Ecoenzymatic Stoichiometry and Ecological Theory

作者：Robert L. Sinsabaugh, Jennifer J. Follstad Shah · 发表于：Annual Review of Ecology Evolution and Systematics · 年份：2012 · DOI：10.1146/annurev-ecolsys-071112-124414 · 被引用次数：1048 · 研究领域：Microbial Community Ecology and Physiology、Microbial Metabolic Engineering and Bioproduction、Photosynthetic Processes and Mechanisms

The net primary production of the biosphere is consumed largely by microorganisms, whose metabolism creates the trophic base for detrital foodwebs, drives element cycles, and mediates atmospheric composition. Biogeochemical constraints on microbial catabolism, relative to primary production, create reserves of detrital organic carbon in soils and sediments that exceed the carbon content of the atmosphere and biomass. The production of organic matter is an intracellular process that generates thousands of compounds from a small number of precursors drawn from intermediary metabolism. Osmotrophs generate growth substrates from the products of biosynthesis and diagenesis by enzyme-catalyzed reactions that occur largely outside cells. These enzymes, which we define as ecoenzymes, enter the environment by secretion and lysis. Enzyme expression is regulated by environmental signals, but once released from the cell, ecoenzymatic activity is determined by environmental interactions, represented as a kinetic cascade, that lead to multiphasic kinetics and large spatiotemporal variation. At the ecosystem level, these interactions can be viewed as an energy landscape that directs the availability and flow of resources. Ecoenzymatic activity and microbial metabolism are integrated on the basis of resource demand relative to environmental availability. Macroecological studies show that the most widely measured ecoenzymatic activities have a similar stoichiometry for all microbial communiti...