DUCKWEED Duckweed, a monocot aquatic species of plants, is a natural purificator of water (Leng,et al., Duckweed - A Potential...). Duckweed is capable of treating wastewater, namely nitrates and phosphates, by absorbing the compounds and converting it to biomass and water. It will only survive under certain conditions and is not found in all areas. Presently, duckweed is being used in some areas as a biological means of wastewater treatment and as biomass to feed livestock.Unfortunately, duckweed can can become so prolific that it overtakes an aquatic ecosystem reducing the amount of dissolved oxygen present and lowering the productivity and plant and animal population present (Hyde, National Aquaculture...). If duckweed populations are to be maintained and used effectively for water purification, an understanding of its physical and biological needs must be attained. This project will look at the characteristic traits of aquatic ecosystems which limit the growth of duckweed.
For
more information on duckweed, check out these web sites and resources:
HYPOTHESIS:
Duckweed has optimum growth between narrow ranges
of nitrate concentrations.
MATERIALS AND METHODS:
Using the Texas Instruments CBL (Calculator- Based Laboratory) with probes and Texas Instruments 82 (TI-82) graphing calculator, water samples from two sites within the Princeton University area will be collected and tested for pH and temperature. Kits for water quality testing will be used to test for nitrate and phosphate concentration. The collected data will be analyzed and correlations will be made between environmental conditions and plant growth.
PROCEDURES:
Information on testing water quality can be found
at these sites:
This research format is not limited to duckweed or
aquatic plants. It is transferrable to the study of any plant or animal,
and can be adapted to the study of any local water source. Correlations
between environmental conditions and their effect on plant and animal
growth can be noted.
Want
to do duckweed in your area? Here are some ideas just for you...
If actual "field" areas are not available
to study, aquariums and 2-liter bottles may be used. Appropriate organisms
for study and varying concentrations of pH, nutrients, temperature, and
other variables can be instituted. Data may be collected using CBL's and
probes, or if they are not available, use of pH paper or other indicators
such as cabbage juice and thermometers is suggested.
MODULE:
With our web page we aspire to produce the following:
Data
collected during initial research and its significance
Links to resources and personnel available for further information
A STELLA model correlating environmental conditions with duckweed growth
An ongoing interactive discussion of collaborative studies and ideas
Links to current National Science Content Standards
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