The goal of the Arctic LTER is to predict the future ecological characteristics of Arctic Alaska based upon our knowledge of the controls of ecosystem structure and function as exerted by physical setting and geologic factors, climatic factors, biotic factors, and the changes in fluxes of water and materials from land to water.

Urbanization is one of the major threats to stream ecosystems worldwide. The phrase “urban stream syndrome” has been coined to describe patterns in degraded streams draining urban land. In Puerto Rico, urbanization now covers 16% of the island. The fully protected Luquillo Experimental Forest (focus of the LUQ-LTER) is only 23 km from the center of San Juan, a city of 1.3 million. Therefore, LUQ is assessing the impacts of urbanization on tropical stream ecosystem structure and function.

Despite substantial changes in climate, sea-ice and glacier extent, and vegetation in much of the Arctic, the area near Toolik Lake, Alaska has experienced no significant trends of increasing temperature, altered precipitation, or increasing active-layer thaw depth. There has been, however, a near doubling of alkalinity in Toolik Lake since 1975 and increases in alkalinity in many lakes of all depths and sizes in the surrounding area. Lake monitoring indicates that in-lake processes such as sulfate or nitrate reduction cannot account for these alkalinity increases.

Coastal bays, which are typically shallow, located in the photic zone, and have little freshwater input, respond differently to nutrient enrichment than deeper estuaries. Because of the diversity of benthic and pelagic autotrophs they support, coastal bays are capable of modulating the effects of nutrient enrichment, derived from both allochthonous and autochthonous sources. We describe a study performed in Hog Island Bay, Virginia, located along an eutrophication gradient on the Delmarva Peninsula, to determine sources, sinks, and fates of nitrogen (N).

The Chicago Region ULTRA-Ex will address a question fundamental to understanding the dynamic interactions between biodiversity conservation, ecosystem processes, and human well being in urban landscapes: In a complex urban/metropolitan system, what are the synergies and tradeoffs between conserving biodiversity and providing ecosystem services to people? The project focuses on the Green Infrastructure Vision of the Chicago Wilderness alliance, a conservation consortium of over 240 organizations.

The experimental research in Salatín (Western Tatra Mts., Slovakia) address the impact of nitrogen (N) deposition on ecosystem of alpine grasslands. The site was exposed during last 50 years to high acid deposition with maximum rates of wet deposition at least 15–20 kg N ha-1 yr-1 and 20–25 kg S ha-1 yr-1. The experiment consists of 5 replicated treatments: 20, 60, and 150 Kg N ha-1 yr-1, 50 Kg P ha-1 yr-1 and the control, 25 plots in total.

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.

The temperate forests of eastern North America support high biodiversity and critical ecosystem functions while providing natural resources and cultural benefits to an expanding human population. The region is shaped by a legacy of landscape change: major shifts in climate, vegetation and disturbance at millennial time scales; extensive deforestation for agriculture in the 17th – 19th centuries; and abandonment of farmlands, natural reforestation and increasing urbanization through the mid-21st century.

A field experiment has been initiated in August 2008 to determine if the vegetation of a coastal marsh is in synchrony with hydrologic conditions that have developed with rising sea-level. The hypothesis being tested is that plant community structure will persist in existing zones of vegetation in the face of sea-level rise unless disturbance provides opportunities for species change under more frequent tidal inundation.

Seagrass meadows are declining worldwide as a result of nutrient over-enrichment, warming water temperatures, and anthropogenic disturbances. In many areas, restoration projects are attempting to the reverse the trend with varying success. In the Virginia coastal lagoons, seagrasses (Zostera marina) were lost in the 1930’s due to a large hurricane impacting meadows already weakened by the wasting disease. A large-scale restoration effort has been underway since the early 2000’s and has resulted in >1000 acres of seagrass coverage.