Monthly Archives: April 1997

The PEDDER BAY MIDDEN Lab

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PEDDER BAY MIDDEN

Just west of Pearson College in Pedder Bay is a bank along the estuary which is being eroded under the roots of a large Douglas Fir. We do a field lab there using the evidence from the First nations midden to piece together a picture of what the original system of Pedder Bay must have been like when First Nations people lived in the area, several centuries ago.

 

We are able to make observations of the exposed midden shell fragments and determine the species of shellfish harvested here. One interesting find was a shell of a native rock oyster, a species that is no longer found in Pedder Bay, but which was obviously part of the diet several hundred years ago.

The objective of this lab is to construct a systems diagram of this Bay Ecosystem which includes these early indigenous  people

Ecological Succession Lab-Part 1. BIOMASS

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ECOLOGICAL SUCCESSION-PART 1. BIOMASS
Objective 2.3.6,
Background reading reference, Odum page 193-194,
PART 1: LAB ON BIOMASS ACCUMULATION ON SUCCESSION PLATES
PROCEDURE:1. You will be taken to the docks where you will retrieve a succession slide box that has been left suspended in the bay for the past year. Return to the lab and clear off all life forms, (mostly invertebrates) that have grown in that time.

2. Separate the organisms into different species groups. Identify the groups to family or genus level and put them in the small trays provided and leave for at least 24 hours in the marine dryer. You may as an option at this point take a wet biomass determination.

3. Weigh the species in order to get a dry biomass of the different life forms.

4. Calculate the surface area from which the organisms were removed .

5. Do a biomass determination on each species — grams per square cm.
6. Enter your own results in an Excel chart on the computer. Produce a pie graph of the results.7. Obtain the raw data from the other teams in the class and make another graph of the cumulative results.
Discussion:1. Referring to page 194 of Odum, explain how biomass in a community is affected by succession.

2. Design the protocol of a lab using similar materials that you could use to test this theory and that of how species diversity is affected by succession .
3. Compare your graph with the total class results. What would you consider to be the best result and why? (use the word replication in your answer)
 :
ECOLOGICAL SUCCESSION IN PEDDER BAY -PART 2
Objective: 2.3.5 ,Objective 2.3.6,
Background reading reference, Odum page 186-207
PART 2 :Succession –
PROCEDURE:1.Place 10 clean microscope slides in a cleaned succession slide box.

2.Suspend the box in 1 meter of water in the designated location on the docks.
3. After 2 weeks, remove one slide and examine 5 fields of view under 100X in the compound microscope. Use the diagrams and booklets provided to identify the species to the genus level.4. Tally the number of each species in each field of view and then make a cumulative tally. It may help to make sketches of the species in order to be able to associate a name with the appearance.

5. In EXCEL , enter your counts and make a pie chart of the results which is labelled with % as well as number for each species.

6. Repeat this procedure at two week intervals, for at least 8 weeks.

OPTION A: Compare your results with those freom previous years: Consult the teacher if you wish to do more complex statistics on the variations observed.

OPTION B: Add to the collection of photographs of diatoms .

OPTION C: Dip at least one slide in the antifouling compund ” EASY NET” and compare after 8 weeks the effectiveness of this treatment.
Discussion:1. Referring to page 193- 194 of Odum, explain how species diversity in a community changes with succession. Provide evidence from your work to support or reject this theory.

2. Examine the model provided for a similar succession sequence from Oregon waters. Using that model , make your own flow chart to compare the two locations.

EVALUATION: Include an extensive evaluation of the lab.