Exposure to progressive inputs of anthropogenic N deposition elicits a series of changes in terrestrial ecosystems associated with both enhancement and inhibition of biogeochemical processes. Initially, growth of plants is enhanced as the constraint of N supply on NPP is relaxed, sometimes associated with altered dominance of species and gains or losses in diversity. Higher rates of nitrification and leaching of base cations eventually lead to acidification of soils, increases in soluble aluminum, and potentially to decreases in rates of NPP.

Human settlements in both arid lands and cities must, of necessity, alter hydrological regimes and geomorphology to provide clean, reliable drinking water, water for agriculture, and protection from flooding. Additionally, people also create substantial modifications to provide water for manufacturing, recreation, aesthetics, and sense of place. All of these practices can result in elimination or degradation of existing aquatic ecosystems, as well as creation of new ecosystems such as artificial lakes, stormwater retention basins, mitigation wetlands, groundwater recharge ponds, etc.

This would be an updated stable isotope working group that we ran in 2006. It was done at the last LTER to a room that overflowed, and some were not able to come in the room.

Stable isotope analyses remain proven technologies for characterizing long term change within ecosystems. This workshop/ information exchange/brainstorming group will focus on new technologies of continuous monitoring, or continuous flow analyses, as well as new elements that could be or are being employed for assessment of processes and sources within LTER ecosystems.

Urbanization has led to an increase of combustion-derived, organic carbon emissions that can deposit diffusely to soils within and surrounding cities. One of the most common types of urban pollutants, Polycyclic Aromatic Hydrocarbons (PAHs), may be toxic and are detrimental to environmental quality. Despite this concern, there is a considerable gap in our knowledge about the environmental fate of PAHs in highly populated urban areas.

Join us for an update on the progress of the EcoTrends project, an introduction to the functionality of the new EcoTrends website (http://www.ecotrends.info), lessons learned during the project, and a description of plans for the future. We will also use this time to solicit and discuss ideas on how to better incorporate and display data via database design, web services and tools (e.g., mapping, analysis tools, modeling tools, and customizable features) that will further engage and support the research and information management community.
 

The major contribution of land-based activities to climate change and greenhouse gas emissions (GHG) is widely recognized by the scientific community. The question of how and whether to include the agriculture and forestry sectors in GHG emission reduction projects suitable for carbon emissions trading in ‘cap–and–trade’ programs however, remains controversial.

We have developed an autonomous underwater vehicle (AUV) capable of generating for the first time 3-D biogeochemical datasets in the extreme environment of perennially ice-covered Antarctic dry valley lakes. The ENDURANCE (Environmentally Non-Disturbing Under-ice Robotic ANtarctic Explorer) is in the middle of a two year campaign to map the under-ice lake dimensions of West Lake Bonney in the McMurdo Dry Valleys, and is equipped to measure a comprehensive suite of physical and biogeochemical indices in the water column.

Dissolved organic material (DOM) is a major pool of organic carbon in all aquatic ecosystems and has high concentrations in soil interstitial water. DOM represents both a substrate for microbial growth and an important characteristic of aquatic and soil environments, regulating light penetration in lakes and streams and the bioavailability of trace metals and organic contaminants, for example. Diverse studies have shown that the concentration and chemical properties of DOM reflects the predominant DOM sources.

Land uses and management practices in residential parcels (e.g., aesthetic/recreational/economic uses, land-cover choices, irrigation and chemical applications) impact and are impacted by social (e.g., stratification and status, environmental perceptions, zoning) and ecological (e.g., carbon sequestration, nutrient cycling, water demand and quality) processes.

Both slow and fast variables interact to produce ecosystem change observable in a human lifetime. Unfortunately, ecosystem processes that operate over hundreds to millions of years are difficult to document, but are likely essential for understanding future ecosystem changes. Ecologists have traditionally studied these long-term ecosystem variations using the chronosequence approach, which adopts a “space-for-time” substitution.