Biogeochemical Stoichiometry of Antarctic Dry Valley Ecosystems

Authors

John E. Barrett, Dartmouth CollegeFollow
Ross A. Virginia, Dartmouth CollegeFollow
W. Berry Lyons, Ohio State UniversityFollow
Diane M. McKnight, University of Colorado at BoulderFollow
John Charles Priscu, Montana State University - BozemanFollow
Peter T. Doran, University of Illinois at ChicagoFollow
Andrew G. Fountain, Portland State UniversityFollow
Diana H. Wall, Colorado State University - Fort CollinsFollow
D. L. Moorhead, University of Toledo

Sponsor

This paper is a contribution to the National Science Foundation sponsored McMurdo LTER Program (OPP 9810219 and 0096250).

Published In

Journal of Geophysical Research - Biogeosciences

Document Type

Article

Publication Date

2-7-2007

Subjects

Desert ecology -- Antarctica -- McMurdo Dry Valleys, Biogeochemistry -- Cold regions, Nutrient cycles -- Antarctica --McMurdo Dry Valleys

Abstract

Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10–10⁶ years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.

Description

Copyright 2007 American Geophysical Union.

DOI

10.1029/2005JG000141

Persistent Identifier

http://archives.pdx.edu/ds/psu/7391

Citation Details

Barrett, J. E., R. A. Virginia, W. B. Lyons, D. M. McKnight, J. C. Priscu, P. T. Doran, A. G. Fountain, D. H. Wall, and D. L. Moorhead (2007), Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems, J. Geophys. Res., 112, G01010, doi:10.1029/2005JG000141.