Written in Chalk

This activity explores images of chalk formations and coccolithophores, which serve as phenomena for learning about the interactions between biological and geological processes.

Chalk forms from the microscopic skeletons of phytoplankton, such as coccolithophores. When coccolithophores die, their calcium carbonate shells sink to the seafloor and eventually become chalky sediments. Over millions of years, this process has resulted in the vast deposits of chalk found worldwide. These images show one famous chalk formation, the White Cliffs of Dover in England, and a micrograph of the coccolithophore species Emiliania huxleyi.

The “Educator Materials” document includes background information and implementation suggestions for using the images as phenomena. The “Student Handout” includes the images and background information.

“White Cliffs”/Figure 1 image by Scott Chimileski, Harvard University

“Coccolithophore”/Figure 2 image by Jeremy R. Young, University College, London