Search results for "Ecosystem"
showing 10 items of 1752 documents
Wastewater modification processes in a stabilization reservoir: a new mathematical model
2018
The paper presents a mathematical model for the simulation of the ecology of a wastewater stabilization reservoir (WSR). WSRs are hypertrophic aquatic systems devoted to water storage in warm countries where shortage conditions are often encountered. Several factors that affect the stabilization reservoir’s effluent quality were taken into account: hydraulics and hydrology, solar radiation, reaeration, algae, zooplankton, organic matter, pathogens, and sediment-water interactions. The model quantifies the specific influence of each factor on effluent quality, and evaluating the correlation between the different factors. State variables included in the model were: algae, dissolved oxygen, or…
Mercury Speciation in Floodplain Soils and Sediments along a Contaminated River Transect
1998
A novel mercury-specific sequential extraction procedure (SEP) for the assessment of mercury (Hg) speciation in soils and sediments, with emphasis on studying the interaction between Hg and organic matter (OM), was developed and tested. It was applied to determine Hg speciation in floodplain topsoils and surface sediments along the Hg-contaminated part of the river Elbe, and to simultaneously derive some information on the (re)mobilization potentials for Hg from these matrices. The majority of the total Hg in the ecosystem today is bound in the floodplains, which also still geographically reflect the historic emission record. Most of the Hg in both matrices is bound strongly to OM, suggesti…
Peat humic acid properties and factors influencing their variability in a temperate bog ecosystem
2013
Studies of the properties of soil organic matter are essential for understanding the humification reactions and soil diagenesis processes. The aim of this study is to analyse properties of peat and peat humic acids as well as factors influencing their variability. Humic acids isolated from an ombrotrophic bog peat profile were used as study objects. Relations among peat age, decomposition and humification degree, botanical composition, and properties of peat humic acids (elemental, functional composition, spectral characteristics) were studied. The variability of peat properties was found to be less significant than the differences in the properties of peat-forming living matter, which indi…
Biogenic methane in freshwater food webs
2010
SUMMARY 1. It has long been known that substantial amounts of methane are produced in anoxic lake sediments, and the components of the methane cycle in lakes have been well described. At oxic–anoxic interfaces, methane-oxidising bacteria (MOB) convert methane to microbial biomass and can be highly productive. However, only recently has methane been recognised as a potentially important carbon and energy source for lake food webs, and some instances have also been reported of methane contribution to river food webs. Stable isotope analysis (SIA) has provided compelling evidence in this respect and has been supplemented by other lines of evidence. 2. In the benthic food webs of lakes, profund…
Linking food webs to ecosystem processes: Piecewise linear models of soil microcosms
2008
Abstract A piecewise linear approach to link decomposer biomass and soil nitrogen dynamics is proposed. Dynamics of a detritus–fungus–nematode food chain were studied in a microcosm experiment and modelled to evaluate the role of fungal-feeding nematodes in N mineralization. The nematode dynamics switched from exponential growth to a resource-limited phase. At the same time the amount of ammonium nitrogen in soil started to increase, following an initial immobilization phase. Both nematode and ammonium dynamics could be described by two-phase linear equations. Two nitrogen models were compared. A model in which the nematode accounted for all mineralization could be fitted to the ammonium da…
Long-term Effects of Bioaccumulation in Ecosystems
2005
Extensive damage to organisms and declines in wildlife populations have been observed together with long-term bioaccumulation and biomagnification of persistent xenobiotic chemicals. Heavy metals, especially organic or biomethylated mercury, lead, cadmium and organic tin compounds have caused environmental damage through bioaccumulation on a local scale. Effects on wildife caused by bioaccumulation of persistent organochlorine compounds are more widespread. However, the causal relationship between a biomagnified compound and the long-term effects have been established in only a few cases. Metabolic transformations, and occurrence of several toxic contaminants together in many cases, complic…
Changing forest stakeholders’ perception of ecosystem services with linguistic nudging
2019
This paper explores whether the perceptions of forest owners and professionals could be nudged towards more sustainable management practices by adjusting a policy text's metaphorical content. Recent research has demonstrated a link between information interventions and preference change, but there is a need to further explore individuals' reactions to information on forest-based ecosystem services and to link these to the design of policy instruments. We contribute to narrowing this gap by nudging the content of a policy text comparing rotation forest management (RFM) and continuous cover forestry (CCF), and exposing it to forest stakeholders. The research is carried out in Finland, the so-…
Alternatives to the present global development pattern : ecovillages – a model for sustainable living?
2016
Master thesis development management - University of Agder 2016 The current way of development is exhausting the planets limitations, the continues increase in consumption are degrading the nature that is relied on for human existence. Thus, it is necessary to define an alternative way of developing. The aim is to achieve happiness for all, sustaining the resources of the planet. Ecovillages are recognized as a sustainable alternative which encompasses a holistic approach to the term sustainability. Through qualitative research in the form of participatory observations, interviews and a survey performed in Gambhira, an ecovillage in rural Colombia, the sustainability, educational mission as…
Managing a boreal forest landscape for providing timber, storing and sequestering carbon
2015
Human well-being highly depends on ecosystem services and this dependence is expected to increase in the future with increasing population and economic growth. Studies that investigate trade-offs between ecosystem services are urgently needed for informing policy-makers. We examine the trade-offs between a provisioning (revenues from timber selling) and regulating (carbon storage and sequestration) ecosystem services among seven alternative forest management regimes in a large boreal forest production landscape. First, we estimate the potential of the landscape to produce harvest revenues and store/sequester carbon across a 50-year time period. Then, we identify conflicts between harvest re…