Metsä- ja vesiekosysteemien yhteys : puuston sitoman hiilen kulkeutuminen vesistöihin

The carbon cycle and hydrological cycle are closely connected combining terrestrial and aquatic ecosystems. This study focuses on important processes of the carbon cycle at plant, ecosystem and landscape levels. Carbon allocation was investigated at the seedling scale with microcosm experiments, and carbon fluxes, especially the lateral carbon fluxes from soil to adjacent water bodies, at field sites. The carbon allocation pattern differed between typical boreal tree species, but an increase in temperature did not change the net growth of seedlings, because photosynthesis and respiration increase compensated for each other. A higher temperature did not change the species composition of ectomychorrhizal fungi, but spesific species can alter carbon allocation. This study demonstrates that CO2 efflux from the soil is largely controlled by biological processes (i.e. the rate of photosynthesis and decomposition), whereas aquatic CO2 emissions are mostly affected by physical forces (i.e. convection controlling stratification). Lateral carbon flux from soil to the lake and brook was regulated by hydrology and closely connected to the riparian zone. Dissolved organic carbon (DOC) concentrations in the brook were controlled by precipitation and DOC concentrations in the soil, and rain events increased CO2 concentrations both in the riparian zone and in the brook. The large water volume of the lake buffered it against changes. It is of crucial importance to consider terrestrial and aquatic ecosystems together, since lakes and rivers act as significant pathways for terrestrially bound carbon back to the atmosphere. In the natural old-growth forest of this study, lateral carbon transport accounted for 50% and brook discharge for 19% of the terrestrial net ecosystem exchange. Thus, exclusion of the lateral carbon flux would lead to overestimation of the role of the forest as a carbon sink. However, the role of lateral transport can be less important in younger or managed forests, which are faster growing.Metsät, suot ja järvet ovat tyypillisiä havumetsävyöhykkeen ympäristöjä. Veden liikkuminen eli hydrologinen kierto ja hiilen kierto yhdistävät ne toisiinsa. Ekosysteemien välisiä hiilivirtoja tunnetaan kuitenkin verraten huonosti, koska ekosysteemejä on perinteisesti tutkittu erikseen. Ilmastonmuutoksen edetessä tulee kuitenkin yhä tärkeämmäksi tarkastella yksittäisten kohteiden sijaan kokonaisuuksia. Väitöskirjatutkimukseni tarkasteleekin maa- ja vesiekosysteemien kytkeytymistä toisiinsa. Tutkin valuma-aluetason hiilivirtoja maastomittauksin ja mallintamalla. Lisäksi tutkin laboratoriossa yksittäisten taimien yhteyttämän hiilen allokaatiota eli jakautumista juuri- ja versobiomassan kasvuun sekä hengitykseen. Tavassa, jolla eri puulajit allokoivat sidottua hiiltä maanalaisiin ja -päällisin osiin, oli lajikohtaisia eroja, jotka heijastavat sopeutumista erilaisiin olosuhteisiin. Symbionttiset mykoritsasienet ovat tärkeitä puiden kasvun kannalta ja tutkimustulosteni osoittavat tiettyjen sienilajien voivan muuttaa allokaatiosuhteita. Havaitsin myös sekä yhteytyksen että hengityksen kasvavan maan lämpötilan kohotessa, mutta muutokset kompensoivat toisensa eikä sidotun hiilen määrä muuttunut. Hiilen kiertoa säätelevät prosessit ovat erilaisia maa- ja vesiympäristöissä. Metsäekosysteemin ja ilmakehän välisiä hiilivirtoja säätelevät ennen kaikkea biologiset prosessit kuten yhteyttäminen ja hajotus, kun taas järven ja ilmakehän väliseen hiilenvaihtoon vaikuttavat voimakkaasti fysikaaliset tekijät kuten vesipatsaan kerrostuneisuutta säätelevä konvektio ja tuulen aiheuttama turbulenssi. Maaperä on vakaa ympäristö, jossa kaasut liikkuvat lähinnä molekyläärisen diffuusion avulla, kun taas vesistöissä ne kulkeutuvat liikkuvan vesimassan mukana eli turbulenttinen diffuusio on tärkeämpi. Horisontaalisesti maalta veteen liikkuvan veden mukana maaperän kaasuja ja liuenneita orgaanisia yhdisteitä päätyy vesistöihin. Metsän hiilitaseeksi kutsutaan yhteyttämällä sidotun ja hengityksessä ja hajotuksessa vapautuvan hiilimäärän erotusta. Taseen avulla voidaan arvioida metsän roolia hiilinieluna tai lähteenä. Maa- ja vesiekosysteemejä on tarkasteltava yhdessä, sillä vesistöjen kautta palautuu ilmakehään lopulta merkittäviä määriä metsissä sidottua hiiltä. Tutkimukseni osoittaa, että hiiltä poistuu metsistä veden mukana vesistöihin ja kulkeutumista säätelee erityisesti kuljettavan veden määrä. Ilmastonmuutoksen edetessäkin yleistyvien rankkasateiden jälkeen maalta vesistöihin kulkeutuvan hiilen vaikutus oli tutkimusalueellani selkein purossa. Väitöskirjatutkimukseni osoittaa, että metsistä vesistöihin kulkeutuva hiili voi pienentää metsän hiilitasetta jopa puoleen. Sen vuoksi on tärkeää tarkastella hiilitaseita maisematasolla eri ympäristöjen väliset hiilivuot huomioiden

Sources and sinks of greenhouse gases in the landscape : Approach for spatially explicit estimates

Climate change mitigation is a global response that requires actions at the local level. Quantifying local sources and sinks of greenhouse gases (GHG) facilitate evaluating mitigation options. We present an approach to collate spatially explicit estimated fluxes of GHGs (carbon dioxide, methane and nitrous oxide) for main land use sectors in the landscape, to aggregate, and to calculate the net emissions of an entire region. Our procedure was developed and tested in a large river basin in Finland, providing information from intensively studied eLTER research sites. To evaluate the full GHG balance, fluxes from natural ecosystems (lakes, rivers, and undrained mires) were included together with fluxes from anthropogenic activities, agriculture and forestry. We quantified the fluxes based on calculations with an anthropogenic emissions model (FRES) and a forest growth and carbon balance model (PREBAS), as well as on emission coefficients from the literature regarding emissions from lakes, rivers, undrained mires, peat extraction sites and cropland. Spatial data sources included CORINE land use data, soil map, lake and river shorelines, national forest inventory data, and statistical data on anthropogenic activities. Emission uncertainties were evaluated with Monte Carlo simulations. Artificial surfaces were the most emission intensive land-cover class. Lakes and rivers were about as emission intensive as arable land. Forests were the dominant land cover in the region (66%), and the C sink of the forests decreased the total emissions of the region by 72%. The region's net emissions amounted to 4.37 +/- 1.43 Tg CO2-eq yr(-1), corresponding to a net emission intensity 0.16 Gg CO2-eq km(-2) yr(-1), and estimated per capita net emissions of 5.6 Mg CO2-eq yr(-1). Our landscape approach opens opportunities to examine the sensitivities of important GHG fluxes to changes in land use and climate, management actions, and mitigation of anthropogenic emissions. (C) 2021 The Authors. Published by Elsevier B.V.peerReviewe

Comparison of static chambers to measure CH4 emissions from soils

The static chamber method (non-flow-through-non-steady-state chambers) is the most common method to measure fluxes of methane (CH4) from soils. Laboratory comparisons to quantify errors resulting from chamber design, operation and flux calculation methods are rare. We tested fifteen chambers against four flux levels (FL) ranging from 200 to 2300 g CH4m−2 h−1. The measurements were conducted on a calibration tank using three quartz sand types with soil porosities of 53% (dry fine sand, S1), 47% (dry coarse sand, S2), and 33% (wetted fine sand, S3). The chambers tested ranged from 0.06 to 1.8 m in height, and 0.02 to 0.195 m3 in volume, 7 of them were equipped with a fan, and 1 with a vent-tube. We applied linear and exponential flux calculation methods to the chamber data and compared these chamber fluxes to the reference fluxes from the calibration tank. The chambers underestimated the reference fluxes by on average 33% by the linear flux calculation method (Rlin), whereas the chamber fluxes calculated by the exponential flux calculation method (Rexp) did not significantly differ from the reference fluxes (p < 0.05). The flux under- or overestimations were chamber specific and independent of flux level. Increasing chamber height, area and volume significantly reduced the flux underestimation (p < 0.05). Also, the use of non-linear flux calculation method significantly improved the flux estimation; however, simultaneously the uncertainty in the fluxes was increased. We provide correction factors, which can be used to correct the under- or overestimation of the fluxes by the chambers in the experiment.Peer reviewe

White paper on Terrestrial Ecological and Environmental Research Infrastructures in Finland: Analysis of the current landscape and proposal for future steps

This White Paper presents a vision of globally leading, scientifically important and socially relevant environmental research infrastructures (RIs) in Finland, and identifies what we consider as the key issues to be developed to improve the impact and to support the Finnish national infrastructures in their international visibility. The focus is on: 1. The scientific questions driving the terrestrial ecosystem and environmental research globally and in Finland; 2. Specific requirements by different user groups in Finland for ecological and environmental RIs; and 3. Roadmap for the sustainable ecological and environmental RI in Finland. We also present the strategies of organizations regarding their RI development, and the existing infrastructures and networks which form the basis for future development. The final goal of this document is to encourage the development of a coherent vision at national level, and to increase the scientific significance, national synergies and benefits towards a stronger research community. The need for developing a national RI strategy for environmental field arises from the global challenges, which threaten the ecosystems’ functioning. Human activities are imposing many identified, but also previously unknown pressures to ecosystem properties and functions, which are also feeding back to the societies via the quality and quantity of ecosystem services. However, the ecosystem responses to changes in environment are in many cases poorly quantified and the studies only cover short time scales. In order to succeed in providing answers to the grand challenges (ICSU 2010), integrated research infrastructures and efficient analysis tools are crucially needed. The request to improve our knowledge of the state of the environment and the complex biosphere-hydrosphere-atmosphere interactions, and to detect and analyze the impact of global change on these systems has been recognized as a general priority in developing environmental research infrastructures in EU and globally. Currently, Finland is one of the world leaders in atmospheric and environmental sciences, both in terms of research and in coordinating the European and global observation station networks and infrastructures. With this existing experience from close-by research fields and the high research outputs from ecology and ecophysiology in our research organizations, Finland has also the potential to actively promote the ecosystem RI concept, and to act as an example of integrated RIs for other countries. The vision is to develop the capacity of the Finnish ecosystem research community to integrate, upscale and synthesize the observations with relevant holistic process understanding as well as open and reliable data management practices. This can be implemented by creating functional and cost-efficient in-situ platforms and by providing quality-checked data in findable, accessible, interoperable and reusable (FAIR) manner for high-level environmental research. This White paper was made in connection with the INAR Ecosystems initiative funded by Academy of Finland and updated with proceeding of European processes, and it provides a starting point for national cooperation in environmental research infrastructures. Keywords: Terrestrial ecosystems, research infrastructures, ESFRI</p

White paper on Terrestrial Ecological and Environmental Research Infrastructures in Finland

This White Paper presents a vision of globally leading, scientifically important and socially relevant environmental research infrastructures (RIs) in Finland, and identifies what we consider as the key issues to be developed to improve the impact and to support the Finnish national infrastructures in their international visibility. The focus is on: 1. The scientific questions driving the terrestrial ecosystem and environmental research globally and in Finland; 2. Specific requirements by different user groups in Finland for ecological and environmental RIs; and 3. Roadmap for the sustainable ecological and environmental RI in Finland. We also present the strategies of organizations regarding their RI development, and the existing infrastructures and networks which form the basis for future development. The final goal of this document is to encourage the development of a coherent vision at national level, and to increase the scientific significance, national synergies and benefits towards a stronger research community. The need for developing a national RI strategy for environmental field arises from the global challenges, which threaten the ecosystems’ functioning. Human activities are imposing many identified, but also previously unknown pressures to ecosystem properties and functions, which are also feeding back to the societies via the quality and quantity of ecosystem services. However, the ecosystem responses to changes in environment are in many cases poorly quantified and the studies only cover short time scales. In order to succeed in providing answers to the grand challenges (ICSU 2010), integrated research infrastructures and efficient analysis tools are crucially needed. The request to improve our knowledge of the state of the environment and the complex biosphere-hydrosphere-atmosphere interactions, and to detect and analyze the impact of global change on these systems has been recognized as a general priority in developing environmental research infrastructures in EU and globally. Currently, Finland is one of the world leaders in atmospheric and environmental sciences, both in terms of research and in coordinating the European and global observation station networks and infrastructures. With this existing experience from close-by research fields and the high research outputs from ecology and ecophysiology in our research organizations, Finland has also the potential to actively promote the ecosystem RI concept, and to act as an example of integrated RIs for other countries. The vision is to develop the capacity of the Finnish ecosystem research community to integrate, upscale and synthesize the observations with relevant holistic process understanding as well as open and reliable data management practices. This can be implemented by creating functional and cost-efficient in-situ platforms and by providing quality-checked data in findable, accessible, interoperable and reusable (FAIR) manner for high-level environmental research. This White paper was made in connection with the INAR Ecosystems initiative funded by Academy of Finland and updated with proceeding of European processes, and it provides a starting point for national cooperation in environmental research infrastructures

Developing a spatially explicit modelling and evaluation framework for integrated carbon sequestration and biodiversity conservation: application in southern Finland

The challenges posed by climate change and biodiversity loss are deeply interconnected. Successful co-managing of these tangled drivers requires innovative methods that can prioritize and target management actions against multiple criteria, while also enabling cost-effective land use planning and impact scenario assessment. This paper synthesises the development and application of an integrated multidisciplinary modelling and evaluation framework for carbon and biodiversity in forest systems. By analysing and spatio-temporally modelling carbon processes and biodiversity elements, we determine an optimal solution for their co-management in the study landscape. We also describe how advanced Earth Observation measurements can be used to enhance mapping and monitoring of biodiversity and ecosystem processes. The scenarios used for the dynamic models were based on official Finnish policy goals for forest management and climate change mitigation. The development and testing of the system were executed in a large region in southern Finland (Kokemäenjoki basin, 27 024 km2) containing highly instrumented LTER (Long-Term Ecosystem Research) stations; these LTER data sources were complemented by fieldwork, remote sensing and national data bases. In the study area, estimated total net emissions were currently 4.2 TgCO2eq a-1, but modelling of forestry measures and anthropogenic emission reductions demonstrated that it would be possible to achieve the stated policy goal of carbon neutrality by low forest harvest intensity. We show how this policy-relevant information can be further utilised for optimal allocation of set-aside forest areas for nature conservation, which would significantly contribute to preserving both biodiversity and carbon values in the region. Biodiversity gain in the area could be increased without a loss of carbon-related benefits.The challenges posed by climate change and biodiversity loss are deeply interconnected. Successful co-managing of these tangled drivers requires innovative methods that can prioritize and target management actions against multiple criteria, while also enabling cost-effective land use planning and impact scenario assessment. This paper synthesises the development and application of an integrated multidisciplinary modelling and evaluation framework for carbon and biodiversity in forest systems. By analysing and spatio-temporally modelling carbon processes and biodiversity elements, we determine an optimal solution for their co-management in the study landscape. We also describe how advanced Earth Observation measurements can be used to enhance mapping and monitoring of biodiversity and ecosystem processes. The scenarios used for the dynamic models were based on official Finnish policy goals for forest management and climate change mitigation. The development and testing of the system were executed in a large region in southern Finland (Kokemäenjoki basin, 27,024 km2) containing highly instrumented LTER (Long-Term Ecosystem Research) stations; these LTER data sources were complemented by fieldwork, remote sensing and national data bases. In the study area, estimated total net emissions were currently 4.2 TgCO2eq a−1, but modelling of forestry measures and anthropogenic emission reductions demonstrated that it would be possible to achieve the stated policy goal of carbon neutrality by low forest harvest intensity. We show how this policy-relevant information can be further utilized for optimal allocation of set-aside forest areas for nature conservation, which would significantly contribute to preserving both biodiversity and carbon values in the region. Biodiversity gain in the area could be increased without a loss of carbon-related benefits.Peer reviewe

Transport and transformation of soil-derived CO2, CH4 and DOC sustain CO2 supersaturation in small boreal streams

11 pages, 5 figures, 1 appendixStreams are typically supersaturated in carbon dioxide (CO) and methane (CH), and are recognized as important components of regional carbon (C) emissions in northern landscapes. Whereas there is consensus that in most of the systems the CO emitted by streams represents C fixed in the terrestrial ecosystem, the pathways delivering this C to streams are still not well understood. We assessed the contribution of direct soil CO injection versus the oxidation of soil-derived dissolved organic C (DOC) and CH in supporting CO supersaturation in boreal streams in Québec. We measured the concentrations of CO, CH and DOC in 43 streams and adjacent soil waters during summer base-flow period. A mass balance approach revealed that all three pathways are significant, and that the mineralization of soil-derived DOC and CH accounted for most of the estimated stream CO emissions (average 75% and 10%, respectively), and that these estimated contributions did not change significantly between the studied low order (≤ 3) streams. Whereas some of these transformations take place in the channel proper, our results suggest that they mainly occur in the hyporheic zones of the streams. Our results further show that stream CH emissions can be fully explained by soil CH inputs. This study confirms that these boreal streams, and in particular their hyporheic zones, are extremely active processors of soil derived DOC and CH, not just vents for soil produced COThis study was co-funded by the Natural Sciences and Engineering Research Council of Canada and Hydro-Québec Industrial Research Chair in Carbon Biogeochemistry in Boreal Aquatic Systems (NSERC Grant #592000)Peer Reviewe

What does nature feel like? Using embodied walking interviews to discover cultural ecosystem services

The development of cultural ecosystem services (CES) concept has progressed beyond the common categories of economic benefits from tourism and recreation, and yet definitions of CES remain vague and often shallow. It is necessary to develop methodologies that can more fully express the depth of meaning of non-material benefits humans receive from nature to both strengthen the conceptual foundation of CES, and to support the evaluation, management, and decision-making processes pertaining to protected areas and other environments. This study demonstrates how embodied interviews, conducted with informants while walking in nature, capture real-time intuitive and grounded perceptions of, and reactions to, four different ecosystem types and their associated services. The results provide a deeper and more nuanced understanding of diverse human-nature relationships and reflect two distinct groups of CES values or themes: general (common across research sites) and local (site specific). The twelve General CES include cognitive and psychological services, among them calmness and newness, heightened imagination and curiosity, increased energy and motivation, and gaining new perspectives. Local themes differed from one ecosystem to another and included more biodiversity-and geodiversity-related values pertaining to local species and geology, as well as more sensory-based experiences.Peer reviewe