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  • 11
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    The physiological response of the Arctic key species, Boreogadus saida, to environmental hypoxia: critical oxygen level and swimming performance (2020)
    In:  EPIC379 p.
    Details
    Publication Date: 2020-06-29
    Description: Since the beginning of the industrialization, uncontrolled greenhouse gas emission led to a distinct temperature increase on earth. Arctic environments are projected to experience the most severe changes due to climate change. Higher atmospheric temperatures caused already various environmental changes, for example a decrease in Arctic sea ice of 49 % (1979-2000) and increasing carbon dioxide concentrations which reduced the sea surface pH. A reduced sea ice formation will strengthen the summer stratification of warm, oxygen poor on top of cold, oxygen rich water masses, which may consequently cause local hypoxia in ground water layers. As a result, the deep cold water layers do not receive oxygen-rich water and oxygen consumption extends over more than one season. This can lead to local hypoxia in the ground water layers of the protected fjords. Especially endangered of this long-lasting stratification in winter are the deep fjord systems of the Svalbard archipelago. In this region, the change of winter temperatures from 1961–90 corresponded to an increase of 0.6 °C per decade. Corresponding, an additional increase of 0.9 °C per decade is projected for 2071–2100. Thus, the present study investigates the hypoxia tolerance of Polar cod, Boreogadus saida, one of the main Arctic key species. Therefore, different performance parameters were determined. The respiratory capacity as well as the swimming performance under declining oxygen concentrations were measured in two different experimental setups. A sample size of 30 Polar cod with similar body length and weight were chosen. All individuals were used several times during the experiments. First, the routine (RMR) and standard metabolic rate (SMR) were determined via flow-through respirometry. The calculated SMR for Polar cod accounted 0.44 μmol O2/g∙h. The RMR followed an oxygen regulating pattern, indicating that aerobic metabolic pathways such as lipid oxidation were used, rather than anaerobic pathways. This implies a relatively small contribution of anaerobic metabolism to the energy production in B. saida. This was confirmed in the swim tunnel experiments. However, Ugait (the speed at which the fish changed to anaerobically fuelled swimming) was not significantly affected by hypoxia, the total number of bursts (p = 0.025) and total active swimming time (p = 0.017) significantly decreased with decreasing oxygen saturation. The loss of anaerobic swimming capacity due to hypoxia may endanger this species in regard to predator-prey-interactions and loss of escape reactions. Under exercise Polar cod was able to up-regulate its maximum metabolic rate (MMR) until a threshold of 45 % PO2 was reached. Afterwards, the oxygen consumption significantly decreased with decreasing oxygen concentrations. Throughout both experiments neither RMR nor MMR decreased below SMR level. Furthermore, the present study revealed that Polar cod is an extremely hypoxia tolerant fish species, which is able to handle oxygen saturations down to a Pcrit of 4.81 % PO2. This outstanding capability could give the otherwise rather disadvantaged fish species an advantage under changing climate conditions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Thesis , notRev
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  • 12
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    The Importance of Bottom-Up Approaches to International Cooperation in Ocean Science: The Iron Story (2020)
    In:  EPIC3Oceanography, 33(1), pp. 11-15, ISSN: 10428275
    Details
    Publication Date: 2020-04-02
    Description: In the past decade, several international efforts developed to address urgent societal issues have been identified through, for example, the United Nations 2030 Agenda for Sustainable Development and its associated 17 Sustainable Development Goals and the United Nations Decade of Ocean Science for Sustainable Development (2021–2030). These worthy efforts will bring ocean science research to bear on problems that need attention in the short term. Yet, there is also a continuing need at the international level to support fundamental ocean science and solve methodological issues over the long term. While knowledge needs to be created before it can be applied, national and international science strategy documents often do not mention the need to maintain the health of the basic science enterprise. We argue that international organizations designed to create knowledge must be maintained and strengthened to inform decisions on how to allocate funding for generating knowledge about the ocean versus solving ocean problems. We use the ocean iron cycle as an example of the benefits of using such a “bottom-up” approach to knowledge generation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 13
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    Geochemistry and Microbiology Predict Environmental Niches With Conditions Favoring Potential Microbial Activity in the Bakken Shale (2020)
    In:  Frontiers in Microbiology
    Details
    Publication Date: 2020-12-14
    Description: The Bakken Shale and underlying Three Forks Formation is an important oil and gas reservoir in the United States. The hydrocarbon resources in this region are accessible using unconventional oil and gas extraction methods, including horizontal drilling and hydraulic fracturing. However, the geochemistry and microbiology of this region are not well understood, although they are known to have major implications for productivity and water management. In this study, we analyzed the produced water from 14 unconventional wells in the Bakken Shale using geochemical measurements, quantitative PCR (qPCR), and 16S rRNA gene sequencing with the overall goal of understanding the complex dynamics present in hydraulically fractured wells. Bakken Shale produced waters from this study exhibit high measurements of total dissolved solids (TDS). These conditions inhibit microbial growth, such that all samples had low microbial loads except for one sample (well 11), which had lower TDS concentrations and higher 16S rRNA gene copies. Our produced water samples had elevated chloride concentrations typical of other Bakken waters. However, they also contained a sulfate concentration trend that suggested higher occurrence of sulfate reduction, especially in wells 11 and 18. The unique geochemistry and microbial loads recorded for wells 11 and 18 suggest that the heterogeneous nature of the producing formation can provide environmental niches with conditions conducive for microbial growth. This was supported by strong correlations between the produced water microbial community and the associated geochemical parameters including sodium, chloride, and sulfate concentrations. The produced water microbial community was dominated by 19 bacterial families, all of which have previously been associated with hydrocarbon-reservoirs. These families include Halanaerobiaceae, Pseudomonadaceae, and Desulfohalobiaceae which are often associated with thiosulfate reduction, biofilm production, and sulfate reduction, respectively. Notably, well 11 was dominated by sulfate reducers. Our findings expand the current understanding of microbial life in the Bakken region and provide new insights into how the unique produced water conditions shape microbial communities. Finally, our analysis suggests that produced water chemistry is tightly linked with microbiota in the Bakken Shale and shows that additional research efforts that incorporate coupled microbial and geochemical datasets are necessary to understand this ecosystem.
    Type: info:eu-repo/semantics/article
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  • 14
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    Aplicación de modelos hidrodinámicos para evaluar la dinámica del oleaje y el nivel del mar en el sistema deltaico del río mira (Colombia): bases para la gestión costera (2020)
    Details
    Publication Date: 2021-05-19
    Description: Para evaluar el comportamiento del sistema deltaico del río Mira se implementaron modelos de: (1) propagación de marea y (2) propagación y refracción de oleaje. Para analizar la propagación mareal se procesaron series sintéticas de nivel del mar generadas por modelos numéricos globales y la serie histórica del mareógrafo de Buenaventura (1953-2000). Para caracterizar la dinámica del oleaje se analizó y propagó una serie de oleaje (1979–2000) en aguas profundas con información de altura de ola significante (HS), periodo pico (TP) y dirección dominante (DP). La marea es semi-diurna con rangos promedio de 2.46 y 2.58m. El oleaje proviene principalmente del SW–SWW, con alturas significativas que varían entre 0.25 y 2.23m, y periodos pico entre 5 y 23s. La implementación de modelos numéricos permite evaluar escenarios oceanográficos como base para la toma de decisiones en un contexto de manejo integral de zonas costeras.
    Description: Tide propagation, and wave propagation-refraction numerical models were implemented to asses Mira’s River delta system dynamics. In this study we analyze tide propagation by looking at sea level synthetic data and records from Buenaventura tide gauge (1953-2000). Wave data from deep waters (1979-2000), including significant wave height (HS ), peak period (TP ) and dominant direction (DP ) records, was evaluated and propagated to shallow waters to characterize wave dynamics. Tide’s behavior is semi-diurnal with mean ranges of 2.46 y 2.58m. Waves comes from SW – SWW mainly, with significant wave height between 0.25 and 2.23m., and peak periods from of 5 to 23 s. The implementation of numerical models allows the evaluation of different oceanographic scenarios as a ground for costal management decision-making processes
    Description: Published
    Keywords: Modelos hidrodinámicos ; Nivel del mar ; Parámetros de oleaje ; Procesos hidrodinámicos ; ASFA_2015::G::Geodynamics ; ASFA_2015::H::Hydrology ; ASFA_2015::P::Physical oceanography
    Repository Name: AquaDocs
    Type: Journal Contribution , Not Known
    Format: Pp.31-48
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  • 15
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    The behavioral turn in flood risk management, its assumptions and potential implications (2020)
    In:  WIREs Water
    Details
    Publication Date: 2020-12-14
    Description: Sections PDFPDF Tools Share Abstract Recent policy changes highlight the need for citizens to take adaptive actions to reduce flood‐related impacts. Here, we argue that these changes represent a wider behavioral turn in flood risk management (FRM). The behavioral turn is based on three fundamental assumptions: first, that the motivations of citizens to take adaptive actions can be well understood so that these motivations can be targeted in the practice of FRM; second, that private adaptive measures and actions are effective in reducing flood risk; and third, that individuals have the capacities to implement such measures. We assess the extent to which the assumptions can be supported by empirical evidence. We do this by engaging with three intellectual catchments. We turn to research by psychologists and other behavioral scientists which focus on the sociopsychological factors which influence individual motivations (Assumption 1). We engage with economists, engineers, and quantitative risk analysts who explore the extent to which individuals can reduce flood related impacts by quantifying the effectiveness and efficiency of household‐level adaptive measures (Assumption 2). We converse with human geographers and sociologists who explore the types of capacities households require to adapt to and cope with threatening events (Assumption 3). We believe that an investigation of the behavioral turn is important because if the outlined assumptions do not hold, there is a risk of creating and strengthening inequalities in FRM. Therefore, we outline the current intellectual and empirical knowledge as well as future research needs. Generally, we argue that more collaboration across intellectual catchments is needed, that future research should be more theoretically grounded and become methodologically more rigorous and at the same time focus more explicitly on the normative underpinnings of the behavioral turn.
    Type: info:eu-repo/semantics/article
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  • 16
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    Impact Forecasting to Support Emergency Management of Natural Hazards (2020)
    In:  Reviews of Geophysics
    Details
    Publication Date: 2020-12-14
    Description: Forecasting and early warning systems are important investments to protect lives, properties and livelihood. While early warning systems are frequently used to predict the magnitude, location and timing of potentially damaging events, these systems rarely provide impact estimates, such as the expected amount and distribution of physical damage, human consequences, disruption of services or financial loss. Complementing early warning systems with impact forecasts has a two‐fold advantage: it would provide decision makers with richer information to take informed decisions about emergency measures, and focus the attention of different disciplines on a common target. This would allow capitalizing on synergies between different disciplines and boosting the development of multi‐hazard early warning systems. This review discusses the state‐of‐the‐art in impact forecasting for a wide range of natural hazards. We outline the added value of impact‐based warnings compared to hazard forecasting for the emergency phase, indicate challenges and pitfalls, and synthesize the review results across hazard types most relevant for Europe.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 17
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    Global Drivers on Southern Ocean Ecosystems: Changing Physical Environments and Anthropogenic Pressures in an Earth System (2020)
    Frontiersin
    In:  EPIC3Frontiers in Marine Science, Frontiersin, 7(547188), pp. 1-23
    Details
    Publication Date: 2020-12-29
    Description: This manuscript assess the current and expected future global drivers of Southern Ocean (SO) ecosystems. Atmospheric ozone depletion over the Antarctic since the 1970s, has been a key driver, resulting in springtime cooling of the stratosphere and intensification of the polar vortex, increasing the frequency of positive phases of the Southern Annular Mode (SAM). This increases warm air-flow over the East Pacific sector (Western Antarctic Peninsula) and cold air flow over the West Pacific sector. SAM as well as El Niño Southern Oscillation events also affect the Amundsen Sea Low leading to either positive or negative sea ice anomalies in the west and east Pacific sectors, respectively. This strengthening of westerly winds is also linked to shoaling of deep warmer water onto the continental shelves, particularly in the East Pacific and Atlantic sectors. Air and ocean warming has led to changes in the cryosphere, with glacial and ice sheet melting in both sectors, opening up new ice free areas to biological productivity, but increasing seafloor disturbance by icebergs. The increased melting is correlated with a salinity decrease particularly in the surface 100 m. Such processes could increase the availability of iron, which is currently limiting primary production over much of the SO. Increasing CO2 is one of the most important SO anthropogenic drivers and is likely to affect marine ecosystems in the coming decades. While levels of many pollutants are lower than elsewhere, persistent organic pollutants (POPs) and plastics have all been detected in the SO, with concentrations likely enhanced by migratory species. With increased marine traffic and weakening of ocean barriers the risk of the establishment of non-indigenous species is increased. The continued recovery of the ozone hole creates uncertainty over the reversal in sea ice trends, especially in the light of the abrupt transition from record high to record low Antarctic sea ice extent since spring 2016. The current rate of change in physical and anthropogenic drivers is certain to impact the Marine Ecosystem Assessment of the Southern Ocean (MEASO) region in the near future and will have a wide range of impacts across the marine ecosystem.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 18
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    The benefits of bivalve reef restoration: a global synthesis of underrepresented species. (2020)
    JOHN WILEY & SONS LTD
    In:  EPIC3Aquatic Conservation-Marine and Freshwater Ecosystems, JOHN WILEY & SONS LTD, 30(11), pp. 2050-2065, ISSN: 1052-7613
    Details
    Publication Date: 2020-11-17
    Description: 1.Bivalve habitat restoration is growing in geographic extent and scale globally. While addressing the wide-scale loss of these biogenic habitats is still a key motivation behind restoration efforts, increasingly stakeholders and funders are drawn to shellfish restoration for the many ecosystem services these habitats provide. 2.There is clear evidence for the provision of ecosystem services from species targeted for restoration in the USA, in particular Crassostrea virginica. Ecosystem services remain, however, largely unquantified or even undescribed for the majority of other species targeted for restoration. 3.A structured review of the literature was undertaken and supplemented by expert knowledge, to identify which ecosystem services are documented in the following other bivalve species targeted for restoration: Ostrea edulis, Ostrea angasi, Crassostrea rhizophorae, Perna canaliculus, Modiolus modiolus, Mytilus edulis, Mytilus platensis, Crassostrea gigas, Ostrea denselamellosa, Crassostrea ariakensis, and Crassostrea sikamea. 4.Key knowledge gaps in quantifying ecosystem services and the ecosystem engineering properties of habitat building bivalves contributing to the provision of ecosystem services were identified. Ecosystem services with the potential to be widely applicable across bivalve habitat building species were identified. 5.While there is evidence that many of the ecosystem engineering properties which underpin the provision of ecosystem services are universal, the degree to which services are provided will vary between locations and species. Species-specific, in situ, studies are needed in order to avoid the inappropriate transfer of the ecosystem service delivery between locations, and to further build support and understanding for these emerging targets of restoration.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 19
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    Water demand scenarios for electricity generation at the global and regional levels (2020)
    Details
    Publication Date: 2021-05-18
    Description: Electricity generation requires water. With the global demand for electricity expected to increase significantly in the coming decades, the water demand in the power sector is also expected to rise. However, due to the ongoing global energy transition, the future structure of the power supply - and hence future water demand for power generation - is subject to high levels of uncertainty, because the volume of water required for electricity generation varies significantly depending on both the generation technology and the cooling system. This study shows the implications of ambitious decarbonization strategies for the direct water demand for electricity generation. To this end, water demand scenarios for the electricity sector are developed based on selected global energy scenario studies to systematically analyze the impact up to 2040. The results show that different decarbonization strategies for the electricity sector can lead to a huge variation in water needs. Reducing greenhouse gas emissions (GHG) does not necessarily lead to a reduction in water demand. These findings emphasize the need to take into account not only GHG emission reductions, but also such aspects as water requirements of future energy systems, both at the regional and global levels, in order to achieve a sustainable energy transition.
    Keywords: ddc:600
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: article , doc-type:article
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  • 20
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    Impacts of Human Activity and Global Changes on Future Morphodynamics within the Tien River, Vietnamese Mekong Delta (2020)
    In:  Water
    Details
    Publication Date: 2020-12-10
    Description: The hydro- and morphodynamic processes within the Vietnamese Mekong Delta are heavily impacted by human activity, which in turn affects the livelihood of millions of people. The main drivers that could impact future developments within the delta are local stressors like hydropower development and sand mining, but also global challenges like climate change and relative sea level rise. Within this study, a hydro-morphodynamic model was developed, which focused on a stretch of the Tien River and was nested into a well-calibrated model of the delta’s hydrodynamics. Multiple scenarios were developed in order to assess the projected impacts of the different drivers on the river’s morphodynamics. Simulations were carried out for a baseline scenario (2000–2010) and for a set of plausible scenarios for a future period (2050–2060). The results for the baseline scenario indicate that the Tien River is already subject to substantial erosion under present-day conditions. For the future period, hydropower development has the highest impact on the local erosion and deposition budget, thus amplifying erosional processes, followed by an increase in sand mining activity and climate change-related variations in discharge. The results also indicate that relative sea level rise only has a minimal impact on the local morphodynamics of this river stretch, while erosional tendencies are slowed by a complete prohibition of sand mining activity. In the future, an unfavourable combination of drivers could increase the local imbalance between erosion and deposition by up to 89%, while the bed level could be incised by an additional 146%.
    Language: English
    Type: info:eu-repo/semantics/article
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