Encyclopedia of Environmental Science and Engineering, Volume I and II

I

II A

II B

III-1A

III-1A

III-1B

III 2

III 2 III-3

IV

SUN

ENERGY

FIGURE 3 Diagram of the pond ecosystem. Basic units are as follows? I, abiotic substances—basic inorganic and organic

compounds; IIA, producers—rooted vegetation; IIB, producers-phytoplankton; III-1A, primary consumers (herbivores)—

bottom forms; III-1B, primary consumers (herbivores)—zooplankton; III-2, secondary consumers (carnivores); III-3, tertiary

consumers (secondary carnivores); IV, saprotrophs—bacteria and fungi of decay. The metabolism of the system runs on sun

energy, while the rate of metabolism and relative stability of the pond depend on the rate of inflow of materials from rain and

from the drainage basin in which the pond is located. (From Odum, 1971.)

266 ECOSYSTEM THEORY

C005_003_r03.indd 266C005_003_r03.indd 266 11/18/2005 10:21:03 AM11/18/2005 10:21:03 AM