Ecological Interactions and Biodiversity of Kelp Forests Lesson Plan: Middle School

In one or two class periods, students learn how kelp forests play a vital role in the health of our global oceans.


Kelp forests play a vital role in the health of our global oceans. These fragile biodiverse ecosystems provide the ideal ecosystem to look at ecological interactions among organisms, trophic structure, nutrient cycling, and overall ecosystem dynamics. Oftentimes students who live near the coast get to experience the rock intertidal zone, but rarely do students get a chance to explore and understand what lies beneath the vastness of the ocean. This lesson will allow students to explore the kelp forest using basic concepts in ecology without having ever left the classroom.



Students will: 

● Engage in meaningful activities focus around kelp forest ecology and the role of kelp forests in maintaining the health of our local and global oceans 

● Work cooperatively in small groups to research, brainstorm to while looking at ecological interactions in a kelp forest 

● Work cooperatively as a group within the larger context of the class to connect concepts and organize their representation of a kelp forest food web 

● Discuss ecological implications of changes in the kelp forest ecosystem



In addition to the MyHero film you will need the following materials: 

● Notecards/thick paper 

● Scissors 

● String



1. Exploring Food Chains in the Kelp Forest Ecosystem 

2. Developing Food Webs in the Kelp Forest Ecosystem 

3. Discussion of ecosystem changes/ Role of ecological niche



The following questions will help you determine if your students gained appropriate understanding of Ecological Interactions and Biodiversity in Global Kelp Forest Ecosystems 

Q. Were students able to create accurate food chains and food webs?

Q. Were students able to have a good discussion about changes in the kelp forest ecosystem and how it would impact the environment and other species? 

Q. Did students get a basic understanding of kelp forest ecology and basic ecological terms?


For further assessment students could be tested on ecological terminology and asked to create a food chain/food web.



This lesson is meant to give students a basic introduction into kelp forest ecosystem and basic ecological terminology. However there are several ways to extend or expand the lesson. 

● If you live in an area where kelp is accessible it would be very beneficial to bring in a sample and allow students to examine it either macroscopically or microscopically. Looking at a kelp holdfast you will find multiple small critters and can further discuss biodiversity. 

● You can further expand this issue of changes in the kelp forest ecosystem by discussing human impacts: harvesting, overfishing, pollution, climate change. In addition, you can have them come up with solutions for how to ensure a healthy ecosystem and discuss the idea of restoration.



Kelp forests provide an important role in the health of our global oceans. They are found pole to pole in nutrient rich waters with water temperatures typically 20°C or less. Their dependence on light for photosynthesis restricts them to shallow coastal zones no greater than 40m in depth, an area often referred to as the subtidal zone. These kelp forests rapidly grow, sometimes gaining up to 30cm per day, and provide a rich biodiverse ecosystem for some of the 800 species that call it home. Each species occupies its own specific niche, or role within the environment. The balance of these interactions is what keeps the kelp forest healthy and in balance with the surrounding ocean environment. With more and more human exploitation of our ocean resources, our kelp forests and the species that reside within them have become threatened. To maintain their existence humans have resorted to restoration efforts.


Lesson Plan Activities


1. Q. What is a kelp forest and why is it important for ocean health? 

● Have students think pair share 

● Whole class share out 

● Read overview and background provided 

2. Review or introduce the following terms: 

● Ecology 

● Trophic Structure 

● Food Chain 

● Food Web 

● Biodiversity 

● Niche



3. Describe a kelp forest (see guideline) and compare to the nearby biome that students are most familiar with. Emphasize the biodiversity and the abundance of interactions between organisms. 

4. Show the My Hero film (9 min): The Kelp Lady 

5. Draw a basic trophic structure and food chain of a kelp forest (see handout**) and have students draw as well

6. Discuss the importance of food chains and balance in an ecosystem 

7. Q. How might the balance in a kelp forest be disrupted? 


Practice and Application

8. Give each student and organism card** and have them find 2 other potential organisms in their food chain. Have students create a food chain with string (optional: have them also draw a trophic structure for their group) 

9. Have each food chain create a larger food web by having each student in the chain link with one other. All students should have at least 2 connections and a tangled web of string by the end. 

10. Have one or two students (phytoplankton and algae/kelp) leave the web. Discuss the implications----disruption in biodiversity, ecosystem as a whole, and trophic structure.


** Link to handout and organism cards


11. Provide any feedback based on observations (how could have students more easily formed chains/webs)



12. Review concepts/terms: 

● Ecology 

● Trophic Structure 

● Food Chain 

● Food Web 

● Biodiversity 

● Niche and the role of each organism in the ecosystem 

13. Reiterate goal of activity/essential question(s) 

Q. What is a kelp forest and why is it important for ocean health?) 

14. Have students share out about local Eco Heros in their lives similar to Nancy Caruso in the film (for a longer assignment students could produce a video, art piece, or short story)



Adapted from the SIOP Model by Echevarria,Vogt and Short, 2008.

Created By: Lauren Fieberg, Sage Hill School (revised 2020)

Organizer created on 7/21/2020 2:12:39 PM by Laura Nietzer

Last edited 4/22/2024 11:35:18 AM by Laura Nietzer