ALBERT

Beschreibung: Upwelling of nutrient-rich deep waters make eastern boundary upwelling systems (EBUSs), such as the Humboldt Current system, hot spots of marine productivity. Associated settling of organic matter to depth and consecutive aerobic decomposition results in large subsurface water volumes being oxygen depleted. Under these circumstances, organic matter remineralisation can continue via denitrification, which represents a major loss pathway for bioavailable nitrogen. Additionally, anaerobic ammonium oxidation can remove significant amounts of nitrogen in these areas. Here we assess the interplay of suboxic water upwelling and nitrogen cycling in a manipulative offshore mesocosm experiment. Measured denitrification rates in incubations with water from the oxygen-depleted bottom layer of the mesocosms (via 15N label incubations) mostly ranged between 5.5 and 20 nmol N2 L−1 h−1 (interquartile range), reaching up to 80 nmol N2 L−1 h−1. However, actual in situ rates in the mesocosms, estimated via Michaelis–Menten kinetic scaling, did most likely not exceed 0.2–4.2 nmol N2 L−1 h−1 (interquartile range) due to substrate limitation. In the surrounding Pacific, measured denitrification rates were similar, although indications of substrate limitation were detected only once. In contrast, anammox (anaerobic ammonium oxidation) made only a minor contribution to the overall nitrogen loss when encountered in both the mesocosms and the Pacific Ocean. This was potentially related to organic matter C / N stoichiometry and/or process-specific oxygen and hydrogen sulfide sensitivities. Over the first 38 d of the experiment, total nitrogen loss calculated from in situ rates of denitrification and anammox was comparable to estimates from a full nitrogen budget in the mesocosms and ranged between ∼ 1 and 5.5 µmol N L−1. This represents up to ∼  20 % of the initially bioavailable inorganic and organic nitrogen standing stocks. Interestingly, this loss is comparable to the total amount of particulate organic nitrogen that was exported into the sediment traps at the bottom of the mesocosms at about 20 m depth. Altogether, this suggests that a significant portion, if not the majority of nitrogen that could be exported to depth, is already lost, i.e. converted to N2 in a relatively shallow layer of the surface ocean, provided that there are oxygen-deficient conditions like those during coastal upwelling in our study. Published data for primary productivity and nitrogen loss in all EBUSs reinforce such conclusion.

Beschreibung: Observed oxygen minimum zones (OMZs) in the tropical Pacific Ocean are located above intermediate-depth waters (IDWs), defined here as the 500–1500 m water layer. Typical climate models do not represent IDW properties well and are characterized by OMZs that are too deep-reaching. We analyze the role of the IDW in the misrepresentation of oxygen levels in a heterogeneous subset of ocean models characterized by a horizontal resolution ranging from 0.1 to 2.8∘. First, we show that forcing the extratropical boundaries (30∘ S and N) to observed oxygen values results in a significant increase in oxygen levels in the intermediate eastern tropical region. Second, we highlight the fact that the Equatorial Intermediate Current System (EICS) is a key feature connecting the western and eastern part of the basin. Typical climate models lack in representing crucial aspects of this supply at intermediate depth, as the EICS is basically absent in models characterized by a resolution lower than 0.25∘. These two aspects add up to a “cascade of biases” that hampers the correct representation of oxygen levels at intermediate depth in the eastern tropical Pacific Ocean and potentially future OMZ projections.

Beschreibung: With the negotiations under the United Nations Framework Convention on Climate Change (UNFCCC) failing to provide adequate support to climate victims, vulnerable countries, nongovernmental organizations and affected communities are increasingly exploring legal avenues to obtain recourse for loss and damage. This article contributes to the emerging scholarship on climate litigation by exploring whether, how and with what effects such litigation interacts with the UNFCCC negotiations. For this purpose, the article contextualizes normative claims about the influence of climate court cases through practice‐embedded views of stakeholders in the loss and damage context and provides a typology of loss and damage‐related cases. Having due regard to the fact that litigation for liability and compensation of climate harms is still at an early stage, it argues that this legal avenue offers significant potential to advance the UNFCCC negotiations on loss and damage, and provides recommendations on how both spheres can be more strongly interlinked.

Beschreibung: Carbon dioxide removal (CDR) is often characterized as separate from climate change mitigation. Discussion of CDR governance – despite enjoying growing interest – tends to overlook how key provisions on mitigation apply. Similarly, many climate policy processes have ignored CDR. CDR may have been discursively held separate from ‘mitigation’ due to a partial conceptual overlap with ‘geoengineering’. We unpack how the ‘mitigation of climate change’ – as defined in the United Nations Framework Convention on Climate Change and its Paris Agreement – includes CDR as defined by the Intergovernmental Panel on Climate Change. We point to important implications and opportunities for strengthening governance by enhanced clarity regarding parties’ obligations, principled equitable distribution of removal efforts, prioritization of rapid emissions reductions and careful paths to long-term removals, and a need for considering sustainability and human rights issues in the pursuit of CDR.

Beschreibung: Relational thinking has recently gained increasing prominence across academic disciplines in an attempt to understand complex phenomena in terms of constitutive processes and relations. Interdisciplinary fields of study, such as science and technology studies (STS), the environmental humanities, and the posthumanities, for example, have started to reformulate academic understanding of nature-cultures based on relational thinking. Although the sustainability crisis serves as a contemporary backdrop and in fact calls for such innovative forms of interdisciplinary scholarship, the field of sustainability research has not yet tapped into the rich possibilities offered by relational thinking. Against this background, the purpose of this paper is to identify relational approaches to ontology, epistemology, and ethics which are relevant to sustainability research. More specifically, we analyze how relational approaches have been understood and conceptualized across a broad range of disciplines and contexts relevant to sustainability to identify and harness connections and contributions for future sustainability-related work. Our results highlight common themes and patterns across relational approaches, helping to identify and characterize a relational paradigm within sustainability research. On this basis, we conclude with a call to action for sustainability researchers to codevelop a research agenda for advancing this relational paradigm within sustainability research, practice, and education.

Beschreibung: Modell Deutschland has proven to be extremely stable in the past. Nevertheless, the central sector of the German model of capitalism is currently facing profound transformations, the precise contours of which can only be guessed at. Inspired by regulation theory, this article discusses these emerging changes and argues that the international embedding of Modell Deutschland is of central importance not only with regard to the current double crisis of liberal capitalism but also with regard to the material dimension of the German export model. In addition, a more precise understanding of the reconfiguration of automotive value chains is required; these are changing as a result of digitalization, new mobility services, and changes in the manufacturing processes and the demand for raw materials in the course of powertrain electrification, and have a strong influence on both wage ratios and forms of enterprise.

Beschreibung: Das „Modell Deutschland“ hat sich in der Vergangenheit als überaus stabil erwiesen. Gleichwohl steht aktuell die Automobilindustrie, die zentrale Branche des deutschen Kapitalismusmodells, vor tief greifenden Transformationen, deren genaue Konturen sich jedoch nur erahnen lassen. Der Beitrag diskutiert aus einer regulationstheoretischen Perspektive die sich abzeichnenden Veränderungen und argumentiert, dass die internationale Einbettung des „Modell Deutschland“ nicht nur im Hinblick auf die aktuelle Doppelkrise des liberalen Kapitalismus, sondern auch im Hinblick auf die materiell-stoffliche Dimension des deutschen Exportmodells von zentraler Bedeutung ist. Darüber hinaus bedarf es eines präziseren Verständnisses der Rekonfiguration der automobilen Wertschöpfungsketten, die sich durch Digitalisierung und neue Mobilitätsdienstleistungen sowie eine Veränderung der Rohstoffbedarfe und industrieller Fertigungsprozesse im Zuge der Elektrifizierung des Antriebsstrangs verändern und sowohl das Lohnverhältnis als auch die Unternehmensformen stark beeinflussen.

Beschreibung: Scientists are using a variety of geochemical, geophysical, and numerical methods to study offshore freshened groundwater and better understand its role in the global water cycle.

Beschreibung: The spatial pattern of Antarctic surface air temperature variability on multi–decadal to multi–centennial time scales is poorly known because of the short instrumental records, the relatively small number of high–resolution paleoclimate observations, and biases in climate models. Here, changes in surface air temperature over Antarctica are reconstructed over the past two millennia using data assimilation constrained by different ice core water isotope records in order to identify robust signals. The comparison between previous statistically based temperature reconstructions and simulations covering the full Common Era driven by natural and anthropogenic forcings shows major discrepancies occurring in the period 1–1000 CE over East Antarctica, with the reconstructions displaying a warming over 1–500 CE that is not reproduced by the simulations. This suggests that the trends in the first millennium deduced from the statistically based reconstructions are unlikely to be entirely forced by external forcings. Our reconstructions show the high sensitivity of the 500-year temperature trend in Antarctica and its spatial distribution to selection of the records for the reconstructions, especially during 1–500 CE. A robust cooling over Antarctica during 501–1000 CE has been obtained in three data assimilation–based reconstructions with a larger magnitude in the WAIS than elsewhere over Antarctica, in agreement with previous estimates with the larger changes than simulated in climate models. The reconstructions for atmospheric circulation indicate that the pattern of temperature changes over 501–1000 CE is related to the positive trend of Southern Annular Mode and a deepening of Amundsen Sea Low. This confirms the role of internal variability in the temperature trends on multi–centennial scales.