What are the Chemical and Microbiological Effects of Run-off from a Catfish Pond on the Surrounding Soil and Water?

 

Objectives:  Students will organize and analyze source data from a USDA funded research project on Catfish Pond runoff  to compare and contrast microbial populations and inorganic chemical concentrations along a filter strip.  Students will draw conclusions as to the effectiveness of the filter strip and use their knowledge of biogeochemical cycles to explain the data.

                       

Background:

 

Catfish farms are an important industry in the south.  Catfish farmers must maintain their livestock (catfish) in such a way that the quality of the water and thus the health of the fish are in top condition.  Most catfish ponds have outflow pipes which allow water to flow onto a run-off area.  The ponds are also aerated.  Water flowing from the pond contains high amounts of nitrogen from the fish waste.  What the levels of nitrogen are as well as the effect of the nitrogen on the microbial population are important questions to answer as far as the environment is concerned.  Various methods, such as a grass filter strip, are being tested to see if they provide an effective way of dealing with excessive nitrogen waste from catfish pond run-off.

 

Pre-lab:

 

(1)  In what form does nitrogen exist in the outflow from catfish ponds?

(2)  What tests are used to determine nitrogen content?

(3)  What bacteria would be helpful in the outflow soil area?

(4) What is the function of these bacteria?

(5)  Define the term, Best Management Practice, regarding agricultural applications.

 

References:

http://www.msstate.edu/dept/tcnwac/effdoc.html

http://www.msstate.edu/dept/crec/cwetland.html

http://www.ext.vt.edu/resources/4h/virtualfarm/aquaculture/aquaculture.html

http://www.geog.ouc.bc.ca/physgeog/contents/9s.html

 

 

Procedure:

 

(1)  Using the data provided on the University of West Florida USDA website, http://uwf.edu/usda/research.html plot graphs to show the relationship between nitrogen values and distance on the grass filter strip. From the results on the graph write a statement that reflects the relationship between the nitrogen levels and distance on the grass strip

 (distance in meters will be on the x-axis and nitrogen values will be on the y-axis)

 

(2)  Using the microbial data from the University of West Florida USDA http://uwf.edu/usda/microbe%20data%20catfish_pond.htm  website that plot microbial counts versus distance on the grass strip compare how changes in the populations of various species of bacteria relate to distance along the strip.

 

(3)  Search the web to find information on other reports of nitrogen values and microbial counts from catfish pond outflow.  Construct a table of USDA values and values found in #3  Compare the values from the USDA project and the values found on the internet

 

 

Conclusions:

 

(1)    Explain any relationships you detect between the amounts of nitrogen compounds and bacterial counts in various species as the distance increases on the strip. 

 

(2)    What conclusion would you make as to the effectiveness of the grass strip as a

a good management practice for dealing with catfish outflow ?

           

(3)    Suppose you were an Environmental Specialist giving advice to a catfish farmer.

What advice would you provide him or her regarding the use of  a grass filter strip to deal with excess nitrogen coming from the catfish pond outflow?  What factors do you think might affect whether the use of a grass filter strip is appropriate?

 

 

National Standards:

 

>   Natural ecosystems provide an array of basic processes that affect humans.  Those processes include maintenance of the quality of the atmosphere, generation of soils, control of the hydrologic cycle, disposal of wastes, and recycling of nutrients .  Humans are changing many of these basic processes, and the changes may be detrimental to humans.

 

> Materials from human societies affect both physical and chemical cycles of the earth.

 

Florida Sunshine State Standards:

 

SC.A.1.4

SC.D.1.4

SC.D.2.4

SC.G.1.4

SC.G.2.4

SC.H.3.4