The tiny structures within plankton contain stable isotopes, specifically oxygen-16 and oxygen-18, which they carry with them until their demise. These isotopes play a crucial role in understanding the environmental conditions of the earth over time. Their presence in small organisms like plankton adds depth to our knowledge of historical climate changes and oceanic compositions.

This information highlights the significance of seemingly minor elements in the grand scale of Earth's history. By studying these isotopes, scientists can glean insights into past climates and geological events, illustrating how even the smallest organisms contribute to our overall comprehension of the planet's evolution.