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Ringversuch zur Bestimmung der Kohlenstoffgehalte in Oberflächensedimenten der Deutschen Ostsee
No full textEight laboratories located in northern Germany conducted an interlaboratory comparison to critically evaluate procedures and methods used for the quantification of total carbon (TC), organic carbon (TOC) and inorganic carbon (TIC) in surface sediments from the Baltic Sea. Each laboratory was provided with homogenized sediment subsamples retrieved at three different Baltic Sea stations and an external soil standard with certified concentrations.
TC concentrations determined by the participating laboratories were consistent with each other, even though different analytical instruments were used by the participants and procedures for sample preparation (sample storage, homogenization, drying, grinding) varied across laboratories. Moreover, TC values determined for the external standard agreed with the certified value. These results show that TC is a robust and reliable parameter since procedures for sample preparation and analysis have no significant effect on the TC value. Relative standard deviations (RSD in %) decreased with increasing TC concentrations (in weight percent, wt%) with RSD = 5.45 % for TC = 0.55 wt%, RSD = 1.81 % for TC = 3.86 wt% and RSD = 1.06 % for TC = 5.68 wt%.
TOC concentrations showed more variability. The evaluation showed that procedures applied for the decarbonatization of sediment samples have a significant effect on TOC values. Consistent results and conformity with the certified standard value were achieved when the temperature during decarbonatization and subsequent drying was 50 – 105°C and the concentration (normality, N) of hydrochloric acid (HCl) added to the sample was 0.5 – 3.6 N. Under these conditions, RSD values depend on concentrations with RSD = 9.09 % for TOC = 0.44 wt%, RSD = 2.51 % for TOC = 3.43 wt% and RSD = 2.46 % for TOC = 5.29 wt%. RSD values of TOC were higher than those for TC since concentrations were lower and the decarbonatization step introduced additional variability.
TIC concentration calculated as TIC = TC – TOC were low (0.11 – 0.43 wt%) and showed high variability with RSD = 24.3 - 37.5 %. Large RSD values were caused by small differences between TC and TOC values resulting in low TIC concentrations and large uncertainties.
Additional measurements showed that samples were significantly diluted by seawater salts precipitating during sediment drying. The salt contents in dried sediment samples (0.6 – 6.4 wt%) were calculated from the water contents of wet samples and chloride concentrations in porewaters. Carbon concentrations (TC, TOC, TIC) have to be corrected to account of salt dilution especially in water-rich sediments with a water content of more than 50 wt%.
Standing stocks of carbon in surface sediments were calculated from corresponding concentrations applying the porosity of bulk sediments and density of dry solids. Uncertainties of these standing stocks were largely controlled by the RSD of concentration measurements (TC, TOC, TIC) since porosity and density were determined with higher precision (RSD = 0.1 - 2 %).
The chemical composition of porewaters was analyzed in wet sediment samples stored at 4°C over a period of several months. The data showed significant enrichments in dissolved calcium and sulfate during storage. These increases were probably induced by carbonate dissolution and acidity-generating pyrite oxidation. It is, hence, recommended to store sediments at -20°C to slow-down coupled pyrite oxidation and carbonate dissolution that induced a small but significant decrease in TIC concentrations at 4°C.
Several recommendations were derived from the results of the interlaboratory comparison. 1. Decarbonatization of sediment samples should be conducted with 0.5 – 3.6 N HCl at 50 – 105°C. 2. Salt precipitating needs to be considered especially for water-rich sediment samples (> 50 wt% water). 3. Wet sediment samples should be stored at -20°C rather than 4°C
Bioprospecting cultivable bacteria associated with deep sea (mesopelagic) fish of the North Atlantic Ocean
No full textThe microbiota associated with fish is increasingly recognized as a valuable source of bioactive metabolites for pharmaceutical application. The mesopelagic zone, a deep and unique ecosystem with a diverse biological community, is among the least studied marine environments. This study explored the potential of cultivable microbiota associated mainly with mesopelagic fish for pharmaceutical and agricultural applications. We isolated and identified 643 cultivable bacteria predominantly from various organs of fish collected from the mesopelagic zone of the North Atlantic Ocean, with additional samples from jellyfish, squid and krill. The bacterial community was dominated by the Gram-negative phylum Pseudomonadota, particularly the genera Psychrobacter, Pseudoalteromonas and Vibrio. A total of 394 bacterial isolates were selected and cultured in two growth media. Microbial extracts (590) were assessed for their anticancer and antimicrobial activities against human and fish pathogens. Over 60% of extracts exhibited activity against two ESKAPE pathogens methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium, as well as the fish pathogen Lactococcus garvieae, highlighting their antimicrobial potential. We used an LC–MS/MS-based computational untargeted metabolomics and cutting-edge cheminformatics tools as well as manual dereplication strategies to chemically profile 26 most active extracts, and annotated compound classes such as bile acids, diketopiperazines, indole alkaloids and lipids. Many peak ions remained unannotated, suggesting the presence of new bioactive molecular families. These findings highlight the bioprospecting potential of cultivable bacteria associated with mesopelagic fauna. © The Author(s) 2025
Journey to FAIR Data - Challenges during the practical implementation
No full textDuring the journey to a FAIR data implementation, personal, technical and institutional challenges are highlighted along the data lifecycle. Examples are given on how different systems, like OSIS - PANGAEA are connected
Future poleward distribution shifts of community and functional groups in the Barents Sea modelled under different climate and fisheries scenarios
No full textArctic ecosystems are among the most impacted by climate change globally. To evaluate future spatial distributions of functional groups (FGs) in the Barents Sea, a spatial mass-balance model (Ecospace) was used to simulate future distributions under a combination of 3 climate scenarios (SSP1-2.6 [cool], SSP2-4.5 [intermediate], and SSP5-8.5 [hot]), and 3 fishing effort (E) levels: intermediate, low, and high. The model was driven by monthly 2D surface and bottom temperature, ice concentration, primary production fields, and E time series from 2020 to 2099. Spatial biomass distributions of the community and most FGs shifted mainly northeast with increasing temperature. In the cool and intermediate scenarios, the temperature decreased or stabilised between the 2050s and 2090s, and the centre of distribution of most FGs returned close to the 2020s positions. In the hot scenario, the community shift rate accelerated from 13 (2020s to 2050s) to 23 km per decade (2050s to 2090s). In this scenario, the spread pattern of the distributions depended on the biogeographic category; many Arctic-boreal and boreal FGs showed a greater increase in spread than Arctic FGs from the 2050s to 2090s. Fishing effort levels affected the spreads of spatial distributions but not the distance and directions of shifts. The Northeast Arctic cod (main target species) showed greater spread at lower fishing effort, possibly a density-dependent range increase. Most FGs showed less clear responses to fishing efforts. We conclude that future distribution shifts were largest for boreal groups in hot scenarios, while in intermediate and cool scenarios, groups returned to present distribution patterns
Bachelor MARSYS education cruise in the Baltic Sea Cruise No. AL627, 7st of March 2025 to 9th of March 2025, Kiel (Germany), MARSYS
No full textThis cruise was originally planned as a 9-day teaching cruise for Bachelor students of the Institute of Marine Ecosystem and Fisheries Sciences (IMF), aiming to provide hands-on training in key scientific methods, sampling gears, and working procedures used in fisheries science and biological oceanography aboard a research vessel.
A core objective was to investigate the distribution patterns of key fish species such as cod, whiting, sprat, and herring—particularly juvenile gadoids—in the Kiel Bight and Mecklenburg Bight. In addition, zooplankton and hydrological surveys were planned to explore the spatial distribution of zoo- and ichthyoplankton across different environmental gradients.
Due to a technical failure requiring shipyard repairs, the cruise duration was reduced to 3 days. Despite this, all gears and sampling methods could be demonstrated, and students gained practical experience in their application. However, the reduced cruise track meant that a large portion of the planned sampling stations—especially those representing distinct hydrodynamic conditions and species communities—could not be covered. As a result, students were not able to experience the full ecological context intended for the training.
All core methodological content was successfully taught. Follow-up analysis was conducted in the context of Bachelor and Master theses as well as within coursework at IMF
Opinion: The role of AerChemMIP in advancing climate and air quality research
No full textThe Aerosol Chemistry Model Intercomparison Project (AerChemMIP) was endorsed by the Coupled Model Intercomparison Project 6 (CMIP6) and was designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. AerChemMIP provided the first consistent calculation of effective radiative forcing (ERF) for a wide range of forcing agents, which was a vital contribution to the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change. It supported the quantification of composition–climate feedback parameters and the climate response to short-lived climate forcers (SLCFs), as well as enabled the future impacts of air pollution mitigation to be identified, and the study of interactions between climate and air quality in a transient simulations. Here we review AerChemMIP in detail and assess the project against its stated objectives, its contribution to the CMIP6 project, and the wider scientific efforts designed to understand the role of aerosols and chemistry in the Earth system. We assess the successes of the project and the remaining challenges and gaps. We conclude with some recommendations that we hope will provide input to planning for future MIPs in this area. In particular, we highlight the necessity of sufficient ensemble size for the attribution of regional climate responses and the need for coordination across projects to ensure key science questions are addressed. Summary data for CMIP6 and AerChemMIP models such as model components, model configurations, and emergent quantities are included
Climate impacts of the El Niño–Southern Oscillation in Africa
No full textThe El Niño–Southern Oscillation (ENSO) — describing shifts between warm El Niño and cold La Niña phases — has a substantial effect on the global climate. In this Review, we outline the mechanisms and climate impacts of ENSO in Africa, focusing on rainfall. ENSO’s influence varies strongly by season, region, phase, event and decade, highlighting complex dynamics and asymmetries. Although difficult to generalize, key characteristics include: anomalies across the Sahel in July–September, related to the tropospheric temperature mechanism; a strong dipole in anomalies between eastern and southern Africa during October–December (the short rain reason) and December–February, linked to interactions with the Indian Ocean Dipole and Indian Ocean Basin mode, respectively; and anomalies over southern Africa (with possible indications of opposite anomalies over East Africa) during March–May (the long rain season), associated with continuation of the Indian Ocean Basin mode. These teleconnections tend to be most pronounced for East Pacific El Niño and Central Pacific La Niña events, as well as during decades when interbasin interactions are strongest. Although challenging to simulate, climate models suggest that these impacts will strengthen in the future, manifesting as an increased frequency of ENSO-related dry and wet extremes. Given the reliance of much of Africa on rain-fed agriculture, resolving these relationships is vital, necessitating realistic simulation of regional circulations, ENSO and its interbasin interactions. © Springer Nature Limited 2025
Zircon Inheritance Refines the Cambrian Orogenic Architecture of Southeast Australia
No full textThe Selwyn Block is one of the few accreted terranes identified in the vast Paleozoic Tasmanides of eastern Australia and its incorporation into this orogen marks a first-order event in the tectonic evolution of the Pacific margin of Gondwana. However, the age, composition, and paleogeography of the Selwyn Block are poorly understood because it is almost completely concealed in the middle and lower crust. The prevailing hypothesis suggests the Selwyn Block is a northern continuation of the Proterozoic Western Tasmania Terrane. We test this hypothesis by comparing inherited zircon U-Pb ages (n = 881) from early Paleozoic granitoids intruding the Selwyn Block and the Western Tasmania Terrane. Phase equilibria modelling confirms that typical Western Tasmania Terrane lithologies are melt-fertile and would have contributed inherited zircon grains to local granitoids. The inherited zircon age signature of granitoids in the Western Tasmania Terrane mirrors detrital zircon ages from local Proterozoic strata with age populations at ca. 1430 Ma and 1800–1600 Ma. In comparison, granitoids intruding the Selwyn Block have ca. 600–500 Ma and ca. 1200–900 Ma inherited zircon age populations, likely derived from local Paleozoic strata. Previously published wholerock radiogenic Sr isotopic data and new zircon radiogenic hafnium isotope data also imply distinct melt sources with granitoids intruding the Selwyn Block granitoids having lower initial 87Sr/86Sr and higher initial εHf compositions compared to granitoids intruding the Western Tasmania Terrane. Outcrop and inherited zircon evidence are consistent with the interpretation that the Selwyn Block comprises a Cambrian intra-oceanic island arc, rather than a continuation of the Western Tasmania Terrane
Making the Most of Student Membership: A Preview of ASLO Student Activities at the 2025 Aquatic Sciences Meeting and Beyond
No full textStudents are important members of the ASLO community, comprising about one-third of ASLO membership and representing all corners of the world. The Student Resources and Activities Committee (SRAC) advocates for the interests of ASLO student members. SRAC organizes student activities at ASLO meetings and online, provides a forum for students to voice opinions and questions about ASLO, and represents the student perspective to improve the ASLO student experience. SRAC members are an international and interdisciplinary group and advocate the interests of ASLO students
Expedition Programme PS147/1 and PS147/2
No full textPolarstern PS147/1 and PS147/2,
Stanley – Mindelo – Bremerhaven,
13 March 2025 – 14 April 202