This is the third of a four day lesson plan in the Unit Plankton Ecology. This lesson explores the consequences of a heterogeneous ocean on phytoplankton. Spatial heterogeneity in the ocean arises as a consequence of distance from shore as well as depth: water column stratification greatly affects the ecology and species distribution of phytoplankton. The distribution, population growth rates and general ecology of phytoplankton is explored as a consequence of the heterogeneity of water masses. Students will learn how the environment determines a species distribution and persistence, with a final discussion and understanding that how the ocean changes will include drastic changes to the biological community it holds within.

  • Learn about structure in the ocean: horizontal variability and vertical structure due to stratification.
  • Learn that stratification of the ocean has important consequences for the organisms that live within it, in this case phytoplankton.
  • This lesson begins by revisiting concepts taught in the previous lesson, involving phytoplankton and the marine planktonic food web. This lesson is part of a four lesson plan, which is summarized, along with the standards addressed, in the Unit Plankton Ecology. The introduction can be given using the Phytoplankton PowerPoint. This lecture relates ocean stratification to the environmental characteristics relevant to phytoplankton, linking physical stratification to biology. Ecological strategies of different groups coping with the stratification of nutrients, light and predators are explored. Background information for each slide of the lecture is annotated on the PowerPoint, as well included in the Phytoplankton Lecture Teacher Notes.
  • Finally the last three slides of the Phytoplankton PowerPoint show (roughly) the vertical and horizontal distributions of these phytoplankton groups. A discussion of why these phytoplankton groups have these different distributions ends the lesson. Students should be asked to hypothesize on the reasons for the phytoplankton distribution observed. The following lesson will provide more information on this topic, and students will be able to revisit the hypothesis they put forward as explanations on Day 3 and adjust them to the new information they will obtain from the activity of Day 4.
  • This activity was designed for high school Marine Science and Biology students.
  • Questions and class discussion.

Phytoplankton Satellite Image

Water Column

Lesson Materials
Related Phytoplankton Lessons
Lesson Specifics
  • Grade Level: High School Marine Science and Biology Students
  • Time Frame: 30-45 minutes

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