Vol 1, No 2 (2010)

Atmospheric CO2 and CH4 are the effective greenhouse gases. The increase in the concentration of radiatively active gases such as CO2 and CH4 has the potential to increase surface temperature and affect climate on a global scale. The concentration of atmospheric methane has doubled over the last century from a preindustrial concentration of 0.7 ppmv to the current level of 1.7 ppmv. Because of the potential effects of increased atmospheric CO2 and CH4 on the global energy budget, considerable effort has recently been made to quantify terrestrial CO2 and CH4 sources and sinks. Natural wetlands are important sources of CH4 to the global atmosphere accounting for nearly 30% of the CH4 produced annually. Analysis of global CH4 emissions indicates that more than half of the annual wetland emission is from forested and nonforested wetlands from 50 to 70°N. Russia, Canada and Alaska are the major CH4 sources to the atmosphere from high-latitude soils of the Northern Hemisphere, responsible for 64%, 11%, and 7% of these net emissions, respectively. Estimates of the source and sink strength of boreal, subarctic, and arctic wetlands have received considerable attention in recent initiatives such as the 1988 Arctic Boundary Layer Experiment (ABLE) and the 1990 Canadian Northern Wetlands Study (NOWES). The results of these experiments have been published in dedicated volumes of the Journal of Geophysical Research and other well known scientific journals. Of course the reviews reflect mainly these papers. For example 21 out of the 25 CH4 flux estimates listed by Vourlitis and Oechel [1996] for arctic and subarctic ecosystems are from Alaska and 23 out of the 34 estimates of boreal wetland CH4 flux are derived from studies of Canadian boreal wetlands. Unfortunately reported estimates of CH4 flux extrapolated from plot-level arctic, subarctic, and boreal wetlands (50 to 70°N) range between ca. 25-35 TgCH4 /yr to as high as 65 TgCH4 /yr. The high dispersion probably reflect the relatively limited date base that was available for Russia. Significant amount of CO2 and CH4 flux research has been conducted in Russia over the past 10-20 years. But the results of these experiments have been published mainly in national Russian scientific journals as well as Proceedings and Abstracts of symposiums. Due to the uncertainty in the natural wetland CO2 and CH4 sources and sinks strengths, the aim of our paper is to review the publications which estimate CO2 and CH4 emissions in Russia and discuss how photosynthesis, respiration, methanogenesis, and methyltrophy are controlled here by their environment. Time span covered in this annotated bibliography is from the beginning of the 1990s up to now. The list contains both primary sources and reviews, which report data on carbon dioxide or methane flux densities. Topics not covered are consumption and production of СН4 and СО2 by soil microcosms, time trends for C pools in ecosystems, experimental studies of photoassimilation. While the list is not exhaustive, an effort has been made to mention publications of all known to the compiler research groups, which have been engaged in measurements of СО2 and СН4 fluxes at Russian mires. Totally, about 200 annotations are included. If the original source contains an authors' annotation, it is reproduced in the bibliography, sometimes with minor alterations. Otherwise, an annotation which summarizes methods and results of the study was written by the compiler. When we believed our own appraisals and comments on the original content to be desirable, they were inserted as footnotes.

Methane is a significant «greenhouse gas» and is of fundamental importance in atmospheric photochemistry, as it regulates the formation of ozone and hydroxyl, which are responsible for the breakdown of most gases that are emitted into the atmosphere by natural and anthropogenic processes. Mires are the most important natural methane source. West Siberian mires belong to the biggest wetland area in the world and contribute essentially to the global methane emission. The aim of this study was to summarize results of monitoring of regional methane emissions from Western Siberia, using an approach, which we name the "standard model" (SM), this paper describes the newest SM version at the moment - Bc8. SM consists of data about a duration of methane emission in each zone, digital map and the probability density distribution of the specific methane fluxes from typical ecosystems, based on experimental methane emission measurements. As an example, results of those measurements in forest-steppe fens of Western Siberia and sites description are presented. Methane fluxes were measured with static chamber technique during snow-free period of year. Different mire types have been classified into eight categories and emission were measured in seven climatic zones from forest-steppe to tundra. Bc8 estimates the value of yearly methane emission from Western Siberia mires as 2.9 Mt C-CH4. Results obtained on the basis of the Bc8 give a logical picture of the geographical location of the main methane sources: emission has the maximum values in the southern taiga and subtaiga. Analysis of the probability density functions of specific fluxes from different mire types and climatic zones has shown that there are three types of probability density function of the specific methane fluxes: first, similar to lognormal with a single peak, second, which has two statistically significant peaks, and third, which has three or more statistically insignificant peaks. To understand how global warming influence on the methane emission from West Siberian mires, we can use models that describe the changes of the climatic zones boundaries. For this reason model assumed linear dependency between methane emission and mean air temperature of the previous month. That assumption probably has a physical reason because this dependency reflects influence of temperature wave on activity of methanogenic bacteria.

The data on diurnal and seasonal carbon dioxide emission rates determined by static chamber technique from the surface of oligotrophic mire in southern taiga in Western Siberia in 2005-2007 are presented. The general dynamics of CO2 emission during the summer period is the increase of CO2 emission intensity to the middle of summer and a subsequent decrease towards autumn. The mean values of CO2 emission was 118 mg CO2 m-2 h-1. Analysis of diurnal variations in CO2 emission has showed that the maximum CO2 flux has been observed at 4 PM, and the minimum flux at 7 AM. The average magnitude of daily fluctuations of CO2 emission was 74 mg CO2 m-2 h-1. Ambient CO2 concentration has maximum at 4 AM and minimum at 4 PM. The mean magnitude of CO2 background concentration was about 160 ppm. Established relationships between air temperatures and CO2 flux were used to estimate CO2 fluxes between measurement periods. It was found that the best time interval for measuring CO2 fluxes in summer time is from 10 AM to 1 PM.