110 research outputs found

    Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord

    Get PDF
    The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world oceans. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated pCO2 are yet lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 ÎŒatm to 1420 ÎŒatm. Samples were taken weekly over a six-week period with an Apstein net (55 ÎŒm mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analyzed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (cirripeds, polychaetes, bivalves, gastropod, and decapods) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms; the pCO2 had no significant effect on the overall community structure. However, single taxa responded to elevated CO2 concentrations. The ratio of cirripedia nauplii to cypris larvae, the next developmental stage, in the sediment traps averaged over the entire experiment increased with pCO2 and this suggests that increased pCO2 may have delayed their development. Also, the number of bivalves, averaged over the experimental period, decreased significantly with increasing pCO2. The nature of the CO2 effect, either direct or indirect, remains open and needs to be addressed in future

    From polar night to midnight sun: Diel vertical migration, metabolism and biogeochemical role of zooplankton in a high Arctic fjord (Kongsfjorden, Svalbard)

    Get PDF
    Source at http://dx.doi.org/10.1002/lno.10519 Zooplankton vertical migration enhances the efficiency of the ocean biological pump by translocating carbon (C) and nitrogen (N) below the mixed layer through respiration and excretion at depth. We measured C and N active transport due to diel vertical migration (DVM) in a Svalbard fjord at 79°N. Multifrequency analysis of backscatter data from an Acoustic Zooplankton Fish Profiler moored from January to September 2014, combined with plankton net data, showed that Thysanoessa spp. euphausiids made up > 90% of the diel migrant biomass. Classical synchronous DVM occurred before and after the phytoplankton bloom, leading to a mismatch with intensive primary production during the midnight sun. Zooplankton DVM resulted in C respiration of 0.9 g m−2 and ammonium excretion of 0.18 g N m−2 below 82 m depth between February and April, and 0.2 g C m−2 and 0.04 g N m−2 from 11 August to 9 September, representing > 25% and > 33% of sinking flux of particulate organic carbon and nitrogen, respectively. Such contribution of DVM active transport to the biological pump in this high-Arctic location is consistent with previous measurements in several equatorial to subarctic oceanic systems of the World Ocean. Climate warming is expected to result in tighter coupling between DVM and bloom periods, stronger stratification of the Barents Sea, and northward advection of boreal euphausiids. This may increase the role of DVM in the functioning of the biological pump on the Atlantic side of the Arctic Ocean, particularly where euphausiids are or will be prevalent in the zooplankton community

    Opposition and dissidence: two modes of resistance against international rule

    Full text link
    Rule is commonly conceptualized with reference to the compliance it invokes. In this article, we propose a conception of rule via the practice of resistance instead. In contrast to liberal approaches, we stress the possibility of illegitimate rule, and, as opposed to critical approaches, the possibility of legitimate authority. In the international realm, forms of rule and the changes they undergo can thus be reconstructed in terms of the resistance they provoke. To this end, we distinguish between two types of resistance - opposition and dissidence - in order to demonstrate how resistance and rule imply each other. We draw on two case studies of resistance in and to international institutions to illustrate the relationship between rule and resistance and close with a discussion of the normative implications of such a conceptualization

    On regional security governance once again: how analysis of the Southern Caucasus can advance the concept

    Get PDF
    Already introduced to the academic and political debate some years ago, the concept of “security governance” still needs to be clarified. In particular, four main shortcomings need to be overcome to make the concept more useful for an assessment of current security dynamics: in the first place, attention has been devoted more to “governance” than to “security”, while failing to consider the role of the understandings and perceptions of the actors involved in the governance system. Second, the literature on the actors (governmental or not) involved is still fragmented. Third, the literature on security governance has too often been detached from reflections on regionalism, while it would be useful to further explore the relationship between cognitive definitions of regional and security dynamics. Fourth, the literature has predominantly focused on Europe and the transatlantic area, overlooking processes of “region-building” in security terms in other “unexpected” geographical spaces. After proposing avenues to overcome the current gaps in the literature, the Southern Caucasus is chosen as a case study to show the different instances of security governance emerging, thanks to definitions of the region in security terms that have involved regional and external actors, of a state and non-state nature

    Panel-based Assessment of Ecosystem Condition of Norwegian Barents Sea Shelf Ecosystems

    Get PDF
    The System for Assessment of Ecological Condition, coordinated by the Norwegian Environment Agency, is intended to form the foundation for evidence-based assessments of the ecological condition of Norwegian terrestrial and marine ecosystems not covered by the EU Water Framework Directive. The reference condition is defined as “intact ecosystems”, i.e., a condition that is largely unimpacted by modern industrial anthropogenic activities. An ecosystem in good ecological condition is defined as a system that does not deviate substantially from this reference condition in structure, functions or productivity. This means that, in practice, what is assessed here is the extent to which an ecosystem is impacted by anthropogenic drivers. This report describes the first operational assessment of the ecological condition of Norwegian Arctic and Sub-Arctic marine shelf ecosystems in the Barents Sea. The assessment method employed is the Panel-based Assessment of Ecosystem Condition (PAEC1), and the current assessment has considered to what extent the Barents Sea shelf ecosystems deviate from the reference condition2 by evaluating change trajectories.Panel-based Assessment of Ecosystem Condition of Norwegian Barents Sea Shelf EcosystemspublishedVersio

    Panel-based Assessment of Ecosystem Condition of Norwegian Barents Sea Shelf Ecosystems

    Get PDF
    The System for Assessment of Ecological Condition, coordinated by the Norwegian Environment Agency, is intended to form the foundation for evidence-based assessments of the ecological condition of Norwegian terrestrial and marine ecosystems not covered by the EU Water Framework Directive. The reference condition is defined as “intact ecosystems”, i.e., a condition that is largely unimpacted by modern industrial anthropogenic activities. An ecosystem in good ecological condition is defined as a system that does not deviate substantially from this reference condition in structure, functions or productivity. This means that, in practice, what is assessed here is the extent to which an ecosystem is impacted by anthropogenic drivers. This report describes the first operational assessment of the ecological condition of Norwegian Arctic and Sub-Arctic marine shelf ecosystems in the Barents Sea. The assessment method employed is the Panel-based Assessment of Ecosystem Condition (PAEC1), and the current assessment has considered to what extent the Barents Sea shelf ecosystems deviate from the reference condition2 by evaluating change trajectories

    OVERHEATED SECURITY? The Securitisation of Climate Change and the Governmentalisation of Security

    Get PDF
    Since the mid-2000s, climate change has become one of the defining security issues in political as well as academic debates and amongst others has repeatedly been discussed in the UN Security Council and countless high level government reports in various countries. Beyond the question whether the characterisation as ‘security issue’ is backed up by any robust empirical findings, this begs the question whether the ‘securitisation’ of climate change itself has had tangible political consequences. Moreover, within this research area there is still a lively discussion about which security conceptions apply, how to conceptualise (successful) securitisation and whether it is a (politically and normatively) desirable approach to deal with climate change. The aim of this dissertation is to shed light on these issues and particularly to contribute to a more thorough understanding of different forms or ‘discourses’ of securitisation and their political effects on a theoretical and empirical level. Theoretically, it conceptualises securitisation as resting on different forms of power, which are derived from Michel Foucault’s governmentality lectures. The main argument is that this framework allows me to better capture the ambiguous and diverse variants of securitisation and the ever-changing concept of security as well as to come to a more thorough understanding of the political consequences and powerful effects of constructing issues in terms of security. Empirically, the thesis looks at three country cases, namely the United States, Germany and Mexico. This comparative angle allows me to go beyond the existing literature on the securitisation of climate change that mostly looks at the global level, and to come to a more comprehensive and detailed understanding of different climate security discourses and their political consequences. Concerning the main results, the thesis finds that climate change has indeed been securitised very differently in the three countries and thus has facilitated diverse political consequences. These range from an incorporation of climate change into the defence sector in the US, the legitimisation of far-reaching climate policies in Germany, to the integration of climate change into several civil protection and agricultural insurance schemes in Mexico. Moreover, resting on different forms of power, the securitisation of climate change has played a key role in constructing specific actors and forms of knowledge as legitimate as well as in shaping certain identities in the face of the dangers of climate change. From a normative perspective, neither of these political consequences is purely good or bad but highly ambiguous and necessitates a careful, contextual assessment
    • 

    corecore