters deep with a golf course surrounding it on one side and the forest surrounding its other side. The shallow side contains a large amount of lotus plants mostly located near the shoreline of the golf course, with a fair amount located in the middle of the shallow, and a small amount on the shore line of the forest. The other region of the lake is the harbor side. This side is around 3 to 4.5 meters deep. The forest completely surrounds this side with exception of the dock and harbor. This side has no lotus plants in it, only a small number of cattails.