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Location: Home / Activities / Cold-stun Survey
Background Information:
Sea turtles are reptiles that are very susceptible to quick changes in water temperature. Reptiles are ectothermic animals because they depend on external sources of heat to determine their body temperature. Mammals and birds are endothermic animals that can regulate their own body temperature through internal heat production (metabolic processes). Both sea turtles and humans can become hypothermic in certain situations. Loggerhead sea turtles that are suddenly exposed to very cold water (<10 °C) become lethargic and float to the surface of the water. If the water temperature drops below 5-6 °C death can occur.
Cold-stunned loggerheads can be found stranded on inshore and offshore beaches. Animals in the shallow protected sounds of inshore waters appear to be more susceptible because of quick changes in water temperature. With proper veterinary and husbandry care, these animals recover and can be released back into the wild.
Activity Instructions:
For the past three years the North Carolina Aquarium on Roanoke Island has rehabilitated stranded sea turtles. Data from the past three years can be found at www.ncaquariums.com/turtletrails and contains information on the number of cold-stunned loggerheads stranded, as well as information on their weights, date of stranding and date of release. Have the students work in groups to create one or more graphs using the variables you assign. Examples include number of strandings per year, average weight per species, average length per species, and total number of sea turtles per year. Depending on the graphs that you choose to create, the students should learn about cycles in stranding patterns, species characteristics, and the importance of dependable record keeping.
Now let's see what your students can do with the data!
Cold Stun Survey Data
(Microsoft Excell Spreadsheet, 24 KB)
Procedure:
- Obtain copies of the data sheets. Create a graph using the variables your teacher has assigned.
- Post your graph and then explain what the graph represents. Do you notice any patterns (seasonal, between species)? Develop a reasonable hypothesis for the patterns.
Discussion Questions: (answer these using your classmate's graphs)
- Is the total number of cold-stunned turtles different for each season? Explain.
- What possible reasons could explain the increase in number of stranded loggerheads during the 2002-2003 season?
- Compare the average weights of cold-stunned loggerheads to other cold-stunned species. Do the weights differ? Why?
- Compare the average lengths of cold-stunned loggerheads to other cold-stunned species. Do the lengths differ? Why?
Challenge Question:
This question involves integrating your data with data from an outside source.
The Army Corps of Engineers' Field Research Facility compiles monthly ocean water temperature profiles. This data can be obtained by going to http://www.frf.usace.army.mil. Find the water temperature profile near the bottom of the page. Going to this section will provide you with monthly profiles for each year. Using these profile graphs, look at the months of October through January for one of the stranding seasons. Record the approximate date when water temperature dropped to 50° F. Does this correlate with the date of the season's first stranding?
Conclusion:
Scientists use graphs to help them visualize data and find trends. Did creating graphs give you a better understanding of the aquarium's stranding data?
This Activity is available as a printable PDF for your convenience.
Cold Stun Survey (Adobe PDF, 136 KB)
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