ALBERT

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024

Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 1. Wochenbericht (9.-11. Februar, 2024)

Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 2.Wochenbericht (12. – 18. Februar 2024)

Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 3.Wochenbericht (19. – 25. Februar 2024)

Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 4.Wochenbericht (26.Februar – 03. März 2024)

Description: The exploitation of marine resources has caused drastic declines of many large predatory fishes. Amongst these, sharks are of major conservation concern due to their high vulnerability to overfishing and their ecological role as top predators. The 2 protected and endangered shark species tope Galeorhinus galeus and smooth hammerhead Sphyrna zygaena use overlapping coastal areas around the globe as essential fish habitats, but data to assess their trophic ecology and niche partitioning are scarce. We provide the first comparative assessment of the trophic ecology, ontogenetic shifts, and niche partitioning of the co-occurring tope and juvenile smooth hammerhead around the Azores Islands, mid-north Atlantic, based on delta 13C, delta 15N, and delta 34S (CNS) stable isotope analysis of muscle tissue of the sharks and their putative prey species. Overall, isotopic niches of both species indicated a reliance on similar resources throughout the sampled sizes (tope: 35-190; smooth hammerhead 54-159 cm total length), with significant ontogenetic shifts. Topes displayed a gradual shift to higher trophic levels and a more generalist diet with increasing size (increasing delta 15N values and isotopic niche volumes, respectively), whereas smooth hammerhead diet shifted towards prey with lower delta 34S at a constant trophic level and a more specialized diet than tope of comparable body size (decreasing delta 34S and constant delta 15N and delta 13C values, respectively). Our results indicate contrasting ontogenetic shifts in delta 13C and delta 34S along with pronounced differences between niche overlap of life stages pointing to intra- and interspecific niche partitioning of habitat and prey.

Description: August 14 – August 17, 2023, Kiel (Germany) – Kiel (Germany) CAU pherPraO

Description: FS METEOR Reise M189, 16.04. – 13.05.2023, Walvis Bay (Namibia) – Walvis Bay (Namibia): 1.Wochenbericht (16.04.2023)

Description: FS METEOR Reise M189, 16.04. – 13.05.2023, Walvis Bay (Namibia) – Walvis Bay (Namibia): 2. Wochenbericht (17. - 23.04.2023)

Description: FS METEOR Reise M189, 16.04. – 13.05.2023, Walvis Bay (Namibia) – Walvis Bay (Namibia): 3. Wochenbericht ((24. - 30.04.2023)

Description: FS ALKOR Ausfahrt AL595 GPF 21-2_037 31.05. – 20.06.2023 Kiel – Island – Kiel AUV@Grimsey Bathymetrische und mikrobiologische Untersuchungen am Grimsey Hydrothermalfeld Wochenbericht Nr.1 31.05. – 05.06.2023

Description: FS ALKOR Ausfahrt AL595 GPF 21-2_037 31.05. – 20.06.2023 Kiel – Island – Kiel AUV@Grimsey Bathymetrische und mikrobiologische Untersuchungen am Grimsey Hydrothermalfeld Wochenbericht Nr. 2 6.06. – 12.06.2023

Description: FS ALKOR Ausfahrt AL595 GPF 21-2_037 31.05. – 20.06.2023 Kiel – Island – Kiel AUV@Grimsey Bathymetrische und mikrobiologische Untersuchungen am Grimsey Hydrothermalfeld Wochenbericht Nr.3 13.06. – 19.06.2023

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: 06.06. – 29.07.2023, Townsville (Australien) – Singapur

Description: The Digital Earth Viewer is a tool for the visualisation and exploration of geospatial data in true 3D over time. It runs on Windows, MacOS and Linux and only requires a modern webbrowser to use. Common file formats such as CSV, netCDF, GeoTIFF and many more are natively supported

Description: TRANSFORMERS II, MARIA S. MERIAN 122 Ponta Delgada – Halifax, 19. Oktober bis 9. November 2023 1. Wochenbericht (19.10.- 22.10.2023)

Description: TRANSFORMERS II, MARIA S. MERIAN 122 Ponta Delgada – Halifax, 19. Oktober bis 9. November 2023 2. Wochenbericht (23.10.- 29.10.2023)

Description: TRANSFORMERS II, MARIA S. MERIAN 122, Ponta Delgada – Halifax, 19. Oktober bis 9. November 2023 3. Wochenbericht (30.10.- 05.11.2023)

Description: MSM123 “BELS” Halifax – St. John’s 23. November – 27. Dezember 2023 2.Wochenbericht (27.11. 2023 - 03.12.2023)

Description: MSM123 “BELS” Halifax – St. John’s 23. November – 27. Dezember 2023 3.Wochenbericht (04.12.2023 - 10.12.2023)

Description: MSM123 “BELS” Halifax – St. John’s 23. November – 27. Dezember 2023 4.Wochenbericht (11.12.2023 - 17.12.2023)

Description: MSM123 “BELS” Halifax – St. John’s 23. November – 27. Dezember 2023 5. Wochenbericht (23.12.2023 - 27.12.2023)

Description: Eutrophication-driven harmful algal blooms (HABs) can have secondary effects on larval fishes that rely on estuaries as nurseries. However, few studies worldwide have quantified these effects despite the global rise in eutrophication. This study presents a novel approach using biochemical body condition analyses to evaluate the impact of HABs on the growth and body condition of the larvae of an estuarine resident fish. Recurrent phytoplankton blooms of Heterosigma akashiwo occur in the warm-temperate Sundays Estuary on the southeast coast of South Africa. The response in body condition and assemblage structure on larval estuarine roundherring (Gilchristella aestuaria) was measured in conjunction with bloom conditions, water quality and zooplanktonic prey and predators. Larvae and early juveniles were sampled during varying intensity levels, duration and frequency of hypereutrophic blooms. This study demonstrated that extensive HABs could significantly impact larval roundherring, G. aestuaria, by decreasing larval nutritional condition and limiting their growth, resulting in poor grow-out into the juvenile phase. Poor condition and growth may likely affect recruitment success to adult populations, and since G. aestuaria is an important forage fish and zooplanktivore, poor recruitment will hold consequences for estuarine food webs.

Description: Abundance, biomass and respiration rates of dominant medium- to larger-sized copepod species (ML class) from the upwelling system off Peru (8.5-16°S) were determined along with their carbon ingestion and egestion rates. Small copepods (S class) were included for comparisons of community rates. Overall, abundance/biomass was highest in the upper 50 m and decreased with depth and thus also community ingestion and egestion. Ingestion of the ML class (0-50 m) in shelf regions (14-515 mg C m -2 d -1 ) was lower in the south compared to the north and central study areas, while their offshore ingestion (11-502 mg C m -2 d -1 ) was comparable across regions (8.5-16°S). Ingestion rates (0-50 m) of the S class were in a range similar to those of the ML class in shelf regions (100-417 mg C m -2 d -1 ) but were higher offshore (177-932 mg C m -2 d -1 ). Calanus chilensis and the S class contributed most to total ingestion in the north, while in the south, Centropages brachiatus had the highest community ingestion aside from the S class. Egestion varied from 3-155 mg C m -2 d -1 for the ML class and 30-280 mg C m -2 d -1 for the S class. The high community rates highlight the crucial role of both size classes for carbon budgets in the northern Humboldt Current System off Peru and indicate that the ML class may enhance passive vertical carbon flux, whereas the S class may support carbon remineralization rates in surface waters.

Description: The Humboldt Upwelling System (HUS) supports high levels of primary production and has the largest single-stock fishery worldwide. The high fish production is suggested to be related to high trophic transfer efficiency in the HUS. Mucous-mesh grazers (pelagic tunicates and gastropods) are mostly of low nutritious value and might reduce trophic transfer efficiency when they are locally abundant. Unfortunately, little is known about the spatial dynamics of mucous-mesh grazers from Peruvian waters, limiting our understanding of their potential ecological role(s). We provide a spatial assessment of mucous-mesh grazer abundance from the Peruvian shelf in austral summer 2018/2019 along six cross-shelf transects spanning from 8.5 to 16° S latitude. The community was dominated by appendicularians and doliolids. Salps occurred in high abundance but infrequently and pelagic gastropods were mostly restricted to the North. At low latitudes, the abundance of mucous-mesh grazers was higher than some key species of crustacean mesozooplankton. Transects in this region had stronger Ekman-transport, higher temperature, lower surface turbidity and a broader oxygenated upper water layer compared to higher-latitude transects. Small-scale lateral intrusions of upwelled water were potentially associated with high abundances of doliolids at specific stations. The high abundance and estimated ingestion rates of mucous-mesh grazers in the northern HUS suggest that a large flux of carbon from lower trophic levels is shunted to tunicates in recently upwelled water masses. The data provide important information on the ecology of mucous mesh grazers and stress the relevance to increase research effort on investigating their functioning in upwelling systems.

Description: The Observing Air–Sea Interactions Strategy (OASIS) is a new United Nations Decade of Ocean Science for Sustainable Development programme working to develop a practical, integrated approach for observing air–sea interactions globally for improved Earth system (including ecosystem) forecasts, CO2 uptake assessments called for by the Paris Agreement, and invaluable surface ocean information for decision makers. Our “Theory of Change” relies upon leveraged multi-disciplinary activities, partnerships, and capacity strengthening. Recommendations from 〉40 OceanObs’19 community papers and a series of workshops have been consolidated into three interlinked Grand Ideas for creating #1: a globally distributed network of mobile air–sea observing platforms built around an expanded array of long-term time-series stations; #2: a satellite network, with high spatial and temporal resolution, optimized for measuring air–sea fluxes; and #3: improved representation of air–sea coupling in a hierarchy of Earth system models. OASIS activities are organized across five Theme Teams: (1) Observing Network Design & Model Improvement; (2) Partnership & Capacity Strengthening; (3) UN Decade OASIS Actions; (4) Best Practices & Interoperability Experiments; and (5) Findable–Accessible–Interoperable–Reusable (FAIR) models, data, and OASIS products. Stakeholders, including researchers, are actively recruited to participate in Theme Teams to help promote a predicted, safe, clean, healthy, resilient, and productive ocean.

Description: Expedition SO287 – CONNECT 11.12.2021 - 11.01.2022 Las Palmas-Guayaquil Wochenbericht Nr. 4 27.12.2021- 02.01.2022

Description: Expedition SO287 – CONNECT 11.12.2021 - 11.01.2022 Las Palmas-Guayaquil Wochenbericht Nr. 5 03. - 10.01.2022

Description: FS MARIA S. MERIAN - MSM106 (26.02. - 19.03.2022) 2. Wochenbericht (28.2. – 6.3.2022)

Description: FS MARIA S. MERIAN - MSM106 (26.02. – 19.03.2022) 3. Wochenbericht (07.03. – 13.03.2022)

Description: FS MARIA S. MERIAN - MSM106 (26.02. - 19.03.2022) 1. Wochenbericht (23. – 27.02.2022)

Description: Fahrtabschnitt 14.05. - 22.05.2022

Description: Fahrtabschnitt 30.08. - 04.09.2022

Description: Las Palmas, Spain - Guayaquil, Ecuador 11.12.2021 - 11.02.2022

Description: The blue mussel (Mytilus species complex) is an important ecosystem engineer, and salinity can be a major abiotic driver of mussel functioning in coastal ecosystems. However, little is known about the interactive effects of abiotic drivers and trematode infection. This study investigated the combined effects of salinity and Himasthla elongata and Renicola roscovita metacercarial infections on the filtration capacity, growth, and condition of M. edulis from the Baltic Sea. In a laboratory experiment, groups of infected and uninfected mussels were exposed to a wide range of salinities (6−30, in steps of 3) for 1 mo. Shell growth was found to be positively correlated with salinity and optimal at 18−24 at the end of the experiment, imposed by constraints in shell calcification under lower salinities. Mussel shell growth was not affected by H. elongata infection. While salinity had only a minor effect on tissue dry weight, infected mussels had a significantly lower tissue dry weight than uninfected mussels. Most interestingly, the combination of salinity and trematode infections negatively affected the mussels’ condition indices at lower salinity levels (6 and 9), suggesting that trematode infections are more detrimental to mussels when combined with freshening. A significant positive effect of salinity on mussel filtration was found, with an initial optimum at salinity 18 shifting to 18−24 by the end of the experiment. These findings indicate that salinity and parasite infections act as synergistic stressors for mussels, and enhance the understanding of potential future ecosystem shifts under climate change-induced freshening in coastal waters.

Description: In the deep sea, benthic communities largely depend on organic material from the overlying water column for food. The remains of organisms on the seafloor (food falls) create areas of organic enrichment that attract scavengers. The scavenging rates and communities of food falls of medium-sized squid, fish and jellyfish (1-100 cm) are poorly known. To test our hypothesis that scavenging responses are specific for different food falls, we deployed camera landers baited with squid, jellyfish and fish for 9 to 25 h at 1360 to 1440 m in the southern Norwegian Sea. Image analysis of 8 deployments showed rapid food fall consumption (20.3 +/- 1.4 [SD] to 31.6 +/- 3.7 g h(-1)) by an amphipod-dominated scavenging community that was significantly different between the food fall types. Fish and squid carcasses were mostly attended by amphipods of the genus Eurythenes. Smaller unidentified amphipods dominated the jellyfish experiments together with brittle stars (cf. Ophiocten gracilis) and decapod shrimps (cf. Bythocaris spp.); the latter only occurred on jellyfish carcasses. The removal time for jellyfish (similar to 17 h) was almost twice as long as that for squid and fish (9-10 h). The maximum scavenger abundance was significantly higher on fish carcasses than on jellyfish and squid. The times at which abundances peaked were similar for jellyfish and fish (after 8-9 h) but significantly sooner for squid (3.00 +/- 0.35 h). Our results, although based on a small number of experiments, demonstrate differences in scavenging responses between food fall species, suggesting tight coupling between the diversity and ecology of benthic scavenging communities in the Norwegian Sea.

Description: In this work, we focused on the functional characterization of unicellular eukaryotic assemblages that had previously been taxonomically characterized by 18S rRNA gene amplicon sequencing in a eutrophic coastal site with marked plankton blooms. Biological traits of different functional groups were assigned to the retrieved operational taxonomic units (OTUs). The traits included size, trophic strategy, the presence of spines, mucilage production, colony formation, motility, spore formation, and potential harmfulness. Functional diversity indices were calculated and compared to analogous taxonomic diversity indices, indicating a strong positive coupling of richness and dominance and a negative coupling of evenness, even at a low taxonomic resolution (at the family/genus/species level). Biological trait trade-offs and co-occurrences of specific traits were evident during the succession of plankton blooms. The trophic strategy dominating in the assemblages frequently alternated between autotrophy, mixotrophy, and a few recorded cases of parasitism. Given that there was no indication of nutrient limitation, we suggest that biotic pressures force marine eukaryotes to exploit narrow niches by adopting specific strategies/traits that favour their survival. These traits act by increasing resource acquisition potential and via predator avoidance. This leads to a unique succession of blooms in the system, characterized by adaptations of the bloom taxa that are a direct response to the preceding assemblage.

Description: Recent advancements in telemetry have redefined our ability to quantify the fine-scale movements of aquatic animals and derive a mechanistic understanding of movement behaviours. The VEMCO Positioning System (VPS) is a fine-scale commercial positioning system used to generate highly accurate semi-continuous animal tracks. To date, VPS has been used to study 86 species, spanning 25 taxonomic orders. It has provided fine-scale movement data for critical life stages, from tracking day-old turtle hatchlings on their first foray into the sea to adult fish returning to natal rivers to spawn. These high-resolution tracking data have improved our understanding of the movements of species across environmental gradients within rivers, estuaries and oceans, including species of conservation concern and commercial value. Existing VPS applications range from quantifying spatio-temporal aspects of animal space use and key aspects of ecology, such as rate of movement and resource use, to higher-order processes such as interactions among individuals and species. Analytical approaches have seen a move towards techniques that incorporate error frameworks such as autocorrelated kernel density estimators for home range calculations. VPS technology has the potential to bridge gaps in our fundamental understanding of fine-scale ecological and physiological processes for single and multi-species studies under natural conditions. Through a systematic review of the VPS literature, we focus on 4 principle topics: the diversity of species studied, current ecological and ecophysiological applications and data analysis techniques, and we highlight future frontiers of exploration.

Description: Strong anisotropy of seismic velocity in the Earth’scrust poses serious challenges for seismic imaging. Where in situ seismic properties are not available the anisotropy can be determined from velocity analysis of surface and borehole seismic profiles. This is well established for dense, long-offset reflection seismic data. However, it is unknown how applicable this approach is for sparse seismic reflection data with low fold and short offsets in anisotropic metamorphic rocks. Here we show that anisotropy parameters can be determined from a sparse 3D data set at the COSC-1 borehole site in the Swedish Caledonides and that the results agree well with the seismic anisotropy parameters determined from seismic laboratory measurements on core samples. Applying these anisotropy parameters during 3D seismic imaging improves the seismic image of the high amplitude reflections especially in the vicinity of the lower part of the borehole. Strong reflections in the resulting seismic data show good correlation with the borehole-derived lithology. Our results aid the interpretation and extrapolation of the seismic stratigraphy of the Lower Seve Nappe in Jämtland and other parts in the Caledonides.

Description: Juvenile sea turtles can disperse thousands of kilometers from nesting beaches to oceanic development habitats, aided by ocean currents. In the North Atlantic, turtles dispersing from American beaches risk being advected out of warm nursery grounds in the North Atlantic Gyre into lethally cold Northern European waters (e.g. around the United Kingdom). We used an ocean model simulation to compare simulated numbers of turtles that were advected to cold waters around the UK with observed numbers of turtles reported in the same area over ~5 decades. Rates of virtual turtles predicted to encounter lethal temperatures (≤10 and 15°C, mean 19% ± 2.7) and reach the UK were consistently low (median 0.83%, lower quartile 0.67%, upper quartile 1.02%), whereas there was high inter-annual variability in the numbers of dead or critically ill turtles reported in the UK. Generalized additive models suggest inter-annual variability in the North Atlantic Oscillation (NAO) index to be a good indicator of annual numbers of turtle strandings reported in the UK. We demonstrate that NAO variability drives variability in the dispersion scenarios of juvenile turtles from key nesting regions into the North Atlantic. Coastal effects, such as the number of storms and mean sea surface temperatures in the UK were significant but weak predictors, with a weak effect on turtle strandings. Further understanding how changing environmental conditions such as NAO variability and storms affect the fate of juvenile turtles is vital for understanding the distribution and population dynamics of sea turtles.

Description: Mothers impact the survival and performance of their offspring through the resources they provision, and the degree of maternal investment in an individual offspring can be broadly estimated by egg size for organisms that lack parental care. Animals may also actively maintain symbiotic partnerships with microorganisms through the germ line, but whether microbes are a fundamental component of maternal provisioning is an untested hypothesis in evolutionary symbiosis. We present a preliminary test of this by comparing the egg-associated microbiota of ten sea urchin species with ecological factors known to influence egg size. We found that the microbiota associated with sea urchin eggs had a phylogenetic signal in both composition and richness, which varied between years but not between individuals or within a clutch. Moreover, we found a negative correlation between microbiome richness and taxonomic dominance, and that community diversity covaried with egg size and energetic content but not with pelagic larval duration or latitude. These data suggest that there are multiple parallels between the ecological factors that govern changes in egg size and microbiome composition and diversity, implying that microbial symbionts may be another constituent potentially provided by the mother.

Description: The southern boundary of the Cayman Trough in the Caribbean is marked by the Swan Islands transform fault (SITF), which also represents the ocean-continent transition of the Honduras continental margin. This is one of the few places globally where a transform continental margin is currently active. The CAYSEIS experiment acquired an ∼165-km-long seismic refraction and gravity profile (P01) running across this transform margin, and along the ridge-axis of the Mid-Cayman Spreading Centre (MCSC) to the north. This profile reveals not only the crustal structure of an actively evolving transform continental margin, that juxtaposes Mesozoic-age continental crust to the south against zero-age ultraslow spread oceanic crust to the north, but also the nature of the crust and uppermost mantle beneath the ridge-transform intersection (RTI). The traveltimes of arrivals recorded by ocean-bottom seismographs (OBSs) deployed along-profile have been inverse and forward modelled, in combination with gravity modelling, to reveal an ∼25-km-thick continental crust that has been continuously thinned over a distance of ∼65 km to ∼10 km adjacent to the SITF, where it is juxtaposed against ∼3-4-km-thick oceanic crust. This thinning is primarily accommodated within the lower crust. Since Moho reflections are only sparsely observed, and, even then, only by a few OBSs located on the continental margin, the 7.5 km s-1 velocity contour is used as a proxy to locate the crust-mantle boundary along-profile. Along the MCSC, the crust-mantle boundary appears to be a transition zone, at least at the seismic wavelengths used for CAYSEIS data acquisition. Although the traveltime inversion only directly constrains the upper crust at the SITF, gravity modelling suggests that it is underlain by a higher density (〉3000 kg m-3) region spanning the width (∼15 km) of its bathymetric expression, that may reflect a broad region of metasomatism, mantle hydration or melt-depleted lithospheric mantle. At the MCSC ridge-axis to the north, the oceanic crust appears to be forming in zones, where each zone is defined by the volume of its magma supply. The ridge tip adjacent to the SITF is currently in a magma rich phase of accretion. However, there is no evidence for melt leakage into the transform zone. The width and crustal structure of the SITF suggests its motion is currently predominantly orthogonal to spreading. Comparison to CAYSEIS Profile P04, located to the west and running across-margin and through 10 Ma MCSC oceanic crust, suggests that, at about this time, motion along the SITF had a left-lateral transtensional component, that accounts for its apparently broad seabed appearance westwards.

Description: FS Alkor Reise 556, Fahrtabschnitt 14.05. - 22.05.2021 Die Ostsee hat im Rahmen des Klimawandels und wachsender anthropogener Nutzung in den letzten 50 Jahren tiefgreifende und im globalen Vergleich besonders schnell ablaufende Veränderungen, wie Erwärmung, Versauerung, Eutrophierung, zunehmenden Sauerstoffmangel, Überfischung, und die Ausbreitung invasiver Arten, erfahren. Die ökologischen und ökonomischen Konsequenzen dieser langfristigen Veränderungen sind durch kurzfristige Projekte nur schwer zu verfolgen. Umso wichtiger sind Langzeitdatenreihen, die auch dekadische Muster abbilden. Das Hauptziel der Ausfahrt AL556 ist es, durch Probennahmen und hydrographische Messungen eine der besten verfügbaren Langzeitdatenreihen für die pelagische Ostsee fortzusetzen. So wurden seit 1986 in den tiefen Becken der Ostsee mit Hauptfokus auf dem Bornholmbecken mit konsistenter Methodik pelagische Schleppnetzfischerei und Fischprobennahmen, Beprobungen des pelagischen Nahrungsnetzes (Phyto- und Zooplankton einschließlich Ichthyo- und gelatinösem („Quallen“) Plankton), ozeanographische/hydrographische Messungen und Hydroakustikaufnahmen durchgeführt. Diese Arbeiten werden während der AL556 weitergeführt, wobei die Ausfahrt aufgrund einer Corona-bedingten Unterbrechung der Langzeitdatenreihe in 2020 von besonderer Bedeutung ist. Die gewonnenen Proben und Daten sind dabei für verschiedene Projekte und internationale Kollaborationen der Abteilung „Marine Evolutionary Ecology“ am GEOMAR relevant. Dazu gehören insbesondere das Projekt "Fischereiindizierte Evolution" im Rahmen der DFG-Graduiertenschule TransEvo (CAU /GEOMAR), und das EU Horizon 2020 Projektes GoJelly. Sonderprojekte in 2021 sind zudem die Isolation von marinen Viren und der Phytoyplanktonart Ostreococcus für das Projekt Marine Mikroben und Viren der Ostsee unter dem Einfluß des Klimawandels und Probennahmen für die Untersuchung der Nahrungsökologie von Fischlarven und planktivoren adulten Fischen mit Hilfe molekularbiologischer Ansätze („Metabarcoding“).

Description: Modern digital scientific workflows - often implying Big Data challenges - require data infrastructures and innovative data science methods across disciplines and technologies. Diverse activities within and outside HGF deal with these challenges, on all levels. The series of Data Science Symposia fosters knowledge exchange and collaboration in the Earth and Environment research community.

Description: Global models show generally a large model-data misfit with regard to oxygen. One of the most intense OMZs is located in the Arabian Sea. The scripts serve to give an overview of the main model deficiencies in the Indian Ocean with a detailed comparison of the historical state of ten climate models from the 5th coupled model intercomparison project (CMIP5) that present our present-day understanding of physical and biogeochemical processes.

Description: CMSY++ is an advanced state-space Bayesian method for stock assessment that estimates fisheries reference points (MSY, Fmsy, Bmsy) as well as status or relative stock size (B/Bmsy) and fishing pressure or exploitation (F/Fmsy) from catch and (optionally) abundance data, a prior for resilience or productivity (r), and broad priors for the ratio of biomass to unfished biomass (B/k) at the beginning, an intermediate year, and the end of the time series. For the purpose of this User Guide, the whole package is referred to as CMSY++ whereas the part of the method that deals with catch-only data is referred to as CMSY (catch MSY), and the part of the method that requires additional abundance data is referred to as BSM (Bayesian Schaefer Model). Both methods are based on a modified Schaefer surplus production model (see paper cited above for more details). The main advantage of BSM, compared to other implementations of surplus production models, is the focus on informative priors and the acceptance of short and incomplete (i.e., fragmented, with missing years) abundance data. This document provides a simple step-by-step guide for researchers who want to apply CMSY++ to their own data.

Description: With this script, the Meridional Overturning Circulation (MOC) can be computed from NEMO ocean-model output for the whole globe or the Atlantic (AMOC), Indic (IMOC) and Pacific (PMOC) subbasins. The MOC is computable in z- and sigma coordinates. Moreover, for nested configurations, it is possible to combine data from both host and nest grids. Finally, it is possible to take into account of that the ORCA model grid is curvilinear north of 20°N: it is possible to compute the northward velocity component from the velocity field in x- and y- directions and to sum up the meridional flux over latitudional bands instead of in x-direction. When both steps are applied, the resulting MOC shows however strong variability in meridional direction. It needs to be clarified, whether this is realistic or not. The software is provided in the form of the jupyter notebook "MOC.ipynb" which includes more informations on the possibilites of the computations and an extensive appendix section with comparisons to computations with cdftools, as well as with details on the computation of the MOC including nest data and taking the curvilinearity of the grid into account. Necessary python modules are listed at the beginning of the document.

Description: Expedition SO287 – CONNECT 11.12.2021 - 11.01.2022 Las Palmas-Guayaquil Wochenbericht Nr. 3 20.12. - 26.12.2021

Description: 19.07. – 27.07.2021, Kiel (Germany) – Kiel (Germany) BALTEACH - 1

Description: Expedition SO287 – CONNECT 11.12.2021 - 11.01.2022 Las Palmas - Guayaquil 1. Wochenbericht 10.12. - 12.12.2021

Description: Expedition SO287 – CONNECT 11.12.2021 - 11.01.2022 Las Palmas - Guayaquil 2. Wochenbericht 13.12. - 19.12.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 1. WOCHENBERICHT 27.06. - 04.07.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 5. WOCHENBERICHT 26.07. - 01.08.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 3. WOCHENBERICHT 12.07. - 18.07.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 2. WOCHENBERICHT 05.07. - 11.07.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 6. WOCHENBERICHT 02.08. - 08.08.2021

Description: SONNE 284 Mooring Rescue Emden - Emden, 27.06. - 17.08.2021 4. WOCHENBERICHT 19.07. - 25.07.2021

Description: Dates of Cruise: 02.-06.08.2021 Areas of Research: Aquarium West Shore Port Calls: Grenå DK (03.08. - 05.08.2021, 2 nights) Institute: GEOMAR Helmholtz Centre for Ocean Research Kiel Acquisition of living marine organism for the institute’s own aquarium in the northern Kattegat.

Description: The Net-Zero-2050 cluster aims for a national roadmap for net zero CO2 emissions by 2050, including integrated scenario analyses and negative emission technology assessment (see fact sheet Net-Zero-2050 Structure Project 1). This national target to substantially reduce national CO2 emissions by 2050 stems from the objective to comply with the global long-term temperature goal of well below 2°C of the Paris Agreement (UNFCCC, 2015). Within the cluster it is therefore important to decide on an approach for deriving a national remaining carbon budget from global emissions trajectories in agreement with the Paris Climate Agreement’s longterm temperature goal (UNFCCC, 2015). Allocating national carbon budgets is a balance of environmental effectiveness, equity, national capacity and ability, political feasibility, economic efficiency and technical requirements (Gignac and Matthews, 2015; Höhne et al., 2003; 2014). Given Germany’s capacity and abilities, we decided to follow a sustainable growth trajectory with a convergence phase to equal-per-capita CO2 emissions by 2035, and a net zero CO2 emissions trajectory after 2050 until the end of the century. This approach leads to a remaining Germany CO2 budget of 9 GtCO2 (from 1st January 2018 to 2050 and 2100), which we propose to be used across the Net-Zero-2050 cluster. The remaining carbon budget will serve as a target to be used in all work packages in a concerted way, either qualitatively or quantitatively, and in accordance with other work packages (see also fact sheet Net-Zero-2050 Energy Scenario Approach). The calculated budget is at the lower end of the national budget if allocated by the grandfathering approach (emissions are allocated with respect to today’s emissions shares: 5.5-13.1 GtCO2), but slightly higher than the highest estimate of an equal-per-capita remaining carbon budget (emissions are allocated with respect to Germany’s share of the global population: 3.5-8.4 GtCO2) The 9 GtCO2 national remaining CO2 budget, 6.9 GtCO2 from 1st January 2021, will need to be broken down by category (e.g. energy, land use, industrial processes, and man-made sinks and sources; see Gap Analysis Report) in order to provide a consistent approach across work packages.

Description: This report is thought as a guide to early hydrographic log sheets of bottle data obtained by the former Institut für Meereskunde, Kiel (IFMK, now integrated into GEOMAR) in the post-war years 1946 to 1956, and which in summer 2018 when a building used by GEOMAR was to clear were not available in digitized format at GEOMAR. The data mostly were taken by the research cutter FK “Südfall” in the Baltic. It turned out that some of these data from 1950 to 1956 were available in digitized form at the on-line data bank of the International Council for the Exploration of the Sea (ICES). Comparison with the original logged data sheets, however, showed that they needed to be improved w/r to time and position and to be completed by missing data. This report shortly describes the methods of sampling and measuring these old data, and the processing steps applied to improve the data set by using the data log sheets before archiving and submitting the now improved and complete data set to data centres for archiving.

Description: 14.6. – 18.6.2021 Areas of Research: Public relations and aquarium west shore Port Calls: Grena/ DK (15.6. – 17.6.2021) Acquisition of living marine organisms for the public relations division (GEOMAR), the institute’s own aquarium and the Multimar Wattforum - Tönning in the northern Kattegat.

Description: Diatoms often dominate phytoplankton in temperate, polar and upwelling regions. Decreases in silicate availability or silicon to nitrogen (Si:N) ratios may induce silicon limitation in diatoms and lower their proportion within phytoplankton communities. The effects of such changes on the nutritional quality of phytoplankton are not well understood. To examine how changing Si:N ratios affect plankton nutritional value, we applied a range of Si:N ratios on a natural plankton community and manipulated grazing pressure to assess top-down effects of copepod selective grazing. Diatom proportion in phytoplankton increased with increasing Si:N ratios and so did phytoplankton nutritional quality in terms of major fatty acid concentrations, such as polyunsaturated fatty acids, docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids. However, stoichiometric quality (carbon to nitrogen and carbon to phosphorus ratios), DHA:EPA and omega 3:6 (omega 3:omega 6) ratios declined with increasing Si:N ratios, suggesting that proportions between essential compounds in copepod diet may be more favorable in lowered Si:N ratios. Copepods had a negative effect on DHA contents, DHA:EPA and omega 3:omega 6 ratios, indicating possible selective grazing on more nutritious plankton. Our findings show that declining silicate concentrations can affect stoichiometric and biochemical quality of phytoplankton, which copepods can also moderate by selective grazing.

Description: Temperature and dehydration stress are two major co-occurring environmental stressors threatening the physiology, biochemistry, and ecology of insects. As such, understanding adaptive responses to desiccation stress is critical for predicting climate change impacts, particularly its influence on insect invasions. Here, we assessed water balance and desiccation resistance of the invasive Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), and infer how eco-physiology shapes its niche. We measured basal body water and lipid content, water loss rates (WLRs), and desiccation resistance in larvae (second to fourth instars) and adults. Body -water, -lipid, and WLRs significantly varied across life stages. Second instars recorded the lowest while fourth instars exhibited the highest body water and lipid content. Adult body water and lipid content were higher than second and third instars and lower than fourth instars while proportion of body water and lipid contents were highest in adults and second larval instars respectively. Water loss rates were significantly highest in fourth-instar larvae compared to other life stages, but differences among stages were less apparent at longer exposure durations (48 h). Desiccation resistance assays showed that second instars had greatest mortality while fourth-instar larvae and adults were the most desiccation tolerant. Our results show that T. absoluta fourth-instar larvae and adults are the most resilient developmental stages and potentially contribute most to the invasion success of the pest in arid environments. Incorporation of these species-specific eco-physiological traits in predictive models can help refine invasive species potential spread under changing climates.

Description: The fishery for Northern Atlantic cod (Gadus morhua) off Newfoundland and Labrador, Eastern Canada, presents the most spectacular case of an exploited stock crashed in a few decades by an industrial bottom trawl fishery under a seemingly sophisticated management regime after half a millennium of sustainable fishing. The fishery, which had generated annual catches of 100000 to 200000 tonnes from the beginning of the 16th century to the 1950s, peaked in 1968 at 810000 tonnes, followed by a devastating collapse and closure 24 years later. Since then, stock recovery may have been hindered by premature openings, with vessels targeting the remains of the cod population. Previous research paid little attention towards using multicentury time series to inform sustainable catches and recovery plans. Here, we show that a simple stock assessment model can be used to model the cod population trajectory for the entire period from 1508 to 2019 for which catch estimates are available. The model suggests that if fishing effort and mortality had been stabilized in the 1980s, precautionary annual yields of about 200000 tonnes could have been sustained. Our analysis demonstrates the value of incorporating prior knowledge to counteract shifting baseline effects on reference points and contemporary perceptions of historical stock status.

Description: A large-volume mesocosm-based nutrient perturbation experiment was conducted off the island of Hawai‘I, USA, to investigate the response of surface ocean phytoplankton communities to nutrient addition of macronutrients, trace metals, and vitamins and to assess the feasibility of using mesocosms in the open ocean. Three free-drifting mesocosms (~60 m3) were deployed: one mesocosm served as a control (no nutrient amendments), a second (termed +P) was amended with nitrate (N), silicate (Si), phosphate (P) and a trace metal + vitamin mixture, and a third (termed -P) was amended with N, Si, and a trace metal + vitamin mixture but no P. These mesocosms were unreplicated due to logistical constraints and hence differences between treatments are qualitative. After 6 d, the largest response of the phytoplankton community was observed in the +P mesocosm where chlorophyll a (chl a) and 14C-based primary production were 2–3× greater than the -P mesocosm and 4–6× greater than the control. Comparison between mesocosm and ‘microcosm’ incubations (20 l) revealed differences in the magnitude and timing of production and marked differences in community structure with a reduced response of diatoms in microcosm treatments. Notably, we also observed pronounced declines in Prochlorococcus populations in all treatments: although these were greater in microcosms (up to 99%). Overall, this study confirmed the feasibility of deploying free-drifting mesocosms in the open ocean as a potentially powerful tool to investigate ecological impacts of nutrient perturbations and constitutes a valuable first step towards scaling plankton manipulation experiments.

Description: The trophic ecology of mixotrophic, zooxanthellate jellyfishes potentially spans a wide spectrum between autotrophy and heterotrophy. However, their degree of trophic plasticity along this spectrum is not well known. To better characterize their trophic ecology, we sampled the zooxanthellate medusa Mastigias papua in contrasting environments and sizes in Palau (Micronesia). We characterized their trophic ecology using isotopic (bulk δ13C and δ15N), elemental (C:N ratios), and fatty acid compositions. The different trophic indicators were correlated or anti-correlated as expected (Pearson’s correlation coefficient, rP 〉 0.5 or 〈 -0.5 in 91.1% of cases, p 〈 0.05), indicating good agreement. The sampled M. papua were ordered in a trophic spectrum between autotrophy and heterotrophy (supported by decreasing δ13C, C:N, proportion of neutral lipid fatty acids (NLFA:TLFA), n-3:n-6 and increasing δ15N, eicosapentaenoic acid to docosahexaenoic acid ratio (EPA:DHA)). This trophic spectrum was mostly driven by sampling location with little influence of medusa size. Moreover, previous observations have shown that in a given location, the trophic ecology of M. papua can change over time. Thus, the positions on the trophic spectrum of the populations sampled here are not fixed, suggesting high trophic plasticity in M. papua. The heterotrophic end of the trophic spectrum was occupied by non-symbiotic M. papua, whereas the literature indicates that the autotrophic end of the spectrum corresponds to dominant autotrophy, where more than 100% of the carbon requirement is obtained by photosynthesis. Such high trophic plasticity has critical implications for the trophic ecology and blooming ability of zooxanthellate jellyfishes

Description: The Asian shore crab Hemigrapsus takanoi, native to the northwest Pacific Ocean, was recently discovered in Kiel Fjord (southwestern Baltic Sea). In laboratory experiments, we tested the salinity tolerance of H. takanoi across 8 levels (0 to 35) and across 3 life history stages (larvae, juveniles and adults) to assess its potential to invade the brackish Baltic Sea. Larval development at different salinities was monitored from hatching to the megalopa stage, while survival and feeding of juveniles and adults were assessed over 17 d. Larvae of H. takanoi were able to complete their development to megalopa at salinities 〉= 20 and the time needed after hatch to reach this stage did not differ between salinities of 20, 25, 30 and 35. At a salinity of 15, larvae still reached the last zoea stage (zoea V), but development to the megalopa stage was not completed. All juveniles and adults survived at salinities from 5 to 35. Feeding rates of juveniles increased with increasing salinity across the entire salinity range. However, feeding rates of adults reached their maximum between salinities of 15 and 35. Our results indicate that both juveniles and adults of H. takanoi are euryhaline and can tolerate a wide range of salinities, at least for the time period tested (2 wk). However, larval development was impaired at salinities lower than 20, which may prevent the spread of H. takanoi into the Baltic Proper.

Description: The freshwater sponge Ephydatia muelleri and its Chlorella-like algal partner is an emerging model for studying animal: algal endosymbiosis. The sponge host is a tractable laboratory organism, and the symbiotic algae are easily cultured. We took advantage of these traits to interrogate questions about mechanisms that govern the establishment of durable intracellular partnerships between hosts and symbionts in facultative symbioses. We modified a classical experimental approach to discern the phagocytotic mechanisms that might be co-opted to permit persistent infections, and identified genes differentially expressed in sponges early in the establishment of endosymbiosis. We exposed algal-free E. muelleri to live native algal symbionts and potential food items (bacteria and native heat-killed algae), and performed RNA-Seq to compare patterns of gene expression among treatments. We found a relatively small but interesting suite of genes that are differentially expressed in the host exposed to live algal symbionts, and a larger number of genes triggered by host exposure to heat-killed algae. The upregulated genes in sponges exposed to live algal symbionts were mostly involved in endocytosis, ion transport, metabolic processes, vesicle-mediated transport, and oxidation–reduction. One of the host genes, an ATP-Binding Cassette transporter that is downregulated in response to live algal symbionts, was further evaluated for its possible role in the establishment of the symbiosis. We discuss the gene expression profiles associated with host responses to living algal cells in the context of conditions necessary for long-term residency within host cells by phototrophic symbionts as well as the genetic responses to sponge phagocytosis and immune-driven pathways.

Description: Marine sponges play a major ecological role in recycling resources on coral reef ecosystems. The cycling of resources may largely depend on the stability of the host-microbiome interactions and their susceptibility to altered environmental conditions. Given the current coral to algal phase shift on coral reefs, we investigated whether the sponge-associated bacterial communities of four sponge species, with either high or low microbial abundances (HMA and LMA), remain stable at two reefs sites with different coral to algae cover ratios. Additionally, we assessed the bacterial community composition of two of these sponge species before and after a reciprocal transplantation experiment between the sites. An overall stable bacterial community composition was maintained across the two sites in all sponge species, with a high degree of host-specificity. Furthermore, the core bacterial communities of the sponges remained stable also after a 21-day transplantation period, although a minor shift was observed in less abundant taxa (〈 1%). Our findings support the conclusion that host identity and HMA-LMA status are stronger traits in shaping bacterial community composition than habitat. Nevertheless, long-term microbial monitoring of sponges along with benthic biomass and water quality assessments are needed for identifying ecosystem tolerance ranges and tipping points in ongoing coral reef phase shifts.

Description: Understanding the underlying ecological factors that affect the distribution patterns of organisms is vital for their conservation. Cephalopods such as giant warty squids Moroteuthopsis longimana are important in the diets of marine predators, including grey-headed albatrosses Thalassarche chrysostoma, yet our understanding of their habitat and trophic ecology remains limited. We investigated the habitat and trophic niche utilised by M. longimana through the delta C-13 and delta N-15 profiles captured in their beaks. M. longimana beaks were collected around grey-headed albatross nests at the Prince Edward Islands during 2004 and 2013 (n = 40 beaks). The results showed distinctly Antarctic distributions (delta C-13 = -24.0 +/- 1.0 parts per thousand, mean +/- SD) for M. longimana, consistent with albatrosses foraging at the Southwest Indian Ridge, as opposed to broader foraging zones utilised by albatrosses from Iles Crozet and Iles Kerguelen. Slightly lower delta N-15 values (5.4 +/- 0.7 parts per thousand) were found compared to other islands in the Indian Sector of the Southern Ocean, which may indicate more crustaceans in the squid diets. Sequential sampling along the lateral walls of individual beaks (n = 4) revealed ontogenetic shifts in delta C-13 and delta N-15 values, but individual variation in these shifts requires further investigation.

Description: The maximum sustainable yield (MSY) concept is widely considered to be outdated and misleading. In response, fisheries scientists have developed models that often diverge radically from the first operational version of the concept. We show that the original MSY concept was deeply rooted in ecology and that going back to that version would be beneficial for fisheries, not least because the various substitutes have not served us well.

Description: Food webs are central entities mediating processes and external pressures in marine ecosystems. They are essential to understand and predict ecosystem dynamics and provision of ecosystem services. Paradoxically, utilization of food web knowledge in marine environmental conservation and resource management is limited. To better understand the use of knowledge and barriers to incorporation in management, we assess its application related to the management of eutrophication, chemical contamination, fish stocks, and non-indigenous species. We focus on the Baltic, a severely impacted, but also intensely studied and actively managed semi-enclosed sea. Our assessment shows food web processes playing a central role in all four areas, but application varies strongly, from formalized integration in management decisions, to support in selecting indicators and setting threshold values, to informal knowledge explaining ecosystem dynamics and management performance. Barriers for integration are complexity of involved ecological processes and that management frameworks are not designed to handle such information. We provide a categorization of the multi-faceted uses of food web knowledge and benefits of future incorporation in management, especially moving towards ecosystem-based approaches as guiding principle in present marine policies and directives. We close with perspectives on research needs to support this move considering global and regional change.

Description: The maraena whitefish Coregonus maraena is a threatened anadromous species in the North Sea, which in the past was decimated to near extinction. Since the late 1980s, several re-establishment programs have been implemented in rivers draining into the North Sea, but the scientific basis for sustainable conservation measures is often lacking, since little is known about the biology of this species. In this study, otolith microchemistry of fish ranging from 24.6 to 58.4 cm in total length (median 31.3 cm, SD 8.4 cm) was used to characterize the migration behavior of a reintroduced population of maraena whitefish from the River Elbe, Germany. Our analyses revealed the presence of 3 different migration patterns: (1) one-time migration into high-salinity habitat (North Sea) within the first year of life (29.6%), (2) multiple migrations between lowland high-salinity habitats starting in the first year of life (14.8%) and (3) permanent residency within low-salinity habitats, a pattern displayed by the majority (55.6%) of sampled individuals. Not only do these results reveal differential migration behavior, but they also indicate that permanent river residency is common in the River Elbe population of C. maraena. The role of the Elbe as both a feeding and a spawning habitat should thus be considered more explicitly in current conservation measures to support recovery of this species.

Description: Understanding the behavioural ecology of endangered taxa can inform conservation strategies. The activity budgets of the loggerhead turtle Caretta caretta are still poorly understood because many tracking methods show only horizontal displacement and ignore dives and associated behaviours. However, time-depth recorders have enabled researchers to identify flat, U-shaped dives (or type 1a dives) and these are conventionally labelled as resting dives on the seabed because they involve no vertical displacement of the animal. Video- and acceleration-based studies have demonstrated this is not always true. Focusing on sea turtles nesting on the Cabo Verde archipelago, we describe a new metric derived from magnetometer data, absolute angular velocity, that integrates indices of angular rotation in the horizontal plane to infer activity. Using this metric, we evaluated the variation in putative resting behaviours during the bottom phase of type 1a dives for 5 individuals over 13 to 17 d at sea during a single inter-nesting interval (over 75 turtle d in total). We defined absolute resting within the bottom phase of type 1a dives as periods with no discernible acceleration or angular movement. Whilst absolute resting constituted a significant proportion of each turtle’s time budget for this 1a dive type, turtles allocated 16−38% of their bottom time to activity, with many dives being episodic, comprised of intermittent bouts of rest and rotational activity. This implies that previously considered resting behaviours are complex and need to be accounted for in energy budgets, particularly since energy budgets may impact conservation strategies. © The authors 2021. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are unrestricted. Authors and original publication must be credited

Description: Maria S. Merian - MSM94 - SNAP Westlicher Subpolarer Atlantik 02.08.2020 - 06.09.2020

Description: 31.8.-6.9.2020

Description: 7.9.-13.9.2020

Description: 17.-23.8.2020

Description: 14.9.-20.9.2020

Description: 21.07 – 31.07.2020, Warnemünde (Germany) – Kiel (Germany) BALTEACH - 1

Description: 14. - 16.08.2020

Description: 28.9.-3.10.2020