This lesson was written for the 2012 Arctic Ocean Ecosystem Workshop and was inspired by the research work conducted off the coast of Barrow, Alaska by researchers Steve Okonnen and Patricia Yager with PolarTREC teachers Lollie Garay and Chantelle Rose. Students will engage in a series of exercises to investigate seasonal change in the Arctic ecosystem based on authentic data. As researcher Patricia Yager notes, "In order to understand change over long time spans, you need to understand shorter time spans. The most fundamental controls on life in the ocean are the physical properties of water".
Students will investigate seasonal oceanographic change in the Arctic ecosystem by graphing and analyzing real data.
- Students should have an understanding of density through classroom discussions and hands-on inquiry based labs. Refer to the PolarTREC website for Density labs, for example:
- Students should have an understanding of how to graph data, set up plots and differentiate between independent and dependent variables.
- Students and teachers should be aware that oceanographers create depth profiles from their data. Depth will be plotted on the vertical axis, even though it is the independent variable.
- When checking student graphs, it is helpful to have a "master graph" on a transparency. That can be laid over the student graphs to check for accuracy.
- It may be helpful for students to have an understanding of contour maps or bathymetry to complete the T-S plot.
- This data was collected as a part of three separate research expeditions conducted by Stephen Okonnen, University of Alaska Fairbanks in collaboration with Carin Ashjian, Woods Hole Oceanographic Institution and Patricia Yager, University of Georgia at Athens.
- Have a discussion about seasonality in the Arctic. Seasonality is everything in the Arctic due to the extreme changes that occur with each season.
- Show students images of seasons in your local community as well as a summer image and winter image of the Arctic. Compare and contrast. Discuss the causes for seasonality.
- Discuss the interconnectedness between seasonality and biology. Biology is tightly coupled to seasonality.
- The main biological link between density and biology in the ocean is stratification. Phytoplankton needs light. Stratification keeps the phytoplankton near the surface.
- Show images of the Annika Maria, Healy and ground-based CTD deployment as the sources for the collected data.
- Distribute student data sheets and graph paper.
- Read over instructions to ensure students understand the task.
- Explain that students will be plotting four data sets on four separate graphs. Each graph will have two lines – one for winter data and one for summer data. These should be plotted in different colors.
- Review the vocabulary terms thermocline, halocline and pycnocline. Students will label these on their graphs.
- After the data is plotted, students will answer reflective analysis questions.
- Students will be assessed based on completion of a Post Activity Assessment. This will include a graph of new data to analyze and reflect upon.
- Students will self-evaluate their graphs using the transparency master graph.
- Teacher will assess the reflective questions using a rubric of their choice.
- Post Activity Assessment will be given providing the opportunity for students to apply their learning to a new situation.
PolarTREC teachers Lollie Garay and Chantelle Rose and Scientists Dr. Stephen Okonnen and Dr. Patricia Yager. Credit should be given to the research expeditions from which the data was obtained. Dr. Patricia Yager's 2010-2012 ArcticNITRO project and Dr. Okonnen/ Dr. Ashjian's Collaborative Research projects: Annual Observations of the Biological and Physical Marine Environment in the Chukchi and near shore Beaufort Seas near Barrow Alaska - a Biophysical Component of the Arctic Observing Network; and A Winter Expedition to Explore the Biological and Physical conditions of the Bering, Chukchi and Southern Beaufort Sea.