Carbon and Nutrient Dynamics in Arctic Stream Networks Determined Directly with the Catchment-Scale Estimates of Redox Reactions

• Main Author: Abbott, Ben
• Format: Text
• Language: unknown
• Published: DigitalCommons@USU 2019
• Subjects: Earth Sciences; Environmental Engineering; Environmental Sciences; Hydraulic Engineering; Life Sciences; Arctic; Glacial Lake; north slope; permafrost; Tundra; Alaska
• Online Access: https://digitalcommons.usu.edu/runoff/2019/all/22

In complex ecosystems, redox conditions influence and are influenced by the rate and type of organic matter decomposition. The interactions between carbon, nutrients, and redox conditions are particularly important in the permafrost zone, where much of the Earth’s organic matter is stored in climate-protected soils. However, scaling estimates of redox state from the plot-level to the catchment-level is challenging in any environment, especially in remote landscapes such as the Arctic. Here we attempt to directly quantify redox conditions and associated production and uptake of organic and inorganic nutrients at the catchment scale using snapshots of water chemistry in Arctic stream networks. We sampled carbon and nutrient chemistry five times over three years in 119 subcatchments of three watersheds on the North Slope of Alaska. Subcatchments ranged from 0.1 to 80 km2 and included three distinct types of Arctic landscapes - mountainous, tundra, and glacial-lake catchments. We quantified the stability of spatial patterns of uptake and production of carbon, nitrogen, phosphorus, sulfur, and iron species, and explained these dynamics with catchment characteristics such as slope, vegetation type, catchment size, and storm recession curves. While these network-scale methods of estimating nutrient dynamics are not as precise as plot-level observations, they provide a valuable benchmark for empirical and mechanistic models, commonly used to scale these processes. Additionally, this type of spatially-rich and multi-elemental sampling can allow change detection and quantification of ecohydrological mechanisms in ecosystems in the Arctic and beyond.