Per Stålnacke

Forskningsdirektør

(+47) 932 02 520
per.stalnacke@nibio.no

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Ås - Bygg H7

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Høgskoleveien 7, 1433 Ås

Sammendrag

The determination of environmentally minimum water level in lakes is essential for the protection of their ecosystems. The assessment of minimum water level depends on a number of biotic and abiotic factors of the lake ecosystem; however, in many cases these factors are not easy to collect and assess in their entirety. At the same time, the lakes in many cases consist an important water reserve to meet the requirements arising from economic activities, e.g. industry, agriculture. In this paper, the morphological features in four lakes – Vegoritida, Petron, Cheimaditida and Zazari – of Northern Greece are analysed in order to assess their environmentally minimum water level. The morphological analysis is based on the relationship of the lake surface area and volume with the water level. An optimization method is applied taking into account that the biodiversity is favoured as the surface area covered by the lake is increased and the human water requirements are satisfied to the greatest possible extent by the available water volume of the lake. The environmentally minimum water level determined by the morphological analysis in the four lakes is compared with the minimum water level based on the analysis of the requirements of fish fauna and macrophytes.

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2016 have been estimated in accordance with the OSPAR Commission’s principles. Nutrients, metals and organic pollutants have been monitored in rivers; discharges from point sources have been estimated from industry, sewage treatment plants and fish farming; and nutrient inputs from diffuse sources have been modelled. Trends in riverine inputs have been analysed, and threshold concentration levels investigated.

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Sammendrag

The statistical model MESAW (Matrix Equations for Source Apportionment on Watershed) was used to estimate the diffuse unit-area source emission coefficients of nitrogen in Estonian rivers. The input data included monitored riverine loads, point sources and land use categories from a total of 50 rivers/catchment areas. Two independent studies were conducted: the estimation of emission coefficients for the whole of Estonia and for a smaller study area near Tallinn. The results from both cases showed that drained peat soils were the highest diffuse source contributor in unit-area loads. The results show that the unit-area loads from drained peat soils were up to 2.3 times higher than from arable land. Moreover, a comparison of emission coefficients for the whole of Estonia and for the Tallinn catchment area indicated that coefficients can vary significantly between sources and single years. Additional detailed studies and monitoring are needed to support these conclusions.

Sammendrag

Det grønne skiftet med økt utnyttelse av naturressurser vil ha konsekvenser for både miljøet og samfunnet. Hvordan kan vi kvantifisere det vi får fra vann, og naturen for øvrig, slik at vi ser hva den totale samfunnsgevinsten av ulike miljøtiltak er?

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Sammendrag

A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts- Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons’ stakeholders, complemented by scientic knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations.

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Sammendrag

Agricultural management practices are among the major drivers of agricultural nitrogen (N) loss. Legislation and management incentives for measures to mitigate N loss should eventually be carried out at the individual farm level. Consequently, an appropriate scale to simulate N loss from a scientific perspective should be at the farm scale. A data set of more than 4000 agricultural fields with combinations of climate, soils and agricultural management which overall describes the variations found in the Baltic Sea drainage basin was constructed. The soil–vegetation–atmosphere model Daisy (Hansen et al. 2012) was used to simulate N loss from the root zone of all agricultural fields in the data set. From the data set of Daisy simulations, we identified the most important drivers for N loss by multiple regression statistics and developed a statistical N loss model. By applying this model to a basin-wide data set on climate, soils and agricultural management at a 10 × 10 km scale, we were able to calculate root-zone N losses from the entire Baltic Sea drainage basin and identify N loss hot spots in a consistent way and at a level of detail not hitherto seen for this area. Further, the root-zone N loss model was coupled to estimates of nitrogen retention in catchments separated into retention in groundwater and retention in surface waters allowing calculation of the coastal N loading.

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Sammendrag

A statistical model MESAW was used to estimate the diffuse emission coefficients of nitrogen in Estonia. This includes analysis of data on loads, point sources, land use types etc. Two studies were conducted to determine the emission coefficients for the whole Estonia and for a smaller study area near Tallinn. Investigations showed that in addition to arable lands, drained peat soils can be a significant source of nitrogen. In fact, our results show that the unit-area loads from drained peat soils may be 1.5 to 2.3 times higher than from arable lands. Additional detailed investigations and measurements are needed to support these conclusions. Comparison of emission coefficients for the whole Estonia and of the Tallinn catchment area indicated that the coefficients can vary significantly between sources and single years. Therefore it is suggested that the sources of nitrogen loads should be defined in a catchment area level rather than a country level.

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2015 have been estimated in accordance with the OSPAR Commission’s principles. Nutrients, metals and organic pollutants have been monitored in rivers; discharges from point sources have been estimated from industry, sewage treatment plants and fish farming; and nutrient inputs from diffuse sources have been modelled. Trends in riverine inputs have been analyzed, and threshold concentration levels investigated.

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2014 have been estimated in accordance with the OSPAR Commission’s principles. Nutrients, metals and organic pollutants have been monitored in rivers; discharges from point sources have been estimated from industry, sewage treatment plants and fish farming; and nutrient inputs from diffuse sources have been modelled. Trends in riverine inputs have been analysed, and threshold concentration levels investigated.

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2012 have been estimated in accordance with the requirements of the OSPAR Commission. Water discharges in 2012 were lower than in 2011, but higher than the 30-year normal. This caused a small but overall decrease in inputs since 2011, with an exception of zinc, which increased in the overall loads due to an increase in River Glomma. The reason is presently unknown. Analyses of data since 1990 from nine main rivers in the program revealed downward trends both for nutrients and metals, with an exception of upwards trends for ammonium in one river. Fish farming continued to be a major source of nutrients, with an increase of about 15 % of phosphorus and nitrogen loads since last year. Inputs of PCBs and the pesticide lindane were, as in previous years, insignificant

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2013 have been estimated in accordance with the requirements of the OSPAR Commission. Nutrients, metals and organic pollutants have been monitored in rivers; discharges from point sources have been estimated from industry, sewage treatment plants and fish farming; and nutrient inputs from diffuse sources have been modelled. Trends in riverine inputs have been analysed. Concentrations above given threshold levels have been detected for both metals and organic pollutants in some rivers.

Sammendrag

VIDEO: Issues such as contamination from surrounding agriculture, increased tourism and climate change all pose a threat to Europe’s many lagoons - vulnerable ecosystems in densely populated areas. Scientists are now going new ways to secure better lagoon management in future.

Sammendrag

In Norway, water quality of small streams draining agricultural catchments has been monitored since 1993 by the Agricultural and Environmental Monitoring Program. This article attempted to examine the concentration levels, temporal dynamics and long-term trends (1993–2009 and 1996–2009) of Al, Fe, Cu, Mn and Zn in streams draining the catchment areas of Skuterud (4.5 km2) and Mørdre (6.8 km2), located in south-east Norway. In the Mørdre stream, Al, Fe, Cu, Mn and Zn all showed statistically significant downward trends (p<0.05), whilst in the Skuterud stream only Al and Fe showed statistically downward significance (p<0.05). The general declining trends of metal concentrations are most likely associated with reduction of acid rain deposition in southern Norway. In spite of this declining trends, over the 14–17 years of monitoring mean monthly concentrations of total Al (2.0–3.2 mg L−1), Fe (1.3–2.5 mg L−1) and Cu (8.9–26.1 µg L−1) in Skuterud and Mørdre streams, respectively exceeded the limits of the Norwegian Water Framework Directives, whereas the concentrations of Mn (22.3–40.8 µg L−1) and Zn (13.1–99.4 µg L−1) fell within the range of desired limits. Of the total water samples analysed from Skuterud (n=370) and Mørdre streams (n=255), nearly 80–84%, 70–87% and 79–96% were above the desired limits for Al (0.2 mg L−1), Fe (0.3 mg L−1) and Cu (3 µg L−1), respectively. In 2011, water analysis from drainage of forest soils (in Skuterud catchment) measured total Al: 0.42–0.79 mg L−1 and total Fe: 0.84–1.0 mg L−1 which were two to three folds greater than the desired limits. In general, weak correlations between runoff and concentrations of the metals in the streams were noted. Future research should focus on identifying the sources of Al, Fe and Cu and management interventions of elevated metal inputs to Skuterud and Mørdre streams.

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Sammendrag

Access to sufficient quantities of water of acceptable quality is a basic need for human beings and a pre-requisite to sustain and develop human welfare. In cases of limited availability, the allocation of water between different sectors can result in conflicts of interests. In this study, a modified version of the Building Block Methodology (BBM) was demonstrated for allocation of waters between different sectors. The methodology is a workshop-based tool for assessing water allocation between competing sectors that requires extensive stakeholder involvement. The tool was demonstrated for allocation of water in the Sri Ram Sagar water reservoir in the Godavari Basin, Andhra Pradesh, India. In this multipurpose reservoir, water is used for irrigation, drinking water supply and hydropower production. Possible water allocation regimes were developed under present hydrological conditions (normal and dry years) and under future climate change, characterized by more rain in the rainy season, more frequent droughts in the dry season and accelerated siltation of the reservoir, thus reducing the storage capacity. The feedback from the stakeholders (mainly water managers representing the various sectors) showed that the modified version of the BBM was a practical and useful tool in water allocation, which means that it may be a viable tool for application also elsewhere.

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Sammendrag

Riverine inputs and direct discharges to Norwegian coastal waters in 2011 have been estimated in accordance with the requirements of the OSPAR Commission. Due to high water discharges in 2011, the riverine inputs of both nutrients and metals were greater than 2010. Analyses of data since 1990 from nine main rivers in the program revealed downward trends both for nutrients and metals, with an exception of upwards trends for nitrogen in one river. Fish farming continued to be a major source of nutrients and copper to coastal waters. Inputs of PCBs and the pesticide lindane were, as in previous years, insignificant.

Sammendrag

Riverine inputs and direct discharges to Norwegian seas in 2009 have been estimated in accordance with the requirements of the OSPAR Commission. Due to the general lower water discharges in 2009 than in 2008, there was a reduction in all nutrient fractions in riverine loads in 2009. Long-term (1990-2009) trends show that nutrient loads have decreased in some Norwegian rivers, although nitrogen concentrations have increased in others. Direct discharges of nutrients from fish farming continue to increase. The riverine loads of all metals except mercury were lower in 2009 than in 2008. The copper discharges from fish farming continue to increase. Analyses of long term trends (1990-2009) in metal inputs showed that zinc and copper loads have been reduced in several rivers. Inputs of PCBs and the pesticide lindane in 2009 were insignificant.

Sammendrag

Undersøkelser av tilførsler til kystområdene i 2009 viser at både næringsstoff- og metalltilførsler i vassdragene generelt har avtatt siden 2008, hovedsakelig på grunn av lavere vannføringer. Unntak omfatter bl.a. kvikksølvtilførsler som har økt i elvene i de siste årene. Langtidstrender for perioden 1990-2009 viser at tilførsler av nitrogen, fosfor, sink og kobber har gått ned i enkelte vassdrag. Direkteutslipp fra fiskeoppdrett øker fortsatt, både når det gjelder næringsstoffer og kobber. Tilførsler av PCB og pesticidet Lindan er ubetydelige.

Sammendrag

The major objective of this study was to compile and examine empirical relationships between the driving forces and pressures that affect nitrogen cycling. Special attention was paid to riverine loads, fluxes, and concentrations of nitrogen in relation to agricultural factors (e.g., land use and fertilisers) at various spatial scales (plot, field, catchment, river basin, nation, region, continent, and world). Results of the present analyses and assessments reported in the literature indicate that at global, continental and inter-river basin scales, the level of riverine nitrogen loads (pressures) can be readily derived from simple empirical relationships with driving forces like population density and agricultural factors (e.g., proportion of arable land and fertiliser use). It seems that statistically derived relationships do not hold or are much weaker at the scales of single river basins and smaller catchments, whereas nitrogen losses appear to be correlated with fertiliser use at the smallest scales (plot and field). It is important to recognize this spatial nutrient paradox, particularly when such functional relationships are applied in the contexts of management and decision making. The implications for management are given further consideration in this paper.

Sammendrag

Geoffrey D. Gooch and Per Stålnacke. 2009. THE LAKE PEIPSI AND ITS DRAINAGE BASIN CASE STUDY IWA Publishing. In: Water Framework Directive: Model supported Implementation A Water Manager"s Guide. Edited by Fred F Hattermann and Zbigniew W Kundzewicz. ISBN: 9781843392736. Published by IWA Publishing, London, UK.pp. 184-201

Sammendrag

Sukkertareprosjektet (2005-2008) viste at om lag 80 prosent av sukkertaren var forsvunnet på Skagerrakkysten og 40 prosent på Vestlandet. Bortfallet ble knyttet opp mot en kombinasjon av klimaendringer og menneskeskapte tilførsler av næringsstoffer og partikler. Det er et langsiktig arbeid å redusere økningen i temperatur som følge av klimaendringer, mens det forholdsvis raskt kan settes inn tiltak mot lokale og regionale tilførsler av næringsstoffer og partikler. Dette er bakgrunnen for at Miljøverndepartementet har bedt Arbeidsgruppen for sukkertare om å foreslå konkrete, nasjonale tiltak som på kort sikt kan settes inn i områder med generelt dårlig miljøtilstand. Det har vært en forutsetning at sektormyndighetene skal bidra aktivt i denne prosessen og foreslå tiltak på sine områder. I denne rapporten er det utarbeidet en oversikt over områder med dårlig miljøtilstand fra svenskegrensen til og med Møre og Romsdal. Det mangler imidlertid fortsatt undersøkelser langs store deler av kysten, særlig på Vestlandet og nordover, og det er grunn til å anta at det er områder med dårlig sukkertaretilstand også her. Som grunnlag for vurderingene av tiltak er det utarbeidet kart over tilførslene av næringsstoffer til spesifiserte kystavsnitt for de forskjellige vassdragsområdene. Kartene kan legges til grunn for fremtidige tiltak, både for sektorene og på regionalt og lokalt nivå. Arbeidsgruppen har gitt en oversikt over generelle tiltak som kan iverksettes i de forskjellige sektorene, og det er foreslått konkrete tiltak i vannregionene. De mest aktuelle tiltakene inngår i vannregionenes forvaltingsplaner etter vannforskriften i første planperiode. I denne rapporten er det gitt harmoniserte oversikter over tiltakene. For de deler av kysten som ikke omfattes av første planperiode er forslagene til tiltak mindre fullstendige, og det er behov for til dels omfattende kartlegging av miljøtilstanden før det kan foreslås detaljerte tiltak i disse områdene. Rapporten fra Sukkertareprosjektet viste at lokale næringssaltutslipp med stor sannsynlighet bidrar til eutrofiering og generelt dårlig miljøtilstand i mange områder, med bortfall av sukkertare som en synlig konsekvens. Sommerstid har normalt lokale tilførsler relativt større innflytelse på kystvannet enn langtransporterte tilførsler. Store, lokale næringssalttilførsler om sommeren ser også ut til å ha størst negativ virkning på sukkertaren, særlig på indre kyst og i fjorder. Tilførsler av partikler kan ha betydning for rekrutteringen av nye tareplanter i fjorder med stor avrenning fra land eller store tilførsler fra elver. Kombinerte effekter av klimaendringer og modifisering av elveløp kan ha ført til betydelige økninger i sedimenttransporten til sjø i mange områder. Lenger ut på kysten vil slam fra nedbryting av organisk materiale, som planteplankton og trådalger, ha større betydning. De største nasjonale tilførslene til Skagerrak kommer fra landbruk og avløp, mens det på Vestlandet er sterkt økende utslipp fra akvakultur. Rensing av avløpsvann til Skagerrak har ført til en betydelig nedgang i fosforutslippene, mens nitrogenutslippene har avtatt relativt lite. Utslippene fra jordbruk til Skagerrak er også lite redusert. På Vestlandet er utslipp fra avløp og jordbruk generelt av mindre betydning, mens utslippene fra akvakultur har økt dramatisk, særlig i sommersesongen. Ut fra en føre var-betraktning er det grunnlag for å sette i verk generelle tiltak innenfor disse sektorene for større kystavsnitt. Lokalt varierer miljøtilstanden mye, og vannregionene må vurdere tilpassede tiltak i disse områdene. Innen mange sektorer er resultatet av tiltaksgjennomføring i stor grad avhengig av god informasjon og veiledning, og lokal forankring. Det vil også være uheldig å frikoble tiltak fra helheten i vannforvaltnings-prosessen. Gjennomføring av tiltak bør derfor hovedsakelig skje i vannregionene. Sentrale myndigheter må i betydelig sterkere grad være pådrivere og tilrettelegge for best mulig tiltaksgjennomføring.  

Sammendrag

Agricultural management and losses of nitrogen (N), phosphorus (P) and suspended sediments (SS) from eight small (85-2830 ha) catchments in Norway were analysed. The catchments represent areas with different agricultural production systems, soils and climate. Results from the long-term (9-16 years) in-stream monitoring show (i) large differences in levels of losses between the catchments, (ii) large interannual variability and (iii) few time-trends in losses. These results are discussed in relation to changes in agricultural policies and the implementation of soil management practices, such as reduced autumn-ploughing, catch crops, constructed wetlands and changes in nutrient application. Overall, these data demonstrate changes in farmer behaviour driven by economic incentives in combination with active extension services stimulating environmental friendly management practices. However, despite the increased implementation of mitigation methods by farmers, improvements in water quality at the catchment scale can be attenuated. More long-term monitoring programmes are clearly required. (C) 2007 Elsevier Ltd. All rights reserved.

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Sammendrag

Eksisterende data fra Vansjø-Hobølvassdraget i perioden 1983-2006 er benyttet til å utføre følgende analyser: (1) Ny beregning av tilførsler i Hobølelva i perioden 1985-2006; (2) Beregning av trender for fosfor, nitrogen og partikler i Hobølelva i perioden 1985-2006; (3) Beregning av mulige trender i vannkvalitet i Svinna, Veidalselva og Mørkelva; (4) Analyse av flomvannføring i Hobølelva; og (5) Trendanalyse av vannkvalitetsdata i Storefjorden og Vanemfjorden for perioden 1983-2006.

Sammendrag

Simple risk assessment tools for agricultural phosphorus (P) losses, like the P index, have been developed in the U.S.A. and in some European countries. Despite its popularity, there have been surprisingly few studies, which try to test the index close to the field scale. For Norway, the P index approach comprises the risk related to both the source of P (soil P status, amount of fertilizer and manure as well as method of application, plant P release by freezing and P balance) and the risk related to transport of P (erosion, flooding, surface runoff, contributing distance, modified connectivity, soil profile, subsurface drainage). In this paper, we have applied the Norwegian P index to farmer fields within a small agricultural catchment, the Skuterud catchment (450 ha), in southeastern Norway. The Norwegian P index was tested for two agricultural fields (0.3 to 0.4 ha) and nine subcatchments (6 to 65 ha). Total P concentrations in runoff from the eleven study areas were measured during the year from May 2001 to April 2002. Results from the testing showed that the Norwegian P index described 66% of the variation in measured relative total P concentration for fields and subcatchments included in this study. Additionally, the P index was able to detect fields and subcatchments with the highest measured P concentrations. Results also showed that the source factor contributed most to the variation between fields and hence were important for the identification of high-risk areas in Skuterud catchment. It was found that the soil P status described 66% of the variation in the source factor. Among the transport variables, it was found that both erosion risk and contributing distance had an important influence on the transport factor. Overall, the study illustrated the potential of the P index to detect areas with the highest risk of P loss.

Sammendrag

Vannprøvetaking ved overvåkning av avrenning fra landbruksarealer har vært gjort ulikt i de Nordisk land. Behovet for å se på hvor store forskjeller i estimering av næringsstofftransport som de ulike prøvetakingsstrategiene gir, var bakgrunnen for dette prosjektet. I tre bekker i Sør-Norg ble det foretatt sammenlignende studier av tre prøvetakingsopplegg: ukentlige vannføringsproporsjonale blandprøver, ukentlige tidsproporsjonale blandprøver og stikkprøver. De ulike prøvetakingsstrategiene ga mer like utslag for nitrogen enn for fosfor og suspendert materiale. Stikkprøver fanget i mindre grad opp høye konsentrasjoner av fosfor og suspendert materiale i flomsituasjoner enn blandprøvemetodene, og ga følgelig underestimering av stofftapet. Blandprøver uttatt proporsjonalt i forhold til vannføringen ga mest pålitelige resultater både i perioder med høy og med liten vannføring. Vannføringsproporsjonal prøvetaking ble derfor anbefalt for videre studier av vannkvalitet i landbruksområder.