Browsing by Subject "aineiden kierto"

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  • Lehtoranta, Jouni; Ekholm, Petri; Vihervaara, Petteri; Kortelainen, Pirkko (Suomen ympäristökeskus, 2014)
    Reports of the Finnish Environment Institute 21/2014
    Human activities disturb the biogeochemical cycles often resulting in limited eco-system services. The cycles of biologically active elements are also coupled to each other which is rarely acknowledged in ecosystem studies. Many of the regulating and maintenance services are linked to element cycles driven by micro-organisms, but these have often been omitted in ecosystem service studies. In the present publication the terminology of ecosystem services are used to help to define and describe the coupled biogeochemical processes and to highlight their importance in both terrestrial and aquatic ecosystems. The extended abstracts offer fresh viewpoints on biogeochemical cycles and on the management of their fluxes. The abstracts may also function as basis for new themes for research.
  • Wymore, Adam S.; Johnes, Penny J.; Bernal, Susana; Brookshire, E. N. Jack; Fazekas, Hannah M.; Helton, Ashley M.; Argerich, Alba; Barnes, Rebecca T.; Coble, Ashley A.; Dodds, Walter K.; Haq, Shahan; Johnson, Sherri L.; Jones, Jeremy B.; Kaushal, Sujay S.; Kortelainen, Pirkko; López-Lloreda, Carla; Rodríguez-Cardona, Bianca M.; Spencer, Robert G. M.; Sullivan, Pamela L.; Yates, Christopher A.; McDowell, William H. (American Geophysical Union, 2021)
    Global Biogeochemical Cycles, 35(8), e2021GB006953
    A comprehensive cross-biome assessment of major nitrogen (N) species that includes dissolved organic N (DON) is central to understanding interactions between inorganic nutrients and organic matter in running waters. Here, we synthesize stream water N chemistry across biomes and find that the composition of the dissolved N pool shifts from highly heterogeneous to primarily comprised of inorganic N, in tandem with dissolved organic matter (DOM) becoming more N-rich, in response to nutrient enrichment from human disturbances. We identify two critical thresholds of total dissolved N (TDN) concentrations where the proportions of organic and inorganic N shift. With low TDN concentrations (0–1.3 mg/L N), the dominant form of N is highly variable, and DON ranges from 0% to 100% of TDN. At TDN concentrations above 2.8 mg/L, inorganic N dominates the N pool and DON rarely exceeds 25% of TDN. This transition to inorganic N dominance coincides with a shift in the stoichiometry of the DOM pool, where DOM becomes progressively enriched in N and DON concentrations are less tightly associated with concentrations of dissolved organic carbon (DOC). This shift in DOM stoichiometry (defined as DOC:DON ratios) suggests that fundamental changes in the biogeochemical cycles of C and N in freshwater ecosystems are occurring across the globe as human activity alters inorganic N and DOM sources and availability. Alterations to DOM stoichiometry are likely to have important implications for both the fate of DOM and its role as a source of N as it is transported downstream to the coastal ocean.
  • Mickwitz, Per; Seppälä, Jyri; Kauppi, Lea; Hildén, Mikael (Suomen ympäristökeskus, 2014)
    SYKE Policy Briefs
  • Antikainen, Riina (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 27
    Nitrogen (N) and phosphorus (P) are essential elements for all living organisms.However, in excess, they contribute to such environmental problems as aquatic and terrestrial eutrophication (N, P), acidification (N), global warming (N), groundwater pollution (N), depletion of stratospheric ozone (N), formulation of tropospheric ozone (N) and poor urban air quality (N). Globally, human action has multiplied the volume of N and P cycling since the onset of industrialization. Themultiplication is a result of intensified agriculture, increased energy consumption and population growth. Industrial ecology (IE) is a discipline, inwhich human interactionwith the ecosystems is investigated using a systems analytical approach. The main idea behind IE is that industrial systems resemble ecosystems, and, like them, industrial systems can then be described using material, energy and information flows and stocks. Industrial systems are dependent on the resources provided by the biosphere, and these two cannot be separated from each other. When studying substance flows, the aims of the research from the viewpoint of IE can be, for instance, to elucidate theways howthe cycles of a certain substance could be more closed and how the flows of a certain substance could be decreased per unit of production (= dematerialization). IE uses analytical research tools such as material and substance flow analysis (MFA, SFA), energy flow analysis (EFA), life cycle assessment (LCA) and material input per service unit (MIPS). In Finland, N and P are studied widely in different ecosystems and environmental emissions. A holistic picture comparing different societal systems is, however, lacking. In this thesis, flows of N and P were examined in Finland using SFA in the following four subsystems: I) forest industry and use of wood fuels, II) food production and consumption, III) energy, and IV) municipal waste. A detailed analysis at the end of the 1990s was performed. Furthermore, historical development of the N and P flows was investigated in the energy system (III) and the municipal waste system (IV). The main research sources were official statistics, literature, monitoring data, and expert knowledge. The aim was to identify and quantify the main flows of N and P in Finland in the four subsystems studied. Furthermore, the aim was to elucidate whether the nutrient systems are cyclic or linear, and to identify how these systems could be more efficient in the use and cycling of N and P. A final aim was to discuss how this type of an analysis can be used to support decision-making on environmental problems and solutions. Of the four subsystems, the food production and consumption system and the energy system created the largest N flows in Finland. For the creation of P flows, the food production and consumption system (Paper II) was clearly the largest, followed by the forest industry and use of wood fuels and the energy system. The contribution of Finland to N and P flows on a global scale is low, but when compared on a per capita basis, we are one of the largest producers of these flows, with relatively high energy and meat consumption being the main reasons. Analysis revealed the openness of all four systems.The openness is due to the high degree of internationality of the Finnish markets, the large-scale use of synthetic fertilizers and energy resources and the low recycling rate ofmanywaste fractions. Reduction in the use of fuels and synthetic fertilizers, reorganization of the structure of energy production, reduced human intake of nutrients and technological development are crucial in diminishing the N and P flows. To enhance nutrient recycling and replace inorganic fertilizers, recycling of such wastes as wood ash and sludge could be promoted. SFAis not usually sufficiently detailed to allow specific recommendations for decision-making to bemade, but it does yield useful information about the relative magnitude of the flows and may reveal unexpected losses. SFA studies should be supported with other methods such as LCA. Data uncertainties are high in this type of analysis. Use of quantitative uncertainty analysis is therefore recommended. Definition of the system boundaries significantly affects conclusions drawn from SFA results. Sustainable development is a widely accepted target for all human action. SFA is one method that can help to analyse how effective different efforts are in leading to a more sustainable society. SFA?s strength is that it allows a holistic picture of different natural and societal systems to be drawn. Furthermore, when the environmental impact of a certain flow is known, the method can be used to prioritize environmental policy efforts.
  • Rantakari, Miitta (Finnish Environment Institute, 2010)
    Monographs of the Boreal Environment Research 35
    Lakes are an important component of ecosystem carbon cycle through both organic carbon sequestration and carbon dioxide and methane emissions, although they cover only a small fraction of the Earth’s surface area. Lake sediments are considered to be one of the rather permanent sinks of carbon in boreal regions and furthermore, freshwater ecosystems process large amounts of carbon originating from terrestrial sources. These carbon fluxes are highly uncertain especially in the changing climate.The present study provides a large-scale view on carbon sources and fluxes in boreal lakes situated in different landscapes. We present carbon concentrations in water, pools in lake sediments, and carbon gas (CO2 and CH4) fluxes from lakes. The study is based on spatially extensive and randomly selected Nordic Lake Survey (NLS) database with 874 lakes. The large database allows the identification of the various factors (lake size, climate, and catchment land use) determining lake water carbon concentrations, pools and gas fluxes in different types of lakes along a latitudinal gradient from 60oN to 69oN.Lakes in different landscapes vary in their carbon quantity and quality. Carbon (C) content (total organic and inorganic carbon) in lakes is highest in agriculture and peatland dominated areas. In peatland rich areas organic carbon dominated in lakes but in agricultural areas both organic and inorganic C concentrations were high. Total inorganic carbon in the lake water was strongly dependent on the bedrock and soil quality in the catchment, especially in areas where human influence in the catchment is low. In inhabited areas both agriculture and habitation in the catchment increase lake TIC concentrations, since in the disturbed soils both weathering and leaching are presumably more efficient than in pristine areas.TOC concentrations in lakes were related to either catchment sources, mainly peatlands, or to retention in the upper watercourses. Retention as a regulator of the TOC concentrations dominated in southern Finland, whereas the peatland sources were important in northern Finland. The homogeneous land use in the north and the restricted catchment sources of TOC contribute to the close relationship between peatlands and the TOC concentrations in the northern lakes. In southern Finland the more favorable climate for degradation and the multiple sources of TOC in the mixed land use highlight the importance of retention.Carbon processing was intensive in the small lakes. Both CO2 emission and the Holocene C pool in sediments per square meter of the lake area were highest in the smallest lakes. However, because the total area of the small lakes on the areal level is limited, the large lakes are important units in C processing in the landscape. Both CO2 and CH4 concentrations and emissions were high in eutrophic lakes. High availability of nutrients and the fresh organic matter enhance degradation in these lakes. Eutrophic lakes are often small and shallow, enabling high contact between the water column and the sediment. At the landscape level, the lakes in agricultural areas are often eutrophic due to fertile soils and fertilization of the catchments, and therefore they also showed the highest CO2 and CH4 concentrations. Export from the catchments and in-lake degradation were suggested to be equally important sources of CO2 and CH4 in fall when the lake water column was intensively mixed and the transport of substances from the catchment was high due to the rainy season. In the stagnant periods, especially in the winter, in-lake degradation as a gas source was highlighted due to minimal mixing and limited transport of C from the catchment.The strong relationship between the annual CO2 level of lakes and the annual precipitation suggests that climate change can have a major impact on C cycling in the catchments. Increase in precipitation enhances DOC export from the catchments and leads to increasing greenhouse gas emissions from lakes. The total annual CO2 emission from Finnish lakes was estimated to be 1400 Gg C a-1. The total lake sediment C pool in Finland was estimated to be 0.62 Pg, giving an annual sink in Finnish lakes of 65 Gg C a-1.
  • Mickwitz, Per; Seppälä, Jyri; Kauppi, Lea; Hildén, Mikael (Finnish Environment Institute, 2014)
    SYKE Policy Brief