Coastal Carolina University 2

Introduction to Salinity and Tides

In this study, we focus on understanding how various factors impact salinity levels, specifically regarding tides, evaporation, and precipitation. Tides play a crucial role, with water levels fluctuating as tides come in and go out, thereby influencing salinity.

Impact of Evaporation and Precipitation

  • Evaporation: Results in higher salinity levels because as water evaporates, the concentration of salt in the remaining water increases. This leads to a significant elevation in salinity.

  • Precipitation: Conversely, rainwater entering the system through precipitation lowers salinity levels by diluting the salt concentrations in the water. Thus, understanding the relationship between these factors is essential for data interpretation.

Research Objectives

The study aims to achieve two main objectives:

  1. To determine the difference in salinity levels between Sun Sound and Rainy Island Beach.

  2. To compare two salinity measurement methods: the live side (YSI) and titration.

Expected results should indicate differences in salinity levels based on location and measurement methodology. A prediction could be that titration proves to yield more accurate results than the YSI due to its precision in measuring salinity changes.

Methods of Data Collection

Field Activities

  • Date and Location: Specify the date of data collection (as found on the data sheet) and confirm the site (e.g., Rainy Island).

  • Data Collection: Collect various parameters like temperature, oxygen levels, chlorophyll, phosphate, and nitrogen; however, focus primarily on salinity for the report.

  • Salinity Measurement: Collect salinity samples using two simultaneously deployed buckets, filled with water from the study sites, which will be measured using the YSI PRO2030 sensor, a salinity and temperature probe manufactured by YSI.

Laboratory Activities

In the laboratory, perform titrations to measure salinity using a method adapted from Strickland and Parsons (1972). Use the Knudsen titration method, which is a recognized technique for determining salinity without detailing every step involved in the process. This method is derived from established guidelines and requires only a basic acknowledgment in the report.

Data Analysis and Figures

Two primary figures will be generated for this lab report:

  • Salinity levels measured by the YSI sensor.

  • Salinity levels determined through titration. Formatting instructions for these graphs will be provided to ensure uniformity throughout the report.

Citation Requirements

Only one citation is required in the methods section for the Strickland and Parsons paper. In-text citations should follow a defined format depending on the number of authors and can include additional sources if desired. Ensure to include a reference section listing all cited works, particularly the required one.

Results and Discussion

Overview of Results

The results will be discussed in detail once graphs are created, focusing on the relationship between the two measurement methods and any observed variances in salinity levels. This section should analyze the data collected and compare salinity readings from both sites.

Key Discussion Points

  • Evaluate the accuracy of the Knudsen titration compared to the YSI measurements.

  • Discuss potential reasons for disparities in salinity levels between Dunn Sound and Rainy Island Beach, addressing the controlling factors like evaporation, precipitation, and tidal influence.

  • Anticipate seasonal salinity variations, referencing any historical data available for Ladies Island salinity to explain patterns observed during certain weather events.

    • Include specific observations such as when salinity was at its highest (e.g., summer) and lowest (e.g., after storms).

    • Utilize Dr. Benitez’s unpublished data from an 18-month period if relevant, citing it correctly in the report to discuss historical trends.

Titration Process

The titration method involves adding potassium chromate and silver nitrate to the sample to precipitate silver chloride visually:

  1. Begin with a clear yellow sample, adding silver nitrate until a milky yellow color appears, indicating the presence of silver chloride.

  2. Continue adding silver until a persistent red color signals the end of the reaction, indicating all chloride has reacted.

  3. Measure the amount of silver nitrate used to calculate salinity and record your results.

Precautions

Be cautious while handling silver nitrate due to its staining properties. Maintain safety protocols, including wearing gloves and handling substances carefully to avoid spills.

Final Remarks

The lab report should be concise, focusing primarily on the salinity aspect while summarizing data collection between field measurements and laboratory analysis. Ensure to reference all data correctly and adhere to the grading rubric provided in the lab manual. Submit your completed report in PDF format to avoid formatting issues.