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Second visit: Nov
16, 2007, Delaware Valley Friends School
7th Grade Science Class will visit Bryn Mawr
College 4 Fridays over the academic 2007 - 2008 year.
They will Investigate aquatic ecology--make field environmental
observations; sample the macroinvertebrate fauna at
Mill Creekand Rhoads pond sites on the BMC campus; examine
samples under the microscope in the lab, and use GPS
to map sample site locations; overlay their data on
an aerial map of the study
area. The students will use a blogging
site set up by Wil Franklin (Senior Biology Lab
Instructor) to provide life history information on an
organism they found.
To read the definitions of an ecosystem, ecology, watershed,
macroinvertebrates, and about leaf pack experiments
click here.
In the lab:
1) Discussion of physical and chemical characteristics
of the pond and stream bottom habitat, why these vary
from place to place, and how these characteristics
influence aquatic organisms.
2) Description of how we quantitatively measure bottom
characteristics, e.g., relative amounts of mud, sand
and gravel; oxygen levels in the sediment; and amount
of organic detritus (leaves).
Outside field work:
1) Measure and record water temperature and oxygen
levels at each sampling site; qualitative observations
of other site characteristics such as water clarity/turbidity,
seasonal change in shade levels and sunlight amounts.
Brief discussion of how/why these differences arise.
2) Collection of pond and stream bottom sediment samples
for lab analysis.
3) Retrieval of leaf packs from each sample location.
Back in the lab:
1) Wet-sieve analysis of stream and pond sediment
samples; separation of the gravel, sand and mud fractions
to be dried then weighed. Create and view a histogram
plot of these sediment texture results.
2) Observation and mineralogical identification of
sand and gravel particles under the microscope.
3) Identification and counting of macroinvertebrate
fauna collected in leaf pack samples.
4) Evaluation of Water Quality from Biotic Index?
System from the leaf pack sample results. Visit Stroud
Water Research Center (http://www.stroudcenter.org/lpn/more/data.htm)
for a description.
5) Wrap-up discussion.
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