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We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because variability both within and among replicate experimental enclosures was high. Average emission rates resulted primarily from ebullition (0.2–30.3 mmol CH4 m−2 d−1), which were 4 orders of magnitude higher than estimated diffusive fluxes and were of similar importance as the coarsely estimated advective methane transport through plants. Significant correlations between dissolved oxygen and dissolved methane and ebullition flux suggest that methane release from the sediment might feed back positively on methane production by reducing dissolved oxygen in the water column and oxygen flux into the sediment. Nitrate may have a similar effect. Extrapolation of our limited data indicates that total methane fluxes from vegetated littoral zones of temperate lakes may contribute 0.5%–7% of the global natural CH4 emissions. These results emphasize the importance of freshwater marshes as sources of methane emissions to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.

This following special issue of the European Journal of Transport Infrastructure Research (EJTIR) containing 4 scientific papers is the result of the work conducted under the research project ‘National Transport Planning – Sustainability, Institutions and Tools’ (SUSTAIN) (2012- 2017) financed by the Danish Innovation Fund. SUSTAIN was coordinated by first the Department of Transport of the Technical University of Denmark (DTU Transport) and later as the result of a reorganisation of the transport research at DTU by the Department of Management Engineering (DTU Management Engineering). The project was carried out in cooperation with several Danish and international partners. In SUSTAIN the following definition of national sustainable transport planning (NSTP) was adopted: deliberate, knowledge-based, and strategic endeavours to integrate sustainability principles, criteria and goals in the development, management, regulation and assessment of nationally significant transport systems and services. This paper presents the research outcome by reviewing some of the major findings and seeing these collectively as a basis for promoting sustainability through the formulated research topic of NSTP. This basis includes defining criteria and indicators for use in NSTP combining evidence-based and performance oriented planning approaches. Furthermore, it contains a flexible evaluation framework that includes a decision support model that when informed by criteria and indicators can structure and assist an NSTP practice. This practice can support a planning process aiming at realising a sustainable transport development. Finally, the basis comprises a review of the complex political and administrative fabric in which NSTP is embedded, and thereby it can condition the ability to promote sustainability in practice.

Abstract The Transpolar Drift (TPD) plays a crucial role in regulating Arctic climate and ecosystems by transporting fresh water and key substances, such as terrestrial nutrients and pollutants, from the Siberian Shelf across the Arctic Ocean to the North Atlantic. However, year-round observations of the TPD remain scarce, creating significant knowledge gaps regarding the influence of sea ice drift and ocean surface circulation on the transport pathways of Siberian fresh water and associated matter. Using geochemical provenance tracer data collected over a complete seasonal cycle, our study reveals substantial spatiotemporal variability in the dispersal pathways of Siberian matter along the TPD. This variability reflects dynamic shifts in contributions of individual Siberian rivers as they integrate into a large-scale current system, followed by their rapid and extensive redistribution through a combination of seasonal ice–ocean exchanges and divergent ice drift. These findings emphasize the complexity of Arctic ice–ocean transport pathways and highlight the challenges of forecasting their dynamics in light of anticipated changes in sea ice extent, river discharge, and surface circulation patterns.

Ocean surface warming is resulting in an expansion of stratified, low-nutrient environments, a process referred to as ocean desertification [1]. A challenge for assessing the impact of these changes is the lack of robust baseline information on the biological communities that carry out marine photosynthesis. Phytoplankton perform half of global biological CO2 uptake, fuel marine food chains, and include diverse eukaryotic algae that have photosynthetic organelles (plastids) acquired through multiple evolutionary events [1-3]. While amassing data from ocean ecosystems for the Baselines Initiative (6,177 near full-length 16S rRNA gene sequences and 9.4 million high-quality 16S V1-V2 amplicons) we identified two deep-branching plastid lineages based on 16S rRNA gene data. The two lineages have global distributions, but do not correspond to known phytoplankton. How the newly discovered phytoplankton lineages contribute to food chains and vertical carbon export to the deep sea remains unknown, but their prevalence in expanding, low nutrient surface waters suggests they will have a role in future oceans.

Energy management systems are used to find a compromise between conflicting goals that can be identified for battery electric vehicles. Typically, these are the powertrain efficiency, the comfort of the driver, the driving dynamics, and the component aging. This paper introduces an optimization-based holistic energy management system for a battery electric vehicle. The energy management system can adapt the vehicle velocity and the power used for cabin heating, in order to minimize the overall energy consumption, while keeping the total driving time and the cabin temperature within predefined limits. A genetic algorithm is implemented in this paper. The approach is applied to different driving cycles, which are optimized by dividing them into distinctive time frames. This approach is referred to as the sliding window approach. The optimization is conducted with two separate driving cycles, the New European Driving Cycle (NEDC) and a recorded real-world drive. These are analyzed with regard to the aspects relevant to the energy management system, and the optimization results for the two cycles are compared. The results presented in this paper demonstrate the feasibility of the sliding window approach. Moreover, they reveal the differences in fundamental parameters between the NEDC and the recorded drive and how they affect the optimization results. The optimization leads to an overall reduction in energy consumption of 3.37 % for the NEDC and 3.27 % for the recorded drive, without extending the travel time.

A variety of measures are currently being taken on both the national and international levels in order to mitigate the negative effects of climate change. The promotion of electric mobility is one such measure for the transport sector. As a key component in a more environmentally-friendly, resource-saving, and efficient transport sector, electric mobility promises to create better sustainability. Several challenges still need to be met to exploit its full potential. This requires adapting the car technology, the value chain of vehicles, loads on the electricity network, the power generation for the drive, traffic, and charging infrastructure. The challenges to this endeavor are not only technical in nature, but they also include social acceptance, concerns, and economic, as well as ecological, aspects. This paper seeks to discuss and elucidate these problems, giving special focus to the issues of driving range, phenomenon of range anxiety, charging time, and complexity of the charging infrastructure in Germany. Finally, the development of social acceptance in Germany from 2011 to 2020 is investigated.