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Interview für das Deutsche Schifffahrtsmuseum für die Ausstellung zur Deutschen Atlantischen Expedition 1925
No full textCoupled hydrothermal venting and hydrocarbon seepage discovered at Conical Seamount, Papua New Guinea
No full textDuring research expedition SO299 with the German RV Sonne, we discovered the first deep-sea hydrothermal vent system along the Tabar-Lihir-Tanga-Feni island chain in northeastern Papua New Guinea. The Karambusel vent field is hosted by a volcanic center on the western flank of Conical Seamount that formed ~ 89 ka ago. Karambusel is remarkable in that it hosts both a fossil high-temperature, gold-rich mineralization and an active low-temperature (< 51 °C) vent system precipitating arsenic-, antimony-, thallium-, and mercury-rich sulfide minerals. Chemosymbiotic fauna is associated with the vent system and we identified more endemic species than in previous studies on nearby seeps. Our study shows that the magmatic event at Karambusel likely triggered the epithermal mineralization at Karambusel and at the central summit of Conical Seamount. The current hydrothermal fluids originate from condensed magmatic vapor or connate fluids. Gas bubbles were observed at some vent sites and the proportion of methane in the gas phase exceeds that of any other hydrothermal vent system. The composition of the light hydrocarbons points towards a thermogenic origin. Karambusel is thus the first hybrid magmatic-hydrothermal vent and hydrocarbon seep system discovered globally which explains the highly endemic vent fauna as a consequence of the unique ecological niche
Revealing Chronotypes Across Aquatic Species Using Acoustic Telemetry
No full textAcoustic telemetry offers valuable opportunities to investigate individual variability in circadian-related and other behaviours and how environmental cues shape these patterns in wild fish populations. However, this potential has not yet been fully exploited. We conducted a meta-analysis on 44 datasets from 34 distinct marine and freshwater species and different types of data (acoustic detections, depth, acceleration and positioning). Our aim was to explore the potential of acoustic telemetry in identifying chronotypes as consistent among-individual differences in circadian-related behaviours. First, we applied hidden semi-Markov models to classify individual time series into active and rest states. Subsequently, we computed two classical circadian-related behavioural traits: awakening time (as the activity onset) and rest onset (as the activity offset). Subsequently, we identified distinct phenotypes by decomposing behavioural variation into within- and among-individual components based on repeatability scores. We found evidence of distinct chronotypes in 17 species, with average repeatability scores of 0.52 for awakening time and 0.43 for rest onset, revealing that chronotypes are common in aquatic species. Our findings highlight that both the data type, particularly acceleration sensors, and the number of detections are effective tools for exploring chronotypes. Our study proposes a novel approach to characterising daily activity patterns in aquatic species, predominantly in fishes, and provides guidelines for investigating chronotypes across diverse taxa. We emphasise the promise of biotelemetry and advanced statistical models for improving our understanding of the behaviour of aquatic species and highlight the value of synthesising across large data sets collected in networks of biotelemetryprojects
Gradual Warming of Western Pacific Warm Pool Due To Weakening of Indonesian Throughflow During the Late Mid‐Pleistocene Transition
No full textThe nature and cause(s) of the Mid-Pleistocene Transition (MPT) remain enigmatic. Notably, the role of tropical Pacific oceanographic changes during the late MPT (∼0.9–0.6 Ma) remains understudied. Here, we generated ∼1.4-Myr-long Mg/Ca and δ18O records for the planktonic foraminifer Trilobatus sacculifer from IODP Site U1490 to reconstruct sea-surface temperature and regional seawater δ18O (ice-volume-corrected, a proxy for salinity) variation in the Western Pacific Warm Pool (WPWP). We find that the WPWP was characterized by a gradual warming and slight freshening of surface waters at ∼0.9–0.6 Ma, caused by the Indonesian Throughflow weakening and consequent accumulation of oceanic heat. These effects were likely driven by sea-level fall due to global icesheet expansion and/or Australian monsoonal intensification. The gradual warming signal was subsequently propagated eastward via strengthened North Equatorial Countercurrent, which may have acted as a positive climatic feedback, contributing to the expansion of the North American icesheet during the late MPT
A Global Account of Established Non‐Native Fish Species
No full textThe introduction of non-native aquatic species has fundamentally transformed aquatic assemblages, primarily due to human activities, such as aquaculture, fisheries enhancement, aquarium trade, the creation of artificial corridors, and deliberate and accidental releases. Despite growing concern for biological invasions, there is no overall global appraisal of successful non-native fishes. This study compiled a comprehensive dataset from several global sources to examine the taxonomic diversity, geographical distribution, introduction pathways, and ecological impacts of non-native freshwater and marine fishes. Our dataset includes 1535 established non-native fish species in 193 countries (82% of the global coverage), with Leuciscidae, Cichlidae, Salmonidae, and Cyprinidae being the most represented families. Although the incline in first reportings appears almost linear, annual reporting has been declining for decades, suggesting fish introduction rates are decreasing. The main introduction pathways are aquarium trade, aquaculture, fishery augmentation, and the creation of artificial corridors. The importance of introduction pathways substantially differed between freshwater species (primarily the aquarium trade and aquaculture) and marine species (corridors). While extensive records exist for hundreds of non-native fish species, information on their impact types and impact mechanisms remains available only for a third of these species, highlighting broad knowledge deficiencies. Available impact information indicates that non-native fish species may threaten native biodiversity through primarily competition and predation as dominant mechanisms. The magnitude of highest-risk invasions suggests remediation is possible through urgent proactive policy and management interventions. This comprehensive global evaluation of established fish species and their ecological effects thus addresses critical data deficiencies, strengthens risk assessment frameworks, and supports the development of targeted biosecurity policies on priority pathways, approaches essential for helping mitigate the environmental and economic impacts of non-native fish introductions
Short cruise report AL636b | Kiel – Kiel
No full textAim: The cruise aimed at testing different types of underwater equipment for optical or hydroacoustically map and inspect the seafloor. We tested three different AUVs (AUV Abyss, AUV Albert, AUV REMUS), two types of ROVs (BlauBär, PolBär), a moonpool based SAS system, the ship-based EM2040 MBES system and finally the MOMO system, that was used for the second time on board of ALKOR testing the new fiber optical cable. Technical tests of equipment but also exchange of knowledge and training of people were the focus of the cruise that we run for three days at sea with exchange of crew and day guest joining the cruise for a day. Next to scientists and technicians from GEOMAR we had people from the German Navy as well as the Federal Police onboard of RV ALKOR
Digital Twins in Manufacturing: A Systematic Literature Review With Retrieval-Augmented Generation
No full textThis paper presents a systematic literature review on the use of digital twins in manufacturing, with the goal of developing a comprehensive taxonomy that synthesizes existing categorizations. Given the increasing complexity and volume of literature in this domain, conventional review methods are becoming insufficient. To address this challenge, the study applies a novel approach named retrieval augmented generation. This is a technique that combines large language models with real-time information retrieval, enabling the automated identification and summarization of typologies across a broad corpus of publications. A total of 1,354 publications were initially screened, leading to 144 distinct categorizations relevant to digital twins in industrial contexts. The resulting taxonomy classifies digital twins along multiple dimensions, including life cycle stages, physical domain and hierarchy levels, model characteristics, digital thread connectivity and deployment strategies. This work provides both researchers and practitioners with a structured approach to understanding and implementing digital twins in manufacturing environments, as well as a guideline to completely describe a specific implementation. The taxonomy serves as a foundation for future research and as a practical tool for industrial applications, since it defines design decisions, which have to be made
Student cruise: Observation techniques for Physical Oceanographers Cruise No. AL638
No full textAugust 21 – August 23, 2025,
Kiel (Germany) – Kiel (Germany)
CAU pherPra
The hidden diversity of Saudi Arabian Red Sea octocorals revealed through a morpho-molecular assessment across bathymetric and latitudinal gradients
No full textOctocorals, a globally distributed class of Cnidaria, inhabit a wide range of environments, from cold to tropical waters and from shallow to deep-sea ecosystems. In the Red Sea, studies on octocoral diversity have mostly been focused on the Gulf of Aqaba and selected families or genera. While these studies have revealed a remarkable richness and diversity of shallow-water species, mesophotic and deep-sea octocoral research remains limited in the region, in particular along the Saudi Arabian coast. Here, we provide a first comprehensive assessment of this group’s genetic diversity across the basin’s bathymetric and latitudinal gradients. Following six Red Sea oceanographic expeditions and various biodiversity surveys conducted between 2020 to 2023, we analysed a collection of 728 octocoral specimens sampled along 13 degrees of latitude in the Saudi Arabian Red Sea, from shallow-water reefs to deep-sea habitats. We combined morphological identification and sequencing of mitochondrial barcode markers (mtMutS and COI) to delimit lineages. Our integrated results revealed the occurrence of 26 families and 56 genera in the basin from 3 to 859 m of depth. While the description of new species was beyond the scope of this work, here we provide a reference dataset for octocoral diversity from a biodiversity hotspot, as well as essential insights to inform biodiversity management and planning of conservation measures, particularly relevant for the rapidly developing Saudi Arabian Red Sea coast