Following relaxations prevailing equatorward winds, warm water from the Santa Barbara Channel flows poleward around Point Conception and along the central California coast. Sequences of satellite sea surface temperature images show the events as bands of warm water extending up to 20 km offshore. Characteristics of these flows were examined using time series of currents and temperature from an array of moorings along the inner shelf (15 m depth), a mooring on the mid-shelf (100 m depth), and surface current observations from high frequency radars.

The California Current System is a coastal upwelling biome, as found along the eastern margins of all major ocean basins. These are among the more productive ecosystems in the world ocean. The California Current Ecosystem (CCE) LTER site (centered on 32.9° N, 120.3° W) is investigating nonlinear transitions in the California Current coastal pelagic ecosystem, with particular attention to long-term forcing by a secular warming trend, multi-decadal oscillations (e.g., PDO and NPGO), and ENSO in altering the structure and dynamics of the pelagic ecosystem.

The Sevilleta LTER is located at the intersection of several aridland ecosystem types. Although it is axiomatic that water is the key limiting resource in aridland ecosystems, most arid land soils are also chronically low in nutrients and organic matter. Resource availability is a function of the frequency and size of precipitation events as well as the time between events. As a consequence, NPP and organic matter decomposition are often decoupled in space and time, and soil nutrient supply rates may limit NPP during periods when soil moisture is sufficient for plant growth.

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.

The Virginia Coast Reserve (VCR) is an extremely dynamic, heterogeneous coastal barrier landscape comprising mainland watersheds, tidal marshes, lagoons, and barrier islands. Our goal for the VCR LTER program is to develop a predictive understanding of the response of coastal barrier systems to long-term environmental changes in climate, sea level and land use, and to relate these to the ecological services the coastal barrier systems provide.

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.

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.

The KBS LTER site is in a diverse, rural-to-semirural landscape typical of the U.S. Great Lakes and upper Midwest regions. Research at KBS asks how diverse plants, animals, and microbes in agricultural landscapes can contribute to farm productivity, environmental performance, and profitability. We study annual and perennial crops including corn, soybean, and wheat rotations, forage crops such as alfalfa, and biofuel crops such as poplars, switchgrass, and native successional communities.

Tropical environments are changing fast due to deforestation and regrowth, urbanization, climate change, and other forces. The consequences are immense for the whole array of ecosystem services people require. The Luquillo Long-Term Ecological Research Program (LUQ) is tackling these issues in Puerto Rico. LUQ began in 1988 and focused on natural disturbances (hurricanes, landslides, droughts, floods) and ecosystem response. That work revealed patterns of resistance and resilience to cycles of natural disturbance.

    Turbulent mixing in lakes plays a crucial role in nutrient transport (e.g. phosphorus) and thus influences the water quality within the lake. Field experiments were conducted in Lake Mendota in the summer 2008 to determine the interior and boundary mixing. The interior mixing is generally several orders of magnitude smaller than the boundary mixing because the thermal stratification inhibits vertical mixing through the metalimnion.