ALBERT

Description: One of Earth’s most fundamental climate shifts – the greenhouse-icehouse transition 34 Ma ago – initiated Antarctic ice-sheet build-up, influencing global climate until today. However, the extent of the ice sheet during the Early Oligocene Glacial Maximum (~33.7–33.2 Ma) that immediately followed this transition, a critical knowledge gap for assessing feedbacks between permanently glaciated areas and early Cenozoic global climate reorganization, is uncertain. Here, we present shallow-marine drilling data constraining earliest Oligocene environmental conditions on West Antarctica’s Pacific margin – a key region for understanding Antarctic ice sheet-evolution. These data indicate a cool-temperate environment, with mild ocean and air temperatures preventing West Antarctic Ice Sheet formation. Climate-ice sheet modeling corroborates a highly asymmetric Antarctic ice sheet, thereby revealing its differential regional response to past and future climatic change.

Description: This paper introduces SEISMONOISY, an application designed for monitoring the spatiotemporal characteristic and variability of the seismic noise of an entire seismic network with a quasi-real-time monitoring approach. Actually, we have applied the developed system to monitor 12 seismic networks distributed throughout the Italian territory. These networks include the Rete Sismica Nazionale (RSN) as well as other regional networks with smaller coverage areas. Our noise monitoring system uses the methods of Spectral Power Density (PSD) and Probability Density Function (PDF) applied to 12 h long seismic traces in a 24 h cycle for each station, enabling the extrapolation of noise characteristics at seismic stations after a Seismic Noise Level Index (SNLI), which takes into account the global seismic noise model, is derived. The SNLI value can be used for different applications, including network performance evaluation, the identification of operational problems, site selection for new installations, and for scientific research applications (e.g., volcano monitoring, identification of active seismic sequences, etc.). Additionally, it aids in studying the main noise sources across different frequency bands and changes in the characteristics of background seismic noise over time.

Description: Published

Description: 3474

Description: JCR Journal

Description: Based on its morphology and in accordance with modern circumscriptions of genera among the Gleicheniaceae, a new combination in Sticherus is made for the Papua New Guinean fern originally described as Gleichenia hooglandii.

Description: Urban air pollution remains a challenge in European cities, despite decades of improvement, especially with respect to recent updates to the World Health Organization’s (WHO) air quality guidelines in 2021. At the same time, a new generation of small sensors for air pollution measurement have opened up new avenues for understanding air pollution in cities. In this study, we use Plantower PMS 5003 sensors to measure PM2.5 alongside three local traffic policies implemented in 2020 and 2021. These measures include a new bike-lane and a temporary community space, as well as the creation of a pedestrian zone through the closure of a street to through-traffic. The measurement campaign used the sensors in both mobile and stationary deployments, utilizing their small size and lower cost to increase spatial and temporal resolution measurements. We calibrate the Plantower sensors using Schmitz et al.’s (2021) methodology and test three different models: multiple linear regression (MLR), gradient-boosting machines (GBM), and support vector machines (SVM). Results show that sensors are useful for measuring PM2.5. We also find no significant effect of any of the local transport policies on local concentrations of PM2.5, despite previous studies of these policies showing reductions in local NO2 concentrations. This indicates that larger-scale policies tackling urban and regional emissions of PM will be needed to improve PM concentrations and meet WHO standards.

Description: Key message: A decolonial approach is needed to fulfil IASC’s commitment to recognizing that Traditional Knowledge, Indigenous Knowledge and academic scientific knowledge are co-equal and complementary knowledge systems that all can and should inform its work (website ICARP IV, retrieved October 2023). This document summarizes key recommendations for actions regarding five themes: 1. Indigenous Peoples’ right to self-determination as a prerequisite for high-quality Arctic research 2. Ethics, methods and methodology as key for decolonial research 3. Indigenous-led research in design and practice 4. Indigenous Peoples’ co-equal participation in Arctic research funding structures and decision-making for securing decolonial Arctic research in practice 5. Funding for Co-Creative and Indigenous-Led Arctic Research

Description: Local policies are part of the toolbox available to decision makers to improve air quality but their effectiveness is underevaluated and underreported. We evaluate the impact of the pedestrianization of a street in the city centre of Berlin on the local air pollution. Nitrogen dioxide (NO2) was measured on the street where the policy was implemented and on two parallel streets using low-cost sensor systems supported by periodic calibrations against reference-grade instruments and constrained by passive samplers. Further measurements of NO2 were conducted with a reference-grade instrument mounted on a mobile platform. The concentrations were evaluated against the urban background (UB) to isolate the policy-related signal from natural fluctuations, long-term trends and the COVID-19 lockdown. Our analysis shows that the most likely result of the intervention is a reduced NO2 concentrations to the level of the UB on weekdays for the pedestrian zone. Kerbside NO2 concentrations exhibited substantial differences to the concentrations measured at lampposts highlighting the difficulty for such measurements to capture personal exposure. The results have implications for policy, showing that an intervention on the local traffic patterns can possibly be effective in improving local air quality.

Description: Political science and the public know what has gone wrong with liberal democracy and continues to go wrong, but what can be done to counter this trend? What can slow down the de-democratisation, what can reverse the development that has been observed ever more urgently since shortly after the turn of the millennium? As one instrument the chapter discusses citizens’ councils, which have been field-tested in many places in recent years and whose strengths and shortcomings can now be evaluated. We will give an insight into the theoretical foundations of deliberative and participative democratic innovations focusing more closely on citizen assemblies with an exemplary evaluation of France’s climate assembly, the Convention Citoyenne pour le Climat (CCC), a rather elaborate one of citizen participation, associated with a wide public attention and accompanied by an intense scientific and intellectual debate in France. The CCC has been, in terms of political activation and discourse, successful, whereas in terms of its general policy impact and structural changes of French society and politics, it has not been a full success story. Instead of promoting a positive French exception to the conventional antagonism of etatism and street protest, this experiment perished in 2022/23.

Description: The deep-sea is the largest habitat on Earth, but its biodiversity and ecosystem dynamics are still underexplored. Deep-sea sponge grounds (syn. aggregations, gardens) are sponge-dominated ecosystems that are found throughout the world´s oceans. They are considered vulnerable marine ecosystems (VMEs) and warrant protection against human intervention. Deep-sea sponge grounds are considered hotspots of diversity and function in the deep ocean. While a significant body of information has been accrued on shallow-water sponges, our understanding of deep-sea sponges and their associated microbiomes at the beginning of this PhD thesis was still very limited. This PhD thesis therefore aims to provide a first comprehensive overview on the diversity, evolution, biogeography, and ecology of deep-sea sponge microbiomes. The overarching aim was to assess whether the concepts obtained in shallow-water sponge microbiology would also hold in the deep-sea. In addition, novel themes such as biogeochemistry, physical oceanography, and trait-based approaches were integrated and further expand the existing theoretical framework in sponge microbiology. Sampling was conducted during 20 deep-sea expeditions, largely to sponge grounds of the North Atlantic in the context of the EU project “SponGES: Deep-sea sponge grounds ecosystems of the North Atlantic - an integrated approach towards their preservation and sustainable exploitation”. In total 1077 sponge-associated microbiomes were sampled along with 355 seawater microbiomes and 114 sediment microbiomes from 52 sponge ground locations. Microbial diversity was assessed by 16S rRNA gene amplicon sequencing and host taxonomy was determined by a combination of taxonomic and molecular markers. To this end, a state-of-the-art high-throughput 16S amplicon pipeline was established and corresponding metadata workflows were developed. The resulting data were analysed by six specific case studies (of which all were published) and one overarching meta-analysis (manuscript in preparation). The microbial community composition of deep-sea sponges was explored across different scales, from the ecosystem- and biogeography-level, to individual sponge species and to the microbial taxon (Amplicon Single nucleotide Variant; ASV) level. By exploring sponge microbiomes on different levels of integration and by using a nested sampling design, I was able to identify overarching factors, that drive microbiome composition in a statistically proven manner. The main identified environmental drivers of microbial community variability were temperature, salinity, nutrients/oxygen, and depth. It is noteworthy, that these parameters were identified from a total set of 24 environmental parameters. Furthermore, sponge phylogeny, taxonomy, and morphology were found to be related with the microbial community composition. Interestingly, microbial diversity can be predicted based on sponge morphology, which offers exciting opportunities for future studies in respect to imaging or trait-based approaches. My conclusions on the microbiome composition of deep-sea sponge microbiomes are that each deep-sea sponge harbours an individual set of microbes and a large pool of hidden diversity. Furthermore, deep-sea sponge microbiomes are globally not well connected and rather display heterogeneity on local scales. Interestingly, a deep-sea specific sponge microbiome was discovered. Overall, the results of my thesis suggest a strong nestedness of deep-sea sponge microbiomes within their ecological context. In the context of this PhD thesis, I established a baseline of deep-sea sponge-associated microbiomes, discovered a large extent of novel diversity and described patterns of specificity, stability and variability. I further identified the environmental and host-related drivers of sponge microbiome composition. From a methodological point, I have designed and developed a software tool (termed SVAmpEx) that allows the archiving and user-friendly accessibility of deep-sea sponge microbiome baseline data. Since microbiome composition is directly related to sponge health, reference baselines are valuable to monitor the integrity and resilience of deep-sea sponges. The collective information gathered in this PhD thesis provides the scientific basis to improve conservation and management strategies of the vulnerable deep-sea sponge ground ecosystems in the long run.

Description: FS METEOR Expedition M201 VebVolc, 09.06. – 18.07.2024 | Reykjavik – Praia da Vitoria

Description: The Arctic Ocean plays an important role in the regulation of the earth's climate system, for instance by storing large amounts of carbon dioxide within its interior. It also plays a critical role in the global thermohaline circulation, transporting water entering from the Atlantic Ocean to the interior and initializing the southward transport of deep waters. Currently, the Arctic Ocean is undergoing rapid changes due to climate warming. The resulting consequences on ventilation patterns, however, are scarce. In this study we present transient tracer (CFC-12 and SF6) measurements, in conjunction with dissolved oxygen concentrations, to asses ventilation and circulation changes in the Eurasian Arctic Ocean over three decades (1991–2021). We constrained transit time distributions of water masses in different areas and quantified temporal variability in ventilation. Specifically, mean ages of intermediate water layers in the Eurasian Arctic Ocean were evaluated, revealing a decrease in ventilation in each of the designated areas from 2005 to 2021. This intermediate layer (250–1,500 m) is dominated by Atlantic Water entering from the Nordic Seas. We also identify a variability in ventilation during the observation period in most regions, as the data from 1991 shows mean ages comparable to those from 2021. Only in the northern Amundsen Basin, where the Arctic Ocean Boundary Current is present at intermediate depths, the ventilation in 1991 is congruent to the one in 2005, increasing thereafter until 2021. This suggests a reduced ventilation and decrease in the strength of the Boundary Current during the last 16 years. Key Points Temporal variability of ventilation in the Eurasian Arctic Ocean during the past 30 years is estimated by observations of transient tracers We found a slow down of the ventilation between 2005 and 2021 in the intermediate waters Evidence of multidecadal variability of ventilation in the intermediate waters of the Eurasian Arctic Ocean is present Plain Language Summary The Eurasian Arctic Ocean, the region of the Arctic Ocean connected to the European and Asian continents, is an important pathway for recently ventilated water from the Nordic Seas. These waters are exported back to the North Atlantic following their travel through the Arctic Ocean. Ventilation describes the process of surface waters being transported into the interior ocean due to increasing density, which affects the underlying water masses. In this study we investigate how the ventilation patterns have evolved in the Eurasian Arctic Ocean over the past three decades, using transient tracer (CFC-12 and SF6) measurements. We observed a significant change in the intermediate layer (250–1,500 m) with older waters found in measurements in 1991 and 2021 compared to 2005 and 2015. Moreover, our data suggest a slowdown in ventilation throughout the three decades in the northern Amundsen Basin, implying a decrease in the circulation time-scale of the Arctic Ocean Boundary Current over the past 16 years. This has potentially important implications for the transport of, for example, heat, salt or oxygen from the Atlantic Ocean around the Arctic Ocean, and back.