Freshwater Macroinvertebrates


Maria Papadimitropoulos

Henry Street School for International Studies



Summer Research Program for Science Teachers

August 2008



Grade Level: Middle School (6-8)



To sample, identify and count macroinvertebrates at a Hydrology Site



Students will collect, sort, identify, and count macroinvertebrates from habitats at their site.


Student Outcomes

Students will be able to:

- identify taxa of macroinvertebrates at their site;

- understand the importance of representative sampling;

- examine reasons for changes in the macroinvertebrate community at the hydrology site (if conducting the sampling can be done more than once a year);

- communicate project results


Science Concepts

Earth and Space Sciences

Soils have properties of color, texture and composition

Soils consist of weathered rocks and decomposed organic matter.

Life Sciences

Organisms have basic needs.

Organisms can only survive in environments where their needs are met.

Earth has many different kinds of environments that support different combinations of organisms.

Organisms’ functions relate to their environment.

Organisms change the environment in which they live.

Humans can change natural environments.

Ecosystems demonstrate the complementary nature of structure and function.

All organisms must be able to obtain and use resources while living in a constantly changing environment.

All populations living together and the physical factors with which they interact constitute an ecosystem.

Populations of organisms can be categorized by the function they serve in the ecosystem.

Living systems require a continuous input of energy to maintain their chemical and physical organizations.

The interactions of organisms have evolved together over time.


Materials and Tools

Equipment used to collect water chemistry measurements (YSI meter)

Latex gloves

Many clear plastic jars

Spray bottles

Several eyedroppers


Magnifying glasses

Shallow trays

Locally-applicable macroinvertebrate identification keys



Collect pictures or books illustrating local macroinvertebrates

Practice identifying the macroinvertebrates using local keys to macroinvertebrates

Sort groups (3-4 students)



At your hydrology site:

1. Locate the areas where you will collect your samples in the water.

2. Collect water chemistry measurements (pH, water temperature, dissolved oxygen) using the YSI meter before collecting macroinvertebrates. Be careful not to disturb the areas where you will be collecting macroinvertebrates.

3. Fill a bucket with water and organic matter (leaves, rocks, mud).

4. Find macroinvertebrates in substrate:

            -students should wear gloves to pick up individual leaves & rocks to look for organisms

            -using a forceps, eye dropper and spray bottle to “spray” off any macroinvertebrates, drop all organisms into a shallow tray containing water from hydrology site

            -continue these steps until all leaves and rocks are sorted through and all organisms have been put into the tray (tray should only contain macroinvertebrates and water)

5. Sort macroinvertebrates into taxonomic groups: (keep handling of the organisms to a minimum)

            -gently identify macroinvertebrates using local keys

-count or estimate the number of individuals in each taxon

-record all data

6. Gently release all organisms back into original habitat.


Back in classroom:

1. Have all groups share data & observations

2. Identify the dominant taxon at your hydrology site

3. Research required dissolved oxygen ranges, temperature ranges, pH ranges for certain macroinvertebrates to form a conclusion for your results


National Science Standards


Identify questions and concepts that guide scientific investigations.

Formulate and revise scientific explanations and models using logic and evidence.

Recognize and analyze alternative explanations and models.


Communicate and defend a scientific argument.


Design and conduct scientific investigations. Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for the use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation. The investigation may also require student clarification of the question, method, controls, and variables; student organization and display of data; student revision of methods and explanations; and a public presentation of the results with critical response from peers. Regardless of the scientific investigation performed, students must use evidence, apply logic, and construct an argument for their proposed explanations.