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Interdisciplinary Field Investigations of a Campus Pond

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Don Barber Bryn Mawr College
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This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.


This page first made public: Nov 9, 2004

The primary activity described here is measurement of sub-surface water properties in a local pond (e.g., temperature and dissolved oxygen). This activity combines concepts and skills from Geology, Biology and Chemistry.
GSA Poster (Acrobat (PDF) 1.2MB Nov9 04)

Learning Goals

Content/Concepts:
mixing/stratification in a hydrologic basin;
solubility of oxygen in water as function of temperature;
primary productivity, O2/CO2 consequences of photosynthesis/respiration;
deposition of organic-rich sediments in a restricted basin setting

Geologic Skills:
survey planning/design; mapping; construction of cross-sections; drawing contours; field observations: sampling and recording data; spreadsheet data analysis and calculations

Higher Order Thinking Skills:
posing testable hypotheses; applying spatial and quantitative reasoning for pattern evaluation; interpreting and synthesizing results of observations

Other Skills:
experience operating water quality meter in field setting; coordinating/cooperating with other team members and with team assigned to different tasks

Context

Instructional Level:
Undergraduate entry/advanced level, but probably could work at 9-12th grade levels, too, if classes are small.

Skills Needed:
It is helpful to have some students with basic mapping/map-reading skills as learned in an introductory geology course, but not necessary for all participants. Facility with a spreadsheet program such as Microsoft Excel speeds the data analysis/reduction/plotting process.

Role of Activity in a Course:
Carried out during a 3-hr lab period for either introductory or mid-level undergraduate courses; builds on some material presented earlier, but almost can stand alone.

Data, Tools and Logistics

Required Tools:
A small boat is used to survey across pond (ideally–other approaches can work, too).
A portable, battery-powered, submersible water quality meter on a cable is required. These range in price; unit must include at least temperature and dissolved oxygen sensors for this exercise.
Computers are helpful for spreadsheet work, although plots could be made on graph paper with use of a calculator.
One also needs info on the equilibrium saturation of dissolved oxygen in water vs. water temperature (students can look this up).

Logistical Challenges:
Main problem is getting students out on water SAFELY to make observations.
Water quality meters are generally reliable and simple to use, but needs to be carefully checked well in advance.
This project is seasonally dependent; summer or early fall works better, while there is still lots of plant photosynthesis near surface, and pond is temperature stratified. Winter/early spring would be least interesting if pond is homogeneous at 4 degrees C and no plant growth and little decay.

Evaluation

Evaluation Goals:
I'm curious about whether students adequately conceive of the pond setting as a small scale analogue of larger hydrographic and depositional environments, and whether they are able to use this knowledge in understanding these larger systems.

Evaluation Techniques:
No pre-testing has been done, although student experiences with the activity have been gauged through questionnaires at end of course.

Description

Sedimentology students use a small boat to measure vertical temperature and dissolved O2 profiles to evaluate a local pond as a small-scale basin wherein organic carbon-rich sediments are deposited. Students observe algal growth (i.e., photosynthesis and oxygen supersaturation) near the surface, whereas the sinking of excess organic matter into the poorly ventilated, deepest part of the pond produces suboxic-to-anoxic conditions and accumulation of organic-rich mud.