Marine Chemistry Lab Report PDF

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Final Marine Chemistry Lab Report...

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Threat and variation of eutrophication in surface waters within Waties Island, South Carolina

Gabrielle Hamilton & Katherine Prandi Coastal Carolina University [email protected] [email protected]

Abstract Chemical analysis of an aquatic system can provide insight into the overall health of the system. Excessive input of nutrients into a body of water causes the system to become overly enriched, inducing rapid growth of algae. This can deprive the system of oxygen, detrimentally affecting the marine life. This process is called eutrophication. By testing nutrient concentration between two different study sites located on Waties Island, SC the results can be compared to the eutrophication parameters set by Bricker et al. (1999). The physical parameters and nutrient concentrations at the two sites were tested both in the field and laboratory setting. By analyzing the concentrations and comparing them to standard values and indicative ranges, it can be determined whether or not each nutrient is contributing towards eutrophication-like effects. It can be concluded that the water systems on Waties Island are currently experiencing low to medium eutrophication-related problems. Introduction Eutrophication is a process in which excess nutrients are added to bodies of water, like nitrogen and phosphorous, and causes an increase in algal and plant growth (Bricker et al. 1999). The addition of nutrients is a natural process and can vary in scale, intensity, and impact; however, more recent anthropogenic factors have greatly affected and accelerated these input levels (Bricker et al. 1999). Estuaries are bodies of water typically where fresh river water combines with the sea. This combination of freshwater runoff from land and salty water from the ocean creates brackish waters. Estuary systems are amongst the most productive and unique ecosystems in the world (Boynton, 1996) and are becoming more susceptible to eutrophication and the external inputs of nitrogen and phosphorous.

The experiment site was conducted at the Anne Tilghman Boyce Coastal Reserve (Waties Island), an undeveloped, wave-dominated barrier island located on the northeastern South Carolina coast. This reserve includes a wide variety of habitats including upland woods, tidal creeks, fresh and saltwater marshes, as well as the ocean. Dunn Sound, an estuary that is tidally flushed and influenced by a freshwater source and the ocean, acts as the main source of saltwater impacting this tidal estuary. This site, as well as a beach site was where sampling took place. Both systems provided water content data and oxygen, nitrate and nitrite, phosphate, Chlorophyll a, and phaeophytin were specifically tested on site and within the laboratory. By comparing the water composition within each system present within the same barrier island, differences in nutrient levels should be structurally distinguished between the estuary and ocean. Oxygen is one of the two most important gases in aquatic systems and is very crucial for some biological processes. Low dissolved oxygen concentrations can be expressed as anoxic, hypoxic, or biological stress. Anoxic concentrations are total depletions of oxygen within an environment, falling around 0 milligrams per liter (Libes 2009; Appendix A: Methods). Hypoxic conditions are still low in concentration, but a minimum amount of oxygen is present, typically around >0 milligrams per liter

≤ 2 milligrams per liter (Libes 2009; Appendix A: Methods).

Biological stress falls within the range of being almost hypoxic but is more defined as >2 milligrams per liter

≤ 5 milligrams per liter (Libes 2009; Appendix A: Methods).

Nitrogen is one of the primary nutrients that leads to eutrophication and algal growth (Bricker et al. 19999). There are many ways nitrogen can be inputted into an estuary system. Little River is a river that creates runs off that can enter the system, precipitation causes groundwater runoff, and basic ocean processes all contribute to the input of nitrogen. Nitrogen is needed in aquatic systems, but too much leads to eutrophication. Plants take up some of the

nitrogen, followed by fish eating the plants and therefore, nitrogen is passed along the food chain. This nutrient can be characterized into three different groups; low ( ≥ 0,...