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Full-Text Articles in Physical Sciences and Mathematics
Water Table Height And Microtopography Control Biogeochemical Cycling In An Arctic Coastal Tundra Ecosystem, David A. Lipson, Donatella Zona, Ted K. Raab, Francis Bozzolo, Marguerite Mauritz, Walter C. Oechel
Water Table Height And Microtopography Control Biogeochemical Cycling In An Arctic Coastal Tundra Ecosystem, David A. Lipson, Donatella Zona, Ted K. Raab, Francis Bozzolo, Marguerite Mauritz, Walter C. Oechel
Ted K. Raab
Drained thaw lake basins (DTLB’s) are the dominant land form of the Arctic Coastal Plain in northern Alaska. The presence of continuous permafrost prevents drainage and so water tables generally remain close to the soil surface, creating saturated, suboxic soil conditions. However, ice wedge polygons produce microtopographic variation in these landscapes, with raised areas such as polygon rims creating more oxic microenvironments. The peat soils in this ecosystem store large amounts of organic carbon which is vulnerable to loss as arctic regions continue to rapidly warm, and so there is great motivation to understand the controls over microbial activity in …
An Empirical Model Of Amino Acid Transformations In An Alpine Soil, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson
An Empirical Model Of Amino Acid Transformations In An Alpine Soil, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson
Ted K. Raab
Amino acids are potentially important nitrogen (N) sources for plants in many ecosystems. However, a quantitative understanding of organic N availability is lacking for most ecosystems. This study estimates seasonal amino acid fluxes in an alpine tundra soil using three independent data sets. In previous work in an alpine dry meadow ecosystem in the Front Range of the Colorado Rocky Mountains, we measured signifcant rates of amino acid production from soil peptides during the plant growing season. This suggested that proteolysis of native soil peptides could serve as a measure of amino acid availability to plants. Here we use a …
Soil Amino Acid Utilization Among Species Of The Cyperaceae: Plant And Soil Processes, Ted K. Raab, David A. Lipson, Steven K. Scmidt, Russ K. Monson
Soil Amino Acid Utilization Among Species Of The Cyperaceae: Plant And Soil Processes, Ted K. Raab, David A. Lipson, Steven K. Scmidt, Russ K. Monson
Ted K. Raab
Amino acids are released during the decomposition of soil organic matter and have been shown to be utilized as a nitrogen source by some non-mycorrhizal species in the family Cyperaceae (the sedge family). Twelve out of 13 Cyperaceae species examined in the current study were capable of absorbing soil amino acids in the non-mycorrhizal state. With two exceptions (two species in the genus Kobresia), species from subalpine or alpine habitats exhibited lower rates of total nitrogen uptake compared to species from more temperate habitats, which is possibly explained by lower growth rates in the alpine and subalpine species and a …