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.

Bacteria community dynamics and metabolism are relevant to understanding the mechanism of phosphorus cycling in eutrophic lake systems. In Lake Mendota, WI, heterotrophic bacterial abundance as measured by catalyzed reporter deposition fluorescence in situ hybridization (CARD FISH), 33PO4-3 uptake and regeneration, 14C- leucine incorporation, alkaline phosphatase activity, and a suite of chemical analysis were measured during 2009 ice-off period in order to identify seasonal and spatial trends.

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.

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.

Coastal ecosystems play a key role in the transformation, transport, burial and exchange of water and organic and inorganic carbon and nitrogen between land, atmosphere and the ocean. With an overwhelming majority of the human population living in the coastal zone, coastal ecosystems are among the most heavily impacted ecosystems in the world. Like many other coastal regions, the Plum Island Ecosystem region, which lies just north of Boston, Massachusetts, is experiencing population growth in the watershed, land use change, climate change, altered hydrologic cycles, and sea level rise.

     Coastal watersheds provide valuable ecosystem goods and services to society. Both anthropogenic and natural changes may alter the ability of natural systems to provide these goods and services. To maintain resilient ecosystems in the face of future change, we need to understand their structure and how they function. One indicator of ecosystem function is species diversity. Substantial evidence exists to suggest that more diverse systems can be more resilient to ecosystem alterations.

Coral reefs are known for their exceptional species diversity and productivity, yet are sensitive to biotic and abiotic perturbations. Many reefs have experienced phase shifts as the result of alterations in herbivore abundance. This research in Moorea, French Polynesia, is aimed at elucidating differential effects of sea urchin species on the coral reef community.

The north slope of the Brooks Range has been glaciated several times since the Late Tertiary, resulting in a landscape with glacial sediments of various ages (modern to ca. 2 million years old) in close proximity. We used space as a substitute for time to investigate how terrain age affects biological attributes of streams in the Toolik Lake region of Arctic Alaska. Similar studies have been limited to successional sequences of streams on terrains deglaciated for up to only 200 years. We extended this model to streams draining terrains that have been deglaciated for up to ca.

The distribution of Adélie penguins along the West Antarctic Peninsula (WAP) is spatially heterogeneous. Large Adélie colonies occur spatially in regions characterized by deep seafloor canyons. Often associated with these regions is persistent upwelling of warm, nutrient-rich UCDW, which is hypothesized to provide a predictable food resource close to the colonies such that they can be accessed by the penguins given their limited foraging range.