Earthworks
Earth System Science for Secondary Teachers

Margaret Peterson (Earthworks 2001; 2002; 2003)
mgpeterson@rcn.com

Lichens as Air Quality Indicators: A beginning lichen identification study (2003)

Grade level: 6-8

Content Area: Integrated science, life science, earth science

Time: 2 weeks

Standards: Science as Inquiry, populations and ecosystems, nature of science, diversity & adaptations of organisms

Background knowledge/skills: Measuring, microscope, variables, tree identification, keeping field notes, GPS

Materials: (per student team) compass, measuring tape, GPS, string, basic lichen ID book, 100 circle grid on transparency, vis-s-vie marker

Procedures:

1. Indicate to students that a coal powered plant in a local city has released chemicals in the air that may or may not contribute to local pollution. The community is very concerned about their air quality and wants to conduct some tests. You as a lichen specialist have been hired to conduct these tests and report your findings. The first step is to identify lichens on local trees and determine which lichens are the best bio-indicators of air quality. You will be sampling the % of various types.
2. Students select appropriate trees to study by researching background information on lichens as bioindicators and investigating tree species.
3. As small teams students select set of similar size trees
4. Determing latitude and longitude using GPS and record in field notes.
5. Students use compass to determing geographical orientation of tress N,S,E,W.
6. Students measure from bottom of tree to mark 1 ft. study area. This needs to be predetermined by student and done consistently throughout the study.

   Suggested protocol:

   a) At predetermined height students measure two location on tree and wrap string around tree.

   b) Determining center point on study area for west side of tree students place 100-circle grid on tree - tape in place [may need other sticky type substance].

   c) Using 100-circle grid, students identify types of lichens based on criteria such as green crusty, yellow leafy, orange shrubby....

   d) In field notebook record findings.

   e) Calculate % cover for each type of lichen.

7. Repeat for S.E.W tree quadrant
8. Learning objectives:

   1) students will collect lichen data on 100-cirlce grid,
   2) students will measure and establish research parameters,
   3) student will calculate % of lichen types,
   4) students will communicate findings as a research report.

Assessment: As teacher, I will create a rubric that includes student requirements for creating their research site, such as measurements, 100 circle grid, % of lichen findings, and research report as the assessment.

Enrichment/Reflection: From this point students will continue their study by moving toward new questions about lichens as air quality indicators and the micro-invertebrates that live within the lichens.

Resources:Forested area to study, Univ. of CT professor who works with lichens as bioindicators or air quality, administrative support, appropriate equipment

Barriers:-Students tend to be cynical when given a question or problem to solve if perceived as "fluff"

Responses:Prior to introducing this problem, have smaller PBL/I's for students to investigate so they become used to the "real world" applications.

Color identification system

Comparing Pond & Stream (2002)

Question: Why do we need healthy ponds & streams?

Learning Objectives:

1. Conduct pond & stream chemistry tests
2. Key 3-5 pond invertebrates & 3-5 stream invertebrates
3. Compare results of invertebrates & chemistry tests with state department standards in terms of most wanted (healthy) to least wanted (less healthy).
4. Research What is a healthy water system?

Where: To ponds outside Captain Nathan Hale Middle School, Coventry, CT. Aws well as streams within the community of Coventry.

Who: 8^th graders - science - 100 students (25 to a class - average)

What:

• Teacher to collect stream sample based on predetermined suggested Wetzel protocol.
• Students research pond collection protocol.
• Based on student plan, collect pond samples
• Identify invertebrates
• Conduct chemical testing on both systems (use LaMaott green kits or Vernier probes - compare & discuss results)
• Students research parameters of healthy water systems by meeting with local water authorities
• Students research watershed based on results.

When: Activities will begin in October and continue through December (7-10 visits to pond).

Potential Barriers:

• Student interest
• Weather
• Student behavior

Possible Strategies:

• Connection of healthy water with student life
• Have students watch weather patterns to determine to conduct outside research
• Student behavior - use strategies suggested at Earthworks to teach outside behavior.

Extensions: Depending on results students to write letters or report to local commissions on findings and suggestions for future.

Pond Sediment Study ( EW 2001)

Who: 8^th graders

What: Core Pond Sediments

Why: Explore history of ponds in terms of ecological events (environmental events).

Where: Two ponds - Capt. Nathan Hale School - CT

When: Fall -Winter

Potential Barriers: $, equipment, # of students per class, making sure each student has a task

Materials: 3-4 ft. plastic tube (8" in diameter), rubber stopper, rope attached to stopper, individual cups for samples, waders, sieves

Methods:

1. Take core samples
2. Measure and describe core
3. Cut in half, lengthwise
4. Create stratigraphic column (Using Munsell Color Book)*
5. Divide column by 1 cm sections
6. Place sample in constant sample size
7. Wet sieve each sample
8. Weigh container and dry sample
9. Determine sample weight
10. Graph data
11. Draw conclusions

Connections:

1. Samples indicated the presence of organic materials - Key out plant animal materials
2. Compare with stream samples
3. Compare with tree cores

Extensions: Conduct chemical analyses; explore other aspects of the pond.

* Munsell Color Book is a little much for 8^th graders (at least for many of my students). If and when I can come up with a simplified version, I will let everyone know.