INTRODUCING NC MIDDLE-HIGH SCHOOL STUDENTS TO QUATERNARY CLIMATE AND VEGETATION CHANGE

As part of a project to involve middle and high school students in scientific research on pollen in honey, to show them study of pollen has other applications, I adapted an existing college-level activity of mine. This activity has the students interpret a Quaternary pollen diagram that shows interglacial/glacial climate changes on the North Carolina Coastal Plain. The diagram comes from local lakes in Carolina Bays and is based on David Frey’s classic work from 1950’s. The oldest part of the record contains a diverse pollen assemblage, broadly similar to today, representing a previous interglacial. Then most of the trees (Hickory, Tupelo, Sweet Gum, Elm, Birch, Bald Cypress, and most Oak) disappear, leaving Pine, Spruce, Holly, grasses, and ragweed as the taxa during the Wisconsinan glacial. This is followed by a deglaciation succession where the trees reappear as the climate warms.

I made important modifications to the activity for this new, less prepared audience. I needed to explain how lake sediments are cored and basics of superposition. Feedback from teachers showed the value of putting photomicrographs of pollen directly on the pollen diagram rather than in a separate handout. I added drawings from the classic Britton and Brown illustrated floras to help students understand what the plants are. This is particularly important as some don’t grow in this area of North Carolina today (e.g., spruce, now living only in the mountains, or elm, wiped out by disease). Multiple iterations during summer workshops with the students were required to find gaps in the approach and fine-tune the activity.

The students were able to recognize the three major assemblages in the vertical succession and come to a broad climatic interpretation. Finally, they could recognize that the increase in ragweed pollen at the very top of the core represents disturbance created by European agricultural clearing. This is a time marker because of historical knowledge of when this event occurred.

There are obviously no glaciers in North Carolina today and Pleistocene ice sheets didn’t reach North Carolina, but this activity helps middle-high school students understand that glacial climate change had profound changes on the environment and ecology of this region. They can also contemplate how this region can change as today’s climate changes into the future.