@article {4063, title = {Biogeochemical weathering of soil apatite grains in the McMurdo Dry Valleys, Antarctica}, journal = {Geoderma}, volume = {320}, year = {2018}, month = {01/2018}, pages = {136-145}, abstract = {

The biogeochemical weathering of the mineral apatite links the lithosphere to the biosphere by releasing the essential nutrient phosphorus (P) into the soil ecosystem. In Taylor Valley, Antarctica, faster rates of apatite weathering may be responsible for the higher concentrations of bioavailable soil P that exist in the Fryxell Basin as compared to the Bonney Basin. In this study, we use scanning electron microscopy to quantify the morphology and surface etching of individual apatite grains to determine whether the degree of apatite weathering differs between the Fryxell and Bonney Basins as well as saturated and dry soil sediments. We show that apatite grains from the Fryxell Basin are rounder, have fewer intact crystal faces, and are more chemically etched than grains from the Bonney Basin. In the Bonney Basin, apatite grains from dry soils show few signs of chemical dissolution, suggesting that soil moisture is a stronger control on the rate of apatite weathering in the Bonney Basin than in the Fryxell Basin. In addition, etch-pit morphologies in the Bonney Basin are more clearly controlled by the hexagonal crystal structure of apatite, while in the Fryxell Basin, etch pits demonstrate a wide range of morphologies without clear crystallographic control. Higher rates of apatite weathering in the Fryxell Basin may be due to the legacy of the physical abrasion of apatite grains during transport by a warm-based ice sheet, as well as the higher levels of precipitation and soil moisture closer to the coast. Our grain-scale approach provides a new perspective on P cycling in the McMurdo Dry Valleys and has implications for apatite weathering and P dynamics in the early stages of soil development.

}, keywords = {LTER-MCM}, issn = {00167061}, doi = {10.1016/j.geoderma.2018.01.027}, url = {https://www.sciencedirect.com/science/article/pii/S0016706117320694}, author = {Heindel, Ruth C and W. Berry Lyons and Sue Welch and Spickard, Angela M and Ross A. Virginia} } @article {1236, title = {Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems}, journal = {Journal of Geophysical Research}, volume = {112}, year = {2007}, month = {02/2007}, pages = {G01010+12}, 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.

}, keywords = {LTER-MCM, Biggie}, doi = {10.1029/2005JG000141}, author = {John E. Barrett and Ross A. Virginia and W. Berry Lyons and Diane M. McKnight and John C. Priscu and Andrew G Fountain and Diana H. Wall and Daryl L. Moorhead and Peter T. Doran} } @inbook {1261, title = {Biogeochemistry, terrestrial}, booktitle = {Encyclopedia of the Antarctic Vol 1}, volume = {1}, year = {2006}, pages = {154-155}, publisher = {Routledge Press}, organization = {Routledge Press}, address = {New York}, keywords = {LTER-MCM}, doi = {LTER}, author = {John E. Barrett and Ross A. Virginia}, editor = {B. Riffenburgh} } @article {1323, title = {The Biodiversity and Biogeochemistry of Cryoconite Holes from McMurdo Dry Valley Glaciers, Antarctica}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {36}, year = {2004}, pages = {84-91}, keywords = {LTER-MCM}, author = {Porazinska, D and Andrew G Fountain and Thomas H. Nylen and Martyn Tranter and Ross A. Virginia and Diana H. Wall} } @inbook {1411, title = {Basic Principles in ecosystem functioning}, booktitle = {Encyclopedia of Biodiversity}, volume = {2}, year = {2001}, pages = {345-352}, publisher = {Academic Press}, organization = {Academic Press}, keywords = {LTER-MCM}, author = {Ross A. Virginia and Diana H. Wall}, editor = {S. Levin} }