Second LTER Intersite CO2 Workshop

The second LTER Intersite Workshop on “Carbon Dynamics in Aquatic Ecosystems: Continental-Scale Patterns and Landscape-Scale Processes” was held at the Marine Biological Laboratory in Woods Hole, MA on February 10-12, 1995. The workshop, organized by George Kling (Arctic Tundra), Tim Kratz (North Temperate Lakes), Jon Cole and Nina Caraco (Hubbard Brook), brought together 21 scientists representing eight LTER sites (ARC, BNZ, CWT, HBR, LUQ, MCM, NTL, SEV), and federal agencies (National Biological Survey, U.S. Geological Survey) to discuss continental-scale patterns in the role of surface waters in landscape-scale carbon dynamics. Representatives from research institutions in Canada and Scotland also attended. The first workshop was held at Trout Lake in Wisconsin in February 1994.

Three Project Objectives:

• Identify the continental-scale patterns in CO₂ saturation and compare the relative importance of terrestrial carbon inputs to lakes and streams in arctic, temperate and sub-tropical environments.
• Begin to determine at the landscape scale how specific processes, such as hydrologic inputs or carbon uptake by primary producers, relate to observed variation of CO₂ saturation in neighboring or interconnected lakes and streams.
• Evaluate, using long-term data records of CO₂ saturation, the magnitude of change over time and the relative importance of land-water linkages.

Because each participating site made a series of PCO₂ measurements during the summer of 1994, collectively participants were able to examine patterns of CO₂ saturation over a wide variety of habitats, environments, and latitudes. Several intriguing, but preliminary, patterns were identified at the workshop, patterns that could not have been discerned without the diversity of sites that contributed data. For example, as a group, streams appeared to be consistently above saturation in CO₂ despite widespread differences in latitude, size, and geologic setting of individual streams. However, the range of CO₂ saturation in streams appeared to be narrower than that observed in lakes or groundwaters. Another interesting pattern was that lakes with associated wetlands tended to have higher PCO₂ than those without adjacent wetlands.

Working groups have been established to continue analyzing results presented at the workshop, to address methods-related issues, and to investigate the potential use of stable isotopes in addressing mechanisms associated with patterns of CO₂ saturation.

All interested sites are invited to participate. A group electronic mail list has been established at the Network Office; to subscribe, send a message to request_CO₂@LTERnet.edu. For more information: Tim Kratz, tKratz@LTERnet.edu.