Isotopic composition of Antarctic Dry Valley nitrate: Implications for NO<sub>y</sub> sources and cycling in Antarctica

Michalski, Greg

doi:10.1029/2004gl022121

Cited by 107 publications

(123 citation statements)

References 39 publications

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“…Atmospheric deposition is the dominant source of NO − 3 in the McMurdo Dry Valleys (Campbell and Claridge, 1987;Michalski et al, 2005), whereas NH + 4 may result from both physical (aerial deposition) and biological (decomposition of organic matter) processes (Barrett et al, 2002). Phosphorus availability in near-shore terrestrial environments and adjacent aquatic ecosystems is strongly influenced by geological substrate, and extent of chemical weathering processes Bate et al, 2008 are associated with high organic matter and water content (Figs.…”

Section: Discussionmentioning

confidence: 99%

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Barrett

Gooseff

Takacs-Vesbach

2009

Hydrol. Earth Syst. Sci.

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Abstract. Polar deserts are characterized by severe spatialtemporal limitations of liquid water. In soil active layers of the Antarctic Dry Valleys, liquid water is infrequently available over most of the arid terrestrial landscape. However, soils on the margins of glacial melt-water streams and lakes are visibly wet during the brief Austral summer when temperatures permit the existence of liquid water. We examined the role of these hydrologic margins as preferential zones for the transformation and transport of nutrient elements and solutes in an environment where geochemical weathering and biological activity is strictly limited by the dearth of liquid water. We report on hydropedological investigations of aquatic-terrestrial transition zones adjacent to 11 stream and lake systems in the Antarctic Dry Valleys. Our results show that wetted zones extended 1-11 m from the edges of lotic and lentic systems. While capillary demand and surface evaporation drive a one-way flux of water through these zones, the scale of these transition zones is determined by the topography and physical characteristics of the surrounding soils. Nutrient concentrations and fluxes appear to be influenced by both the hydrology and microbialmediated biogeochemical processes. Salt concentrations are enriched near the distal boundary of the wetted fronts due to evapo-concentration of pore water in lake margin soils, while organic matter, ammonium and phosphate concentrations are highest in stream channel sediments where potential for biological activity is greatest. Thus, in the Antarctic Dry Valleys, intermittently wet soils on the margins of streams and lakes are important zones of both geochemical cycling and biological activity.

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Section: Discussionmentioning

confidence: 99%

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Barrett

Gooseff

Takacs-Vesbach

2009

Hydrol. Earth Syst. Sci.

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“…v www.esajournals.org tionally old surfaces that are not exposed to liquid water during the austral summer (Marchant and Denton 1996) accumulate high concentrations of soluble nitrate from atmospheric deposition (Michalski et al 2005, Bockheim 2008), which may explain why soil TN levels negatively covaried with cyanobacterial presence in edaphic habitats.…”

Section: Edaphic Cyanobacteria Exhibit Biogeographymentioning

confidence: 99%

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

Sokol¹,

Herbold²,

Lee³

et al. 2013

Ecosphere

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Abstract. The metacommunity concept provides a useful framework to assess the influence of local and regional controls over diversity patterns. Culture-independent studies of soil microbial communities in the McMurdo Dry Valleys of East Antarctica (778 S) have shown that bacterial diversity is related to soil geochemical gradients, while studies targeting edaphic cyanobacteria have linked local diversity patterns to dispersal-based processes. In this study, we increased the spatial extent of observed soil microbial communities to cover the Beardmore Glacier region in the central Transantarctic Mountains (848 S). We used community profiling techniques to characterize diversity patterns for bacteria and the cyanobacterial subcomponent of the microbial community. Diversity partitioning was used to calculate beta diversity and estimate among-site dissimilarity in the metacommunity. We then used variation partitioning to assess the relationship between beta diversity and environmental and spatial gradients. We found that dominant groups in the soil bacterial metacommunity were influenced by gradients in pH and soil moisture at the Transantarctic scale (800 km). Conversely, beta diversity for the cyanobacterial component of the edaphic microbial metacommunity was decoupled from these environmental gradients, and was more related to spatial filters, suggesting that wind-driven dispersal dynamics created cyanobacterial biogeography at a local scale (,3 km).

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“…1). University Valley and nearby valleys contain elevated concentrations of NO 3 À primarily of atmospheric origin (Michalski et al, 2005) as well as elevated concentrations of ClO 4 À (Kounaves et al, 2010). University Valley is located in a hyper-arid region of the MDV and receives a current water equivalent precipitation of less than 5 cm/year.…”

Section: Antarctica-soilmentioning

confidence: 99%

Global patterns and environmental controls of perchlorate and nitrate co-occurrence in arid and semi-arid environments

Jackson

Böhlke

Andraski

et al. 2015

Geochimica et Cosmochimica Acta

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Isotopic composition of Antarctic Dry Valley nitrate: Implications for NO_y sources and cycling in Antarctica

Cited by 107 publications

References 39 publications

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

Global patterns and environmental controls of perchlorate and nitrate co-occurrence in arid and semi-arid environments

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Isotopic composition of Antarctic Dry Valley nitrate: Implications for NOy sources and cycling in Antarctica

Cited by 107 publications

References 39 publications

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

Global patterns and environmental controls of perchlorate and nitrate co-occurrence in arid and semi-arid environments

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Isotopic composition of Antarctic Dry Valley nitrate: Implications for NO_y sources and cycling in Antarctica