Alkyyliamiinit pohjoisissa metsä- ja kaupunkiympäristöissä

Low-molecular-weight alkyl amines are reactive organic nitrogen compounds that are im- portant precursors in secondary aerosol formation. Atmospheric aerosols have direct and indirect effects on Earth's climate system. Alkyl amines are emitted from marine and terrestrial ecosystems, agricultural activities and other anthropogenic sources. In terrestrial ecosystems, the quantities in the different parts of an ecosystem and formation processes are not well understood. Alkyl amine soil concentration and biosphere atmosphere exchange measurements are scarce. The main focus of this thesis is to determine concentrations of alkyl amines in ambient air in boreal forest and urban area, and further identify possible sources and reservoirs of alkyl amines in boreal forest. The main results presented in the thesis consist of a timeseries of gas- phase concentrations of alkyl amines measured over several months, concentrations of alkyl amines in the soil and fungal biomass, and an emission estimation based on the measured concentrations. Alkyl amines were studied in two northern latitude environments: in a boreal Scots pine (Pinus sylvestris L.) forest at the SMEAR II station in Hyytiälä and in an urban background area at the SMEAR III station in Helsinki. To quantify ambient air concentrations of alkyl amines in these environments, sample collection and analytical methods were developed. Ambient air concentrations of alkyl amines were measured from May to October 2011 in the forest site and from May to August 2011 in the urban site. The effect of the measured ambient air concentrations of alkyl amines on the local air chemistry was also assessed together with aromatic hydrocarbons and terpenoids. To assess boreal forest soil as a source of alkyl amines, a pot-scale experiment was set up. In the experiment Scots pine seedlings were grown on humus soil collected from the forest site, and the effects of Scots pine and soil organic matter (SOM) degrading enzymes on alkyl amine soil concentrations were studied. In addition, fungal strains common in boreal forest soils were cultured, and the alkyl amine concentrations in the grown fungal biomass were quanti- fied. The role of boreal forest soil as a source or as a sink of atmospheric alkyl amines was studied using a gradient-diffusion approach. In the approach, the soil atmosphere exchange of selected alkyl amines was estimated. This was done by describing dissolution/volatilisation on water and transport processes, and utilizing the quantified soil and ambient air gas-phase concentrations of the selected alkyl amines found in the studied boreal forest. The gas-phase concentrations of alkyl amines in ambient air were found to be higher in the forest site than in the urban site. In the forest site, the atmospheric concentrations appeared to be linked to soil and vegetation activity based on the seasonal course of the measured alkyl amines. Litterfall, a phenological event, coincides with the concentration maxima of some of the measured alkyl amines. In the pot-scale experiment, the SOM degrading enzymes were found to have no effect on the soil concentrations of alkyl amine while the presence of Scots pine was found to have an effect on the concentrations of some of the measured alkyl amines. The soil concentrations of alkyl amines were found to be lower than those measured from the fungal biomass. The most abundant fungal groups (ectomycorrhizal and saprotrhopic fungi) in the forest soil contained the highest quantities of alkyl amines revealing that fungal biomass may be an important reservoir of alkyl amines in boreal forest soil. Based on the flux estimate, the boreal forest soil was found to act as both a source and a sink of alkyl amines. The direction of the flux was dependent on the studied alkyl amines and environmental conditions in the forest site. Soil pH was found to be one of the most critical factors determining the direction of the flux between the soil and the atmosphere.Alkyyliamiinit ovat typpipitoisia orgaanisia yhdisteitä. Ilmakehässä nämä yhdisteet osallistuvat moniin kemiallisiin reaktioihin sekä pienhiukkasten muodostumis- ja kasvuprosesseihin. Riittävän suuret pienhiukkasten voivat toimia pilvipisaroiden tiivistymisytiminä. Pienhiukkaset vaikuttavat pilvien heijastukseen, elinikään sekä sateisuuteen. Alkyyliamiineilla on todettu olevan monia lähteitä ilmakehään. Lähteet voivat olla luonnollista alkuperää tai ihmistoiminnasta aiheutuvia. Alkyyliamiinien ilmakehälähteitä ei ole tarkasti määritetty, ja erityisesti maaekosysteemeissä alkyyliaminiien pitoisuuksia, muodostumisprosesseja ja kulkeutumista ei juurikaan tunneta. Koska alkyyliamiinien pitoisuuksia maaekosysteemeissä tai kaasunvaihtoa ekosysteemien ja ilmakehän välillä ei juurikaan tunneta, alkyyliamiinien ilmapitoisuuksia mitattiin kahdesta erilaisesta ympäristöstä, mäntymetsässä ja kaupunkialueella. Mäntymetsän maaperän kykyä toimia alkyyliamiinien lähteenä tutkittiin kokeellisesti sekä laskennallisin menetelmin. Alkyyliamiinien vaikutusta metsä- ja kaupunkiympäristön ilmakemiaan arvioitiin suhteessa muihin reaktiivisiin ilmakehän orgaanisiin hivenkaasuihin. Väitöskirjan päätulokset koostuvat kuukausien mittaisista ilmapitoisuusaikasarjoista, alkyyliamiinien metsämaan ja sienirihmastojen pitoisuuksista. Näiden avulla tehtiin kaasunvaihtoarvioita maaperän ja ilmakehän välillä metsäympäristössä erilaisissa ympäristöolosuhteissa. Kaasunvaihtoarvion perusteella maaperän toimintaa mahdollisena lähteenä pystyttiin arvioimaan. Ilmakehäpitoisuudet metsäympäristössä olivat korkeammat kuin kaupunkiympäristössä. Metsäympäristön korkeimmat pitoisuudet ajoittuivat syksyyn ja ovat mahdollisesti yhteydessä esimerkiksi maaperän mikrobiologiseen toimintaan ja metsäkasvillisuuteen. Alkyyliamiinien suhteellinen vaikutus ilmakehän hapetusreaktioihin oli samaa suuruusluokkaa tai hieman vähemmän kuin haihtuvilla hiilivedyillä. Alkyyliamiineja todettiin olevan eloperäisessä pintamaassa sekä metsämaassa yleisesti esiintyvissä sienirihmastoissa. Alkyyliamiinien pitoisuus oli tutkitussa maassa suuri ja mitattujen alkyyliamiinien yhteispitoisuus oli samaa suuruusluokkaa kuin nitraatilla. Metsämaassa yleisesti esiintyvät sienet sisälsivät alkyyliamiineja pintamaata enemmän. Laskennallisesti pystyttiin osoittamaan, että metsämaa voi toimia lähteenä ilmakehän alkyyliamiineille. Maaperän happamuudella huomattiin olevan merkittävä rooli. Väitöskirjan tärkein tulos on kuitenkin luoda tiekartta jatkotutkimuksille, joissa selvitetään tarkemmin alkyyliamiinien lähteitä ja nieluja pohjoisessa metsäympäristössä

Forest mosses sensitively indicate nitrogen deposition in boreal background areas

Mosses take up nitrogen (N) mainly from precipitation through their surfaces, which makes them competent bioindicators of N deposition. We found positive relationships between the total N concentration (mossN%) of common terrestrial moss species (feather mosses Pleurozium schreberi and Hylocomium splendens, and a group of Dicranum species) and different forms of N deposition in 11-16 coniferous forests with low N deposition load in Finland. The mosses were collected either inside (Dicranum group) or both inside and outside (feather mosses) the forests. Deposition was monitored in situ as bulk deposition (BD) and stand throughfall (TF) and detected for ammonium (NH4+-N), nitrate (NO3--N), dissolved organic N (DON), and total N (N-tot, kg ha(-1)yr(-1)). N-tot deposition was lower in TF than BD indicating that tree canopies absorbed N from deposition in N limited boreal stands. However, mossN % was higher inside than outside the forests. In regression equations, inorganic N in BD predicted best the mossN% in openings, while DON in TF explained most variation of mossN% in forests. An asymptotic form of mossN% vs. TF N-tot curves in forests and free NH4+-N accumulation in tissues in the southern plots suggested mosses were near the N saturation state already at the N-tot deposition level of 3-5 kg ha(-1) yr(-1). N leachate from ground litterfall apparently also contributed the N supply of mosses. Our study yielded new information on the sensitivity of boreal mosses to low N deposition and their response to different N forms in canopy TF entering moss layer. The equations predicting the N-tot deposition with mossN% showed a good fit both in forest sites and openings, especially in case of P. schreberi. However, the open site mossN% is a preferable predictor of N deposition in monitoring studies to minimize the effect of tree canopies and N leachate from litterfall on the estimates. (C) 2020 Elsevier Ltd. All rights reserved.Peer reviewe

Temperature sensitivity patterns of carbon and nitrogen processes in decomposition of boreal organic soils – Quantification in different compounds and molecule sizes based on a multifactorial experiment

Climate warming and organic matter decomposition are connected in a recursive manner; this recursion can be described by temperature sensitivity. We conducted a multifactorial laboratory experiment to quantify the temperature sensitivity of organic carbon (C) and nitrogen (N) decomposition processes of common boreal organic soils. We incubated 36 mor and 36 slightly decomposed Carex-Sphagnum peat samples in a constant moisture and ambient temperature for 6 months. The experiment included three temperature and two moisture levels and two food web manipulations (samples with and without fungivore enchytraeid worms). We determined the release of carbon dioxide (CO2) and dissolved organic carbon (DOC) in seven molecular size classes together with ammonium N and dissolved organic N in low molecular weight and high molecular weight fractions. The temperature sensitivity function Q10 was fit to the data. The C and N release rate was almost an order of magnitude higher in mor than in peat. Soil fauna increased the temperature sensitivity of C release. Soil fauna played a key role in N release; when fauna was absent in peat, the N release was ceased. The wide range of the studied C and N compounds and treatments (68 Q10 datasets) allowed us to recognize five different temperature sensitivity patterns. The most common pattern (37 out of 68) was a positive upwards temperature response, which was observed for CO2 and DOC release. A negative downward pattern was observed for extractable organic nitrogen and microbial C. Sixteen temperature sensitivity patterns represented a mixed type, where the Q10function was not applicable, as this does not allow changing the sign storage change rate with increasing or decreasing temperature. The mixed pattern was typically connected to intermediate decomposition products, where input and output fluxes with different temperature sensitivities may simultaneously change the storage. Mixed type was typical for N processes. Our results provide useful parameterization for ecosystem models that describe the feedback loop between climate warming, organic matter decomposition, and productivity of N-limited vegetation.Peer reviewe

Soil concentrations and soil-atmosphere exchange of alkylamines in a boreal Scots pine forest

Alkylamines are important precursors in secondary aerosol formation in the boreal forest atmosphere. To better understand the behavior and sources of two alkylamines, dimethylamine (DMA) and diethylamine (DEA), we estimated the magnitudes of soil-atmosphere fluxes of DMA and DEA using a gradient-diffusion approximation based on measured concentrations in soil solution and in the canopy air space. The ambient air concentration of DMA used in this study was a sum of DMA and ethylamine. To compute the amine fluxes, we first estimated the soil air space concentration from the measured soil solution amine concentration using soil physical (temperature, soil water content) and chemical (pH) state variables. Then, we used the resistance analogy to account for gas transport mechanisms in the soil, soil boundary layer, and canopy air space. The resulting flux estimates revealed that the boreal forest soil with a typical long-term mean pH 5.3 is a possible source of DMA (170 +/- 51 nmolm(-2) day(-1)) and a sink of DEA (-1.2 +/- 1.2 nmolm(-2) day(-1)). We also investigated the potential role of fungi as a reservoir for alkylamines in boreal forest soil. We found high DMA and DEA concentrations both in fungal hyphae collected from field humus samples and in fungal pure cultures. The highest DMA and DEA concentrations were found in fungal strains belonging to decay and ectomycorrhizal fungal groups, indicating that boreal forest soil and, in particular, fungal biomass may be important reservoirs for these alkylamines.Peer reviewe

Modelling spatio-temporal soil moisture dynamics in mountain tundra

Abstract Soil moisture has a fundamental influence on the processes and functions of tundra ecosystems. Yet, the local dynamics of soil moisture are often ignored, due to the lack of fine resolution, spatially extensive data. In this study, we modelled soil moisture with two mechanistic models, SpaFHy (a catchment-scale hydrological model) and JSBACH (a global land surface model), and examined the results in comparison with extensive growing-season field measurements over a mountain tundra area in northwestern Finland. Our results show that soil moisture varies considerably in the study area and this variation creates a mosaic of moisture conditions, ranging from dry ridges (growing season average 12 VWC%, Volumetric Water Content) to water-logged mires (65 VWC%). The models, particularly SpaFHy, simulated temporal soil moisture dynamics reasonably well in parts of the landscape, but both underestimated the range of variation spatially and temporally. Soil properties and topography were important drivers of spatial variation in soil moisture dynamics. By testing the applicability of two mechanistic models to predict fine-scale spatial and temporal variability in soil moisture, this study paves the way towards understanding the functioning of tundra ecosystems under climate change. This article is protected by copyright. All rights reserved.Peer reviewe

Partitioning of forest floor CO2 emissions reveals the belowground interactions between different plant groups in a Scots pine stand in southern Finland

Changes in the climate may have unpredictable effects on belowground carbon processes and thus, the carbon balance of boreal forests. To understand the interactions of these processes in soil and to quantify the potential changes in the carbon cycle, partitioning of forest floor respiration is crucial. For this purpose, we used nine different treatments to separate the sources of forest floor carbon dioxide (CO2) emissions in a mature Scots pine (Pinus sylvestris L.) stand in southern Finland. To partition the belowground CO2 emissions, we used two different trenching methods: 1) to exclude roots and mycorrhizal fungal mycelia (mesh with 1-mu m pores) and 2) to exclude roots, but not mycorrhizal hyphae (mesh with 50-mu m pores). Additionally, we used 3) a control treatment that included roots and fungal hyphae. To partition the CO2 emissions from the forest floor vegetation, we 1) removed it, 2) left only the dwarf shrubs, or 3) left the vegetation intact. The forest floor CO2 emissions were regularly measured with a flux chamber throughout the growing seasons in 2013-2015. The total forest floor respiration was partitioned into respiration of tree roots (contributing 48%), heterotrophic soil respiration (30%) and respiration of ground vegetation other than shrubs (10%), dwarf shrubs (8%), and hyphae of mycorrhizal fungi (4%). Heterotrophic respiration increased in the trenched treatments without ground vegetation over time, due to the so-called 'Gadgil effect'. In the absence of tree mots, but when hyphal access was allowed, respiration in the dwarf shrub treatment increased throughout the experiment. This indicated that dwarf shrubs had fungal connections to outside the experimental plots via their ericoid mycorrhiza. At the same time, other ground vegetation, such as mosses, suppressed the dwarf shrub respiration in trenched treatments. Our results show that competition on the forest floor is intense between plant roots and soil microbes.Peer reviewe

Nitrogen balance of a boreal Scots pine forest

The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems by increasing the availability of reactive nitrogen. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurements at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating in the system, mainly in woody biomass, at a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the inputs in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were equally important sources of N for plant growth. Most of the assimilated N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably, but there are no signs of N saturation. Further research is needed to estimate soil N2 fluxes (emission and fixation), which may amount up to several kg N ha−1 yr−1.Peer reviewe

Vegetation controls of water and energy balance of a drained peatland forest: Responses to alternative harvesting practices

We quantified the response of peatland water table level (WTL) and energy fluxes to harvesting of a drained peatland forest. Two alternative harvests (clear-cut and partial harvest) were carried out in a mixed-species ditch-drained peatland forest in southern Finland, where water and energy balance components were monitored for six pre-treatment and three post-treatment growing seasons. To explore the responses caused by harvestings, we applied a mechanistic multi-layer soil-plant-atmosphere transfer model. At the clear-cut site, the mean growing season WTL rose by 0.18 +/- 0.02 m (error estimate based on measurement uncertainty), while net radiation, and sensible and latent heat fluxes decreased after harvest. On the contrary, we observed only minor changes in energy fluxes and mean WTL (0.05 +/- 0.03 m increase) at the partial harvest site, although as much as 70% of the stand basal area was removed and leaf-area index was reduced to half. The small changes were mainly explained by increased water use of spruce undergrowth and field layer vegetation, as well as increased forest floor evaporation. The rapid establishment of field layer vegetation had a significant role in energy balance recovery at the clear-cut site. At partial harvest, chlorophyll fluorescence measurements and model-data comparison suggested the shade-adapted spruce undergrowth was suffering from light stress during the first post-harvest growing season. We conclude that in addition to stand basal area, species composition and stand structure need to be considered when controlling WTL in peatland forests with partial harvesting. Our results have important implications on the operational use of continuous cover forestry on drained peatlands. A continuously maintained tree cover with significant evapotranspiration capacity could enable optimizing WTL from both tree growth and environmental perspectives.Peer reviewe

Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event

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Pan-Eurasian Experiment (PEEX) : towards a holistic understanding of the feedbacks and interactions in the land–atmosphere–ocean–society continuum in the northern Eurasian region

Contributors: Hanna K. Lappalainen1,2, Veli-Matti Kerminen1, Tuukka Petäjä1, Theo Kurten3, Aleksander Baklanov4,5, Anatoly Shvidenko6, Jaana Bäck7, Timo Vihma2, Pavel Alekseychik1, Stephen Arnold8, Mikhail Arshinov9, Eija Asmi2, Boris Belan9, Leonid Bobylev10, Sergey Chalov11, Yafang Cheng12, Natalia Chubarova11, Gerrit de Leeuw1,2, Aijun Ding13, Sergey Dobrolyubov11, Sergei Dubtsov14, Egor Dyukarev15, Nikolai Elansky16, Kostas Eleftheriadis17, Igor Esau18, Nikolay Filatov19, Mikhail Flint20, Congbin Fu13, Olga Glezer21, Aleksander Gliko22, Martin Heimann23, Albert A. M. Holtslag24, Urmas Hõrrak25, Juha Janhunen26, Sirkku Juhola27, Leena Järvi1, Heikki Järvinen1, Anna Kanukhina28, Pavel Konstantinov11, Vladimir Kotlyakov29, Antti-Jussi Kieloaho1, Alexander S. Komarov30, Joni Kujansuu1, Ilmo Kukkonen31, Ella Kyrö1, Ari Laaksonen2, Tuomas Laurila2, Heikki Lihavainen2, Alexander Lisitzin32, Aleksander Mahura5, Alexander Makshtas33, Evgeny Mareev34, Stephany Mazon1, Dmitry Matishov35,†, Vladimir Melnikov36, Eugene Mikhailov37, Dmitri Moisseev1, Robert Nigmatulin33, Steffen M. Noe38, Anne Ojala7, Mari Pihlatie1, Olga Popovicheva39, Jukka Pumpanen40, Tatjana Regerand19, Irina Repina16, Aleksei Shcherbinin27, Vladimir Shevchenko33, Mikko Sipilä1, Andrey Skorokhod16, Dominick V. Spracklen8, Hang Su12, Dmitry A. Subetto19, Junying Sun41, Arkady Yu Terzhevik19, Yuri Timofeyev42, Yuliya Troitskaya34, Veli-Pekka Tynkkynen42, Viacheslav I. Kharuk43, Nina Zaytseva22, Jiahua Zhang44, Yrjö Viisanen2, Timo Vesala1, Pertti Hari7, Hans Christen Hansson45, Gennady G. Matvienko9, Nikolai S. Kasimov11, Huadong Guo44, Valery Bondur46, Sergej Zilitinkevich1,2,11,34, and Markku Kulmala1 1Department of Physics, University of Helsinki, 00014 Helsinki, Finland 2Finnish Meteorological Institute, Research and Development, 00101 Helsinki, Finland 3Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland 4World Meteorological Organization, 1211 Genève, Switzerland 5Danish Meteorological Institute, Research and Development Department, 2100, Copenhagen 6International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria 7Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland 8Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK 9Institute of Atmospheric Optics, Russian Academy of Sciences, Tomsk 634021, Russia 10Nansen International Environmental and Remote Sensing Center, St. Petersburg, Russia 11Lomonosov Moscow State University, Faculty of Geography, Moscow 119899, Russia 12Max Planck Institute for Chemistry, 55128 Mainz, Germany 13Institute for Climate and Global Change Research & School of Atmospheric Sciences, Nanjing University, 210023 Nanjing, China 14Institute of Chemical Kinetics & Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia 15Institute of Monitoring of Climatic & Ecological Systems SB RAS, 634055 Tomsk, Russia 16A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Russia 17National Centre of Scientific Research "DEMOKRITOS", Greece 18Nansen Environmental and Remote Sensing Center/Bjerknes Centre for Climate Research, 5006 Bergen, Norway 19Northern Water Problems Institute, Karelian Research Center, Russian Academy of Sciences,185003 Petrozavodsk, Russia 20P. P. Shirshov, Institute of Oceanology, Russian Academy of Sciences, Russian Academy of Sciences, 117997 Moscow, Russia 21Institute of Geography, Russian Academy of Sciences, Moscow, Russia 22Depart ment of Earth Sciences of the Russian Academy of Sciences, Russian Academy of Sciences, 119991, Moscow, Russia 23Max-Planck-Institute for Biogeochemistry, 07745 Jena, Germany 24Wageningen University, 6708 Wageningen, Nederland 25Institute of Physics, University of Tartu, 18 Ülikooli St., 50090 Tartu, Estonia 26University of Helsinki, Department of World Cultures, 00014 Helsinki, Finland 27Department of Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland 28Russian State Hydrometeorological University, 195196 Saint Petersburg, Russia 29Institute of Geography, Russian Academy of Sciences, Moscow, Russia 30Institute of Physico-chemical & Biological Problems in Soil Science, Russian Academy of Sciences, 142290 Institutskaya, Russia 31University of Helsinki, Geophysics and Astronomy, 00014 Helsinki, Finland 32Shirshov Institute of Oceanology, Russian Academy of Sciences, 117997 Moscow, Russia 33Actic & Antarctic Research Institute, Russian Academy of Sciences, St. Petersburg 199397, Russia 34Department of Radiophysics, Nizhny Novgorod State University, Nizhny Novgorod, Russia 35Southern Center of Russian Academy of Sciences, Rostov on Don, Russia 36Tyumen Scientific Center, Siberian Branch, Russian Academy of Science, Russia 37Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia 38Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 51014 Tartu, Estonia 39Skobeltsyn Institute of Nuclear Physics, Moscow State University, Department Microelectronics, Russia 40University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland 41Craduate University of Chinese Academy of Sciences, 100049 Beijing, China 42Aleksanteri Institute and Department of Social Research, 00014 University of Helsinki, Finland 43Sukachev Forest Institute, Russian Academy of Sciences, Krasnoyarsk 660036, Russia 44Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing, 100094, China 45Environmental Science and Analytical Chemistry, Stockholm University, Sweden 46AEROCOSMOS Research Institute for Aerospace Monitoring, 105064, Moscow, Russia †deceased, 20 August 2015The Northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The arctic-boreal natural environments play a crucial role in the global climate via the albedo change, carbon sources and sinks, as well as atmospheric aerosol production via biogenic volatile organic compounds. Furthermore, it is expected that the global trade activities, demographic movement and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but is also able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX is setting a research approach where large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land–atmosphere–aquatic–society continuum in the Northern Eurasian region. We introduce here the state of the art of the key topics in the PEEX research agenda and give the future prospects of the research which we see relevant in this context.Peer reviewe