A wet grassland in Florida is called a prairie. Nutrients flow in with rain, and in and out through the area streams that may be eutrophic. Grasses photosynthesize using the nutrients rapidly and building up standing grass biomass (Q2). As the grass dies, some is decomposed and recycled back to nutrients in the soil water (Q1). The rest of this dead grass becomes a build-up of peat. Q3 includes peat as well as dead grasses and roots.

As you can see in Figure III-12b, grasses grow in the summer and die down in the winter, although some grass and most of the root mass remain alive during the winter. Over the ten year, there is an on increasing build-up of peat until its decomposition equals its production. The figures used in the program (Table III-12) were obtained from a study of Paynes Prairie, in north-central Florida.

The changes in sunlight are programmed as an array; the monthly averages are listed as data in statement 11. How to program an array is explained in Part VIII.

Examples of Wet Prairies

All around the world areas of grasslands, which are wet, grow peat. This model is appropriate for wet parts of the grasslands in the center of the U.S and wet parts of the tropical savannas in Kenya.

"What if" Experimental Problems

1. What would change if the city decided to use this prairie to dump its treated sewage? Increase the inflow of nutrients, J, to 0.025.
   Would it change the looks of the prairie? On the basis of this program, would you advise the city to go ahead?
   


2. If this area were partially drained so that the peat decomposed twice as fast, how would you change the program to indicate this?
   How would the graph change?
   


3. What would happen to the system if the outflowing stream were blocked off?

COMPUTER MINIMODELS AND SIMULATION EXERCISES FOR SCIENCE AND SOCIAL STUDIES

Howard T. Odum* and Elisabeth C. Odum+
* Dept. of Environmental Engineering Sciences, UF
+ Santa Fe Community College, Gainesville

Center for Environmental Policy, 424 Black Hall
University of Florida, Gainesville, FL, 32611
Copyright 1994

Autorização concedida gentilmente pelos autores para publicação na Internet
Laboratório de Engenharia Ecológica e Informática Aplicada - LEIA - Unicamp
Enrique Ortega
Mileine Furlanetti de Lima Zanghetin
Campinas, SP, 20 de julho de 2007