7 research outputs found

    Computer vision enables short- and long-term analysis of Lophelia pertusa polyp behaviour and colour from an underwater observatory.

    Get PDF
    Osterloff J, Nilssen I, Jarnegren J, Van Engeland T, Buhl-Mortensen P, Nattkemper TW. Computer vision enables short- and long-term analysis of Lophelia pertusa polyp behaviour and colour from an underwater observatory. Scientific reports. 2019;9(1): 6578.An array of sensors, including an HD camera mounted on a Fixed Underwater Observatory (FUO) were used to monitor a cold-water coral (Lophelia pertusa) reef in the Lofoten-Vesteralen area from April to November 2015. Image processing and deep learning enabled extraction of time series describing changes in coral colour and polyp activity (feeding). The image data was analysed together with data from the other sensors from the same period, to provide new insights into the short- and long-term dynamics in polyp features. The results indicate that diurnal variations and tidal current influenced polyp activity, by controlling the food supply. On a longer time-scale, the coral's tissue colour changed from white in the spring to slightly red during the summer months, which can be explained by a seasonal change in food supply. Our work shows, that using an effective integrative computational approach, the image time series is a new and rich source of information to understand and monitor the dynamics in underwater environments due to the high temporal resolution and coverage enabled with FUOs

    Environmental impacts of the deep-water oil and gas industry: a review to guide management strategies

    Get PDF
    The industrialization of the deep sea is expanding worldwide. Increasing oil and gas exploration activities in the absence of sufficient baseline data in deep-sea ecosystems has made environmental management challenging. Here, we review the types of activities that are associated with global offshore oil and gas development in water depths over 200 m, the typical impacts of these activities, some of the more extreme impacts of accidental oil and gas releases, and the current state of management in the major regions of offshore industrial activity including 18 exclusive economic zones. Direct impacts of infrastructure installation, including sediment resuspension and burial by seafloor anchors and pipelines, are typically restricted to a radius of ~100 m on from the installation on the seafloor. Discharges of water-based and low-toxicity oil-based drilling muds and produced water can extend over 2 km, while the ecological impacts at the population and community levels on the seafloor are most commonly on the order of 200–300 m from their source. These impacts may persist in the deep sea for many years and likely longer for its more fragile ecosystems, such as cold-water corals. This synthesis of information provides the basis for a series of recommendations for the management of offshore oil and gas development. An effective management strategy, aimed at minimizing risk of significant environmental harm, will typically encompass regulations of the activity itself (e.g., discharge practices, materials used), combined with spatial (e.g., avoidance rules and marine protected areas), and temporal measures (e.g., restricted activities during peak reproductive periods). Spatial management measures that encompass representatives of all of the regional deep-sea community types is important in this context. Implementation of these management strategies should consider minimum buffer zones to displace industrial activity beyond the range of typical impacts: at least 2 km from any discharge points and surface infrastructure and 200 m from seafloor infrastructure with no expected discharges. Although managing natural resources is, arguably, more challenging in deep-water environments, inclusion of these proven conservation tools contributes to robust environmental management strategies for oil and gas extraction in the deep sea.Copyright © 2016 Cordes, Jones, Schlacher, Amon, Bernardino, Brooke, Carney, DeLeo, Dunlop, Escobar-Briones, Gates, GĂ©nio, Gobin, Henry, Herrera, Hoyt, Joye, Kark, Mestre, Metaxas, Pfeifer, Sink, Sweetman and Witte. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

    Effects and recovery of larvae of the cold-water coral Lophelia pertusa (Desmophyllum pertusum) exposed to suspended bentonite, barite and drill cuttings

    Get PDF
    Fossil fuel drilling operations create sediment plumes and release waste materials into the ocean. These operations sometimes occur close to sensitive marine ecosystems, such as cold-water corals. While there have been several studies on the effects of energy industry activities on adult corals, there is very little information on potential impacts to their early life history stages. Larval stages of many marine organisms, including cold-water corals use cilia as a means of feeding and swimming, and if these structures become clogged with suspended particulates, the larvae may sink and be lost to the system. The objective of this study was to understand the response of Lophelia pertusa larvae to a different drilling waste components, and assess post-exposure recovery. Larvae of two ages (eight and 21 days) were exposed to a range of concentrations of bentonite, barite and drill cuttings. Larval sensitivity was assessed using the concentration at which 50% of the larvae showed behavioral effects (EC50) or lethal effects (LC50). Larvae showed greatest sensitivity to bentonite, followed by barite and drill cuttings, and also showed age-related responses that differed among the test materials. Post exposure recovery was variable across materials, with larvae exposed to bentonite having the lowest recovery rates. Understanding the vulnerability of early life history stages to human activities can help inform management strategies to preserve reproductive capacity of important marine ecosystems.publishedVersio

    Electricity spot price : May the changes be explained by fundamental factors?

    No full text
    Denna uppsats undersöker vilka faktorer som pĂ„verkar förĂ€ndringar i elspotpriset pĂ„ Nord Pool. Avsikten Ă€r att resultatet skall ligga till grund för en prisuppskattningsmodell för Lunds Energikoncernen AB. Faktorerna bestĂ€mdes genom en förstudie dĂ€r viktig litteratur om elmarknaden studerades samt samtal med Lunds Energikoncernen AB. De faktorer som undersöks i denna uppsats Ă€r priset pĂ„ utslĂ€ppsrĂ€tter, nettoexport till Tysk-land, temperatur, nederbörd, priset pĂ„ kol och villaolja samt konjunkturutveckling i Sve-rige. Undersökningen av faktorerna bestod av en multipel regressionsanalys med undersökta faktorer som oberoende variabler och elspotpriset pĂ„ Nord Pool som den beroende va-riabeln. Faktorerna blev indelade i tvĂ„ grupper dagsgruppen och mĂ„nadsgruppen, grunden till uppdelningen Ă€r som namnen antyder att statistiken var observerad dygnsvis och mĂ„-nadsvis. I mĂ„nadsgruppen ingick nettoexport till Tyskland, priset pĂ„ kol, villaolja samt konjunktur och ur denna grupp visade sig endast nettoexport till Tyskland ha statistisk signifikans. I dagsgruppen ingick de faktorer som oftast omnĂ€mns i litteraturen som prispĂ„verkande, nĂ€mligen temperatur, nederbörd och priset pĂ„ utslĂ€ppsrĂ€tter. Dock visade sig nederbörd inte ha nĂ„gon statistisk signifikant pĂ„verkan pĂ„ elpriset varvid ett nytt test pĂ„ ett nytt sta-tistiskt underlag gjordes för nederbörden vilket gav samma resultat, vilket var förvĂ„nan-de. BĂ„de temperatur och priset pĂ„ utslĂ€ppsrĂ€tter visade sig dock ha statistisk signifikans och detta intygades genom ytterligare test. HĂ€refter gjordes en regressionsanalys med de faktorer visat sig ha statistisk signifikans som oberoende variabler, det vill sĂ€ga nettoexport till Tyskland, temperatur och priset pĂ„ utslĂ€ppsrĂ€tter gentemot elpriset som beroende variabel. Denna enkla prognosmodell kunde förklara sĂ„ mycket som 70 procent av förĂ€ndringarna i elpriset. Slutligen diskuteras prognosmodellen av författarna, en brist Ă€r bland annat att den inte kan förutse hastiga förĂ€ndringar i priset och att den behöver kalibreras om nĂ€r den nya handelsperioden för utslĂ€ppsrĂ€tter sĂ€tter i gĂ„ng 2008. Dock gav analysen positiva signa-ler om att det kan vara möjligt att basera en prismodell pĂ„ el med de faktorer som har störst inverkan pĂ„ den dyraste produktionsteknologi som oftast anvĂ€nds i elproduktio-nen, dĂ„ elmarknaden i praktiken tillĂ€mpar marginalprissĂ€ttning.This thesis examines which factors that drive changes in the electricity spot price on the Nordic energy exchange Nord Pool. The intention with this thesis is to support Lunds Energikoncernen AB to create a pricing model. The factors were determined though a pre-study in which important literature on the electricity market were studied and inter-views with Lunds Energikoncernen AB. The examined factors in this thesis are; the price of emission allowances, net export to Germany, temperature, precipitation, the prices of coal and burning oil and Sweden’s business cycle. The factor study was a multiple regression analysis with the above factors as independ-ent variables and the spot price of electricity on Nord Pool as the dependent. The fac-tors were divided in two groups, the day group and the month group, the two groups were decided due to statistical observations. The factors from the former group had daily ob-served data and the latter monthly data. The month group included net exchange with Germany, oil and coal prices and the business cycle which are measured in GDP. In the month group only the net exchange with Germany had statistical significance and was used in further studies. In the day group the factors that are mostly discussed in the literature to impact on the electricity price namely, temperature, precipitation, and the price of emission allowances. As it, some what unexpected, turned out the precipitation did not have a statistical affect on the electricity price. The authors chose to carry out another analysis with precipita-tion from another area, neither this result had statistical significance. However, both the temperature and the price of emission allowances did have a statistical significant effect on the electricity price, the result were verified through one more round of analysis. After the two initial analyses, a regression analysis with the three factors that had statis-tical significance and the electricity price were used in a final analysis. The factors in-cluded in this regression were net exchange with Germany, temperature and the price of emission allowances. This, somewhat, simple forecasting model explained as much as 70 percent of the changes in the electricity spot price. At last the forecasting model were discussed by the authors who identified two major weaknesses, first the model may not explain sudden changes in the electricity price, and second the model has to be re-calibrated when the next trading period for emission al-lowances starts in early 2008. However the analysis did indicate that it might be possible to base an electricity price forecasting model on the factors that affects the most expen-sive production facility that are used to create energy, since the electricity market prac-tice marginal pricing

    Corporate Bonds : Analyzing the availability of the Swedish bond market

    No full text
    In the past, the Swedish bond market has been distinguished for its illiquidity and difficulties with retrieving information. This is the starting point of our thesis and the purpose is to analyze and describe the availability of the present corporate bond market for manufacturing firms in Sweden. In order to fulfill the purpose, a qualitative method was used and interviews with different operators of the market were conducted. Our respondents were sampled from large issuing companies, the major intermediaries and companies that have not tried bonds as a financing tool. To fulfill our purpose, we analyzed subjects as credit rating, capital market segmentation, regulations and volume. We came to the conclusion that the Swedish corporate bond market is somewhat underdeveloped. This is due to the lack of public information regarding the bonds, such as prices, outstanding bonds and interest rates. The availability for already active companies is good, mainly due to the important role the intermediaries play. The regulations set by authorities do not have great effect on the large companies in general, since they issue large amounts, the cost associated with the regulations do not affect them in a considerable way. One could rather see a positive side with the regulations, for example the increase of foreign issuers that entered the market the last couple of years and hence increasing the liquidity. A credit rating is sometimes beneficial but not always, it is not a necessity to enter the bond market. As a matter of fact, it seems like volume is the most important reason to why medium-sized companies have limited access to the market. Since the minimum recommended volume to issue is 50 million SEK, many companies are excluded due to lack of financing need. Another important factor concerning medium-sized companies is that they do not have sufficient experience, knowledge or interest in the bond market. There are probably companies that would like to enter the bond market, who do not have the opportunity to do so, but this do not have anything to do with the lack of credit rating, rather the high cost associated with it. The conclusion drawn is that it is hard to compare small and medium-sized companies with large already established actors. This is due to different need of capital and overall knowledge about the debt market

    Effects and recovery of larvae of the cold-water coral Lophelia pertusa (Desmophyllum pertusum) exposed to suspended bentonite, barite and drill cuttings

    Get PDF
    Fossil fuel drilling operations create sediment plumes and release waste materials into the ocean. These operations sometimes occur close to sensitive marine ecosystems, such as cold-water corals. While there have been several studies on the effects of energy industry activities on adult corals, there is very little information on potential impacts to their early life history stages. Larval stages of many marine organisms, including cold-water corals use cilia as a means of feeding and swimming, and if these structures become clogged with suspended particulates, the larvae may sink and be lost to the system. The objective of this study was to understand the response of Lophelia pertusa larvae to a different drilling waste components, and assess post-exposure recovery. Larvae of two ages (eight and 21 days) were exposed to a range of concentrations of bentonite, barite and drill cuttings. Larval sensitivity was assessed using the concentration at which 50% of the larvae showed behavioral effects (EC50) or lethal effects (LC50). Larvae showed greatest sensitivity to bentonite, followed by barite and drill cuttings, and also showed age-related responses that differed among the test materials. Post exposure recovery was variable across materials, with larvae exposed to bentonite having the lowest recovery rates. Understanding the vulnerability of early life history stages to human activities can help inform management strategies to preserve reproductive capacity of important marine ecosystems

    Heterogeneous energetic pathways and carbon sources on deep eastern Mediterranean cold seep communities

    No full text
    Cold seep communities in the Mediterranean Sea have only been discovered two decades ago, and their trophic ecology has been the subject of very few studies. We investigated the benthic food web of two deep chemosynthesis-based ecosystems on the Napoli and Amsterdam mud volcanoes (MVs) in the eastern Mediterranean Sea (similar to 2,000 m depth). Seeping methane has been detected at the surface of both MVs during pioneering cruises and has been hypothesised to be assimilated by benthic fauna as observed in other oceans' margins. Given the extreme oligotrophic character of the eastern Mediterranean Sea, we a priori expected that chemosynthetic food sources, especially methane-derived carbon (MDC), played a major trophic role in these deep seep communities relative to what has been observed in other seep systems worldwide. We aimed at unravelling the trophic relationships on Napoli and Amsterdam MVs through the analysis of carbon, nitrogen and sulphur isotopes both in the dominant benthic invertebrates including the small endofauna (300 mu m < size < 1 cm) and in the sedimented organic matter. In particular, we assessed the fraction of MDC in the tissue of several heterotrophic and symbiotic species. Low mean delta(34)S and delta(13)C values (0.4 +/- A 4.8aEuro degrees and -31.6 +/- A 5.7aEuro degrees, respectively) obtained for mega- and macrofauna suggested that the investigated benthic food webs are virtually exclusively fuelled by carbon of chemosynthetic origin. A few grazer invertebrates (delta(34)S up to 11aEuro degrees) depart from this trend and could complement their diet with sedimented and decayed phytoplanktonic organic matter. Faunal delta(13)C values indicated that the oxidation of sulphur is likely the predominant energetic pathway for biosynthesis on both MVs. Nevertheless, mytilid bivalves and small capitellid, ampharetid and spionid polychaetes were (13)C-depleted (delta(13)C < -37aEuro degrees) in a way indicating they assimilated a significant portion of MDC. For these later heterotrophic species, MDC ranged between 21 and 31% (lower estimates) and 97 and 100% (upper estimates). However, our results highlighted that the origin of assimilated carbon may be complex for some symbiotic species. The vestimentiferan tubeworm Lamellibrachia sp., which exclusively depends on its sulphur-oxidising endosymbionts, showed a similar to 20aEuro degrees inter-individual delta(13)C variability on a very small spatial scale (< 1 m) at the summit of Napoli MV. This mostly reflects the variable isotopic composition of pore-water-dissolved inorganic carbon (DIC) and evidenced that tubeworms (and subsequently their endosymbionts) uptake DIC derived from multiple methane oxidation processes in varying proportions. The lower and upper MDC estimates for the vestimentum of Napoli's individuals were 11-38 and 21-73%, respectively. Finally, data on trophic ecology of Napoli and Amsterdam MVs clearly corroborate previous geophysical results evidencing the spatial heterogeneity of Mediterranean MV environmental conditions.IFREMERHERMES - 511234ANR DeepOases - ANR06BDV00
    corecore