Molecular Approaches to the Nitrogen Cycle

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This chapter provides an overview of studies of key protein coding genes, enzymes, and other functional markers, ''functional gene'' approaches, that have been used to dissect the contributions of uncultivated organisms to various nitrogen transformations. The increasing application of molecular biological techniques to studies in marine nitrogen cycling demonstrates the feasibility of assigning functional roles in biogeochemical transformations to individual organisms. Molecular biological methods have been instrumental for identifying the presence of organisms for major nitrogen transformation pathways that may have long remained undetected otherwise. Gene-based detection methods often uncover a vast diversity of uncultivated organisms that may in part explain missing N-budget terms. Measurements of the expression of specific genes makes possible to determine the distribution of individual genotypes that are physiologically active. It is now feasible to determine the correlations between the distributions of individual genotypes, expression of genes and physicochemical factors in the marine environment. It may be years from now before this explosion of molecular and genetic data can inform predictive ecosystem models directly, but knowledge of the genetic potential and responses of organisms in the environment can provide a blueprint for refining considerations impacting ecosystem function. © 2008 Copyright © 2008 Elsevier Inc. All rights reserved..

Publication Title, e.g., Journal

Nitrogen in the Marine Environment