Introduction to Oceanography: Abiotic
Water Temperature
Research Question: How and why does the water temperature change from the surface to the bottom of Long Island Sound?
Part A: Background Information
Water Temperature is very important because it helps to determine what kinds of organisms we expect to find in the estuary. Animals and plants have a certain temperature range that they can be successful in. If the temperature gets too cold or too hot, some of the organisms in the estuary could die, or might be forced to move to a different area. Some animals in Long Island Sound can withstand large temperature ranges and can be found in the sound year round, while others migrate in and out of the sound seasonally.
Air temperature, tide and time of year all influence the water temperature. The temperature of the air can influence the water temperature because heat can be exchanged between the air and the surface of the water. Tide influences the water temperature in coastal areas like Long Island Sound because water flowing into Long Island Sound from land via rivers and streams may be a different temperature than water flowing in from the Atlantic Ocean. Time of year influences the water temperature, because Long Island Sound gradually heats up in the summer and then gradually cools in the winter.
Water temperature is measured in degrees Celsius (℃). The temperature in Long Island Sound varies based on time of year and sample location. It can range from 1-24℃ depending on the season. The water temperature may also change with depth. The surface of the water is often a different temperature than the bottom water. (You may be more familiar with the Farenheit scale. To get a sense of large temperature range you can convert Celsius to Fahrenheit by multiplying the Celsius temperature by 1.8 and adding 32.)
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Source: Long Island Sound Study
This graph shows the yearly seasonal temperatures from 1976-2012, measured in nearby Niantic Bay by the Millstone Environmental Lab.
Part B: Sampling Method
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Source: Project Oceanology
The YSI Meter is a very important tool that can measure water temperature, salinity and dissolved oxygen all at the same time. The photo above (left) shows the sensor portion of the YSI meter that is deployed into the water (the weight attached helps the sensor to sink down straight). The photo above (right) shows the handheld computer portion of the YSI meter. Each number on the screen represents the temperature, salinity or dissolved oxygen reading in real time. This sensor is deployed just under the surface of the water for the first reading and then it’s lowered every meter after that until it reaches the bottom of the sample location.
To learn more about the YSI meter watch this brief video:
Part C: Prediction and Reasoning
Study the background information provided on Temperature (above) and look at the field notes (below).
Field Notes
Sample Location: Mouth of the Thames River estuary. (View map here)
Time of Year: Early May
Weather Conditions: Day time air temperatures are about 61 Fahrenheit and evening air temperatures are
Sample Depth: Temperature samples were collected at the surface (0 meters) and recorded every meter until
reaching the bottom at 9 meters. This is called a depth profile.
about 48 Fahrenheit.
Write answers to the following prompts on your sheet of paper.
1. Make a prediction: Will the surface water temperature and bottom water temperature be the same?
2. Explain your reasoning. WHY do you think the temperatures will or will not be different?
Part D: Analyze the Data
Look at the data table below. On your piece of paper, illustrate the data by making a special graph called a depth profile. The axes look a little different than you might be used to; simply plot the depth numbers on the vertical axis (y) and temperatures on the horizontal (x). The origin is still (0,0). Connect your points to form a line. Remember good graphs have a title, a labeled x-axis (including units), a labeled y-axis (including units) and an appropriate scale.
This table shows the temperature measured at each depth from surface to bottom in May.
Part E: Interpret the Results and Make Arguments from Evidence
Write answers to the following prompts on your sheet of paper.
1. Make a claim that answers the research question (one sentence).
2. What evidence was used to write your claim? Reference specific parts of your graph.
3. Explain your reasoning. Make sure to connect your answer to what you have learned about the estuary.
4. Was your prediction supported by the results? Use evidence to explain why or why not.
5. What do these numbers mean for the health of Long Island Sound? Are these readings within the normal range for this area? Standard Ranges for Water Chemistry
6. How would you follow up? Describe a new question that should be investigated to build on these results, and what future data should be collected to answer your question.
7. Extension: Organisms within an estuary can be significantly affected by the temperature of their environment. Check out this website about how rising temperatures are affecting the American Lobster. Write a paragraph that (1) identifies at least one factor that might cause temperature in an estuary to change, (2) explains how temperature affects lobsters, and (3) explains how this affects (or is affected by) people.
Congratulations! Your final analysis should include the following components:
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A statement of the research question that you chose/were assigned
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Your prediction and your reasoning
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Your labeled graph
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Your answers to the results questions
Share your results with your teacher!