Through classroom and field activities, students sort, categorize and come up with a common definition of marine debris.

MARINE DEBRIS Composition and Abundance: Materials for Grades 9-12

Lesson 1: Beach Box Exploration
from Oregon Sea Grant

What is marine debris? Bring the beach into the classroom. In this activity, students explore contents of ‘beach boxes’ in groups at tables, sorting contents into “marine debris”, “NOT marine debris” and “not sure”. What evidence do they use to decide how to categorize each item?

What evidence did you use to decide if an item was marine debris or not? Did you detect any similarities or patterns in the box contents? Were you surprised to find particular objects in the box? Sort materials by other criteria such as materials, size, possible origin, etc.

Lesson 2: Investigating the Great Pacific Garbage Patch

How abundant is marine debris? There is a great deal of information and misinformation about how much marine debris exists in the open ocean and how it is distributed. We often hear that “The Great Pacific Garbage Patch is twice the size of Texas”, but what exactly does that mean? Have students read and discuss the article “Pacific Ocean 'garbage patch' exaggerated, new analysis asserts” [pdf]. What are some of the exaggerated claims that are identified by researchers in this article? How could the way marine debris is sometimes described lead to misconceptions? How can we convey the magnitude of the problem accurately?

Ask students to research the issue further using the resources listed below and others.  Brainstorm ways to convey the problem of marine debris to others in ways that are both compelling yet based on accurate information. Students can then write their own news story about marine debris.


Lesson 3: Quantifying Marine Debris - General Protocol  or Microplastic Protocol
from Plastic Beach Project from 5 Gyres

How much and what kind of marine debris is on the beach? Students use a sampling protocol to collect, sort and quantify marine debris on a beach.

Create a graphical representation of the types and quantity of marine debris collected. What were the main types of marine debris found at your study site? What further questions do you have about marine debris at your study site? How could you design an experiment to answer one of those questions?


Lesson 4: Plastics in the Water Column
from Monterey Bay Aquarium

Where can you find plastics in the water column, and why? Students explore the densities of different plastics to see where in the water column they would likely be found. Then they relate the location of plastics in the water column to the feeding behavior of various marine organisms and discuss how marine debris can cause problems for different animals inhabiting a variety of ocean depths.

How is density related to buoyancy? Based on your findings, would you expect to find marine debris only at the surface of the ocean? Why or why not?


Lesson 5: A Degrading Experience
from NOAA Turning the Tide on Trash

How long does it take different materials to degrade? Students perform an experiment to learn how different types of debris break down over time and how they are their degradation is affected by environmental conditions.

Which objects persisted the longest? What physical factors in the ocean might affect rates of degredation? Does the ability of an item to degrade affect whether it is likely to be found in the marine environment? Could marine debris continue to impact ecosystems even after fragmentation?

When plastics break down, they become smaller microplastics, and even smaller nanoplastics.

More about this focus area

Marine debris is any solid, persistent, human-created waste that has been deliberately or accidentally introduced into a waterway or ocean. Marine debris is a global problem which impacts ecosystems and organisms from shorelines to the ocean floor.

  • What is marine debris?
  • Where do we find marine debris?
  • What physical characteristics do marine debris materials have in common?
  • Marine debris is any persistent solid material that is manufactured or processed and disposed of or abandoned into the marine environment.
  • Marine debris exists where humans can easily see it, as well as places where humans cannot easily see it.
  • The majority of marine debris is made of plastic materials.

ESS3.C - Human Impacts on Earth Systems - Sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources, including the development of technologies