The impact of wildfire on microbial C:N:P stoichiometry and the fungal-to-bacterial ratio in permafrost soil

New paper by Zhou et al 2018 dealing with the impact of wildfire on microbial C:N:P stoichiometry and the fungal-to-bacterial ratio in permafrost soils.

The results of the study indicate that forest wildfire increased the active layer depth and subsequently decreased soil moisture and vegetation coverage. This consequently led to a decrease in the microbial C and N contents as well as the F:B ratios. However, the C:N:P ratios in the microbial biomass remained relatively constant over time following a wildfire, indicating homeostatic regulation. Wildfire also failed to affect the microbial communities in the deep soil layers.

These results indicate a complex interaction between the decomposer community, resource availability, and successional stage. Forest wildfire either shifted the microbial diversity or suppressed the microbial growth rate for several decades.

Changes in fluxes of carbon dioxide and methane caused by fire in Siberian boreal forest with continuous permafrost

New paper by Köster et al., 2018 is dealing with the long-term effects of fires on the fluxes of two main C-based GHGs (CO2 and CH4) in boreal coniferous forest areas in central Siberia with underlying permafrost.

The results of the study indicate that fire significantly affected the fluxes of CO2, and the impact of fire lasted much longer than expected based on previous studies. There was a significant decrease in soil CO2 efflux shortly after the fire, but over time the emissions started to increase and this increase continued for more than 50 years after the fire. The effect of fire on the CH4 flux was not significant in Siberian boreal forest with a permafrost base, but all the studied areas acted as a CH4 sink. There was a clear negative correlation between CO2 emissions and depth of the active layer, while CH4 fluxes were not influenced by it. The results also confirmed that the role of recovering vegetation in CO2 emissions is significant as the main factors driving the CO2 flux were the biomass of birch and alder trees, and the biomass of the vascular plants in the ground vegetation.

Reindeer grazing alter soil fungal community structure and litter decomposition related enzyme activities in boreal coniferous forests in Finnish Lapland

New paper by Santalahti et al., 2018 is the first to describe detailed fungal community structure using a 454-pyrosequencing analysis in reindeer grazed and nongrazed
sites in northern boreal coniferous forest soils.

The results of the study indicate that reindeer grazing alters significantly the soil fungal community structures and the abundance of Ascomycota, as well as certain fungal genera and species. Within longer time scales, grazing may affect litter decomposition through changes in fungal community structure and enzyme activities in the northern boreal forest soils.

Canada 2018 expedition is over!

This year’s Canada campaign (25.07. – 15.08.2018) was divided into two. Part of the team was working on permafrost areas along the Dempster Higway (NWT and Yukon, Canada), the other part of the team was working on non-permafrost areas, on FireSmart project sites (NWT, Canada).

On Dempster Highway (works done by Prof. J. Pumpanen and PhD student H. Aaltonen) the sample plots that were established in summer of 2015 were re-visited. This year’s focus was on VOC measurements along fire chronocequence (fires in years 2012, 1990, and fire about 100 years ago).

The short term effects of fires and the effect of different fire severity on SOM turnover was studied on experimental burning areas (the Canadian Boreal Community FireSmart Project sites and old International Crown Fire Modeling Experiment (ICFME) sites close to Fort Providence, NWT, Canada (works done by PhD K. Köster and PhD student C. Ribeiro). The research was conducted based on intensive field sampling to study soil C and N stocks, soil CO2, CH4 and N2O fluxes, soil temperature and soil chemical and microbiological properties, tree and vegetation composition and biomass changes. Unfortunately this year there was no possibility to perform high intensity crown fire, but we managed to measure in many low intensity surface fire plots. The measurements were conducted before the fire experiment, straight after fire experiment, and couple of days after fire experiment. We also measured on old fire experiment areas, where the fires took place 1, 2, 3, 4, 6 and 18 years ago.

Water quality and GHG study close to Värriö

In June 2018, Jukka Pumpanen and Frank Berninger had a joint field trip to Värriö sub-arctic research station in Värriö, Finland for studying the water quality and greenhouse gas emissions in rivers and forests with researchers from the University of Helsinki (Finland), Austrian Academy of Sciences / International Institute for Applied System Analysis (Austria), Fukuoka University (Japan), Shinshu University (Japan), University of Hyogo (Japan) and the Institute of Mountain Hazards and Environment (Chinese Academy of Sciences Chengdu). 


Two oral presentations lately

17.04.2018 EGU 2018 follow-up at Luke (Helsinki, Kuopio)

Biogenic volatile organic compound emissions from forest floor along a fire chronosequence on permafrost in Central Siberia, Russia

Huizhong Zhang-Turpeinen


17.04.2018 Viikki Soil Science Seminar (Helsinki)

Fires in northern boreal forests – effects of disturbance on biogeochemistry

Kajar Köster

Our team in EGU2018

The EGU General Assembly 2018 (held in Vienna, Austria, 08.-13.04.2018) will bring together geoscientists from all over the world.

This year our team will present the following topics:

Biogenic volatile organic compound emissions from forest floor along a fire chronosequence on permafrost in Central Siberia, Russia
Huizhong Zhang-Turpeinen, Minna Kivimäenpää, Anatoly Prokushikin, Frank Berninger, Kajar Köster, and Jukka Pumpanen
Wed, 11 Apr, 17:30–19:00, Hall A, A.223

Fire caused changes in CO2 and CH4 fluxes in Siberian permafrost forests.
Egle Köster, Frank Berninger, Kajar Köster, Heidi Aaltonen, Xuan Zhou, Huizhong Zhang-Turpeinen, Anatoly Prokushkin, and Jukka Pumpanen
Wed, 11 Apr, 17:30–19:00, Hall A, A.220

Forest fires and their effect on soil carbon turnover — comparison of permafrost and non-permafrost areas from Canada
Kajar Köster, Egle Köster, Heidi Aaltonen, Xuan Zhou, Frank Berninger, and Jukka Pumpanen
Wed, 11 Apr, 17:30–19:00, Hall A, A.227

How time since last forest fire affects soil greenhouse gas (CO2, CH4 and N2O) fluxes in hemiboreal Scots pine forest fire chronosequence
Marek Metslaid, Argo Orumaa, Egle Köster, Kristi Parro, Kalev Jõgiste, Frank Berninger, Jukka Pumpanen, and Kajar Köster
Wed, 11 Apr, 17:30–19:00, Hall A, A.219

Biochar as a possible new tool for afforestation practices
Egle Köster, Jukka Pumpanen, and Kajar Köster
Thu, 12 Apr, 17:30–19:00, Hall X3, X3.47