Jump to ContentJump to Main Navigation
Processes in Microbial Ecology$
Users without a subscription are not able to see the full content.

David L. Kirchman

Print publication date: 2011

Print ISBN-13: 9780199586936

Published to Oxford Scholarship Online: December 2013

DOI: 10.1093/acprof:oso/9780199586936.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2020. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 24 October 2020

Degradation of organic material

Degradation of organic material

(p.79) Chapter 5 Degradation of organic material
Processes in Microbial Ecology

David L. Kirchman

Oxford University Press

This chapter focuses on the aerobic oxidation of organic material by microbes. Microbes account for about 50 per cent of primary production in the biosphere, but they probably account for more than 50 per cent of organic material oxidization and respiration (oxygen use). The traditional role of microbes is to degrade organic material and to release plant nutrients such as phosphate and ammonium as well as carbon dioxide. Microbes are responsible for about half of soil respiration while size fractionation experiments show that bacteria are responsible for about half of respiration in aquatic habitats. In soils, both fungi and bacteria are important, with relative abundances and activity varying with soil type. In contrast, fungi are not common in the oceans and lakes, where they are out-competed by bacteria with their small cell size. Dead organic material – detritus – used by microbes comes from dead plants and waste products from herbivores. This, and associated microbes, can be eaten by many eukaryotic organisms, forming a detritus food web. These large organisms also break up detritus to small pieces, creating more surface area on which microbes can act. Microbes in turn need to use extracellular enzymes to hydrolyze large molecular weight compounds, which releases small compounds that can be transported into cells. Photochemical reactions are also important in the degradation of certain compounds. Some compounds are very difficult to degrade and are thousands of years old.

Keywords:   detrital food web, microbial loop, turnover time, residence time, growth efficiency, litter, dissolved organic carbon, dissolved organic matter

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .