Carbon Through Time: Legacy of Energy vs. Environment

The goal of this activity is to enable students to understand and explain the big picture of how carbon through time changes---to a kindergartener as well as to a senator! Although this activity focuses on written analysis of findings, results, and implications, extensions into in-depth discussions can easily be made. These understandings are foundational for geoscientists as well as all citizens of Earth for the 21st century. Failure to understand and act on knowledge of the big picture is not an option if humans are to sustain a healthy future. Most geoscience careers will interact extensively with this issue. The ecosystems of Earth and health of humans are both dependent on actions we take from here on.

This activity is designed for an upper division science course focused on geological and biological oceanography. It can be used as a lab, or as a series of field, lab, and class activities. It was tested in an oceanography course with 23 students. All students were juniors, seniors, or graduate students majoring in Biology, Environmental Science, Geology, Meteorology, Secondary Education-Earth Sciences, or Environmental Geosciences-Professional Science Master's. All students had taken an introductory science course with a lab (Introductory Geology or Meteorology). The course meets 3 days a week for 50 minutes at a time, and the lab or field work meets each week for two or more hours (for field work on the lake). This activity took 3 class sessions. The activity was situated at the end of the course, after we had collected the field data, taken a pre-test on the material, and undertaken all the laboratory research necessary to ascertain the carbon content of specimens collected.

This activity can be considered best as three pedagogical steps.

Step 1 (one two hour lab/field collection project): Faculty and students work together to collect a variety of common geological and biological specimens that contain a wide range of carbon contents. They also work to determine carbon contents of the materials by using a muffle furnace or other method of burning the specimens. See Student handout "Carbon Through Time: Legacy of Energy vs. Environment" (Microsoft Word 2007 (.docx) 25kB Nov28 16) and Loss on Ignition (LOI) Analysis Standard Operating Procedure (Microsoft Word 2007 (.docx) 13kB Nov28 16). Also see this example: Bar Graph Loss on Ignition of 12 Materials (Acrobat (PDF) 55kB Nov28 16).

Step 2 (one two hour lab or class period): Students explore and examine background about how organic carbon is generated, preserved in the geological record, and burned in the production of energy. Production of carbon dioxide as a result of burning is an entry point into the short-and long-term implications for the carbon cycle and humans' part in it.
Data showing various carbon contents of materials are entered into spreadsheets and plotted out in a graphical format. The bulk of the two hours is students wrestling with a series of carbon cycle questions and the data we use to track what is going on. Students have legion misconceptions that often confound instructors. Patience with instruction of fundamental chemistry, physics, and biology is necessary in most cases.

Step 3 (~50 minutes): In the third part of this activity, students critically read a review article on the acidification of oceans measured in recent decades, and compile ten observations that have been made. The intent here is for students to extend and apply understandings of the carbon cycle gained in the first two steps by applying their knowledge in a new situation that is more complex.

Group discussions and whole-class engagement on these findings can further extend what students gleaned from the work.

There are a few things that will help this activity run a bit more smoothly:

1. If faculty and students have access to bottom sediment and plankton sampling devices, almost any body of water can yield specimens that can be used for the research and data collection parts of this activity.
2. Other common geological and biological specimens can be acquired in most academic settings or just around the house: limestone, sandstone, chalk, coal, marble, oil shale, peat moss, salt, and wood. Substitutions of materials would be fine if all are not available.
3. Having access to a muffle furnace and doing the research to determine carbon content of materials is a good thing for students to experience. Likewise, using computers to produce spreadsheets of the data and plot graphical results can really drive home and make real the wide variety of carbon contents of common materials.

PRE-ASSESSMENT: Prior to introducing the activity, a pre-assessment quiz of seven items was taken by all 23 students in the class. Questions were true-false, multiple choice, ranking carbon contents of 12 geological/biological materials into three bins, and three extensive essay questions covering carbon through time. Scores on the pre-assessment quiz averaged 58.5%. Pre-Post Assessment/Grading Rubric (Microsoft Word 2007 (.docx) 15kB Nov28 16)

FINAL ASSESSMENT: Students were given the same quiz for post-assessment as they took for pre-assessment, but a month later, and after the activity and analyses were completed. The post-assessment scores averaged 95.7%, and improvement of 37.3%.

1) Student handout "Carbon Through Time: Legacy of Energy vs. Environment" (Microsoft Word 2007 (.docx) 25kB Nov28 16) is a 4-page document that includes background information, data presentation of laboratory results obtained, instructions on analytical procedures for making graphical displays of the data, analysis of the data, answering questions about the data and its implications, and reading, observations, and extensions to the ocean environment from a published review article "Acidification and More".

2) Students read this four-page article carefully: Henson, Bob, 2011, Acidification and More, UCAR Magazine, winter issue, p. 7-11. Using the instructions and table they are given in the "Carbon Through Time" activity described above, students record ten observations or findings from the article, and explain how they think data were gathered to support findings.

3) Analytical laboratory procedures to use a muffle furnace to measure carbon content of materials are found here: Loss on Ignition (LOI) Analysis Standard Operating Procedure (Microsoft Word 2007 (.docx) 13kB Nov28 16)
4) Acquisition of bottom sediment samplers and plankton nets can be found through several vendors. One that has durable and relatively inexpensive equipment is Forestry Suppliers. Another is LaMotte.