Carbon sinks and sources
Markku Oinonen, docent, Director of Laboratory
The carbon cycle is one of the biochemical cycles that helps to sustain life on Earth. The amount of radiocarbon in a natural sample gives information about the date when atmospheric carbon dioxide was stored into the sample through photosynthesis. Radiocarbon measurements will, therefore, provide a temporal dimension to the research of carbon cycle. Soil carbon is one of the largest reservoirs of carbon on Earth. Hence, it is important to know how the soil carbon affects the amounts of atmospheric carbon dioxide, and therefore future climate conditions. We are developing methods and conducting research with different universities, Finnish Environmental Institute and Finnish Forest Research Institute on how the soil carbon affects the global carbon balance.
This research is based on measuring the radiocarbon content of organic samples and the carbon dioxide that is released from them. Carbon dioxide samples are collected with a highly sensitive mechanical molecule trap. Carbon released from the Northern European soils is found to be partially temperature dependent. When climate changes, the rate of carbon being released also changes, which then affects the global carbon balance. Concern about the future climate is global. Therefore it is crucial to strengthen our knowledge also about other significant carbon reservoirs. For example, Amazonian peatlands form a major carbon sink, and their fate is being largely affected by future land use.
Biasi C, Tavi N, Jokinen S, Shurpali N, Hämäläinen K, Jungner H, Oinonen M & Martikainen P (2011) Differentiating sources of CO2 from organic soil under bioenergy crop cultivation: A field-based approach using 14C. Soil Biology & Biochemistry 43: 2406–2409.
Hilasvuori E, Akujärvi A, Fritze H, Karhu K, Laiho R, Mäkiranta P, Oinonen M, Palonen V, Vanhala P & Liski J (2013) Temperature sensitivity of decomposition in a peat profile. Soil Biology & Biochemistry 67: 47–54.
Hämäläinen K, Fritze H, Jungner H, Karhu K, Oinonen M, Sonninen E, Spetz P, Tuomi M, Vanhala P and Liski J (2010) Molecular sieve sampling of CO2 from decomposition of soil organic matter for AMS radiocarbon measurements. Nucl. Instr. Meth. Phys. Res. B 268: 1067–1069.
Karhu K, Fritze H, Hämäläinen K, Vanhala P, Jungner H, Oinonen M, Sonninen E, Tuomi M, Spetz P & Liski J (2010) Temperature sensitivity of soil carbon fractions in boreal forest soil. Ecology 91(2): 370-376.
Lähteenoja O, Ruokolainen K, Schulman L, Oinonen M (2009) Amazonian peatlands: an ignored C sink and potential source. Global Change Biology 15: 2311–2320.
Lähteenoja O, Reategui YR, Räsänen M, Torres DDC, Oinonen M & Page S (2012) The large Amazonian peatland carbon sink in the subsiding Pastaza-Maranon foreland basin, Peru. Global Change Biology 18: 164–178
Palonen V & Oinonen M (2013) Molecular Sieves in 14CO2 Sampling and Handling. Radiocarbon 55: 416–420.