This EPA site for Teaching Climate Change has lots of resources compiled from a variety of agencies for teachers of all grade levels who teach environmental content. Lesson plans include activities for the classroom and also for student activities in the outdoors.
There are also quite a few lesson plans about oil spills and their effects on ecosystems. Examples include:
How would an oil spill affect a marine sanctuary--Students engage in a mock town meeting to determine how to clean up an oil spill in Monterray Bay. The factors involved in the discussions can be applied to oil spills in most other marine environments.
Liquid Density and Oil Spills Grades 6-8
Lesson plan on liquid density and oil spills for teachers of middle school students
National Wildlife Federation Oil Spill and Wetlands Education Grades 6-8
Lesson plan for middle school students about effects of oil spills and ways to clean it up.
Prince William Sound Regional Citizens' Advisory Council K-12, Teachers
Before the Gulf oil spill there was an oil spill from a tanker in Alaska. Getting and using oil continues to be an process that can threaten the environment. The activities in this curriculum teach students about oil spill issues regardless of the location of the spill.
How to talk with kids about the oil spill--A guide for parents and teachers when talking with kids about the Gulf oil spill. This has various other teaching tools and activities for kids.
The site also lists EPA ecosystem links with resources for teaching about wetlands, estuaries, coral reefs, watersheds, and more.
Access the site at: http://www.epa.gov/teachers/ecosystems.htm