Variation in the seston C:N ratio of the Arctic Ocean and pan-Arctic shelves

Studying more than 3600 observations of particulate organic carbon (POC) and particulate organic nitrogen (PON), we evaluate the applicability of the classic Redfield C:N ratio (6.6) and the recently proposed Sterner ratio (8.3) for the Arctic Ocean and pan-Arctic shelves. The confidence intervals for C:N ranged from 6.43 to 8.82, while the average C:N ratio for all observations was 7.4. In general, neither the Redfield or Sterner ratios were applicable, with the Redfield ratio being too low and the Sterner ratio too high. On a regional basis, all northern high latitude regions had a C:N ratio significantly higher than the Redfield ratio, except the Arctic Ocean (6.6), Chukchi (6.4) and East Siberian (6.5) Seas. The latter two regions were influenced by nutrient-rich Pacific waters, and had a high fraction of autotrophic (i.e. algal-derived) material. The C:N ratios of the Laptev (7.9) and Kara (7.5) Seas were high, and had larger contributions of terrigenous material. The highest C:N ratios were in the North Water (8.7) and Northeast Water (8.0) polynyas, and these regions were more similar to the Sterner ratio. The C:N ratio varied between regions, and was significantly different between the Atlantic (6.7) and Arctic (7.9) influenced regions of the Barents Sea, while the Atlantic dominated regions (Norwegian, Greenland and Atlantic Barents Seas) were similar (6.7–7). All observations combined, and most individual regions, showed a pattern of decreasing C:N ratios with increasing seston concentrations. This meta-analysis has important implications for ecosystem modelling, as it demonstrated the striking temporal and spatial variability in C:N ratios and challenges the common assumption of a constant C:N ratio. The non-constant stoichiometry was believed to be caused by variable contributions of autotrophs, heterotrophs and detritus to seston, and a significant decrease in C:N ratios with increasing Chlorophyll a concentrations supports this view. This study adds support to the use of a power function model, where the exponent is system-specific, but we suggest a general Arctic relationship, where POC = 7.4 PON0.89

Seasonal variation in marine C:N:P stoichiometry: can the composition of seston explain stable Redfield ratios?

Seston is suspended particulate organic matter, comprising a mixture of autotrophic, heterotrophic and detrital material. Despite variable proportions of these components, marine seston often exhibits relatively small deviations from the Redfield ratio (C:N:P = 106:16:1). Two time-series from the Norwegian shelf in Skagerrak are used to identify drivers of the seasonal variation in seston elemental ratios. An ordination identified water mass characteristics and bloom dynamics as the most important drivers for determining C:N, while changes in nutrient concentrations and biomass were most important for the C:P and N:P relationships. There is no standardized method for determining the functional composition of seston and the fractions of POC, PON and PP associated with phytoplankton, therefore any such information has to be obtained by indirect means. In this study, a generalized linear model was used to differentiate between the live autotrophic and non-autotrophic sestonic fractions, and for both stations the non-autotrophic fractions dominated with respective annual means of 76 and 55%. This regression model approach builds on assumptions (e.g. constant POC:Chl-a ratio) and the robustness of the estimates were explored with a bootstrap analysis. In addition the autotrophic percentage calculated from the statistical model was compared with estimated phytoplankton carbon, and the two independent estimates of autotrophic percentage were comparable with similar seasonal cycles. The estimated C:nutrient ratios of live autotrophs were, in general, lower than Redfield, while the non-autotrophic C:nutrient ratios were higher than the live autotrophic ratios and above, or close to, the Redfield ratio. This is due to preferential remineralization of nutrients, and the P content mainly governed the difference between the sestonic fractions. Despite the seasonal variability in seston composition and the generally low contribution of autotrophic biomass, the variation observed in the total seston ratios was low compared to the variation found in dissolved and particulate pools. Sestonic C:N:P ratios close to the Redfield ratios should not be used as an indicator of phytoplankton physiological state, but could instead reflect varying contributions of sestonic fractions that sum up to an elemental ratio close to Redfield

Undersøkelser av avrenning fra sulfidholdige bergarter rundt Travparken/Sørlandshallen i Kristiansand kommune

I avrenningsvann fra områdene rundt Travparken og Sørlandshallen i Kristiansand er det funnet pH-verdier ned mot 3,4, sulfatkonsentrasjoner opp mot 1100 mg/l og konsentrasjoner av totalt aluminium på hele 70 mg/l. Forholdene kan tilbakeføres til utsprenging og oksidasjon av sulfidholdig berggrunn i området. Det er påviselig svovelkis tilstede i flere tynne lag innenfor en ca. 75 m bred sone, som strekker seg langs utbyggingsområdet. Grastjern, som ligger like nordøst for Travparken, er tydelig påvirket av utbyggingsområdet, med lav pH og høy aluminiumskonsentrasjon. I sjøaurebekken Åna, som ligger sør for området, ble det funnet pH-verdier på mellom 4,6 og 6.8 (5,5 i middel) og konsentrasjoner av relativt aluminium på mellom 0,14 og 0.29 mg/l i samme periode. Vannkvaliteten i Åna skilte seg med dette ikke vesentlig fra andre forsurende småvassdrag langs kysten av Sørlandet. Det er foreslått forurensningsbegrensende tiltak for igangsatt virksomhet i området og forebyggende tiltak knyttet til evt. nye utbyggingsprosjekter

Strategic analysis of Statoil’s international competitiveness

The oil industry is becoming increasingly competitive and with the rising nationalisation of resources, international oil companies are struggling to secure access to new oil and gas reserves. Statoil faces challenging tasks as it seeks to move from a protected home market to the extremely competitive international arena. Its ambitious internationalisation strategy relies heavily on getting access to new oil and gas reserves and large investments in new and leading technology. However, Statoil needs to consider different growth alternatives to increase its international competitiveness. In this paper, we recommend the proposed merger with Norsk Hydro to be the most politically feasible alternative. Nevertheless, we question whether this will give Statoil sufficient international strength required for the fiercely competitive international arena. Consequently, Statoil might have to consider other growth alternatives even after the merger or adapt its business model to better fit the needs and requirements of the industry today

Biogeochemical variations at the Porcupine Abyssal Plain sustained Observatory in the northeast Atlantic Ocean, from weekly to inter-annual timescales

We present high-resolution autonomous measurements of carbon dioxide partial pressure p(CO2) taken in situ at the Porcupine Abyssal Plain sustained Observatory (PAP-SO) in the northeast Atlantic (49° N, 16.5° W; water depth of 4850 m) for the period 2010–2012. Measurements of p(CO2) made at 30 m depth on a sensor frame are compared with other autonomous biogeochemical measurements at that depth (including chlorophyll a fluorescence and nitrate concentration data) to analyse weekly to seasonal controls on p(CO2) flux in the inter-gyre region of the North Atlantic. Comparisons are also made with in situ regional time series data from a ship of opportunity and mixed layer depth (MLD) measurements from profiling Argo floats. There is a persistent under-saturation of CO2 in surface waters throughout the year which gives rise to a perennial CO2 sink. Comparison with an earlier data set collected at the site (2003–2005) confirms seasonal and inter-annual changes in surface seawater chemistry. There is year-to-year variability in the timing of deep winter mixing and the intensity of the spring bloom.The 2010–2012 period shows an overall increase in p(CO2) values when compared to the 2003–2005 period as would be expected from increases due to anthropogenic CO2 emissions. The surface temperature, wind speed and MLD measurements are similar for both periods of time. Future work should incorporate daily CO2 flux measurements made using CO2 sensors at 1 m depth and the in situ wind speed data now available from the UK Met Office Buoy

Links between surface productivity and deep ocean particle flux at the Porcupine Abyssal Plain sustained observatory

In this study we present hydrography, biogeochemistry and sediment trap observations between 2003 and 2012 at Porcupine Abyssal Plain (PAP) sustained observatory in the Northeast Atlantic. The time series is valuable as it allows for investigation of the link between surface productivity and deep ocean carbon flux. The region is a perennial sink for CO2, with an average uptake of around 1.5 mmol m?2 day?1. The average monthly drawdowns of inorganic carbon and nitrogen were used to quantify the net community production (NCP) and new production. Seasonal NCP and new production were found to be 4.57 ± 0.85 mol C m?2 and 0.37 ± 0.14 mol N m?2, respectively. The C : N ratio was high (12) compared to the Redfield ratio (6.6), and the production calculated from carbon was higher than production calculated from nitrogen, which is indicative of carbon overconsumption. The export ratio and transfer efficiency were 16 and 4 %, respectively, and the site thereby showed high flux attenuation. Particle tracking was used to examine the source region of material in the sediment trap, and there was large variation in source regions, both between and within years. There were higher correlations between surface productivity and export flux when using the particle-tracking approach, than by comparing with the mean productivity in a 100 km box around the PAP site. However, the differences in correlation coefficients were not significant, and a longer time series is needed to draw conclusions on applying particle tracking in sediment trap analyses

Bolts detection and a combination of conventional and reinforcement learning based control of UR5 industrial robot

Master's thesis in Mechatronics (MAS500)The main objective of this paper is to investigate the possibilities for using reinforcement learning to control a UR-5 robot. The paper also looks at how well reinforcement learning works to control a UR-5 robot. These questions are answered by constructing of matlab and simulink programes. Based on different mathworks example programs and scripts. In this study, reinforcement learning only works in the situation it is trained to perform. The author believe that it could work better if it were given other configurations/parameters. This will still be an interesting subject for further studies. According to the research done in this paper, the conventional control have the best control accuracy

Investigating the Yield Rate of Office Real Estate in Oslo : A Vector Error Correction Approach

The yield rate of office real estate is little researched, yet it is an important figure for measuring rate of return. In this thesis, the drivers of the yield rate of office real estate in Oslo, Norway, has been investigated through the use of several relevant factors. Using the Johansen framework for cointegration to determine the existence of long term relationships, we construct a vector error correction model to analyse the effects of both real estate factors and macroeconomic factors. This enables the possibility of investigating both short term and long term drivers. We asses the effect of monetary supply, real rate, consumer expectation and office supply on yield, based on Nowaks (2021) model for the yield office rate in Warsaw, Poland. We also construct an alternative model, using gdp, real rate and office supply. Both models suggest a return to a long term equilibrium yield. The findings establish a connection of the real rate, consumer expectations, M2 and office supply to long run yield. In the short term, M2, consumer expectation and real rate are significant in explaining movements in the yield rate. The results do not indicate any significant effect due to the growth in GDP. We also find evidence of structural breaks in the yield rate, both from 2015, and from Ql 2020. Overall, our findings are in line with similar research conducted in other cities.nhhma

Kommunikasjon og elevers innsats i kroppsøving

Formålet med studien er å vise hvordan student og forsker i lærerutdanningen kan få innsikt i hvordan kommunikasjon innvirker på elevers innsats i kroppsøving. Studien bygger på en forundersøkelse, observasjon av en undervisningstime på ungdomstrinnet og påfølgende intervju med en masterstudent i pedagogikk som har kroppsøving som fordypning. Sentralt i intervjuet er refleksjon over kommunikasjonshandlinger som tale, lytte, kroppsspråk og artefakter. Undersøkelsen synliggjør at kommunikasjon i kroppsøving kan være sammensatt og krevende og at det ikke alltid er mulig å redegjøre for alle valg som tas. Samtidig viser den at det å studere kommunikasjon, på en planmessig systematisk måte, kan gi grunnlag for refleksjon og læring. Studenten oppgir blant annet at han har fått en mer nyansert forståelse av hvordan han kommuniserer og hva som påvirker innsats. Det gir han et bedre grunnlag når han skal planlegge, gjennomføre og vurdere framtidig undervisning.publishedVersio

Inkluderende læringsmiljøer

Denne kvalitative studien utforsker hvordan lærere kan skape inkluderende læringsmiljøer i møte med det kulturelle og etniske mangfoldet blant elevene. Studien er basert på intervjuer med lærere, og fokuserer på temaer som inkludering, mangfold, verdigrunnlaget for inkludering, og inkluderende praksiser. Gjennom analyse av intervjudataene identifiserte jeg fire gjentagende kategorier blant deltakerne. Disse inkluderer lærerens rolle, kommunikasjon og samarbeid, relasjonsbygging, samt behovet for støtte og ressurser. Resultatene av studien gir innsikt i hvordan lærere kan legge til rette for inkludering og skape et miljø som er positivt og støttende for alle elever, uavhengig av deres kulturelle og etniske bakgrunn