With recent shifts in public attitudes across the United States concerning the problem of global climate change, momentum is building for aggressive action to mitigate greenhouse gas emissions. At the same time, the ongoing economic recession presents challenges for financing an aggressive climate change abatement campaign; hence, it is imperative that cost-effective strategies for reducing greenhouse gas emissions be identified and pursued. To accomplish this, policy instruments will need to be tailored to a complex range of local and regional conditions.

Wet deposition of ammonium in Rocky Mountain National Park (RMNP) and along the eastern slope of the Rocky Mountains has reached a “critical load” where negative impacts on alpine ecosystems are evident. Results from the recently completed Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS) suggest that many different sources are contributing to atmospheric nitrogen deposition in the park. Sources include long distance transport from western states, regional contributions from agricultural and urban sites in Colorado, and local emissions from soils within the park.

The objective of this work was to compare estimates of microbial and biogeochemical processes obtained from year round versus field season only data. We also aimed to capture the response of soils to simultaneous warming and nitrogen fertilization in both winter and summer months. Our research took place at the chronic Soil Warming and Nitrogen Fertilization experiment at the Harvard Forest Long Term Ecological Research site. The experiment includes four treatments in a completely randomized design: control, +heat, +N, and +heat +N.

Streams in the McMurdo Dry Valleys, Antarctica, flow during the short summer melt season (4-12 weeks) when air temperatures are close to the freezing point of water. Because of the extreme low precipitation rates, streams originate from glacial meltwater and flow to closed-basin lakes located on the valley floor. Water samples have been collected from the streams in the dry valleys since the start of the MCM LTER in 1993 and these have been analyzed for major ion and nutrient chemistry. The chemistry of the streams varies by location.

 Phytoplankton production in the Santa Barbara Channel supports one of the richest marine ecosystems in the Southern California Bight. The climatology of chlorophyll biomass in the area reveals maxima over the Santa Barbara Basin in the western Channel and along the mainland in the eastern channel where the continental shelf broadens and where two rivers discharge seasonally.

Suspended solids in streams are important to monitor and manage because high levels of suspended solids have been shown to affect the primary and secondary production of a stream. The loading rate of total suspended solids (TSS) can greatly be influenced by the land management of a stream site’s catchment area. A computer-based geographic information system (GIS) was used to assess what land cover/land use variables were highly correlated to high levels of TSS in Kansas Flinthill streams on a long-term data set collected by the Kansas Department of Health and Environment.

 Seventy-four catchments, with a total area of 790 km2 (ranging from 1 to 50 km2), drain from the Santa Ynez Mountains along the northern coast of Santa Barbara Channel. The topography of these coastal catchments is characterized as mountainous headwaters and sloping coastal plains separated by transitional foothills. From west to east, there are both elevational and land use gradients. Headwater elevations increase from approximately 300 to 1400 m, and land uses on the coastal plain and foothills change from mostly rangeland to a combination of urban and agricultural lands.

Elevational Controls on Organic and Inorganic Nutrients in Stream Waters, Boulder Creek Watershed, Colorado Front Range

Jordan N. Parman and Mark W. Williams

Department of Geography and Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA

Understanding the impacts of landuse and/or climate change on streamflow characteristics, such as peak discharge, sediment transport capacity, flow velocities and depths, within a given region or watershed requires knowledge of fine scale (0.01-10 m) hydraulic channel properties (i.e., detailed cross-sections, roughness, bed material). However, data for channel/reach properties are limited to primarily in-situ measurements.

Diverse plant litter mixtures frequently decompose substantially differently than expected, compared to the average of the individual component species. These strong “non-additive” effects constitute an important way in which biodiversity influences key components of below-ground ecosystem function like soil C and N cycling, and it remains unclear which plant traits drive diversity effects on soil C and N cycling.