The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Denitrification is the conversion of nitrates to gaseous nitrogen. It is carried out by several genera of free-living soil bacteria. Denitrifying bacteria are especially active in waterlogged, anaerobic soils where they tend to deplete soil nitrates, forming free atmospheric nitrogen. Organic matter in the soil tends to promote denitrification when oxygen from the nitrate ion is used to oxidize the organics in the absence of atmospheric oxygen. Denitrification, thus, supports active anaerobic growth of the denitrifying organisms. In agricultural soils denitrifying bacteria can reduce soil fertility and lessen agricultural productivity by removing growth promoting nitrate from the soil before plants are able to utilize it. In swampy soils, denitrifiers may reduce the amount of soil nitrogen by as much as 50%. Some of the microbial forms involved in denitrification include Thiobacillus denitrificans, Micrococcus denitrificans, and species of Serratia, Pseudomonas, and Achromobacter. Denitrification has its positive side, however. The process helps to reduce the amount of nitrogen salts that might otherwise accumulate in oceans and lakes. Nitrates are highly soluble and readily leached from soil to aquifers, streams, and lakes, where they might accumulate to toxic levels. Converting this over supply of nitrate to the nontoxic nitrogen gas removes the threat to plants and animals that might otherwise be harmed.