How does Siberian forest respire

In vast remote taiga not far from the Yenisei river, where one can get only by helicopter within one third of the year, the construction of a huge 300-meter high mast is to be completed this summer. In the underground shelter under the mast, a research laboratory will be located, which is stuffed with the most contemporary scientific equipment. Researchers needed that in order to thoroughly investigate who or, more precisely, what is responsible for the greenhouse effect, where oxygen, carbonic acid gas and some other gases come from to Earth’s atmosphere, what part of carbonic acid Siberian swamps and forests manage to absorb, and to answer a lot of other questions, part of which seems trivial – but only to dilettantes.

The surprising construction is being erected in the framework of partnership project between the ISTC and the V.N. Sukachev Institute of Forest, Siberian Branch, Russian Academy of Sciences ( Krasnoyarsk). The project is called “Response of Biogeochemical Cycles to Climate Change in Eurasia”. The project will be accomplished by Russian researchers in cooperation with their German colleagues – specialists of the Institute of Biogeochemistry (Jena) and the Institute for Chemistry (Mainz). Both these institutes are members of the largest in Europe Max Planck scientific community and are named after Max Planck.

However, the mast per se is not unique. A twin-mast has been installed in Germany and it allows to carry out similar investigations not in the forestland, like this Siberian one does, but in the region of exceptionally highly developed industry and agriculture. But together they will indeed provide a unique opportunity to compare the atmosphere composition in the regions with fundamentally different antropogenic load and to find out how and due to what the composition changes. As a result, the atmosphere composition can be analyzed, or more precisely – it is possible to determine concentration in it of the most important (from the point of view of this investigation) gases at different heights, right up to 300 meters. It will be possible to study not simply chemical but also isotopic composition. And this will be the very key, which will allow to reveal the contribution by antropogenic and natural components into the general gaseous exchange flow in the atmosphere.

Sergei Verkhovets, project manager, explained in a general way why it was needed to build a tower of such height and how isotopic composition of gases will help to determine their origin.

Measurements of CO2 concentrations at the height of 200 to 300 meters above the earth surface allow us to investigate relatively homogeneous part of atmosphere, the so-called mixed bed. Along with that we can study the processes taking place above a vast territory, avoiding the “noise” caused by daily changes in the photosynthesis process close to the surface.

As per isotope ratio in CO2, CH4, CO and N2O, and the O2/N2 ratio, they allow to distinguish various carbon emission and sink processes – photosynthesis and respiration of ground biosphere, burning of fossil combustible materials, as well as the atmospheric-oceanic gaseous exchange.

For example, plants not only absorb CO2 in the course of photosynthesis, but also educe it while breathing. So, the carbonic acid gas “expired” by plants is enriched by a lighter isotope 12?. And above the ocean, where gaseous exchange processes obey to a greater extent to physical but not to biochemical laws, the difference in isotopic composition substantially aligns. Thus, if two air samples are taken and CO2 is educed out of them, and isotopic composition is determined, it is possible to establish its origin. The isotopic trace (signature) of fossil combustible is also well-known. Carbon monoxide (CO), in its turn, bears information about anthropogenic emissions, because one of its main sources is the incomplete burning of fossil combustible materials. Continuous measurements of carbon and oxygen isotopes on the continents are necessary to discover climatic influence on carbon sink. Methane observations will help us better understand connection between the climate and ecosystem: judging by change of concentration of “common” and “heavy” methane 14CH4, researchers can watch breathing of peatbogs and, probably, of permafrost soils.

The data obtained in the course of observations will be basic data for construction of carbonic balance models both at the regional and continental levels.

This task is particularly urgent for Russia. The point is that due to approval of the Framework Convention and the Kyoto Protocol, the situation occurred when Russia can make its contribution into investigation of global climate changes, but also obtain significant economic benefits. The Protocol stipulates that carbon dioxide removal from the atmosphere by natural absorbent ecosystems is acccounted as fulfilment of discharge reduction indices. Forests of Siberia constitute one fifth of the entire forests of the world, in any case – in terms of square. However, it is necessary to know exactly their capacity as an atmospheric carbon absorber.. It will be possible to obtain such data due to this project.