Lab 13
57
Lab 13
Intertidal Communities
Description of the Lab
Students are introduced to an investigation of vertical zonation of invertebrates
intertidal. This lab will take approximately 2 hours (not including travel time to field
site).
Laboratory Materials and Equipment for Student Use
Materials and Equipment
Per
Student
Per Pair of
Students
Per Lab
Group
Per
Room
Light meter
1
Thermometer
1
Refractometer
1
Shovel (if sampling muddy or sandy
shores)
1
Sieve (if sampling muddy or sandy
shores
1
Large plastic garbage bags (if
sampling muddy or sandy shores)
1
Reference charts and Invertebrate
1
GPS (optional)
1
tape
colorful string (five 20 m pieces)
1
clipboards
pencils
Lab 13
58
Outline of Investigation
Exercise 1 – Habitat and Community Profile
Materials needed:
• Light meter
• Thermometer
• Refractometer
• clipboards
• pencils
• reference charts and identification keys
Note: Prepare students for appropriate field dress and variable weather. Pencils are
better for taking data in wet conditions, compared to regular pens. Waterproof field pens
Answers to Questions for Lab 13
1. Name 3 stressors that organisms experience living in intertidal zones.
• Salinity
• Temperature changes: hot during low tide and cold during high tide
2. What kind of adaptations do organisms use to cope with these stressors?
• Salt excluding and salt excreting mechanisms
3. Did you observe differences in the invertebrate communities found at different sites?
4. How did the physical and chemical characteristics changes from your first site to your
last site?
5. If the physical and chemical characteristics did change from sampling site to sampling
site, are there any additional factors that you need to consider before interpreting your
data (e.g., if you started sampling at 9am and finished at noon)?
Answers will vary, but students should notice that for example the temperature of
6. Did you observe vertical zonation?
Answers will vary depending on site, but in general the answer should be yes in a
subtle
7. Based on the distribution of organisms which of your sites would you characterize as
being in the supralittoral? Midlittoral? Infralittoral fringe? Infralittoral zone?