Quantifying landscape-level methane fluxes in subarctic Finland using a multiscale approach.

Quantifying landscape-scale methane (CH4 ) fluxes from boreal and arctic regions, and determining how they are controlled, is critical for predicting the magnitude of any CH4 emission feedback to climate change. Furthermore, there remains uncertainty regarding the relative importance of small areas of strong methanogenic activity, vs. larger areas with net CH4 uptake, in controlling landscape-level fluxes.

The human footprint in the carbon cycle of temperate and boreal forests.

Temperate and boreal forests in the Northern Hemisphere cover an area of about 2 x 10(7) square kilometres and act as a substantial carbon sink (0.6-0.7 petagrams of carbon per year).

Variations in 13C discrimination during CO2 exchange by Picea sitchensis branches in the field.

We report diurnal variations in (13)C discrimination ((13)Delta) of Picea sitchensis (Bong.) Carr. branches measured in the field using a branch chamber technique.

A comparative analysis of simulated and observed photosynthetic CO2 uptake in two coniferous forest canopies.

Gross canopy photosynthesis (P(g)) can be simulated with canopy models or retrieved from turbulent carbon dioxide (CO2) flux measurements above the forest canopy. We compare the two estimates and illustrate our findings with two case studies. We used the three-dimensional canopy model MAESTRA to simulate P(g) of two spruce forests differing in age and structure.

Atmospheric O2, CO2 and delta13C measurements from aircraft sampling over Griffin Forest, Perthshire, UK.

Regular vertical aircraft sampling has been performed in the lower troposphere above Griffin Forest, near Aberfeldy, Perthshire, UK (56 degrees 37'N, 3 degrees 47'W), between February 2003 and May 2004, for analysis of O2/N2, CO2 and delta13C of CO2. We sampled flasks between 800 and 3100 m above sea level. The peak-to-peak amplitude of the seasonal cycle of O2/N2 decreases from 171 per meg at 800 m to 113 per meg at 3100 m.

Similar response of labile and resistant soil organic matter pools to changes in temperature.

Our understanding of the relationship between the decomposition of soil organic matter (SOM) and soil temperature affects our predictions of the impact of climate change on soil-stored carbon. One current opinion is that the decomposition of soil labile carbon is sensitive to temperature variation whereas resistant components are insensitive. The resistant carbon or organic matter in mineral soil is then assumed to be unresponsive to global warming.