Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2006
Forfattere
Ingvild Wartiainen Bjørn Frantzen Alexei Bambulyak Pål B. Mortensen Espen Hansen Sergey Zhavoronkin Ole Anders Lindseth Bjørn Kristoffersen Dag Nagoda Vladimir Bakharev Ole Kristian Bjerkemo Tom Gederø Mikhail Kalentchenko Terje Alling Vladislav Pesko Alf E. Jakobsen Harald Larsen Aksel JensenSammendrag
Gjennom artikler skrevet av forskere, myndigheter, miljøorganisasjoner og politikere på norsk og russisk side presenteres nærings- og biologiske interesser i Barentshavet. Det gis også et innblikk i hvilke forventninger og bekymringer lokalsamfunn i området har til petroleumsaktiviteten og annen næringsaktivitet i havet.
Sammendrag
The strategy to mitigate phosphorus (P) losses in areas of arable cropping in Norway has focused on measures to reduce erosion. Risk assessment of erosion has formed the basis for implementation of measures. The soil P content has increased during the last decades motivating an evaluation of its effect on P transfer in the landscape. The present study describes the spatial variability of runoff P concentrations from an agricultural dominated catchment (4.5 km2) representative for agriculture in south-eastern Norway. The concentrations of suspended sediments (SS), total P (TP) and dissolved reactive P (DRP) in runoff from 22 subcatchments (0.3 "263 ha) during one year (monthly and during runoff-events) were evaluated. Contributions from point sources were 38 kg TP yr-1 compared to a total P loss of 685 kg yr-1 from the whole catchment. During low flow, mean diffuse TP concentration in runoff from subcatchments varied from 28 to 382 µg L-1. The mean low flow TP concentration was 39 µg L-1 from the housing area (only diffuse runoff) and 33 µg L-1 from the forested area. During high flow the highest diffuse TP concentration was measured in an area with high erosion risk and high soil P status. At the subcatchment level the transfer of SS varied from 25 to 175% of the whole catchment SS transfer. Correspondingly for TP, the transfer varied from 50 to 260% of the whole catchment TP transfer. For each of five agricultural subcatchments the slope of the relationship between TP and SS concentrations reflected the mean soil P status of the subcatchment. Erosion risk estimates were closely related to the SS concentration (R2 = 0.83). The study illustrates that soil P status in addition to soil erosion are important factors for P transfer.
Forfattere
Jens Kværner Bjørn KløveSammendrag
Content of 18O, 2H, 3H and geochemical components in rainfall, stream water, peat water and bedrock groundwater in four headwater catchments were compared to reveal differences in sources of runoff and hydrological vulnerability to tunnel drainage during summer. Water previously stored within the catchments was the predominant component of streamflow during small and moderate events. The proportion of event water increased at high discharge in autumn. Neither the isotopic nor the hydrochemical composition of stream water indicated any considerable contribution from old bedrock groundwater. Stream water hydrochemistry revealed clear influence of soil water pathways. The differences in land cover could be seen in water quality and runoff generation. Water storage and mixing in lakes and lowland wetlands reduced fluctuations in runoff and water quality. Runoff retention and the solute trapping effect in peatlands were most efficient in flat areas near the catchment outlet. In lowflow periods fluxes from hillslopes were of minor importance compared to discharges from wetland water storage. Water delivery from hillslopes with thin till cover (
Sammendrag
Zero-valent iron improves the transformation of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites in aged and highly contaminated lake sediment under biotic conditions. The addition of Feº has a strong effect on transformation rates at 22 ºC and 9 ºC, the most enhanced degradation being obtained for DDT and DDOH [2,2-bis(pchlorophenyl) ethanol]. At 22 ºC and 10 weeks´incubation, the DDT concentration is reduced from 2.75 lmol g-1 (974 mg kg-1) to 0.98 lmol g-1 (346 mg kg-1) and 1.98 lmol g-1 (702 mg kg-1) in samples with and without the addition of iron, respectively. After 40 weeks` incubation these concentrations have further decreased to 0.19 lmol g-1 (66 mg kg -1) and 0.74 lmol g-1 (264 mg kg-1).There is no significant transformation of any of the compounds at 9 ºC without the addition of Feº. In the presence of iron, however, DDT is reduced to 1.25 lmol g-1 (442 mg kg-1) within 40 weeks´ incubation. This study demonstrates the ability of adapted microorganisms to transform DDT under elevated temperatures in original, aged sediments, and also the stimulating effect of zero-valent iron, which is significant even at low temperatures.
Sammendrag
In order to investigate the influence of biological growth on flow and transport patterns in horizontal subsurface flow constructed wetlands, bromide tracer experiments were conducted in two 3m long tanks. The tanks were filled with light weight aggregates and shell sand, respectively. The hydraulic conductivity, drainable porosity and dispersivity of the two filter mediawere determined before and after biological growth. The obtained breakthrough curves of bromide tracer showed that biological growth caused a pronounced reduction in drainable porosity, mainly for shell sand, whereas its effect on saturated hydraulic conductivity was negligible. The spatial distribution of the bromide after biological growth in the two filter media showed that the flow occurred preferentially along certain paths. However, in the light"weight aggregates filter medium, biological growth with possible clogging effects seems to reduce the efficiency of some preferential flow paths, increase the retention time, and hence, improves the system treatment efficiency. This study showed that selecting a filter medium including coarse fractions to some extent can mitigate the potential negative effects of bioclogging.
Sammendrag
Transient starch production is thought to exert a strong control over plant growth and response to elevated CO2. Here we tested this hypothesis with an experimentally-based mechanistic model in Arabidopsis thaliana. " Experiments were conducted on wild type (WT) of A. thaliana, starch-excess and starchless mutants under ambient- and elevated-CO2 conditions to determine parameters and validate the model. Central to the model, we experimentally demonstrated that dark respiration is directly proportional to soluble sugar concentration in A. thaliana leaves. " The model correctly predicted that: 1) mutant growth is about 20% of that of WT, and 2) absolute response of both mutants to elevated CO2 is an order of magnitude lower than that of the WT. " Our study demonstrates that effects of the diurnal starch cycle on growth can be captured by a fairly simple set of allocation equations. Our results further suggest that the maximum rate of leaf growth, and broadly the sink capacity, exert a strong control over the response to elevated CO2 of herbaceous plants such as A. thaliana.
Sammendrag
Winter conditions with seasonally frozen soils may have profound effects on soil structure and erodibility, and consequently for runoff and erosion. Such effects on aggregate stability are poorly documented for Nordic winter conditions. The purpose of this study was to quantify the effect of variable freeze-thaw cycles and soil moisture conditions on aggregate stability of three soils (silt, structured clay loam-clay A and levelled silty clay loam-clay B), which are representative of two erosion prone areas in southeastern Norway. A second purpose was to compare aggregate stabilities measured by the Norwegian standard procedure (rainfall simulator) and the more widely used wet-sieving procedure. Surface soil was sampled in autumn. Field moist soil was sieved into the fraction 1-4 mm and packed into cylinders. The water content of the soil was adjusted, corresponding to matric potentials of -0.75, -2 and -10 kPa. The soil cores were insulated and covered, and subjected to 0, 1, 3 or 6 freeze -thaw cycles: freezing at -15 °C for 24 h and thawing at 9 °C for 48 h. Aggregate stability was measured in a rainfall simulator (all soils) and a wet-sieving apparatus (silt and clay B). The rainfall stability of silt was found to be significantly lower than of clay A and clay B. Clay A and clay B had similar rainfall stabilities, even though it was expected that the artificially levelled clay B would have lower stability. Freezing and thawing decreased the rainfall stability of all soils, but the effect was more severe on the silt soil. There was no evident effect of water content on the stability, probably due to experimental limitations. The same effects were observed for wet-sieved soil, but the wet-sieving resulted in less aggregate breakdown than the rainfall simulator. Rainfall impact seemed to be more detrimental than wet-sieving on more unstable soil, that is, on silt soil and soil subjected to many freeze-thaw cycles. Such conditions are expected to occur frequently during field conditions in unstable winters.
Sammendrag
Innen utgangen av 2006 må Norge beslutte om de ønsker å velge å få kreditter for 3.4-aktiviteter under Kyoto-protokollen. Tiltak i jordbruket er en opsjon for slike aktiviteter. Valg av jordbruksaktiviteter må ta hensyn til potensiell gevinst i form av opptak av karbon i jord, men også synergier og konflikter med andre mål inkludert erosjonskontroll, biodiversitet, bevaring av kulturlandskap og matproduksjon. Skogplanting på dyrkede myrer vil kunne føre til reduserte CO2 og N2O-utslipp på lengre sikt, men denne aktiviteten faller inn under artikkel 3.3 (tilskoging) og kan ikke velges under artikkel 3.4.. Restaurering av dyrkede myrer tilbake til naturtilstanden (våtmark) og naturlig degradering vil også redusere utslippene av CO2 og N2O på lang sikt (over flere tiår) men metan-utslippene vil øke. Denne økningen kombinert med stor usikkerhet med hensyn til utslipp fra restaurerte og dyrkede myrer er det viktigste argumentet mot slik restaurering som klimatiltak. Satsing på dyrking av energivekster kan gi gevinster i form av binding av karbon i jord Effekten av tiltak i jordbruket innen 2012 (utgangen av første forpliktelsesperiode) er imidlertid små. Valg av jordbruksaktiviteter vil kreve bedre overvåkning av karbon i jord og utslipp av klimagasser som medfører store kostnader. I lys av de små gevinstene, store usikkerheter, mulig økning i utslipp av klimagasser og konflikter med andre miljø- og jordbrukspolitiske mål samt overvåkingskostnader, er det lite hensiktsmessig å velge jordbruksaktiviteter for første forpliktelsesperiode. Valg i senere forpliktelsesperioder forutsetter bedre kunnskap.
Forfattere
Aud Tennøy Jens Kværner Karl Idar GjerstadSammendrag
Uncertainty is almost unavoidable in environmental impact assessment (EIA) predictions, for complex and manifold reasons. In this paper, evidence is presented that decision-makers and other stakeholders are often not made aware that such uncertainty exists. Also, they are given only limited access to information about input data and the assumptions underlying predictions. It is argued that more emphasis should be given to improving the communication of uncertainty in EIA predictions and to making the prediction processes more transparent in order to improve EIA as a decision-aiding tool. The discussion is based on a study including 22 cases.
Forfattere
Jens Kværner Grete Swensen Lars ErikstadSammendrag
I tradisjonelle konsekvensutredninger (KU) blir miljøets sårbarhet betraktet kun i begrenset omfang i innledende faser hvor prosjektalternativer utarbeides. En alternativ KU-framgangsmåte, en integrert sårbarhetsmetode (ISM) som legger vekt på miljøets sårbarhet og alternativutvikling i tidlige faser i KU, er blitt utviklet og prøvd ut i pilotprosjekter av Statens vegvesen Buskerud, nå Statens vegvesen Region sør. Denne artikkelen gransker innholdet og bruken av sårbarhetsbegrepet i ISM-metoden og drøfter begrepet i KU-sammenheng. Arbeidets formål er å gi grunnlag for forslag om tilpasninger og forbedringer i sårbarhetskonseptet og dets anvendelse i KU. Sårbarhet og verdi bør betraktes som atskilte dimensjoner. Sårbarhet kan defineres som graden av følsomhet for miljøendringer ved eksterne påvirkninger. En slik definisjon er dekkende for hvordan begrepet vanligvis brukes i ulike fag, og kan også lett nyttes i fag med liten eller ingen tradisjon for sårbarhetsanalyser. Sårbarhetsbegrepet er best egnet for overordnete analyser og arealbetraktninger i grov, oversiktlig målestokk. Konseptet er særlig nyttig i tidlige faser av KU, der alternativer utformes og undersøkes. Ved å innføre oversiktsanalyser av miljøets sårbarhet i starten av KUprosessen, kan miljøhensyn få en mer framtredende stilling ved utarbeidingen av prosjektalternativer, samtidig som grunnlaget for avgrensing og presisering av undersøkelsesomfanget (scoping) bedres. Sårbarhetsbegrepet har vist seg nyttig i mange fag, men ulike fag har ulik erfaringsbakgrunn på dette feltet. I fag som landskapsarkitektur og hydrogeologi finnes komponenter som kan nyttes som grunnelementer i den videre utviklingen av en tverrfaglig metodikk. Økt fokus på utviklingsarbeid for helhetlige sårbarhetsanalyser på oversiktsnivå i KU anbefales. En videre utvikling av sårbarhetskriterier for forskjellige fagområder samt økt involvering av berørte parter i tidlige KU-faser tilrådes.