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Brown bag seminar - Stacy Tellinghuisen and Samantha Weintraub

Wednesday, November 20, 2013, 12:00PM - 1:00PM

Speaker

Stacy Tellinghuisen; Samantha Weintraub

Western Resource Advocates senior water/energy policy analyst; INSTAAR and EBIO PhD candidate

Location:

RL-1 room 269

Tomorrow we will have two half hour talks during the noon hour.

Managing energy, water, and drought: Solutions from the Interior West

by Stacy Tellinghuisen, Western Resource Advocates

Water plays a critical role in meeting the West’s energy needs. In 2005, thermoelectric power plants in the five southwestern states of Arizona, Colorado, Nevada, New Mexico, and Utah consumed an estimated 292 million gallons per day, equal to the water consumed by Denver, Phoenix, and Albuquerque, combined. Throughout the Southwest, climate change and drought compound the challenge of meeting a growing population’s water and energy needs. More frequent or severe droughts and changing patterns of runoff affect management of the region’s thermoelectric and hydroelectric resources. Increasingly, power companies, regulators, and other decision-makers are recognizing the impact of energy choices on water resources. This recognition has, in many states, led to greater consideration of water resources in energy planning.

This presentation will highlight several cases where drought has affected power generation, trends of water use for electricity generation in the region (and the energy policies driving those trends), and additional strategies that can help mitigate the impacts of the energy sector on water resources.

Erosion, soil development and nitrogen cycling in a topographically dissected wet tropical landscape, Osa Peninsula Costa Rica

by Samantha Weintraub, Institute of Artic and Alpine Research

Lowland tropical forests are thought to cycle nitrogen in relative excess because old, highly weathered soils are broadly viewed as poor in rock-derived nutrients, such as phosphorus. However, exposure to diverse geomorphologic and hydrologic processes can give rise to differential weathering and erosion across topographically dissected landscapes, especially those in a transient state. Topographic variation has been shown to influence the availability of rock-derived nutrients, such as phosphorus, through effects on soil erosion and residence times, though analogous effects remain unexplored for nitrogen.

In this talk I will demonstrate that spatial patterns in soil N availability are closely associated with landscape position in a highly dissected, wet (~ 3,500 mm annual rainfall) tropical lowland forest on the Osa Peninsula, Costa Rica. I will discuss how correlations between soil biogeochemical data with soil development and weathering indices suggest a strong geomorphic control on the N cycle. Measurements of overland erosional N transport from this forest suggest that slopewash fluxes (~ 64 mg N m-2 yr-1) are relatively small. However, if slopewash is only ~ 7 % of annual erosion rates (which we think it is), then when all erosion is considered the N flux (954 mg N m-2 yr-1) may be high enough to constrain the accumulation of N within the ecosystem, potentially contributing to N limitation in eroding zones. Overall, these results demonstrate how topography and erosion drive within-watershed gradients in soil N availability, which may be relevant to biogeochemical dynamics in watersheds worldwide.