Abstract

1. Abstract • The Cove River Watershed extends about 15km2 south of New Haven and West Haven, CT. This is shown on the map of the Cove River (Graves). It is a freshwater and tidal estuary/ wetland that flow into the Long Island Sound. The invasive species of phragmities (see picture of very tall phragmities plants, "Die, phragmities, die!") was eradicated here In an area recovering from herbicide treatment, it is important to monitor the re-growth of native plants. (See photo of marsh grasses, "Photojournalist"). So in the Cove River Watershed, it was imperative that the state of the water and soil be monitored along with the growth of the plants. Since recovering from the takeover of invasive Phragmitesaustralisspecies, this area has been studied by local researchers. Students have monitored plant growth along with different soil and water qualities. This research involved collective research through several researchers and a collective conclusion to the state of the current Cove River environment. Remembering the environmental factors that affect the readings, the plants have undergone both growth and decay in their heights. More research must be done to fully return the environment to its natural state, but this research shows that it is slowly recovering. This research has been completed under GLOBE research protocols and contributes to the international database as well. Hypothesis The goal of this project was to monitor plant growth and determine that the Cove River environment is returning to a more natural state. By monitoring this recovery, researchers can conclude that eradication was successful. If the plant growth of marsh grasses is monitored along with water and soil data and all data is of normal range, then the plants should grow normally with the seasons because the plants are in their natural environment. The independent variable would be the levels of salinity, pH, conductivity, nitrate, phosphate, and dissolved oxygen. The dependent variable is the height of the plants. The constants would be the area where this research is conducted, the time of day, and the plants being observed. Conclusion After reviewing the data from the river analysis, it can be concluded that the overall plant growth was increasing and growing normally with stable levels of salinity, pH, conductivity, nitrate, phosphate, and dissolved oxygen. The seasons can be contributed to the decrease in the environmental temperatures and also the dissolved oxygen levels. The graph shows the levels of plant growth over three dates. The levels both increased and decreased, but this is normal. Since dissolved oxygen is inversely related to the temperature, the dissolved oxygen was lower in the summer months, when it was hot, and greater in the winter months, when it is colder. According to the Cove River Readings chart, the Dissolved oxygen level is around 9 and 9.5 during the colder month of November. In the warmer month of June, the dissolved oxygen level was 3.6. This would affect the aquatic life in the river such as bacteria and other small organisms in water. The pH of the environment began at 7 in the month of June, but it lowered to 6.6. 6.51, 6, and 6.58 in the dates recorded on the chart. The readings seem to be increasing so it is projected that the environment will return to a pH7 of 7. The environment is still close enough to neutral where the ecosystems are not greatly affected. Plant growth was not greatly affected by this factor since it was generally neutral throughout the readings. "The conductivity of rivers in the United States generally ranges from 50 to 1500 µmhos/cm. Studies of inland fresh waters indicate that streams supporting good mixed fisheries have a range between 150 and 500 µhos/cm" (5.9 Conductivity). The conductivity ranged around 320 µhos/cm so this was within normal range of this type of marsh environment. "Salinity in salt marshes is highly variable because of the influx of both fresh and saltwater into the environment" (Salt Marshes). The normal salinity of seawater is approximately 35ppt, but since freshwater and saltwater mix in this environment, it would naturally be lower. "Perhaps one of the greatest stresses for salt marsh plants to overcome is the difficulty of roots to take up water due to the lowered water potential of salty soil, which averages 10 to 20 ppt. Many marsh plants adjust to this physiological strain by accumulating sugars and other organic solutes in their tissues, thereby increasing the vascular pressure needed to absorb water from the soil" (Salt Marshes). The plants monitored have adjusted to this particular issue. Nitrate concentrations should stay around 0.1 to 1 mg/l, while the phosphorus concentration should stay around 0.1 to .1 mg/l. Both these concentrations were measured to be high in the environment at first. This might have affected the environment in the form of algal blooms if it had stayed that high, around 4 mg/L, and not decreased, as it did. The last reading shows significant increase in nitrate and phosphate levels showing possible effects to the environment. These levels could result in algal blooms and affect plant growth in the future. Continual monitoring is needed. Effects of Nitrate , Phosphate, Dissolved Oxygen, Conductivity & Soil Salinity on Plant Growth in the Cove River Watershed Introduction             Different elements or qualities of the soil and water can affect plant growth. The plant species grown are common marsh plants that thrive in these environments. Tidal marshes are usually kept at a neutral pH. Water environment that is too basic or acidic affects the life of the plant species and other animal species.             “If a nitrogen limited system is supplied with high levels of nitrogen, significant increases in phytoplankton (algae) and macrophyte (larger aquatic plants) production may occur. The recommended level of nitrogen in estuaries to avoid algal bloom is 0.1 to 1 mg/l, while the phosphorus concentration is .01 to .1 mg/l. Higher concentrations of both will support less diversity” (Nitrate-Nitrite). Nitrogen and phosphorous levels directly affect the environment since organisms need a certain amount of each element to function properly. "Conductivity is a measure of the ability of water to pass an electrical current. Conductivity in water is affected by the presence of inorganic dissolved solids that carry a negative charge or ions that carry a positive charge. " (5.9 Conductivity). The measurements of conductivity can help to determine the compounds that are entering the system since certain elements affect the level one way or another. Salinity measures the amount of salts in the soil or water and can be found by testing samples for salt concentration. It is an important factor in plant growth because the intake of salts increases the osmotic pressure of the plants and its energy. Too many salts can inhibit nutrient and water intake which may cause the plant to wilt even if the surrounding is saturated (Soil Salinity). The amount of dissolved oxygen in an aquatic environment is important to the survival of any aquatic life. Areas of high water flow tend to have high dissolved oxygen levels and stagnant waters tend to have less. The concentration of dissolved oxygen is inversely related to water temperature so as the temperature Water).  It is important to note that the Cove River does not have a high water flow and the seasons which the readings are taken should be considered when analyzing dissolved oxygen levels. Works Cited Graves, Scott M. Ph.D. "Phragmites on the Cove River." Science Education & Environmental Studies. Southern Connecticut State University. PowerPoint. 2012. 03 June 2014.\ "Nitrate-Nitrite." Water Resource Characterization DSS. N.p., n.d. Web. 03 June 2014. "Photojournalist: Mary Schwalm." Photojournalist Mary Schwalm. N.p., n.d. Web. 04 June 2014. <http://maryschwalm.wordpress.com/tag/nature/>. "Salt Marshes." Salt Marshes. N.p., n.d. Web. 05 June 2014. <http://www.sms.si.edu/irlspec/Saltmarsh.htm>. "Soil Salinity." Soil Salinity. N.p., n.d. Web. 03 June 2014. "Understanding Algal Blooms." News Releases. N.p., n.d. Web. 05 June 2014. <http://floridaswater.com/algae/>. "Water Properties: Dissolved Oxygen."Dissolved Oxygen, from USGS Water Science for Schools: All about Water.N.p., n.d. Web. 05 June 2014. <http://water.usgs.gov/edu/dissolvedoxygen.html>. • "5.9 Conductivity." Home. N.p., n.d. Web. 03 June 2014. <http://water.epa.gov/type/rsl/monitoring/vms59.cfm>. • GLOBE.gov. N.p., n.d. Web. 10 June 2014. <http://www.globe.gov/home>. Methods of Research This research was conducted at the Cove River site behind West Haven High School. Researchers used water and soil samples from the river and Vernier probes to obtain the data. Research tools were generously bought by Mr. Kevin Dickson, West Haven High School’s AP Biology instructor, through grants. Students used these tools to obtain data for their projects, such as this one, and to contribute to GLOBE data research. Plant growth was monitored by measuring plant height with meter sticks. This research was made possible by Dr. Scott Graves, Mr. Kevin Dickson, and the AP Biology Class of 2013-2014. Graves Photojournalist Kharl Reynado .AP Biology .Mr. Dickson. 09 June 2014. Graves