Search results for "ravinteet"
showing 10 items of 26 documents
A New Method to Reconstruct Quantitative Food Webs and Nutrient Flows from Isotope Tracer Addition Experiments
2020
Understanding how nutrients flow through food webs is central in ecosystem ecology. Tracer addition experiments are powerful tools to reconstruct nutrient flows by adding an isotopically enriched element into an ecosystem and tracking its fate through time. Historically, the design and analysis of tracer studies have varied widely, ranging from descriptive studies to modeling approaches of varying complexity. Increasingly, isotope tracer data are being used to compare ecosystems and analyze experimental manipulations. Currently, a formal statistical framework for analyzing such experiments is lacking, making it impossible to calculate the estimation errors associated with the model fit, the…
Short-term responses of decomposers and vegetation to stump removal
2011
The influence of lipid content and taxonomic affiliation on methane and carbon dioxide production from phytoplankton biomass in lake sediment
2021
The greenhouse gases methane (CH4) and carbon dioxide (CO2) are end products of microbial anaerobic degradation of organic matter (OM) in lake sediments. Although previous research has shown that phytoplankton lipid content influences sediment methanogenesis, current understanding on how OM quality affects methanogenesis is still limited. Such information is needed to more accurately assess how lake greenhouse gas emissions may change in response to anthropogenic activities. We cultured 11 phytoplankton species from five classes and studied how taxonomic identity, C : N ratio, lipid content, and fatty acid composition of phytoplankton biomass affects the CH4 and net CO2 production in anaero…
Vieraslajin, komealupiinin (Lupinus polyphyllus), vaikutus koiranputken (Anthriscus sylvestris) kasvun allokointiin ja siemenpainoihin
2013
Vieraslajin leviäminen uudelle alueelle luo haasteita niin vieras- kuin paikalliselle lajille. Molempien lajien on sopeuduttava ja vastattava toistensa aiheuttamiin valintapaineisiin. Koska vieraslajit ovat monesti uudessa ympäristössä voimakkaita kilpailijoita, ja siten vaikuttavat muihin lajeihin sekä ympäristöönsä voimakkaasti ja jopa haitallisesti, on mahdollista, että vieraslajin kanssa esiintyvissä paikallisissa lajeissa on havaittavissa muutoksia niiden elinkiertopiirteissä. Vaikka kilpailun tiedetään olevan yksi merkittävimpiä valintapaineita, tietoa vieraslajien vaikutuksista yksittäisiin suomalaisiin lajeihin on vähän. Tutkimalla vieraslajin aiheuttamia evolutiivisia muutoksia pai…
Environmental context determines pollution impacts on ecosystem functioning
2023
Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides and industrial chemicals in the environment. Part of the problem reflects the multifarious origins of these micropollutants, which can derive from urban and agricultural sources. Understanding how micropollutants harm ecosystems is a major scientific challenge due to asymmetries of stress across trophic levels and ecological surprises generated by multiple drivers interacting in human-impacted landscapes. We used field assays above and below municipal wastewater treatment plants (WWTPs) in 60 sampling locations across 20 Swiss streams to test how micropoll…
Effects of mechanical mixing on lake water quality, with special emphasis on under-ice phytoplankton
2015
Lake Load Response (LLR) – mallityökalu vesialueiden hoidon suunnittelun apuvälineenä
2010
For eutrophic lakes, achieving good water quality usually requires a reduction in external loading. The Lake Load Response (LLR) tool, based on the LakeState (LS) model, can be used to predict the necessary loading reduction, which can be utilized when making decisions on the management of the lake. The best predictions are made when the input values of the incoming loading, water outflow and in-lake total phosphorus, total nitrogen and chlorophyll a concentrations are as accurate as possible. Accurate loading data is often hard to collect because of the lack of resources for observations. However, LLR-runs made for the lake Lehesjärvi-Vähäjärvi in Jyväskylä showed that examining the needed…