Treesearch

RMFRES RWU 4452 has made several ozone (O3) and carbon dioxide (CO2) trace gas flux measurements in the Snowy Range, WY GLEES research area over the past few years. These measurements were made using the micrometeorological eddy correlation technique at two sites: one 6 m above tree canopy height on the Brooklyn tower (ozone only); and the other below canopy height, 1-2m above a wet alpine meadow surface near the Brooklyn tower. Diel C02 vertical flux cycles change dramatically from expected daytime uptake (downward) and nighttime emissions (upward) during the growing season to predominantl...

The Glacier Lakes Ecosystem Experiments Site (GLEES) was established to examine the effects of atmospheric deposition and climate change on alpine and subalpine ecosystems. The site contains East Glacier Lake (3282 m elevation) and West Glacier Lake (3276 m elevation), and their watersheds. These two small lakes are located 120m from each other at the alpine/subalpine transition. The lakes are similar in surface area, depth, and volume, but differ in watershed size, flow patterns of input, and water chemistry (Musselman 1994). Water chemistry has been monitored on these lakes periodically...

Hydrological and chemical fluxes were examined for East and West Glacier Lakes and their adjacent high-elevation (3200-3700 m) catchments in the Snowy Range of southern Wyoming. Both lakes are approximately 3 ha, but the East Glacier catchment (29 ha) is about half the size of West Glacier. Bedrock is primarily quartzite that has been heavily fractured and crossed with mafic intrusions.

A new strategy to estimate the sensitivity of alpine plant species to atmospheric deposition is presented. This approach utilizes plant physiological and morphological characteristics to estimate pollutant uptake. The plant characteristics can be determined quickly and easily in the field within the constraints of allowable activities in Class I wilderness areas. Species in two alpine sites have been sampled and the first potential sensitivity rankings of alpine species have been constructed. While the accuracy of these rankings still needs to be verified, they provide a framework for...

Stable isotopes of S are used in conjunction with dissolved SO2-|4 concentrations to evaluate the utility of ä34S ratios in tracing contributions of bedrock-derived S to SO2-|4 in runoff. Water samples were collected over the annual hydrograph from two tributaries in the West Glacier Lake, Wyoming, catchment. Concentrations of SO2-|4 ranged from 12.6 to 43.0 Ìeq L-1; ä34S ratios ranged from -1.8‰ to +4.9‰ The ä34S value of atmospherically derived SO2-|4 is about +5.6%c.; four samples of pyrite from the bedrock had ä34S ratios that ranged from +0.7 to +4.1‰ Concentrations of SO2-|4 were...

The movement of trace gases through porous media results from a combination of molecular diffusion and natural convection forced by turbulent atmospheric pressure pumping. This study presents observational and modeling results of an experiment to estimate the C02 flux through a seasonal snowpack in the Rocky Mountains of southern Wyoming, USA. Profiles of C02 mole fraction in the top 1 m of the snowpack, C02 mole fraction just above and at the base of the snowpack, and snowpack density profiles were obtained at a meadow site during February and March 1994, when the snowpack was about 2 m...

Research was conducted to determine wind patterns and snow deposition at a high elevation alpine/subalpine ecotone site using deformation response of trees to prevailing winds. The research has provided detailed maps of wind speed, wind direction, and snow depth as determined from tree deformation. The effects of prevailing wind on tree blowdown at the site have also been described. This research is an example of interaction of biological and physical scientists working together to provide detailed description of an ecosystem response to the atmospheric environment.

The authors review sources of error in radiosonde measurements in the atmospheric boundary layer and analyze errors of two radiosonde models manufactured by Atmospheric Instrumentation Research, Inc. The authors focus on temperature and humidity lag errors and wind errors. Errors in measurement of azimuth and elevation angles and pressure over short time intervals and at higher altitudes introduce wind vector errors greater than 5 m s-1. Mean temperature and humidity lag errors were small, and collectively, these lag errors had little effect on the calculation of the vertically integrated...

Relative efficiencies of sampling methods were evaluated for bull trout Salvefinus confluentus and cutthroat trout Oncorhynchus clarki in small, high-gradient streams with low conductivities. We compared day and nighttime observations by snorkelers to enumerate bull trout and cutthroat trout, and at night we also used a bank observer. Methods were developed for capturing juvenile bull trout in areas where traditional methods such as electrofishing were ineffective. Juvenile salmonids were counted during the day and night in two reaches (200 m) of Trestle Creek, Idaho, in August 1991. In...

Knowledge of how stream habitats change over time in natural and human-influenced ecosystems at large, regional scales is currently limited. A historical stream survey (1934-1945) was compared to current surveys to assess changes in pool habitats in the Columbia River basin. Streams from across the basin, representing a wide range of geologies, stream sizes and land-use histories, were used to evaluate habitat change. We classified streams as managed or unmanaged, based on their land-use histories. Managed basins were watersheds managed predominantly for multiple-use (e.g., timber harvest,...