Environmental engineers use concepts from microbiology and sometimes deal with just one type of microorganism. Much more often, the behavior of mixtures of microorganisms determines how pollutants affect the environment or how treatment process perform. This requires study of the community instead of focussing on the individuals. Population dynamics is the term for following the time behavior of concentrations of the components of an ecosystem. The explanations for population dynamics hinge on the roles that various organisms play.
Same link as previous page to definitions of Microbial Interactions
Quantitative ecology should appeal to engineers because the transfer of
energy and materials through populations is important, and engineers thrive
on mass and energy balancing. The main concept, however, is dealing with communities of
organisms.
Some physical factors that affect populations are:
silting
erosion - either loss by land areas or deposition into natural waters
temperature
mixing - this can be of catastrophic proportions as when a lake suddenly
turns over because temperature differences send the top waters to the bottom
and the bottom waters to the top
Unfinished material about dosage of a trickling filter
Unfinished material about seasonal changes of a trickling filter
Populations are said to have pyramidal structure. This means that there are very large numbers of very tiny organisms, lesser numbers of slightly larger organisms that feed on them, and still fewer of each greater size group until there are relatively few of the largest organisms. A bar chart of numbers versus size resembles a pyramid. Metabolic rates tend to be much higher for smaller organisms.
some important terms: (this section presently undeveloped)
elective culture
habitat
niche
zooplankton
phytoplankton
food web or food chain
natural cycles of elements
maintenance - nutrition from the outside just to hang on to life; no reproduction
endogenous metabolism - using own resources
relation of growth rate to nutrition
efficiency - % of input energy used for life processes. Low efficiency best for waste treatment.
indicator organisms - link