ALBERT

Description: In the boreal summer of 2021, the equatorial Atlantic experienced the strongest warm event, that is, Atlantic Niño, since the beginning of satellite observations in the 1970s. Such events have far‐reaching impacts on large‐scale wind patterns and rainfall over the surrounding continents. Yet, developing a paradigm of how Atlantic Niño interacts with the upper‐ocean currents and intraseasonal waves remains elusive. Here we show that the equatorial Kelvin wave associated with the onset of the 2021 Atlantic Niño modulated both the background flow and the eddy flux of the equatorial upper‐ocean circulation, causing an extremely weak and delayed tropical instability wave (TIW) season. TIW‐induced variations of sea surface temperature (SST), sea surface salinity, sea surface height, and eddy temperature advection were exceptionally weak during May to July, the climatological peak of TIW activity, but rebounded in August when higher than normal variability was observed. Moored velocity data at 23°W show that during the peak of the 2021 Atlantic Niño from June to August, the Equatorial Undercurrent was deeper and stronger than usual. An anomalously weak eddy momentum flux strongly suppressed barotropic energy conversion north of the equator from May to July, likely contributing to low TIW activity. Reduced baroclinic energy conversion also might have played a role, as the meridional gradient of SST was sharply reduced during the Atlantic Niño. Despite extremely weak TIW velocities, modest intraseasonal variability of chlorophyll‐a (Chl‐ a ) was observed during the Atlantic Niño, due to pronounced meridional Chl‐ a gradients that partly compensated for the weak TIWs. Plain Language Summary Every few years the eastern equatorial Atlantic Ocean is significantly warmer than usual during boreal summer. Such warm events are referred to as Atlantic Niño events, and share similarities with El Niño events in the Pacific. In 2021, the strongest Atlantic Niño in at least four decades was observed in the equatorial Atlantic. This study is the first that investigates the complex interaction between Atlantic Niño, tropical Atlantic upper‐ocean currents, and equatorial waves based on various observational data sets. We show that the developing 2021 Atlantic Niño weakened both the background flow and the variability of near‐surface currents in May, which in turn largely reduced the strength of intraseasonal (20–50 days) waves that are usually generated by instability of the upper‐ocean zonal currents. As a consequence, the cooling effect that these waves usually have north of the equator and the warming effect along the equator vanished from May to July 2021. Interestingly, variability of chlorophyll concentration was enhanced, suggesting that enhanced meridional chlorophyll gradients compensated for reduced wave activity. Key Points The developing 2021 Atlantic Niño led to weaker equatorial surface currents and reduced vertical shear of upper‐ocean horizontal velocity Strong reduction of the surface flow, eddy flux, and meridional temperature gradient in May caused extremely weak and delayed tropical instability wave (TIW) season Reduced meridional TIW advection contributed to sharpen the north equatorial Chl‐ a front resulting in modest intraseasonal Chl‐ a variability

Description: The presentwork describes fields of UV-radiances at ground level from the simulation of a Monte-Carlo radiative transfer model as well as the differences of these to observed values. The optical properties of the atmosphere, like the albedo, the single scattering albedo and the Aerosol Optical Depth, were varried, in order to minimize the differences compared with the obbserved radiances. Maximum differences occure with viewing angles towards the sun, which did not become balanced also by the variation of the initial parameters into the model. These are partially due to the smoothing of the measured data in this direction. It could be obtained a optimal agreement without the the sun direction by taking absorbing aerosol particles into account. The difference with viewing angles in the direction of the sun bcomes recognizable in the strewing diagram. The use of observed atmosphere profiles of the huminty, ozone and the aerosols in the radiative transfer model do not supply th most optimal agreement with the measured radiances. It is an agreement with inconsistent behavior, since no uniform atmosphere condition for each wavelength could be found.

Description: Die Analyse der chemischen Mikrostruktur von Fisch-Otolithen ist eine verhältnismäßig moderne Methode, die die Rekonstruktion der Lebensgeschichte gefangener Fische ermöglicht und Informationen über Wanderverhalten und Verbreitung der Fische liefert. Voraussetzung dafür ist allerdings die genaue Kenntnis der Einflüsse sämtlicher Umweltfaktoren auf die Elementzusammensetzung der Otolithen. Im Rahmen dieser Arbeit wurden die Einflüsse von Salinität und Temperatur auf das Sr/Ca-Verhältnis der Flunder (Platichthys flesus) erstmals untersucht. Hierzu wurden die Sr/Ca-Verhältnisse der Otolithen von Flundern aus drei verschiedenen konstanten Salinitäten (22, 17, 12 psu) verglichen. Ein entsprechender Versuch erfolgte mit drei verschiedenen Temperaturen (22°, 19°, 15°C). In beiden Versuchen war kein signifikanter Einfluss des jeweiligen Umweltfaktors auf das Sr/Ca-Verhältnis nachweisbar. Einen deutlich größeren Effekt hatten die individuellen Unterschiede zwischen den Sr/Ca-Verhältnissen einzelner Fische aus identischen Bedingungen. In zwei weiteren Versuchen erfuhr die Salinität, bzw. die Temperatur in einem ähnlich kleinskaligen Wertebereich eine stetige Veränderung. Die Ergebnisse der Versuche zeigten für beide Umweltfaktoren einen positiv korrelierten Zusammenhang zum Sr/Ca-Verhältnis. Der beobachtete Einfluss der Salinität war jedoch eindeutiger zu erkennen. Die Ergebnisse zeigen, dass Flundern sich sehr effektiv in ihrer Osmoregulation an längerfristige Änderungen in den Umweltbedingungen anpassen können. Für ergänzende Untersuchungen wurden Flundern aus der Ostsee in Süßwasser gehalten. Dieser Versuch zeigte, dass großskalige Salinitätsunterschiede auch von der Flunder nicht kompensiert werden können, so dass die Analyse des Sr/Ca-Verhältnisses von Flunder-Otolithen zumindest der Rekonstruktion von Wanderungen entlang eines starken Salinitätsgradienten dienen kann. Zusätzlich wurden juvenile Sprotten ( Sprattus sprattus) veränderten Salinitäten ausgesetzt und ein positiv korrelierter Bezug zwischen der Salinität und dem Sr/Ca-Verhältnis der Sprott-Otolithen gefunden. Weiterhin konnten Wanderungen zwischen Gewässern stark unterschiedlicher Salinität, anhand der Sr/Ca-Verhältnisse der Otolithen, für mehrere Aale (Anguilla anguilla) und Flussbarsche (Perca fluviatilis) rekonstruiert werden. Otolithenbereiche, die in Süß-, Ostsee- oder Atlantikwasser gebildet wurden, konnten dabei sicher unterschieden werden. Es wurden außerdem deutliche artspezifische Unterschiede in den Sr/Ca-Verhältnissen der untersuchten Fischarten gefunden. Dies bedeutet für zukünftige Freiland-Studien, dass für jede zu untersuchende Fischart eine eigene Kalibration der Zusammenhänge zwischen Umweltfaktoren und Elementzusammensetzung der Otolithen, unter Laborbedingungen durchzuführen ist.

Description: Volcanogenic massive sulfide deposits may represent a significant future source of Te, which is a critical element important for the green energy transition. Tellurium is enriched in these settings by up to 10,000 times over its crustal abundance, indicating that fluids in sea-floor hydrothermal systems may transport and precipitate Te. The major element composition of these hydrothermal fluids is controlled by fluid-rock interaction and is well documented based on experimental, modeling, and natural studies; however, controls on Te mobility are still unknown. To better understand Te enrichment in this deposit type, numerical simulations of the mafic-hosted Vienna Woods and the felsic-hosted Fenway sea-floor vents in the Manus basin were performed to predict Te mobility in modern sea-floor hydrothermal vent fluids and Te deposition during sulfide formation. These simulations demonstrate that the mobility of Te in sea-floor hydrothermal systems is primarily controlled by fluid redox and temperature. Tellurium mobility is low in reduced hydrothermal fluids, whereas mobility of this metal is high at oxidized conditions at temperatures above 250°C. Numerical simulations of the reduced vent fluids of the mafic-hosted Vienna Woods site at the back-arc spreading center in the Manus basin yielded Te concentrations as low as 0.2 ppt. In contrast, the more oxidized model fluids of the felsic-hosted Fenway site located on Pual Ridge in the eastern Manus basin contain 50 ppt Te. The models suggest that Te enrichment in these systems reflects rock-buffer control on oxygen fugacity, rather than an enriched source of Te. In fact, the mafic volcanic rocks probably contain more Te than felsic volcanic rocks. The association of elevated Te contents in the felsic-hosted Fenway system likely reflects magmatic volatile input resulting in lower pH and higher Eh of the fluids. More generally, analysis of sulfide samples collected from modern sea-floor vent sites confirms that redox buffering by the host rocks is a first-order control on Te mobility in hydrothermal fluids. The Te content of sulfides from sea-floor hydrothermal vents hosted by basalt-dominated host rocks is generally lower than those of sulfides from vents located in felsic volcanic successions. Literature review suggests that this relationship also holds true for volcanogenic massive sulfides hosted in ancient volcanic successions. Results from reactive transport simulations further suggest that Te deposition during sulfide formation is primarily temperature controlled. Modeling shows that tellurium minerals are coprecipitated with other sulfides at high temperatures (275°–350°C), whereas Te deposition is distinctly lower at intermediate (150°–275°C) and low temperatures (100°–150°C). These predictions agree with geochemical analyses of sea-floor sulfides as Te broadly correlates positively with Cu and Au enrichment in felsic-hosted systems. The findings of this study provide an important baseline for future studies on the behavior of Te in hydrothermal systems and the processes controlling enrichment of this critical mineral in polymetallic sulfide ores.

Description: The current work investigates the effect of small-scale cloud structures on the solar radiative fluxes. To this end a scaling algorithm has been developed, which constructs small scale cloud structures from predefined three-dimensional clouds. Domain averaged solare radiative fluxes have been calculated by means of a Monte-Carlo radiative transfer model as a function of the resolved cloud scale. lt turned out that the initial horizontal resolution of 1000 m already provides quite accurate results. Higher resolutions only lead to small changes in the radiative fluxes. This finding consolidates the results of previous work which made use of a 1000 m resolution. Largest influence of cloud scale was found at absorbing wavelengths and for large solar zenith angles. A further investigation considered the influence of the variability of cloud microphysical properties ( droplet sizes) on the radiative fluxes. To this end, the microphysics of spatially high resolved clouds have been homogenized for each layer and the resulting radiative properties have been compared to those of the original clouds. Also this part shows that the original horizontal variation of the cloud microphysics has little effect on the radiative flux densities. However, it is shown that the stratification leads to a slight underestimation of absorption.

Description: Der Golf von Aqaba ist ein meso-oligotrophes Meeresgebiet mit einer saisonalen Durchmischung der Wassersäule im Winter. Mit acht VerdünnungsreihenExperimenten wurde zwischen Oktober und Dezember 2003 die Herbivorie des Mikrozooplanktons in den Gewässern vor der Marine Science Station in Aqaba untersucht. Mikroskopische Analysen ergänzten die Chlorophyll-basierten Experimente neben exemplarischen Untersuchungen der Bakterivorie durch das Mikrozooplankton. Im eindeutig identifizierbaren Phytoplankton dominierten die Diatomeen. Es wird aber davon ausgegangen, dass auch kleine Falgellaten einen großen Teil der Primärproduktion leisteten. Die Ausgangskonzentrationen des Cholorphyll a betrugen 0,34 - 0,62 μg/1. Im Mikrozooplankton, das 1 - 2% der gefundenen Individuen und 40 - 68% der Biomasse ausmachte, dominierten T intinnen und nackte Ciliaten, aber auch Sarcodina und Crustaceen traten kontinuierlich auf. Die Wachstumsraten des Phytoplanktons lagen zwischen 0,13 und 0,35 d-1 (für die Experimente, die dem Konzept entsprechend ausgewertet werden konnten) und standen einem Fraßdruck durch das Mikrozooplankton von 0,16 - 0,85 d-1 gegenüber. Dies entspricht einem Verlust von 60 - 100% der potentiellen Produktion oder 20 - 30% des Chlorophyll-Bestandes durch das Mikrozooplankton. Durch Bakterivorie gingen 95 - 96% der potentiellen bakteriellen Produktion verloren. Drei der Experimente ergaben einen dem Konzept widersprechenden negativen Fraßdruck. Dieser wird auf methodische Unzulänglichkeiten und auf die mit dieser Methodik kaum zu erfassenden Komplexität mikrobieller Nahrungsnetze oligotropher Gebiete zurückgeführt. Im untersuchten Größenspektrum bis 200 μm waren mit Bakterien und phototrophen Flagellaten, heterotrophen Flagellaten, größeren Protisten und Metazoen bereits drei oder vier trophische Ebenen vertreten. Die Unterschiede in den Zusammensetzungen der Proben deuten auf einen sukzessionsartigen Zusammenhang im Verlaufe des Untersuchungszeitraumes hin, der den beginnenden hydrographischen Übergang von einer sommerlichen zu einer winterlichen Situation wiederzuspiegeln scheint.

Description: Animals have a deep evolutionary relationship with microbial symbionts, such that individual microbes or an entire microbial community can diverge alongside the host. Here, we explore these host-microbe relationships in Echinometra, a sea urchin genus that speciated with the Isthmus of Panama and throughout the Indo-West Pacific. We find that the eggs from five Echinometra species generally associate with a species-specific bacterial community and that the relatedness of these communities is largely congruent with host phylogeny. Microbiome divergence per million years was higher in more recent speciation events than in older ones. We, however, did not find any bacterial groups that displayed co-phylogeny with Echinometra. Together, these findings suggest that the evolutionary relationship between Echinometra and their microbiota operates at the community level. We find no evidence suggesting that the associated microbiota is the evolutionary driver of Echinometra speciation. Instead, divergence between Echinometra and their microbiota is likely the byproduct of ecological, geographic, and reproductive isolations.

Description: The Red Sea is an important example of a continental rift transitioning slowly to an oceanic basin. However, structures that can inform us of how that transition occurred have been poorly reported because deep seismic reflection data capable of imaging basement under the rift sediments are generally lacking publicly. Three lines of multichannel seismic reflection data have recently been published revealing structures on the Nubian side of the central part of the basin. In this study, we reassess these data in the light of recent studies of the central Red Sea. Over continental crust, the data reveal reflection sequences likely due to strata at or near the base of the evaporites, in two cases with varied dips suggesting the presence of syn-rift growth stratigraphy. Almost all of those reflections dip downwards towards the rift axis, not away as would be expected from tilted fault blocks of bookshelf faulting types. That observation, and low relief of basement, confirm inferences made earlier based on gravity anomalies that this part of the Red Sea lacks large-relief fault escarpments and is most likely a syn-rift sag basin. In the transition to oceanic crust, an abnormally broad magnetic anomaly of estimated Chron 5 age is found not to be associated with structures such as sills, so it likely arises from deeper sources. One of the seismic lines traverses a ridge in Bouguer gravity anomalies that runs across the axis. This feature has previously been interpreted as a volcanic ridge similar to those observed at other ultra-slow spreading ridges. The seismic data reveal diffuse basement reflections and confirm that the record immediately above basement lacks reflections typical of sedimentary strata. Both observations are consistent with the presence of oceanic crust. Modelling of gravity anomalies suggests the ridge is likely underlain by igneous intrusive rocks displacing mantle rocks, as expected for a volcanic ridge. The seismic data, combined with recently updated multibeam and high-resolution sparker seismic results, further suggest how the evaporite movements have been modulated by basement topography. These results add to our knowledge of the evaporite movements and continent-ocean transition structures in the central Red Sea.

Description: Highlights: • A cyclonic frontal eddy emerged near the South Java Coast (SJC) in 2019. • The cyclonic eddy induces filaments of Chl-a, cold water, and nutrients. • Anti-cyclonic eddies distribute the filaments further offshore. • The role of wind can't be ignored in distributing filaments in the SJC. • We propose a three-stage mechanism for Chl-a distribution in the offshore SJC. Intense mesoscale eddy activity has been observed off the southern Java coast (SJC), yet its impact on local ecosystems remains largely unknown. To investigate this, we examined remotely sensed altimetry, chlorophyll-a (Chl-a), and sea surface temperature (SST) data, focusing on their response to eddies in the region. Our eddy detection and tracking analysis revealed a unique cyclonic frontal eddy near the SJC coast and a large anticyclonic eddy offshore, active from July to September 2019. The cyclonic frontal eddy induced water transport through eddy filaments, upwelled subsurface cold water, and enhanced Chl-a concentrations by horizontally entraining Chl-a-rich shelf water offshore. The anticyclonic eddy then contributed to further distributing this enriched water southward. The mean cross-shelf transport associated with the frontal eddy was estimated at 1.80–2.33 Sv offshore, exporting approximately 1.87–2.40 × 103 tons of Chl-a to the Indian Ocean during its lifetime. Additionally, the spatial cross-correlation analysis of zonal and meridional wind stress with Chl-a revealed relatively high correlation values (0.6–1) and short lag times (〈5 days) in offshore areas, indicating that the role of wind in the Chl-a advection cannot be ignored. We propose a three-stage mechanism to explain the presence of high Chl-a offshore:1) Wind-driven upwelling intensifies coastal nutrients, elevating Chl-a concentrations in coastal waters, 2) Frontal cyclonic eddy facilitates the retention and offshore export of these upwelling-enriched waters. and 3) Anticyclonic eddy advects these nutrient-rich waters further south. The combination of enhanced coastal upwelling and eddies can explain nutrient-rich coastal waters in offshore regions

Description: Accurate reconstruction of seasonal atmospheric patterns of the past is essential for reliable prediction of how climate will evolve due to anthropogenic CO2 forcing. The Eocene ‘hot house’ climate, as the warmest epoch during the Cenozoic, is considered as a potential analogue for ‘high-CO2’ future climate scenarios. In this context, the reconstruction of variations in seasonality are as important as changes in mean annual conditions. Here we combine stable oxygen (δ18O) and dual clumped isotope (Δ47 + Δ48) measurements of a bivalve shell to determine sub-annual variations in sea surface temperatures and oceanic freshening in the Paris Basin during the Mid-Eocene Climate Optimum, 40 million years ago. Our reconstruction indicates to high mean annual temperatures with a small seasonal amplitude (33.3 °C ± 4.4 °C) and an enhanced fresh water input during the summer period. Our results implying a substantially warmer climate state with different hydrological conditions for Western Europe during the Eocene than previously suggested by proxy data or climate modelling.

Description: Offshore explosive ordnance disposal (EOD) in the marine environment is a high-risk activity. Structured risk assessment (RA) can be a helpful tool to provide EOD experts with decision-making support. This paper hypothesizes that existing RA approaches that address unexploded ordnance (UXO) in the sea do not meet the requirements of EOD RA. To test this hypothesis, the paper proposes a novel categorization tool. It uses five review criteria: study type (qualitative vs. quantitative), level of decision-making (strategic vs. applied), risk component (probability vs. consequence), spatial scale (global vs. local), and temporal scale (long-term vs. short-term). The categorization tool is used to identify the requirements of EOD RA and to test whether nine existing RA methods fulfill these requirements. The study finds that none of the investigated RAs meets the requirements and, hence, concludes that a new method should be developed. However, some aspects of the existing studies should be considered when designing a new method. This includes using risk factors (type and mass of explosive material, type and state of the fuze, and water depth) that are relevant for EOD RA. It also involves setting up a directed graph to assess the complex interdependencies between these risk factors.

Description: Ocean alkalinity enhancement (OAE) is a negative emissions technology (NET) that shows significant potential for climate change mitigation. By increasing the bicarbonate ion concentration in ocean water, OAE could enhance long-term carbon storage and mitigate ocean acidification. However, the side effects and/or potential co-benefits of OAE on natural planktonic communities remain poorly understood. To address this knowledge gap, a mesocosm experiment was conducted in the oligotrophic waters of Gran Canaria. A CO2-equilibrated total alkalinity (TA) gradient was employed in increments of 300 µmol L−1, ranging from ∼ 2400 to ∼ 4800 µmol L−1. This study represents the first attempt to evaluate the potential impacts of OAE on planktonic communities under natural conditions. The results show that net community production (NCP), gross production (GP), community respiration (CR) rates, and the metabolic balance (GP:CR) did not exhibit a linear response to the whole alkalinity gradient. Instead, significant polynomial and linear regression models were observed for all rates up to ΔTA 1800 µmol L−1, in relation to the dissolved inorganic carbon (DIC) concentrations. Notably, the ΔTA 1500 and 1800 µmol L−1 treatments showed peaks in NCP shifting from a heterotrophic to an autotrophic state, with NCP values of 4 and 8 µmol O2 kg−1 d−1, respectively. These peaks and the optimum curve were also reflected in the nanoplankton abundance, size-fractionated chlorophyll a, and 14C uptake data. Furthermore, abiotic precipitation occurred in the highest treatment after day 21, but no impact on the measured parameters was detected. Overall, a damaging effect of CO2-equilibrated OAE in the range applied here on phytoplankton primary production, community metabolism, and composition could not be inferred. In fact, a potential co-benefit to OAE was observed in the form of the positive curvilinear response to the DIC gradient up to the ΔTA 1800 treatment. Further experimental research at this scale is key to gain a better understanding of the short- and long-term effects of OAE on planktonic communities.

Description: The dynamic processes associated with subducting tectonic plates and rising plumes of hot material are typically treated separately in dynamical models and seismological studies. However, various types of observations and related models indicate these processes overlap spatially. Here we use precursors to PP and SS reflecting off mantle transition zone discontinuities to map deflections of these discontinuities near three subduction zones surrounding the Caribbean Plate: 1) Lesser Antilles, 2) Middle America and 3) northern South American subduction zones. In all three regions slow seismic anomalies are present behind the sinking slab within the transition zone in tomographic images. Using array methods, we identify precursors and verify their in-plane propagation for MW ≥ 5.8 events occurring between the years 2000 and 2020 by generating a large number of source receiver combinations with reflection points in the area, including crossing ray paths. The measured time lag between PP/SS arrivals and their corresponding precursors on robust stacks are used to measure the depth of the mantle transition zone discontinuities. In all three areas we find evidence for upward deflection of the 660 discontinuity behind the sinking slab, consistent with the presence of hot plume material (average temperature anomalies of 180 to 620 K), while there is not a corresponding downward deflection of the 410 km discontinuity. One interpretation of these disparate observations is suggested based on comparison to existing models of mantle convection and subduction: plume material rising across 660 km discontinuity could be entrained by lateral flow in the transition zone induced by the nearby sinking slab, and thus delaying the rise of hot material across the 410 km discontinuity.

Description: Three volcanic arcs have been the source of New Zealand's volcanic activity since the Neogene: Northland arc, Coromandel Volcanic Zone (CVZ) and Taupō Volcanic Zone (TVZ). The eruption chronology for the Quaternary, sourced by the TVZ, is well studied and established, whereas the volcanic evolution of the precursor arc systems, like the CVZ (central activity c. 18 to 2 Ma), is poorly known due to limited accessibility to, or identification of, onshore volcanic deposits and their sources. Here, we investigate the marine tephra record of the Neogene, mostly sourced by the CVZ, of cores from IODP Exp. 375 (Sites U1520 and U1526), ODP Leg 181 (Sites 1123, 1124 and 1125), IODP Leg 329 (Site U1371) and DSDP Leg 90 (Site 594) offshore of New Zealand. In total, we identify 306 primary tephra layers in the marine sediments. Multi-approach age models (e.g. biostratigraphy, zircon ages) are used in combination with geochemical fingerprinting (major and trace element compositions) and the stratigraphic context of each marine tephra layer to establish 168 tie-lines between marine tephra layers from different holes and sites. Following this approach, we identify 208 explosive volcanic events in the Neogene between c. 17.5 and 2.6 Ma. This is the first comprehensive study of New Zealand's Neogene explosive volcanism established from tephrochronostratigraphic studies, which reveals continuous volcanic activity between c. 12 and 2.6 Ma with an abrupt compositional change at c. 4.5 Ma, potentially associated with the transition from CVZ to TVZ. Key Points New Zealand's Neogene explosive volcanism based on the marine tephra record Geochemical fingerprinting of marine tephra layers across the study area to establish volcanic events Insights into geochemical variations with time, repose times and spatiotemporal distribution

Description: Thriving in both epipelagic and mesopelagic layers, Rhizaria are biomineralizing protists, mixotrophs or flux-feeders, often reaching gigantic sizes. In situ imaging showed their contribution to oceanic carbon stock, but left their contribution to element cycling unquantified. Here, we compile a global dataset of 167,551 Underwater Vision Profiler 5 Rhizaria images, and apply machine learning models to predict their organic carbon and biogenic silica biomasses in the uppermost 1000 m. We estimate that Rhizaria represent up to 1.7% of mesozooplankton carbon biomass in the top 500 m. Rhizaria biomass, dominated by Phaeodaria, is more than twice as high in the mesopelagic than in the epipelagic layer. Globally, the carbon demand of mesopelagic, flux-feeding Phaeodaria reaches 0.46 Pg C y −1 , representing 3.8 to 9.2% of gravitational carbon export. Furthermore, we show that Rhizaria are a unique source of biogenic silica production in the mesopelagic layer, where no other silicifiers are present. Our global census further highlights the importance of Rhizaria for ocean biogeochemistry.

Description: Mapping and sampling four sections of the slow-spreading Reykjanes Ridge provide insight into how tectonic and volcanic activity varies with distance from the Iceland plume. The studied areas are characterized by significant variations in water depth, lava chemistry, crustal thickness, thermal structure, and ridge morphology. For each study area, fault pattern and dimension, tectonic strain, seamount morphology, and density are inferred from 15 m-resolution bathymetry. These observations are combined with geochemical analysis from glass samples and sediment thickness estimations along Remotely Operated Vehicle-dive videos. They reveal that (a) tectonic and volcanic activity along the Reykjanes Ridge, do not systematically vary with distance from the plume center. (b) The tectonic geometry appears directly related to the deepening of the brittle/ductile transition and the maximum change in tectonic strain related to the rapid change in crustal thickness and the transition between axial-high and axial valley (∼59.5°N). (c) Across-axis variations in the fault density and sediment thickness provide similar widths for the neo-volcanic zone except in regions of increased seamount emplacement. (d) The variations in seamount density (especially strong for flat-topped seamounts) are not related to the distance from the plume but appear to be correlated with the interaction between the V-shape ridges (VSR) flanking the ridge and the ridge axis. These observations are more compatible with the buoyant upwelling melting instability hypothesis for VSR formation and suggest that buoyant melting instabilities create many small magma batches which by-pass the normal subaxial magmatic plumbing system, erupting over a wider-than-normal area. Key Points The distance from the plume center is not the only factor controlling tectonic and volcanic activity along the Reykjanes Ridge Fault dimensions are primarily controlled by the variation of crustal thermal structure with distance from the hotspot Flat-topped seamount abundances peak where a V-shaped ridge intersects the axis, consistent with a buoyant upwelling melting instability

Description: Das Verhalten sowohl adulter Weibchen als auch juveniler Karettschildkröten (Eretmochelys imbricata) auf See wurde aufgezeichnet und die Tauchgänge in Abhängigkeit von unterschiedlichen extrensischen und intrensischen Bedingungen analysiert. In den zwei Karibischen Untersuchungsgebieten wurden an den freilebenden Karettschildkröten Geräte befestigt, die Wassertemperatur, Lichtintensität, Schwimmgeschwindigkeit, Tiefe, Himmelsrichtung und Lage im Raum in Messintervallen zwischen 0.25 und 30 sek aufzeichneten. Während der Reproduktionsphase führten adulte Weibchen Ruhetauchgänge durch, die unabhängig vom Tagesrhythmus waren. Lediglich kurz vor der Eiablage zeigte sich ein nachtaktiver Rhythmus. Während eines Hurrikans war das Verhalten des betroffenen Weibchens kurzfristig verändert und die Wassertemperatur mittelfristig erniedrigt. Immature Karettschildkröten zeigten einen deutlich tagaktiven Rhythmus mit kürzeren, aktiven Tauchgängen am Tag und langen Ruhetauchgängen in der Nacht. Nach Beendigung der Nistsaison suchten die untersuchten Weibchen Nahrungsgründe in verschiedenen Himmelsrichtungen und Entfernungen zwischen 70 und 360 km auf. Im grundsätzlichen Tauchverhalten adulter Weibchen ausserhalb der Reproduktionsphase wurde Tagaktivität nachgewiesen. Die erhobenen Daten zeigen eine Abhängigkeit der Tauchdauer von der saisonal schwankenden Wassertemperatur und von der Körpermasse des Tieres.

Description: The European Commission's REPowerEU plan set the target of importing 10 million tonnes of 'green' hydrogen into the European Union (EU) by 2030. Against this backdrop, this paper sets out to assess a central question: which countries can be identified as suitable partners for European green hydrogen imports? Using Germany as a reference case, the article develops a quantitative sustainability and governance index (SGI), assessing five dimensions identified as central to ranking external partners: (i) the political will to scale up a green hydrogen sector; (ii) a country's integration with the EU/Germany; (iii) its commitment to international engagement and climate targets and policies; (iv) environmental regulatory effectiveness; and, (v) its governance performance. With this, the SGI offers a novel way of thinking about potential EU green hydrogen partnerships. Rather than focusing on the geography of renewables or cost structures underpinning a country's export potential, the present index captures the extent to which countries may be suitable for green hydrogen partnerships if judged by political and environmental factors. The empirical analysis suggests significant differences between a total of 113 assessed countries as per their overall index ranking, but also the individual dimensions composing the index. This allows drawing conclusions on the policy focus of potential partnerships, taking choices when facing trade-offs regarding individual dimensions, and prioritizing among the latter.

Description: This article examines limits to per capita living space (i.e. living smaller and/or sharing living space) as a measure for achieving sufficiency in housing. It studies the acceptance, motivation and side-effects of voluntarily reducing living space in five European Union countries: Germany, Hungary, Latvia, Spain and Sweden. Insights are derived from an extensive collection of qualitative empirical material collected from citizen and stakeholder ‘thinking labs’ across the five case countries. Overall, the data reveal an initial reluctance among citizens to reduce living space voluntarily. They also point to some major structural barriers: the housing market and its regulatory framework, social inequality, or dominant societal norms regarding ‘the ideal home’. Enhanced community amenities can compensate for reduced private living space, though contingent upon a clear allocation of rights and responsibilities. Participants also reported positive effects to living smaller, including increased time for leisure activities and proximity to services. This was often coupled with urbanization, which may also be part of living smaller in the future.

Description: A rapid and full decarbonisation of both energy and industry is essential to meet the targets in the Paris agreement, which brings coal- and carbon-intensive regions under significant pressure. Some regions have advanced in their transition and can provide insights in the system change processes. In this paper, we investigate the socio-economic transition processes of Essen and Duisburg as part of the wider structural change in the Ruhr Region/ Germany. We explore causes and effects of their trajectories in the last 30 + years and identify differences in outcome as a function of the interventions and/or contextual differences, while investigating whether either city crossed a tipping point in their transition process (yet). Therefore, we specifically evaluate the cities’ development trajectories by seeking evidence for “no”, “incremental” or “radical or tipping” changes in sets of qualitative and quantitative indicators. Our analysis shows that both cities experienced incremental changes in their demographic, economic and political trajectories but we found no evidence for either city to have crossed a tipping point in their transition process yet. However, distinct developments in the cities’ policy narratives and visions indicate qualitative changes while putting them on different development trajectories potentially leading to tipping points in the future. Our study shows that the sequence of interventions and timing are important factors for the trajectory of a region determining the quality of societal change. It also suggests that radical change and tipping are the exception rather than the rule, especially in the highly complex social systems of cities.

Description: Disasters and crises affect more people around the world than reported in official documents by national or international agencies. Meanwhile, climate change, the COVID-19 pandemic, several wars worldwide and other crises expose a large proportion of the entire population to substantial risks, as well as profoundly affecting human health globally. Many of these impacts remain unnoticed by governance authorities, since many coping strategies are based on bottom-up activities rather than top-down policies. This raises the question: how can we be adequately prepared for a next pandemic or other unforeseen extreme events? Social capital could provide some clues for resilient responses that could be integrated in risk planning and management practice. In this paper, a comprehensive review is provided based on bibliometric analysis. A total number of 2872 published articles were documented and classified. In addition, the geographic locations and the institutional affiliations were assessed and visualized. Four salient research themes were identified as follows: (1) Knowledge sources of the research domain; (2) Individual social capital and risky behaviors; (3) Disaster management and resilience building; and (4) Health issues in the COVID-19 Era. This study offered some practical insights for mobilizing and developing social capital in different phases of risk management. Nevertheless, more inter- and transdisciplinary research across domains is needed to articulate a more comprehensive view of the development of social capital in various risk situations.

Description: Solar energy is not only the most abundant energy on earth but it is also renewable. The use of this energy is expanding very rapidly mainly through photovoltaic technology. However, electricity storage remains a bottleneck in tackling solar resource variability. Thus, solar thermal energy becomes of particular interest when energy storage is required, as thermal energy storage is much cheaper than electricity storage. The objective of this paper is to make a short update on the CSP (Concentrated Solar Power) market as of the year 2023. It is based on the CSP-GURU database, which lists information on CSP power plants all over the world. Although this database is open, it is not easy to find UpToDate analysis. An overview of this expanding technology is presented and offers readable figures with the most important information. This includes the evolution of installed capacities worldwide along with upcoming projects (under construction) and technological trends. The evolution of storage capacities and operating temperatures is discussed. Investment costs and levelized cost of electricity are also provided to obtain reliable data for comparison with other energy technologies. Specific land requirements are highlighted, along with overall efficiency. Relevant examples are discussed in this paper. Eventually, it outlines the evolution of the CSP landscape with useful information for scientific and educational purposes.

Description: Based on a theoretical framework inspired by the Greed-Efficiency-Fairness-Hypothesis (GEF), it is argued that perceived effectiveness of climate policies, in addition to other policy beliefs (i.e. perceived personal and distributional consequences), influences perceived overall policy fairness and acceptance. However, links between these policy beliefs and perceived overall fairness as well as whether perceived overall fairness might mediate effects of these beliefs on acceptance remains understudied. This study addresses these gaps and extends the GEF-inspired framework: We add procedural fairness to the list of fairness-relevant beliefs and analyze whether perceived overall carbon pricing fairness integrates and mediates their effect on acceptance, using survey data representative of Germany (n = 4646). Additionally, we test whether adherence to the polluter-pays principle (a general fairness principle) moderates the effects of perceived distributional consequences and effectiveness on perceived overall fairness. Results showed that perceived personal consequences, distributional consequences, procedural fairness, as well as perceived effectiveness, all impact perceived overall fairness, and that the latter (partially) mediates their effects on carbon pricing acceptance. We also find weak evidence that the impact of perceived effectiveness and negative distributional consequences on perceived overall fairness is greater for polluter-pays adherents than for non-adherents. These results suggest that, additionally to perceived personal and distributional consequences as well as fair procedures, perceiving a policy to be effective increases its perceived overall fairness.

Description: Shared pooled mobility has been hailed as a sustainable mobility solution that uses digital innovation to efficiently bundle rides. Multiple disciplines have started investigating and analyzing shared pooled mobility systems. However, there is a lack of cross-community communication making it hard to build upon knowledge from other fields or know which open questions may be of interest to other fields. Here, we identify and review 9 perspectives: transdisciplinary social sciences, social physics, transport simulations, urban and energy economics, psychology, climate change solutions, and the Global South research and provide a common terminology. We identify more than 25 000 papers, with more than 100 fold variation in terms of literature count between research perspectives. Our review demonstrates the intellectual attractivity of this as a novel perceived mode of transportation, but also highlights that real world economics may limit its viability, if not supported with concordant incentives and regulation. We then sketch out cross-disciplinary open questions centered around (1) optimal configuration of ride-pooling systems, (2) empirical studies, and (3) market drivers and implications for the economics of ride-pooling. We call for researchers of different disciplines to actively exchange results and views to advance a transdisciplinary research agenda.

Description: Die Kommunikation zur Einführung des CO2-Grenzausgleichsmechanismus lief zwischen der Europäischen Union und Drittländern rigide und wenig koordiniert ab, so das Ergebnis einer neuen Ariadne-Analyse. Forschende untersuchten, wie die EU ihre Diplomatie dabei organisiert hat, um möglichem handelspolitischem Protest schon während der Entwicklung des CO2-Grenzausgleiches zu begegnen. Die eher reaktive diplomatische Begleitung hat den Ariadne-Forschenden zufolge möglicherweise dazu beigetragen, dem Widerstand von Handelspartnern weniger Angriffsfläche zu bieten und die Akzeptanz des Mechanismus als Ausdruck des Führungsanspruchs der EU bei ambitionierter Klimapolitik zu erhöhen.

Description: The European Union’s outreach to third countries during the introduction of the Carbon Border Adjustment Mechanism was rigid and uncoordinated, new Ariadne analysis has found. Researchers investigated how the EU organized its diplomacy to counter trade concerns during the development of the Carbon Border Adjustment Mechanism. According to the Ariadne researchers, the fact that the EU’s diplomatic outreach was rather reactive may have helped to provide less of a target for opposition from trading partners and to increase acceptance of the mechanism as an expression of the EU’s claim to leadership in ambitious climate policy.

Description: The present work describes the influence of the orientation of hexagonal ice crystals on its single scattering and on multiple scattering of solar radiation in cirrus clouds. Scattering phase function and single scattering albedo were calculated with a Ray-Tracing model, the radiance flux density and the radiance of ice clouds by means of a Monte-Carlo radiative transfer model. A total of 13 wavelenghts (0.2 μm 〉 ,\ 〉 4.0 μm), 10 maximum tilt angles of the crystals around the horizontal axis, 5 crystal size distributions, 6 optical thickness (0.5 〉 T 〉 12.0) and 10 solar zenith angles 80 have been considered. The effect of particle orientation is strongest pronounced for Θ0 = 0° and Θ0 = 40°. For a typical optical thickness T = 2 and solar zenith angle of 40° the differences in the solar broadband fluxes are as large as 125.4 m-2 for reflected radiance flux density and as large as 129.9 wm-2 for the transmitted flux. The absorption is less affected by crystal orientation. For hexagonal plates these effects are smaller than for hexagonal columns. The radiance flux density is stronger influenced by crystal orientation for smaller crystals. This sensitivity can also be observed in the transmitted and the reflected radiance. As an application, the tilt angle can be infered from the shape of halo components. This work gives detailed geometrical explanations for the dependence of single and multiple scattering on crystal shape and orientation. The choice of crystal orientation has a similar effect on the radiative properties of cirrus clouds as crystal shape and size distribution.

Description: The objective of this 10-week study was to examine the influence of photoperiod on locomotor activity, food intake, and oxygen consumption of juvenile haddock (Melanogrammus aeg/efinus) in order to assess possible factors responsible for the differences in body growth Trippel & Neil (2003) reported. Plasma cortisol levels were measured to examine the relation between photoperiod and stress potential in haddock. 600 juvenile haddock (fork length 12.46+/-0.12 cm, body weight 22.53+/- 0.63 g) were randomly distributed and reared in eight 1 m2 square tanks with a water inflow of 3.5-4.0 I/min. The set up was partitioned into three treatments of different photoperiod (natural photoperiod NP, continuous light 24 h, and alternated conditions= 24h-NP-24h). Three sub-experiments were conducted to identify possible differences in behaviour. Locomotor activity was recorded daily by counting fish that passed through a fixed station in each tank. Food consumption was measured daily via counting remaining pellets on the bottom of the tanks in the morning. Oxygen consumption was estimated by following the decrease of oxygen saturation in each tank over a 1 hour period in static water conditions. Therefore water in- and outflow was stopped. The blood of 200 fish was sampled at different time periods and plasma was stored at -80° C. A radioimmunoassay was conducted for measuring cortisol levels. Haddock showed significant differences in locomotor activity between treatments. It was greatest under natural photoperiod, less in tanks which received switching photoperiod and lowest at 24h light. Lower energy consumption for locomotion may be translated into savings for other metabolic processes like growth. No significant difference was found in oxygen consumption between treatments with values ranging from 0.16 to 0.27 mg/g/h. All fish exhibited good food utilization efficiency (0.13-0.3) with no significant differences between treatments. Cortisol levels were highly variable with values ranging from 17 ng/ml up to maximum levels of 56 ng/ml independent of treatment. These values are relatively high in comparison to other species resting or stressed. Further investigations are necessary to get more information about resting and stress levels of cortisol in cultured haddock.

Description: Im Rahmen des BMBF - Projektes „Globec Gennany" wurden vom Institut für Meereskunde in Kiel während der 220. Reise des „FS Alkor" im Mai 2002 unter anderem Planktonproben auf einer Dauerstation im zentralen Bornholm - Becken genommen. Mit Hilfe der Proben wurde die klein- und mesoskalige Verteilung von Fischbrut näher untersucht und in einen Zusammenhang mit den vorherrschenden Umweltbedingungen, in Folge eines großen winterlichen Einstrom von Nordseewasser, gebracht. Ein weiterer Teil dieser Arbeit beschäftigt sich mit dem Vergleich der zwei Planktonfangeräte: Biomoc und Multinetz (sog. Maxi - Netz). Die Reproduzierbarkeit der durch Biomoc und Maxi - Netz erhaltenen Daten und Ergebnisse wurde mit Hilfe des IPR überprüft. Durch den Einstrom von sauerstoffreichem Nordseewasser zeigte sich eine Vertikalverteilung von Sprott- und Dorscheiern bis in eine Tiefe von 85 m. Sowohl Sprott- als auch Dorscheier zeigten in Abhängigkeit von der Tiefe und den damit verbundenen Temperatur- und Sauerstoffgehaltsänderungen unterschiedliche relative Sterblichkeiten in Bezug auf den jeweiligen betrachteten abiotischen Faktor. Durch den Einstrom ergaben sich für die Dorscheier bessere Entwicklungsbedingungen während die Sprotteier, durch die niedrigen Temperaturen unterhalb der permanenten Haloline, in ihrer Entwicklung eingeschränkt waren. Dies spiegelt sich bei Betrachtung der Gesamtsterblichkeit wider, Dorscheier zeigten lediglich eine sauerstoffabhängige relative Sterblichkeit von 24 %, während Sprotteier eine 38 %ige temperaturabhängige Sterblichkeit aufwiesen. Die höchsten Sprottlarven - Konzentrationen wurden in Tiefen von O - 20 m gefunden. Eine tageszeitlich bedingte Wanderung konnte nicht festgestellt werden, es wurde lediglich beobachtet, dass sich die Larven am Tage um wenige Meter höher in der Wassersäule aufhalten als in der Nacht. Der Vergleich der zum Einsatz gekommenen Geräte führte zu keinem abschließenden Ergebnis. Die aufgetretenen Unstimmigkeiten bei der Probenentnahme konnten nicht eindeutig einem der Fangeräte zugeordnet werden. Ein weiterer Vergleich der beiden Geräte zur Lokalisierung einer möglichen Fehlerquelle ist ratsam.

Description: The aim of this study is to examine the response of the bio-physical coupling in the equatorial Pacific Ocean to an idealised simulated westerly-wind event (WWE). The event lasts for about 120 days and is characterized by a Gaussian Sharp in time and space. The numerical model used in this study is a coupled ocean-atmosphere model, which is based on the the primitive equations and reduced gravity approximation and formulated on σ-coordinates underneath a dynamic mixed layer. It is driven by an atmospheric mixed-layer model combined with a Gill-type atmosphere model. Ocean biota are simulated using a nine-component NPDZ ecosystem model, wich is coupled to the physical ocean model. The simulated chlorophyll concentrations feed back to the ocean dynamics by modifying the absorption of photosynthetically active radiation in the surface layers, thereby changing the ocean thermodynamics and ocean currents. It is shown that the simulated climate mean state is in uenced by the spatiotemporal characteristics of different biological components, particulary throught changes in the chlorophyll concentraitons. This study extends the study of Timmermann and Jin [2003] and Marzeion et al. [2004] , which have identifed an influence of ocean biota on the climate mean state in the tropical Pacific.

Description: This study concentrated on cell cycle analyses of the coccolithophoride Emiliania huxleyi in relation to calcification in a light:dark cycle of 12:12 hours as well as limitation by nitrogen (N), phosphate (P) and light (E) under continuous light. This unicellular algae is one of the most important marine calcifying organism and shows an enhanced calcification to photosynthesis ratio (C/P) when growing under nitrogen or phosphate limitation. The function of elevated calcification under these conditions related to the cell cycle has not been studied yet. Beside cell cycle analyses data were collected on nutrient consumption, cellsize and the C/P ratio. Emiliania huxleyi is synchronized through the cell cycle in a light:dark period with the event of cell division occuring in the dark. In the dark period the Gl-phase showed a decrease by 20 % with contemporary increase of the S und G2+M phase and following rise in cell number. During the dark period (Sand G2+ M) an enhanced requirement of phosphate whereas an enhanced requirement of nitrogen during the light ( G 1) was visible. This is explained by the need of N for assimilation and biotic synthesis in the light and the demand of P for DNA synthesis plus regulating the steps in the cell cycle. Calcification in samples of the dark period, which were incubated in the light, showed a mean decrease by 25 %. This could maintain a link between G1-phase and calcification. Under continuous light, where a desynchronisation of the cell cycle occured, growth rates were higher than under a light:dark cycle. When cell division stopped through limitation by N or P a bulk cell number arrest in the G1-phase and showed increased C/P ratios with higher evidence in P limited cells. N limited cells decreased in cellsize by 18 % through a lack of N metabolism, whereas P limited cells increased by 30 %. In all experiments the cellsize before division was greater than 4, 75 μm, so a link between the cellsize and the shift from G 1 to S is suggested and another control point in G1 which depends on phosphate availability. The results indicate that calcification is primarily a process of the Gl-phase.

Description: An interactive (multi-access) global identification key (OncIdent) has been developed for the pelagic marine microcopepod family Oncaeidae and made accessible online. Details of the general approach and development of the key are given in Bottger-Schnack and Schnack (J Nat Hist 49:2727-2741, 2015). After beta-testing, new additions include illustrations for all species and feature attributes considered, plus a textual summary of each species' feature states in the key. Additional taxonomic notes are given where required, highlighting morphological or molecular genetic peculiarities or problems, with links to large data bases leading directly to more comprehensive information about each species. The present paper briefly reviews the taxonomic background for key construction, summarizes the opportunities and limitations of the current online version OncIdent2.0, and provides guidance for its practical use.

Description: Die Notwendigkeit der ständigen Kontrolle von Fließgewässern wird durch schwere Vorfälle deutlich und hat zu einer intensivierten Überwachung von Gewässern geführt. Das Detektieren von plötzlich auftretenden Umweltgiften in natürlichen Gewässern kann rechtzeitig durch ein Frühwarnsystem erkannt werden. Sogenannte Biomonitore arbeiten mit Organismen, die auf eine Vielzahl von toxischen Substanzen reagieren. Der Fisch dient dabei als Reaktionsmodell für die menschliche Gesundheit mit dem Ziel das Rohwasser in ausreichender Qualität für die Trinkwassergewinnung zu erhalten. Hier haben Organismen basierte Systeme ihre Anwendung, die das Auftreten eines Schadstoffes dadurch detektieren, dass der Gesamtorganismus beim Auftreten eines Schadstoffes mit messbaren Verhaltensänderungen reagiert. Das Meßsystem „Fischtox" der Firma bbe-moldaenke in Kiel ist ein kontinuierlich aufzeichnendes, computergesteuertes, bildverarbeitendes Verhaltensmeßsystem, das Änderungen im Verhaltensmuster eines Testfischschwarmes, bestehend aus sechs Goldorfen, registriert. Für die Auswertung der Verhaltensänderungen wurden die Verhaltensvariablen Schwimmgeschwindigkeit, Schwimmhöhe und der Abstand der Versuchsorganismen herangezogen. Der Umwelteinfluss abnehmende Sauerstoffsättigung sollte eine Verhaltensänderung der Goldorfen in den Verhaltensvariablen aufzeigen. Es sollte eine Detektion einer Umweltverschlechterung durchgeführt werden. Die starke Sauerstoffreduzierung (20% Sättigung) führte zu einer kurzfristigen Verhaltensänderung der Tiere in Bezug auf alle Verhaltensvariablen, die mit der hier verwendeten Messanordnung detektiert werden konnte. Der zweite untersuchte Umwelteinfluss, der eine Verhaltensänderung der Goldorfen in dem Meßsystem aufzeigen sollte, war eine Schadstoffzuführung. Die subletalen Konzentrationen (0,05 mg/1; 0,1 mg/1) des Insektizids Chlorpyrifos führten aber zu keiner signifikanten Veränderung der Schwimmaktivität der Goldorfen, die das Meßsystem detektieren konnte.

Description: Für die Jahrgangsstärke von Fischbeständen spielen die frühen Entwicklungsstadien eine zentrale Rolle. Insbesondere die Ei- und Larvenstadien reagieren sensibel auf biotische und abiotische Einflüsse. In einem experimentellen Ansatz wurde mit Hilfe eines erstmals an diesem Institut verwendeten Temperatur- Gradienten- Blockes, der Temperatureinfluss im Bereich von 2°C bis 13,8°C auf die frühen Entwicklungsstadien des Ostseedorsches, Gadus morhua, untersucht. Die Vermessung der Larven fand anhand von digitalen Aufnahmen statt. Sowohl die Entwicklungsdauer und die Sterblichkeit in der Eiphase, als auch die Schlupflänge, die Abnahme der Dotterfläche, das Längenwachstum, der Zeitpunkt der Maulöffnung, und die maximale Lebensdauer der Larven im Hungerzustand, wurden vergleichend untersucht. Dabei konnte eine Exponential- Potenzfunktion die stadienspezifische Entwicklung am besten beschreiben. Die Entwicklung bis zum Schlupf verlief bei 2°C nahezu dreimal langsamer als bei 10°C Inkubationstemperatur. Oberhalb von 10°C fand keine Entwicklung bis zum Schlupf statt. Die Anzahl an Tagesgraden bis zum Schlupf nahm im untersten Temperaturbereich deutlich ab. Erhöhte Sterblichkeiten wurden bei der Gastrulation und im Entwicklungsstadium IV bis zum Schlupf registriert. Auch das Schlupfintervall, der Zeitraum zwischen Schlupf der ersten bis zur letzten Larve innerhalb einer Inkubationstemperatur, ließ sich über alle Temperaturen durch eine exponentielle Funktion beschreiben. Mit steigender Temperatur verkürzte sich das Schlupfintervall. Die am kältesten inkubierten Larven schlüpften mit der signifikant geringsten Standardlänge. Am größten schlüpften die bei 4, 7°C inkubierten Larven, während die bei 10 °C inkubierten Larven als zweitkleinste schlüpften. Die Dottersackfläche nahm mit steigender Temperatur schneller ab. Ebenso die Zeit bis zur Öffnung des Mauls, die temperaturabhängig vom Schlupf zwischen neun und drei Tage dauerte. Diese ontogenetische Umgestaltung war längenabhängig und fand bei 4,22±0,05 mm Körperlänge statt. Mit ansteigender Temperatur wurde eine kürzere Überlebensdauer im Hungerzustand beobachtet. Bei 2°C überlebten die Larven maximal fast dreimal so lange (38 Tage), wie bei 10°C Inkubationstemperatur (13 Tage). Insgesamt wurde ein signifikanter Temperatureinfluss auf die Ontogenie früher Entwicklungsstadien des Ostseedorsches festgestellt. Jedoch treten sowohl bei extrem kalten als auch extrem warmen Temperaturen kompensatorische Prozesse auf. Die erzielten Ergebnisse wurden mit in der Literatur beschriebenen Entwicklungszeiten diskutiert und stimmten in wesentlichen Punkten überein.

Description: Numerous vascular plants are known to induce structural and/or chemical defences against mesograzers either after being subjected to direct herbivory or exposed to chemical signals released by attacked neighbouring plants. However, there are only a few examples of a defensive response to direct grazing in marine macroalgae and even less is known about information transfer based on waterborne chemicals in algae-grazer interactions. In a first 'screening' experiment I examined the effect of direct grazing by the mesoherbivorous isopod Idotea granulosa on 10 seaweed species from the Swedish west coast. During a second experiment, 5 seaweed species were tested for their responses to direct grazing or to possible waterborne cues released from damaged conspecifics or I. granulosa alone. The response was assessed in feeding assays where Idotea sp. was allowed to choose between either previously grazed pieces or unexposed controls. Additionally, artificial food prepared from homogenized algal pieces (extracted or directly incorporated into agar-agar) was used to further discriminate between morphological and chemical changes in algal pieces. In addition I analysed the total content of brown algal polyphenolics (phlorotannins) in selected species to observe whether there is an increase in polyphenolic production due to herbivore load. My data show an inducecl resistance in Fucus serratus, Ascophyllum nodosum (Phaeophyceae) and Chondrus crispus, Polyides rotundus (Rhodophyceae). All species reduced their palatability after a 14-day period without any grazing pressure, following 14 clays of exposure to herbivores. Furthermore, I was able to show an increased resistance in P. rotundus and A. nodosum in response to waterborne cues released by grazed conspecifics. The phlorotannin-content was not increased in algal pieces which showed an induction of defence. Thus, two new species (F. serratus and C. crispus) can be added to the short list of macroalgae known to be capable of induced resistance. The results suggest a slow 'switching on' of defensive mechanisms (at least 2 weeks after initial grazing damage) in some species of seaweed off the Swedish west coast as an adaption to seasonal changes in herbivore populations with a slow increase in grazer density twice a year.

Description: In marinen Ökosystemen ist die Gemeine Miesmuschel Mytilus edulis einer der wichtigsten Organismen des Hartbodenbenthos. Sie erfüllt wichtige Funktionen wie Wasserreinigung und Rodenstabihsierung, schafft Lückenhabitate für kleine Arten, steilt sekundäres Hartsubstrat für Aufwuchs bereit und dient anderen Tieren als Nahrung. Um die Auswirkungen der vorhergesagten Klimaveränderungen auf die Entwicklung der Muscheln beurteilen zu können und um festzustellen, welchen Einfluss diese Entwicklung für das Ökosystem Ostsee haben könnte, wurden die Muscheln bei zwei unterschiedlichen Temperaturen, Salinitäten u...r1d Futterstufen tmtersucht. Im Verlauf der sechsmonatigen Laborversuche wurde der Einfluss der drei Faktoren auf das Wachstum, die Schalenstärke und die Schalenbruchstabilität der Tiere untersucht. Dabei wurde wöchentlich die durchschnittliche Temperatur der Ostsee und eine um 5°C höhere Temperatur eingestellt, die Salinität betrug einmal 12 und einmal 17 PSU. Ein Teil der Muscheln bekam die durchschnittliche Phytoplanktonmenge der Kieler Förde und der andern die doppelte Menge als Nahrung zur Verfügung gestellt. Die Probennahme fand monatlich statt. Das Wachstum wurde anhand der Schalenlänge bestimmt. Die Schalenstärke wurde in der Mitte der Schalenhälfte mit einer Mikrometerschraube gemessen. Die Bruchstabilität wurde durch Belastungstests ermittelt. Die Wachstumsrate stieg in jeder Behandlung mit der Temperatur. Eine geringere Salinität führte zu geringeren Wachstumsraten, aber nicht zu einer geringeren Schalenstärke und Bruchstabilität. Eine erhöhte Futtermenge bedingte eine höhere Wachstumsrate, aber keine dünneren Schalen und keine geringem Bruchstabilität. Interessant waren die Auswirkungen von Interaktionen der Faktoren auf die Entwicklung der Muscheln. Die befürchtete Abnahme der Schalenstärke bzw. der Bruchstabilität wird nach diesen Ergebnissen wahrscheinlich nicht eintreffen. Somit wird der Prädationsdruck durch Carcinus maenas auf die Miesmuschel nicht erhöht und Verschiebungen im Gefüge der Benthosgemeinschaften der Ostsee bleiben, zumindest unter diesen Gesichtspunkten, aus.

Description: Die Aufgabe dieser Diplomarbeit war eine Untersuchung auf bestandskundlicher Basis des Einflusses der intensiven Fischerei auf einige marine Fischarten. Anhand von Literatur-Daten wurden die möglichen aufgetretenen Veränderungen bei einigen der am meisten erbeuteten Fischarten in der westlichen Ostsee aufgezeigt, die wahrscheinlich vom intensiven Druck der Fischerei verursacht wurden. Theoretisch war zu erwarten, dass bei diesen Fischarten eine Abnahme der Anzahl der älteren Tiere, der maximalen und mittleren Körperlänge bzw. des Körpergewichts, der 50%-Reifelänge und des 50%-Reifealters stattfindet, während die Zahl der Eier pro Körperlänge und das Wachstum zunehmen. Bei der Altersuntersuchung wurde der erwartete Trend, das heißt eine Zunahme der Anzahl der jüngeren Tiere und eine Abnahme des Anteils der älteren Tiere, was sich in einer Abnahme des mittleren Alters äußert, nur bei den Dorschen und Heringen in der Sd.24 nachgewiesen. Bei der Scholle kann aufgrund des kurzen Untersuchungszeitraums nicht von einem Trend gesprochen werden. Bei der Längen- und Gewichtsuntersuchung zeigen der Dorsch in der Sd.22, der Hering in den beiden Subdivision 22 und 24 und die Scholle in der Sd.24 eine Abnahme der Körperlänge bzw. des -gewichts. Das Wachstum der drei Fischarten weist in den beiden Subdivisionen einen positiven Trend mit unterschiedlicher Stärke von Art zu Art und Subdivision zu Subdivision auf. Bei der Untersuchung der Geschlechtsreife zeigte sich aufgrund des Mangels an Daten nur beim Dorsch in Sd.22-24 eine relative Abnahme des 50%-Reifealters zwischen 1970 und 2001. Bei der Fruchtbarkeits-Längenuntersuchung wurde eine deutliche Zunahme der Anzahl der Eier mit der Körperlänge nur beim Hering in der Sd. 22 zwischen 1900 und 1978 beobachtet, bei der Scholle in der Sd.22 gab es keine signifikanten Unterschiede, und wegen des Mangels an Daten wurden beim Dorsch in der westlichen Ostsee keine Vergleich angestellt.

Description: Neues Konzept soll den Meeresschutz in Kiel voranbringen - Expertin Nicole Walter erläutert die Grundzüge - Mitmach-Angebot am Samstag

Description: Ob Delfine, Seepferdchen oder Schildkröten - in Nord- und Ostsee tummeln sich außergewöhnliche Meeresgäste

Description: 20 Jahre nach der ersten Planungsidee: Geomar-'- Neubau am Seefischmarkt in Wellingdorf eingeweiht

Description: Active seismic investigations were carried out using ocean bottom hydrophones and seismometers along the Pacific margin off Peru. The structure and the P-wave velocities of the obliquely subducting oceanic Nazca plate and overriding South American plate were determined by modeling the wide-angle seismic data combined with the analysis of reflection seismic data from 8◦S to 15◦S. Combining these structural models with the earthquake distribution from a regional seismic network complements the deep crustal structure of the subducting Nazca plate from the trench to the Amazon Plain. Three detailed cross-sections of the subduction zone of the Peruvian margin and one strikeline across Lima Basin are presented here. The oceanic crust of the Nazca plate, with a thin pelagic sediment cover, ranging from 0−200 m, has an average thickness of 6.4 ± 0.1 km. At 8◦S it thins to 4 km in the area of Trujillo Trough, a graben-like structure. Across the margin, the plate boundary can be traced to 25 km depth. The presence of a ∼50-m-thick subduction channel with a P-wave velocity of 4.5 km/s is revealed by amplitude modeling. As inferred from the velocity models, a frontal prism exists adjacent to the trench axis and is associated with the steep lower slope. Terrigeneous sediments are proposed to be transported downslope due to gravitational forces and compose the frontal prism, characterized by low seismic P-wave velocities. The lower slope material accretes against a backstop structure, which is defined by higher seismic P-wave velocities, 3.5−6.0 km/s. The large variations in surface slope along one transect may reflect basal removal of upper plate material, thus steepening the slope surface. Subduction processes along the Peruvian margin are dominated by tectonic erosion indicated by the large margin taper, the shape and bending of the subducting slab, laterally varying slope angles and the material properties of the overriding continental plate. The erosional mechanisms, frontal and basal erosion, result in the steepening of the slope and consequent slope failure. Comparing the widths of the frontal prisms from the northern to the southern Peruvian margin, representing different stages after the Nazca Ridge passage, indicates, that the margin has returned to equilibrium after 11 Ma.

Description: Highlights • New geophysical data and samples redefine submarine volcanism in Sicilian Channel. • Three dominant bands of volcanism are distinguished. • Ancient, eroded structures aligned at 120° are tied to faulted banks in the north. • Younger band of similarly aligned volcanism in the south is linked to grabens. • Youngest structures comprise small, dispersed volcanoes with distinct orientation. Abstract The origin and role of volcanism in continental rifts remains poorly understood in comparison to other volcano-tectonic settings. The Sicilian Channel (central Mediterranean Sea) is largely floored by continental crust and represents an area affected by pronounced crustal extension and strike-slip tectonism. It hosts a variety of volcanic landforms closely associated with faults, which can be used to better understand the nature and distribution of rift-related volcanism. A paucity of appropriate seafloor data in the Sicilian Channel has led to uncertainties regarding the location, volume, sources and timing of submarine volcanism. To improve on this situation, we use newly acquired geophysical data (multibeam echosounder and magnetic data, sub-bottom profiles) and dredged seafloor samples to: (i) re-assess the evidence for submarine volcanism in the Sicilian Channel and define its spatial pattern, (ii) infer the relative age and style of magmatism, and (iii) relate this to the dominant tectonic structures in the region. Quaternary rift-related volcanism has been focused at Pantelleria and Linosa, at the northwest boundaries of their respective NW-SE trending grabens. Subsidiary and older volcanic sites potentially occur at the Linosa III and Pantelleria SE seamounts, collectively representing the only sites of recent volcanism that can be directly related to the main rift process. These long-lived polygenetic volcanic landforms have been shaped by magmatism that is directly correlated with extensional faulting and buried igneous bodies. Older volcanic landforms, sharing a similar scale and alignment, occur to the north at Nameless Bank and Adventure Bank. These deeply eroded volcanoes have likely been inactive since the Pliocene and are probably related to earlier stages of crustal thinning and underlying feeder structures in the northern region of the Sicilian Channel. Along a similar alignment, Pinne Bank, SE Pinne Bank and Cimotoe in the northern Sicilian Channel lack a surface volcanic signature but are associated with intrusive bodies or deeply buried volcanic rock masses. Terrible Bank, in the same region, also shows evidence of ancient, polygenetic magmatism, but was subject to significant erosion and lacks a prominent alignment. The much younger volcanism at Graham Volcanic Field and along the northern Capo-Granitola-Sciacca Fault Zone differs markedly from that observed in the other study areas. Here, the low-volume and scattered volcanic activity is driven by shallow-water mafic magma eruptions, which gave rise to small individual cones. These sites are associated with large fault structures away from the main rift axis and may have a distinct magmatic origin. Dispersed active fluid venting occurs across both ancient and young volcanic sites in the region and is directly associated with shallow magmatic bodies within tectonically-controlled basins. Our study provides the foundation for an updated tectonic and magmatic framework for the Sicilian Channel, and for future detailed chronological and geochemical assessment of the sources and evolution of magmatic processes in the region.

Description: Highlights • Alkaline magmas of the TLTF island chain result from a subduction-modified mantle source and two-stage partial melting. • The role of mantle source and parental melt composition for high Cu-Au mineral potentials is important but limited. • A shallow crustal magma reservoir is key for epithermal ore formation. Abstract The Tabar-Lihir-Tanga-Feni (TLTF) island chain in northeastern Papua New Guinea formed by tectonic and alkaline to shoshonitic magmatic activity since the Pliocene. Several volcanic centers are Cusingle bondAu mineralized including the world-class Ladolam Au deposit and Conical Seamount south of Lihir. The latter has been recognized as a juvenile analogue to the Ladolam deposit located on-shore. Whereas the mineralization at Conical Seamount is reasonably well studied, the specific magmatic processes that promote epithermal mineralization at this seamount but not at others are poorly understood. Here, we present new petrological and geochemical data from Conical Seamount, and compare them with those from the barren (unmineralized) Edison, Tubaf and New World seamounts nearby. We focus on whole rock compositions and major and trace element analysis of melt inclusions and minerals including clinopyroxene, sulfide and magnetite. We combine our observations with modelled constraints on mantle source composition and partial melting as well as magma evolution. A first-stage melting leaves a residual mantle source enriched in Au. Second-stage melting of a previously subduction-metasomatized mantle generally promotes the transfer and concentration of metals and volatiles in the ascending melts. These magmas are unlikely to control ore formation as all seamounts show evidence for similar mantle sources and parental melt composition. However, the presence of a shallow crustal magma chamber is unique to Conical Seamount. It is characterized by frequent melt replenishments and extensive magma fractionation leading to sulfide and magmatic volatile saturation. These specific magma chamber processes lead to the pre-enrichment of the magma in chalcophile elements including Au, while sulfide saturation coeval with magmatic volatile exsolution provide the way for an effective Au transfer from the magmatic to the epithermal system.

Description: Non-technical summary Scenarios compatible with the Paris agreement's temperature goal of 1.5 °C involve carbon dioxide removal measures - measures that actively remove CO2 from the atmosphere - on a massive scale. Such large-scale implementations raise significant ethical problems. Van Vuuren et al. (2018), as well as the current IPCC scenarios, show that reduction in energy and or food demand could reduce the need for such activities. There is some reluctance to discuss such societal changes. However, we argue that policy measures enabling societal changes are not necessarily ethically problematic. Therefore, they should be discussed alongside techno-optimistic approaches in any kind of discussions about how to respond to climate change. Technical summary The 1.5 °C goal has given impetus to carbon dioxide removal (CDR) measures, such as bioenergy combined with carbon capture and storage, or afforestation. However, land-based CDR options compete with food production and biodiversity protection. Van Vuuren et al. (2018) looked at alternative pathways including lifestyle changes, low-population projections, or non-CO2 greenhouse gas mitigation, to reach the 1.5 °C temperature objective. Underlined by the recently published IPCC AR6 WGIII report, they show that demand-side management measures are likely to reduce the need for CDR. Yet, policy measures entailed in these scenarios could be associated with ethical problems themselves. In this paper, we therefore investigate ethical implications of four alternative pathways as proposed by Van Vuuren et al. (2018). We find that emission reduction options such as lifestyle changes and reducing population, which are typically perceived as ethically problematic, might be less so on further inspection. In contrast, options associated with less societal transformation and more techno-optimistic approaches turn out to be in need of further scrutiny. The vast majority of emission reduction options considered are not intrinsically ethically problematic; rather everything rests on the precise implementation. Explicitly addressing ethical considerations when developing, advancing, and using integrated assessment scenarios could reignite debates about previously overlooked topics and thereby support necessary societal discourse. Social media summary Policy measures enabling societal changes are not necessarily as ethically problematic as commonly presumed and reduce the need for large-scale CDR

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

Description: In the area of the Deep Galicia Margin two multi-channel seismic lines (ISE-1 and ISE-2) have been processed and interpreted in the present study. The main objective was to attempt clarification of the precise nature and origin of the so-called S-reflector. For this purpose a full waveform inversion was carried out for a selected CMP gather besides prestack depth migration and poststack time migration. The results of the full waveform inversion lead to the conclusion that the S-reflector represents an approx. 50m thick low-velocity zone wedged in a stepwise velocity increase between continental crust and mantle. For this zone a compressional wave velocity of 5.2 km/s was determined as compared to 5.45 km/s for the overlying continental crust and 7.0 km/s for the mantle interval below. These p-wave velocities in the uppermost mantle are interpreted to result from a particular serpentinisation history involving two separate stages of seawater influx leading to the development of a detachment fault seismically imaged as the S-reflector.

Description: This study contributes to the inaugural exploration of non-equilibrated Ocean Alkalinity Enhancement (OAE). The manipulation of Total Alkalinity (TA), involving silicate and calcium-based ∆TA gradients ranging from 0 to 600 µmol · L-1, was conducted without prior CO2 sequestration, under natural conditions and at a mesocosm scale (~60 m3). The resulting impact included an increase in pH and a decrease in pCO2, sustained across the experiment, as full natural equilibration via sea-gas exchange did not occur. Implemented in a neritic system under post-bloom conditions, a midway mixing event was simulated. Following an inorganic nutrient addition, discernible delays in bloom formation, as indicated by the Gross Production (GP) and Net Community Production (NCP) rates, as well as by the chlorophyll-a (Chla) concentrations, in relation to the ∆TA gradient, were observed. Notably, the delay was more pronounced for the calcium treatment set compared to the silicate one, where low TA treatments exhibited earlier responses than high TA ones. This delay is likely attributed to the previously documented, species-specific negative relationships between high pH/lowCO2 levels and phytoplankton growth rates. This study underscores the need for further investigation into the implications of this response pattern in terms of trophic transfer and seasonal suitability. Further, it is anticipated that a wider delay in bloom formation would be evident with a larger non equilibrated TA gradient. Thus, highlighting the importance of exploring variations in TA limits for a comprehensive understanding of the OAE’s impacts.

Description: The aim of this study was to elucidate the foraging ecology of South American sea lions (Otaria flavescens) on the Patagonian shelf. Data from satellite tags revealed that male sea lions use a much larger part of the shelf than females and often reach areas close to the shelf break, which may be related to the highly productive shelf break front. The data also showed a high site fidelity, both towards feeding grounds and haul-out sites. Calculations of food consumption revealed that the impact that males have on their prey resources depends on the time that the animals spend at sea, and thus the distance to suitable foraging grounds. A new non-electronic release-mechanism was developed for the recovery of dead reckoners that were used to study the diving behaviour of sea lions. The diving data supported the expectations that males, because of their larger size, had a greater diving capacity than females, which lead to a greater dive efficiency at depths greater than 45m. The use of an Area-Interest-Index to determine space usage revealed that sea lion foraging trips can be divided into distinctive travel and foraging phases. Differences in this index were also visible on the scale of individual dives.

Description: Ocean deoxygenation is becoming a major stressor for marine ecosystems. Climate change affects ocean oxygen by altering wind fields and air-sea heat and freshwater fluxes. However, the quantitative contribution of these drivers to ocean deoxygenation remains uncertain. Here, we use a global ocean biogeochemistry model run under historical atmospheric forcing to show that deoxygenation since the late 1960s has been driven mainly by changing air-sea heat and freshwater fluxes and associated changes in solubility and ocean circulation. However, ~60% of this deoxygenation was offset by a wind-driven increase in ventilation and interior oxygen supply, mainly in the Southern Ocean. In the coming decades, the projected slowdown in wind stress intensification, combined with continued ocean warming, could greatly accelerate ocean deoxygenation. While ocean biogeochemistry models under historical atmospheric forcing struggle to reproduce the observed deoxygenation after 2000, fully coupled Earth system models capture the trend, indicating systematic problems in hindcast simulations.

Description: Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP), two prominent classes of gel−like particles in the ocean primarily produced by phytoplankton, play crucial roles in ecological and biogeochemical processes, influencing microbial nutrition, growth, and particle aggregation. The distribution of these particles is intricately linked to the spatiotemporal dynamics of phytoplankton. Mesoscale cyclonic eddies (CEs) are known to stimulate phytoplankton growth and influence particle transport, but their effects on TEP and CSP remain to be determined. In the Eastern Tropical North Atlantic (ETNA), we examined three CEs: one off the Mauritanian coast during summer (Mau), one offshore during winter (Sal), and another near Brava island during winter. Mau and Brava CEs were in their intensification/maturity phase, while the Sal CE was in its decay phase. Both TEP and CSP concentrations correlated with primary productivity, but TEP increased with chlorophyll−a concentration, whereas elevated CSP coincided also with the highest abundance of pico−nanophytoplankton (〈20 µm), mainly Synechococcus. Both gels exhibited a positive correlation with bacterial biomass production, indicating their consumption by heterotrophic bacteria. TEP total area in the epipelagic waters of all CEs (Mau, Brava, and Sal) was elevated compared to surrounding waters, with on average 4, 2.5, and 1.6−fold higher values, respectively. However, no significant difference in TEP size distribution was observed within any CEs and their surroundings. Similarly, CSP total area increased in the epipelagic waters of Mau and Brava CEs, with on average 5 and 2.4−fold higher values, respectively, compared to surrounding waters. CSP particles were notably larger in these two eddies, while the Sal CE showed no significant difference from surrounding waters in CSP abundance and size. Overall, TEP and CSP exhibited distinct responses to CEs, with increased concentrations during their intensification/maturation stage and remineralization dominating during their decaying stage.

Description: The Atlantic Meridional Overturning Circulation (AMOC) is considered as an important part of the global climate system. The densest component of the AMOC is the Denmark Strait Overflow Water, entering the deep Atlantic across the sill between Greenland and Iceland. Here, four years of overflow measurements in Denmark Strait are analyzed. The data suggest, that the overflow consists of a density driven, hydraulically controlled part, and a barotropic, wind stress forced component. The observed overflow transport reduction of 20% from 1999 (3.7 Sv) to 2003 (3.1 Sv) is likely caused by both a dense water reservoir height decrease in the Iceland Sea, and a reduction of the local wind stress forcing. The interannual fluctuations are consistent with a reduction of the North Atlantic Oscillation (NAO). Interannual temperature variability of 0.5 °C is linked to variable upstream entrainment rates and/or variable percentages of different water masses rather than changes of the individual sources. Further, an anticorrelation with the Faroe Bank Channel Overflow is found, with the total dense water outflow from the Nordic Seas being almost constant at 5.5 Sv from 1999 to 2003.

Description: Mixotrophy, which is the combination of autotrophic and heterotrophic modes of nutrition, is a common phenomenon in aquatic food webs. Mixotrophic feeding strategies are species specific and dependent on environmental factors, such as light and nutrient conditions. In contrast to the plankton, nothing is known about the occurrence and the ecological role of benthic mixotrophs. In the present study, mixotrophic nanoflagellates were investigated in coastal marine sediments. Their quantitative importance and their ecological role were investigated in dependence of light and nutrient conditions and along small-scale vertical and horizontal gradients at the main sampling site at Falckenstein Beach in the Western Baltic Sea. Furthermore, the significance of mixotrophs was compared in sediment and plankton in different systems along a salinity gradient and at different geographical sites, as well as in plankton and sea ice of the Greenland Sea. Mixotrophs showed varying abundances and contributions to the flagellate community, which could not be attributed to particular environmental factors in all cases. Disparate responses in temporal and spatial scales were attributed to differences in community composition of mixotrophs and in the relative importance of environmental factors that determine mixotrophic feeding strategies. Abundances of mixotrophs increased with increasing salinity. However, they contributed low portions to the total nanoflagellates (max. 7%), with higher portions to the total phytoflagellates (max. 25%) than to total bacterivores (max. 10%). Highest contributions were found in sea ice and plankton of the Greenland Sea. Mixotrophic feeding strategies were proposed to play a greater role in oceanic plankton and sea ice than in coastal sediments.

Description: The Denmark Strait overflow is the major gateway for dense water from the Nordic Seas into the North Atlantic and thus it constitutes an important part of the thermohaline circulation under present-day climate conditions. This study focuses on the regional to basin wide dynamics of the Denmark Strait overflow for present-day and Last Glacial Maximum conditions. It contributes to the Research Unit Ocean Gateways located at the University of Kiel which addresses the question how ocean gateways might have affected climate in the past.The volume transport of the overflow is likely to be controlled by hydraulic constraints, thus the transport is set by the relative density contrast between the water masses north and south of the Denmark Strait and the height of dense water above sill level. By using high resolution numerical models it is investigated how the volume transport can be best described using existing hydraulic theories. Hydraulic constraints are shown to be valid over a wide parameter range which allows to transfer this theory to LGM conditions. During the LGM both bathymetry and hydrography have been different and the relative importance of the individual effects is disentangled using a high-resolution numerical model. The drop in eustatic sea-level and glaciated shelves in this area had a comparable smaller effect than the reduced density contrast. In addition to buoyancy forcing wind stress might play a role in setting the overflow transport. In a regional model of the Greenland-Scotland Ridge an influence of wind stress on the overflow can be shown. Therefore, wind stress changes due to different phases of the NAO are expected to imprint a signal on the overflow transport. The same holds for wind field changes from Last Glacial Maximum to present-day conditions. Even though the wind stress was increased the density difference between Nordic Seas and North Atlantic supports almost no buoyancy forcing of the overflows thus the Denmark Strait overflow was probably reduced to less than 0.5 Sv during Last Glacial Maximum summer. However, it is proposed that the increased LGM wind stress is an important factor in keeping the Nordic Seas ice free during summer. The heat transport associated with the volume transport is generally reduced for the Last Glacial Maximum with a pronounced reduction if the Denmark Strait is additionally closed e.g. by iceberg blocking. The relation connecting hydraulic constraints and volume transport was implemented in a global climate model to improve the representation of the Denmark Strait overflow in that model. It results in an increased Atlantic meridional overturning and the associated northward heat transport. A close correlation between overflow representation and climate in northern Europe can be shown. This emphasises the impact of the Denmark Strait overflow on climate even though the response in overturning due to the representation is less than expected from previous studies. There is nearly no stabilising effect of the overflow for large scale freshwater perturbations but a weak effect if the system is perturbed locally in the Labrador Sea.

Description: Methane seepage from different geological structures was investigated along the convergent margin off the Pacific coast of Costa Rica in order to identify the fate and the amount of methane discharging into the ocean. Thus, the water column above four mud extrusions and one of several embayments caused by the subduction of seamounts (scarps) was examined by means of methane concentration analyses, carbon isotopic characterization of the methane and current measurements. It was discovered, that most of the vent derived methane is dispersed and diluted by mixing with seawater having background methane-concentrations whereas only a part of the methane is oxidized. Besides, repeated measurements indicate long-term variations in methane seepage, which might be related to earthquake activity. The amount of methane released from mud extrusions and scarps offshore Costa Rica was estimated to be ~0.2‰ of the global methane output from the seafloor, which is reported to be in the order of 20 Tg yr-1. The estimated methane outputs present the first ones from an erosive convergent margin and are of great significance for assessments of the global methane output in general and of specific geological structures, e.g. mud extrusions, in particular.

Description: In the past the oceanic environment has often been compared with terrestrial deserts and until today relatively little is known about the ecology of the high seas. Within the present study pelagic oceanic communities of cephalopods and fish in the subtropical North Atlantic were investigated, and it was analysed at different spatial scales how these communities varied in response to physical gradients and hydrographic processes. First, the influence of the subtropical convergence zone in the Sargasso Sea on the distribution of early life stages of cephalopods was determined. This large-scale front turned out to represent a distinct faunal boundary, with higher diversity and abundance values in the northern part of the Sargasso Sea compared to the southern area. Second, mesoscale distribution patterns of paralarval cephalopods and larval fish were described at Great Meteor Seamount in relation to the specific hydrographic features, as e.g. the Taylor cap. Processes structuring the pelagic communities were identified and their impact evaluated by different multivariate statistical techniques. Fish and cephalopods were similarly influenced, although the retention potential at the seamount was much more pronounced for larval fish. Third, the diurnal vertical migration behaviour of juvenile and adult cephalopods was investigated from samples collected at three seamounts of different topographic morphology. A logistic regression model was developed to demonstrate the probability of occurrence in relation to daytime and catch depth. Because of the species-specific vertical distribution the seamounts represented a topographic obstacle, resulting in an impoverished fauna at shallower water depth.

Description: The dissertation deals with methodological and field studies of alkenones and their carbon isotopes in the North Atlantic (Madeira Basin). The methodological studies focussed on comparison of measurements with gas chromatography with flame ionisation detection and gas chromatography coupled to mass spectrometry. It was possible to separate and detect three C37-, five C38- und five C39-alkenones with a single measurement, even at low concentrations. A goal of the field studies was to determine the original carbon isotope values in alkenones at the time of synthesis during blooms of coccolithophorids. 1)Modifications of this primary delta13C- alkenones-values in the water column were followed up to the sediment traps at 2,000 m and 3,050 m. 2)The values of the underlying sediments were considered. The controversial use of the delta13C-alkenones-values for paleoreconstruction of the partial pressure of carbondioxid was critically examined. Parallel behaviour in the development of temperature and delta13C-alkenones-values were observed for all measured alkenones. Dependencies of different delta13C- alkenones-indices of the temperature were established

Description: In the present work the impact of broken clouds on solar irradiance at the surface is studied. This study is based on the region of Kiel, becausc of realisation of land and seameasurements. To this end data from pyranometer and ceilometer, which are available at the Institut für Meereswisscnschaften, are used. On thc basis of these data (march 1997 until october 2003) statements about variation in solar irradiance by different cloud amount over land opposite to the reference of clear sky case at the lighthouse Kiel are made. Beside the decrease in irradiance, so-called shadowing effect, an extra amount of irradiance by broken cloudiness adds to the amount of direct irradiance. The extra amount of irrandiance is given by reflection of solar radiance at cloud sides. The english technical literature refers to the enhancemcnt as "broken cloud effect" (bce). The enhancement ranges from some W/m2 until 300 W/m2. This depends on the typ of cloud and the solar zenith angle. The bc rcsults from cumuli, which accumulate by convection at the time of land-sea-breeze-circulation. The frequency of occurrence of thc bc-events are significant coupled with the sea-breeze-circulation. The effect can be observed soonest in spring and in early and late summer, if and only if the formation of sea-breeze-circulation is most likely and as a consequence thereof the fine weather cumuli are developed. In June the broken cloud effect occurs very often owing to the small solar zenith angles of 30°, which arc typical for this month. A further dependance exists in cloud amount. The increase in radiance is maximal by a cloud over of 6/8. Consequently the bce cannot be oberserved neither at cloud1ess nor at completely covered sky. A concluding aspect for this work consists in modelling the bce with the model called GRIMALDI, which is advanced at the Institut für Meereswissenschaften. In this model a homogeneous plan-parallel cumulus cloud is implemented. For different solar zenith angles and cloud covers a relation to the pre-achieved results will be carried out. There is a distinctive bce in the model, too. Differences between the modelled and the calculated radiant fluxcs can be explained by the high simplified cumulus clouds.

Description: The present study was conducted as part of the German contribution to the GLOBEC (Global Ocean Ecosystems Dynamics) program in June 2003. lt was intended to investigate possible effects of frontal systems in the German Bight of the North Sea on the growth characteristics of sprat ( Sprattus sprattus) larvae by means of otolith microstructure examination. However, it turned out that the majority of sampled larvae were not sprat but pilchard (Sardina pilchardus). This unusual occurrence of pilchard spawning coincided with unusually high temperatures in summer 2003. This might be regarded as an indicator for a shift of southern species to areas further north due to climate variability. The species distribution in the two frontal systems investigated, a tidal mixing front and a river plume front, seemed to be influenced by the hydrographic properties. Pilchard dominated in water bodies with characteristics of their usual spawning grounds further south, i.e. waters with higher temperatures and salinities. Sprat, on the other hand, which is a native spawner in the area and known to tolerate very low salinities, was predominantly found in colder and less saline water bodies. The biotic and abiotic properties of waters in and close to the tidal mixing front also seemed to generally provide favourable conditions for growth. Larvae sampled at different stations on a transect across the tidal mixing front also showed differences in growth rates. Highest growth rates were found in larvae caught at a stratified station further offshore. This was probably due to the higher chlorophyll-a content that was observed 6 days prior to catch at this station, which was suspected to also indicate higher abundances of potential larval food. However, a second observation on the day of catch indicated that chlorophyll-a and, thus, suspected food availability had reversed after a storm event that occurred between the two observations. Some evidence was found from the otolith microstructure examination that this shift in food availability is reflected in larval growth performance. Regarded in conjunction with high larval abundance close to the coast, this led to the conclusion that the fronts in the German Bight might act as retention areas for larvae providing conditions that have a positive effect on larval growth, survival and subsequent recruitment. Additionally, it was found that pilchard larvae expressed better growth rates than sprat larvae. This could mean that pilchard larvae are potential rivals to the native sprat, competing for resources like food and habitat, and an effect of the pilchard spawning in the German Bight on the North Sea ecosystem can not be ruled out.

Description: The focus of the present study was to investigate the soft bottom community (including in- and epifauna) at the coastal slope (5 m to 30 m) in Kongsfjorden, and to estimate its importance as food source for demersal fish. For these purposes the macrozoobenthos was sampled at six sampling locations. In total 30 samples were taken (6 x 5 replicates) by means of a steel frame of 192 cm2 area size. A suction pump ("airlift") collected the soft bottom fauna within the designated area. Polychaets (84 %), molluscs (10 %) and crustaceans (3 %) dominated the soft bottom community. In total, 63 species were found, including 30 species which have not been recorded in Kongsfjorden earlier. Seven species have not yet been recorded for the entire archipelago of Svalbard (according to Gulliksen et al. 1999). The average abundance was 6293 individuals m-2, the average biomass was 14 g ash free dry mass (afDM) m-2. Three community types could be identified by means of clusteranalysis and multidimensional scaling: The „shallow water" - community at 5 m (28 species; 2260 individuals m-2; 3.5 g m-2 afDM), the „mid-water"- community between 10 m and 20 m (51 species; 7184 individuals m-2; 20.7 g m-2 afDM) and the deepwater"- community in the range of 25 m and 30 m (44 species; 6982 individuals m-2; 10.6 g m-2 afDM). The species found were then categorized with respect to their feeding ecology and were classified to their zoogeography. Five species were omnivorous, 23 carnivorous, 25 detritivorous and 18 suspesion feeders. Most of the species (34) were arctic-boreal followed by cosmopolitan species (20); only five species were true arctic. Furthermore ecological indices were calculated: the Margalef Index (1.45°-02.23), Shannon-Wiener diversity (1.85°-02.19) and evenness (0.67°- 00.82). Six dominant species (〉 10 %) were identified (Crassicorophium crassicorne, Chaetozone setosa, Dipolydora quadrilobata, Euchone analis, Scoloplos armiger and Spio armata) and three were determined as indicator species (Oipolydora quadrilobata, Euchone analis and Scoloplos armiger). Nine species of demersal fish were found in shallow areas (5 m to 30 m) of Kongsfjorden: Anarhichas lupus, Anisarchus medius, Eumicrotremus derjugini, Gadus morhua, Gymnacanthus tricuspis, Leptoclinus maculatus, Liparis liparis, Lumpenus lampretaeformis and Myoxocephalus scorpius. According to the literature these fish species were feeding on the bottom community, in particular on taxa witch found at this study Priapulus caudatus, Scoloplos armiger, Anonyx sarsi, Crassicorophium sp., Ischyrocerus sp., Monoculodes tesselatus, Onisimus edwardsi, Sclerocrangon boreas and Ophiura sarsi. Polychaets (up to 87 %), amphipods (up to 56 %), molluscs (up to 50 %) and echinoderms (up to 48 %) dominated the spectrum of food source.

Description: The Western Tropical Atlantic Ocean (WTAO) is crucial for understanding CO2 dynamics due to inputs from major rivers (Amazon and Orinoco), substantial rainfall from the Intertropical Convergence Zone (ITCZ), and CO2-rich waters from equatorial upwelling. This study, spanning 1998 to 2018, utilized sea surface temperature (SST) and sea surface salinity (SSS) data from the PIRATA buoy at 8°N 38°W to reconstruct the surface marine carbonate system. Empirical models derived TA and DIC from SSS, with subsequent estimation of pH and fCO2 from TA, DIC, SSS, and SST data. Linear trend analysis showed statistically significant temporal trends: DIC and fCO2 increased and pH decreased, although DIC did not show any trend after data was de-seasoned. Rainfall analysis revealed distinct dry (July to December) and wet (January to June) seasons, aligning with lower and higher freshwater influence, respectively. TA, DIC, and pH correlated positively with SSS, exhibiting higher values during the dry season and lower values during the wet season. Conversely, fCO2 correlated positively with SST, showcasing higher values during the wet season and lower values during the dry season. This emphasizes the influential roles of SSS and SST variability in CO2 solubility within the region.

Description: Difficulties in characterisation of sprat populations in the Baltic Sea have lead to the determination of only one management unit for the ICES subdivisions 22-32. To prevent mistakes in management which could result in overfishing and exploitation, stock differentiation for the Baltic sprat is demanded from several sides. Genetic tools are considered as helpful to meet these demands and it is hoped to lead that they will provide new information about the number and distiibution of existing stocks. The use of microsatellite-loci is an approach for genetic stock identification. Microsatellites are highly informative genetic markers useful for population genetic studies, lineage mapping and parentage detection. Usually, microsatellites have to be identified anew for every species examined because the flanking regions of the repeat sequences differ between most taxa. An approach for isolation of tandem repeated sequences in the genomic DNA of the sprat, Sprattus sprattus is desciibed here. Genomic DNA was fragmented, attached linkers and prepared for ligation into a plasmid vector. Specific repeat elements were captured using biotinylated oligonucleotide probes in solution and subsequent attachment to streptavidin-coated magnetic beads. Captured fragments were amplified by PCR and cloned into the vector. The product of this expeiiment was a library enriched for defined microsatellite-sequences. Clones from this library were selected and their inserts were sequenced due to the detection of repeat motives. The results presented here show that this approach is effective to isolate dinucleotide- repeat sequences. For the enrichment two tetranucleotides, AGAT(7) and TATC(7) and one dinucleotide, GT(15) were used. GT(n) repeats were found in all of the thirty dinucleotideenriched DNA samples, sequenced. Contraiily, in none of the tetranucleotide-enriched samples repeat sequences could be identified. This study shows that in general the isolation of repeat sequences of genomic sprat DNA is possible. The development of microsatellite markers suitable for stock identification of the sprat in the Baltic Sea was discussed here.

Description: Die vorliegende Arbeit befaßt sich mit der Nahrungsökologie von überwinternden Eis- und Trauerenten. ( Clangula hyemalis und Melanitta nigra). Die auf den Mageninhalt untersuchten Vögel stamnen aus Beifängen der Stellnetzfischerei vor der Insel Usedom. Darüber hinaus wurden die Ergebnisse mit verfügbaren vorhandenen Nahrungsdaten der genannten Entenarten verglichen. Die Tatsache, daß solche nur in relativ wenigen Veröffentlichungen zu finden sind, war zugleich Ansporn für diese Arbeit, sich mit der Beziehung zwischen Meeresenten und Benthos näher zu befassen. Die untersuchten Trauerenten hatten vornehmlich Baltische Plattmuscheln (Macoma balthoica) gefressen, während bei den Eisenten die Sandklaffmuschel (Mya arenaria) an erster Stelle stand. Im Vergleich mit anderen Daten ergab sich, daß die Nahrungszusammensetzung regional zwar verschieden ist das unterschiedliche Angebot an Nahrung war dabei aber nicht unbedingt der einzige bestimmende Faktor. So wurden z.B. Miesmuscheln (Mytilus edulis) in der Hohwachter Bucht kaum gefressen, obwohl sie dort sehr häufig siITd (Kirchhoff, 1979). Bei den Eisenten wurden auch einige andere Invertebraten sowie vereinzelt Fisch oder Laich gefunden, während die Trauerenten ausschließlich Muscheln gefressen hatten. Bei der Arbeit auftauchende Fragen sollen Anregung sein, die Thematik weiter im Auge zu behalten, um durch eventuelle künftige Forschungen ein umfassenderes Bild über Meeresenten,deren Verhalten und Ernährung zu bekommen.

Description: Die vorliegende Arbeit entstand m Zusammenarbeit zwischen dem Leibniz-Institut für Meereswissenschaften an der Universität Kiel und der Bundesforschungsanstalt für Fischerei in Hamburg. Ziel der Arbeit war die Beschreibung der räumlichen Verteilungsmuster von Heringen ( Clupea harengus L.) und Sprotten (Sprattus sprattus L.) in der südlichen Nordsee in Relation zu den hydrographischen Bedingungen. Dabei sollten für beide Arten nach Möglichkeit bevorzugte Temperatur- und Salzgehaltsbereiche angegeben werden. Zusätzlich sollten Sehwarmparameter (Länge, Höhe, Umfang und Fläche der Schwärme) für Heringe und Sprotten ermittelt werden. Diese Werte , sollten die Grundlage dafür schaffen, in hydroakustisch untersuchten Gebieten der Nordsee Rückschlüsse auf die ArtenZusammensetzung zu ziehen. Die Auswertungen basierten auf hydroakustischen Daten, die jeweils im Juni und Juli der Jahre 2002 und 2003 mit dem Forschungsschiff „Walter Herwig III" aufgezeichnet wurden. Während der beiden Seereisen wurden neben den hydroakustischen Aufnahmen Fischereistationen und CTD-Stationen durchgeführt. In beiden Jahren konnten identische Verteilungsmuster der beiden Arten festgestellt werden. Die Heringe waren fast ausschließlich in den nördlichen Teilen des Untersuchungsgebietes lokalisiert, während sich die Sprotten vornehmlich in den südlichen Gebieten aufbielten. Es konnten Zusammenhänge der beschriebenen Verteilungsmuster mit den Temperaturen des Tiefenwassers nachgewiesen werden. Die Heringe bevorzugten warme Temperaturen, während die Sprotten kältere Temperaturen präferierten. Es konnten außerdem Zusammenhänge zwischen den Verteilungsmustern von Heringen und Sprotten und dem Auftreten von tidal-mixing-Fronten nachgewiesen werden. Die Heringe hielten sich fast ausschließlich im vertikal geschichteten Bereich auf, während die Sprotten entweder im durchmischten Bereich oder in den Bereichen, in denen die größten horizontalen Schichtungsgradienten beobachtet werden konnten, lokalisiert waren. Weiterhin wurde festgestellt, dass die Heringe in beiden Jahren echointensivere Schwärme als die Sprotten bildeten. Die Unterschiede der ermittelten Sehwarmparameter von Heringen und Sprotten fielen gering aus. Es wurden von diversen Autoren Untersuchungen zu möglichen Präferenzen der Arten Hering und Sprott für hydrographische Bedingungen durchgeführt. Die ermittelten. Temperaturpräferenzen und auch die Zusammenhänge der Verteilungsmuster der beiden Arten mit dem Auftreten von Fronten deckten sich gut mit den Ergebnissen anderer Autoren.

Description: Populationdata help understand the distribution and abundance of animals. They are especially useful for decisions involving protected areas or the assessment of habitat importance. Methods for estimates of populations are numerous e.g. capture-recapture, marked animals with fluorescent pigments or photoidentification. Aerial surveys are used for large animals in a standardized approach (Tasker et al. 1984) and marine animals can be detected by the line transect method (land based surveys, shipboard or aeroplane counts). Line transect surveys involve travel along a predetermined course, counting all animals sighted within this transect. The band width in general takes up to 300 meters and extends to both sides of the ship or aeroplane. It can be difficult, though, to record these animals in a way that represents the population because seals spend most of their time submerged in the water and seabirds have continually changing spatial distributions. Many exogenous factors can influence the visibility; the distance at which animals can be seen at sea, the weather conditions or sea state and the varying capability of the different observers. The aim of this work was to examine the extent to which physical factors influence the probability of seals being seen. Reflection, contrast between the water and the object as well as the carmouflage of seals may all influence the visibility of seals under natural conditions. In addition, variables such as distance to observer, weather conditions and sea state were included. To examine this, digital photographs were taken of a seal model placed at sea to so as to simulate the line transect method. Gull models were also used close to the seal to examine the effect that this conspicuous colours might have on seal perception. A selection of the digital pictures was shown to 120 test persons who had to decide within two seconds if they could recognize a seal in the picture or not. The restricted time was chosen in an attempt to imitate line transect counts. The results of this work is the analysis of answers given by the test persons. The analysis showed that significantly less animals are detected with increasing sea state and distance or decreasing cloud coverage. The visibility of seals appears to depend critically on optical conditions such as the reflection of light, contrast or light intensity. Test persons recognized the seal more often when the picture was taken in mid afternoon, and more often when the model was to the South or North of the position of the photographer. Men spotted the seal more often than women. This study shows what kind of factors could bias the sighting conditions of seals. In order to influence visibility in a positive way, many constraints have to nteract in an optimal way. The results of this work could be integrated in population counts.

Description: Biodiversität ist ein vielschichtiges Konzept. Es ist wichtig, die Faktoren zu untersuchen, die Biodiversität erhöhen, verringern oder erhalten. Zwei der etabliertesten Modelle, die die trotz der aktuellen globalen Krise eines rasanten Artenverlusts tatsächlich sehr hohe Artenvielfalt zu erklären versuchen, sind die „Intermediate Disturbance Hypothesis“ (IDH) und die Produktivitäts-Diversitäts-Beziehung. Die IDH beschreibt die Diversität in Abhängigkeit von Störungen. Danach ist bei mittlerer Störungsintensität die höchste Diversität zu erwarten, da sowohl störungstolerante als auch konkurrenzstarke Arten koexistieren können. Die Abhängigkeit der Diversität von der Produktivität soll in ihrer Form vergleichbar sein. So ist auch bei mittlerer Produktivität mit maximaler Diversität zu rechnen, da die Minimalanforderungen (an die Versorgung mit Ressourcen) einer großen Zahl von Organismen erfüllt sind, das Angebot der Ressourcen aber noch nicht so hoch ist, dass Dominanz einiger überlegener Arten entsteht. Mit dem Ziel, die Konzepte zum Einfluss von Störungen und Produktivität auf die Artenvielfalt zu vereinen, hat Kondoh (2001) ein Modell entwickelt, das die vielfältigen Reaktionsmuster der Diversität auf Störungs- und Nährstoffregimes erklären könnte. Es sagt voraus, dass bei starken Störungen und niedriger Produktivität überlegene Kolonisierer und bei schwachen Störungen und hoher Produktivität überlegene Wettstreiter dominieren, in beiden Fällen die Artenvielfalt also niedrig bleibt. Höchste Artenzahlen sind nach diesem Modell bei ausgeglichenen Störungs- und Produktivitätsverhältnissen zu erwarten, da dann sowohl gute Kolonisierer als auch starke Wettstreiter überleben können. Um die Gültigkeit von Kondohs Modell zu prüfen, untersuchte ich in einem 2-faktoriellen ökologischen Experiment die wechselseitigen Effekte, die Störungen und Nährstofferhöhungen auf die Artenvielfalt einer felsigen Gezeitenküste bei zwei Standorten an Südafrikas Ostküste ausüben. Die von der IDH vorhergesagte unimodale Beziehung konnte in der vorliegenden Arbeit nicht empirisch bestätigt werden. Trotz starker Hintergrundvarianz zeigte die Nährstoffbehandlung in einer Reaktion von gemeinschaftsattributen Wirkung, wobei nur bei einem Standort die Diversität mit höherem Nährstoffangebot (entsprechend Kondohs Modell) anstieg. Die Ergebnisse zeigen weiter, dass die Reaktion der Artenvielfalt auf Störungen vom Nährstoffangebot abhängen kann. Der von Kondoh vorgeschlagene stetige interaktive Effekt von Störungen und Produktivität auf die Diversität wurde allerdings nicht bestätigt. Die viel diskutierten unimodalen Muster der Diversität entlang von Störungs- und Produktivitätsgradienten können weder das hier untersuchte noch die Mehrheit anderer untersuchter Systeme befriedigend beschreiben. Ich kann jedoch einige der ökologischen Mechanismen, auf denen die IDH und die Produktivitäts-Diversitäts-Beziehung beruhen, anhand meiner Ergebnisse nachvollziehen, weshalb ich weder diese beiden Konzepte noch Kondohs Modell widerlegen kann. Ich stimme den kürzlich postulierten Ansichten zu, dass die Entschlüsselung einer Vielzahl ökologischer Mechanismen vorangetrieben werden muss, um so durch die Entwirrung und Neuformulierung klassischer Konzepte allgemeingültige Muster aufdecken zu können.

Description: When volcanic mountains slide into the sea, they trigger tsunamis. How big are these waves, and how far away can they do damage? Ritter Island provides some answers.

Description: Deoxygenation is tied to organic carbon (Corg) supply and utilization in marine systems. Under oxygen-depletion, bacteria maintain respiration using alternative electron acceptors such as nitrate. Since anaerobic respiration's energy yield is lower, Corg remineralization may be reduced and its residence time increased. We investigated the influence of oxygen and alternative electron acceptors' availability on Corg cycling by heterotrophic bacteria during a continuous culture experiment with Shewanella baltica, a facultative anaerobic γ-Proteobacteria in the Baltic Sea. We tested six different oxygen levels, from suboxic (〈5 µmol L-1 ) to fully oxic conditions, using media (salinity=14 g L-1 ) supplied with high (HighN) or low (LowN) inorganic nitrogen concentrations relative to glucose as labile Corg source. Our results show that suboxia limited DOC (glucose) uptake and cell growth only under LowN, while higher availability of alternative electron acceptors seemingly compensated oxygen limitation under HighN. N-loss was observed under suboxia in both nitrogen treatments. Under HighN, N-loss was highest and a C:N loss ratio of ~2.0 indicated that Corg was remineralized via denitrification. Under LowN, the C:N loss ratio under suboxia was higher (~5.5), suggesting dominance of other anaerobic respiration pathways, such as dissimilatory nitrate reduction to ammonium (DNRA). Bacterial growth efficiency was independent of oxygen concentration but higher under LowN (34±3.0%) than HighN (26±1.6%). Oxygen concentration also affected dissolved organic matter (DOM) cycling. Under oxic conditions, the release of dissolved combined carbohydrates was enhanced, and the amino acid-based degradation index (DI) pointed to more diagenetically altered DOM. Our results suggest bacterial Corg uptake in low-oxygen systems dominated by S. baltica can be limited by oxygen but compensated by high nitrate availability. Hence, suboxia diminishes Corg remineralisation only when alternative electron acceptors are lacking. Under high nitrate:Corg supply, denitrification leads to a higher N:C loss ratio, potentially counteracting eutrophication in the long run. Low nitrate:Corg supply may favour other anaerobic respiration pathways like DNRA, which sustains labile nitrogen in the system, potentially intensifying the cycle of eutrophication. Going forward, it will be crucial to establish the validity of our findings for S. baltica in natural systems with diverse organic substrates and microbial consortia.

Description: Volcanic flank collapses, especially those in island settings, have generated some of the most voluminous mass transport deposits on Earth and can trigger devastating tsunamis. Reliable tsunami hazard assessments for flank collapse-driven tsunamis require an understanding of the complex emplacement processes involved. The seafloor sequence southeast of Montserrat (Lesser Antilles) is a key site for the study of volcanic flank collapse emplacement processes that span subaerial to submarine environments. Here, we present new 2D and 3D seismic data as well as MeBo drill core data from one of the most extensive mass transport deposits offshore Montserrat, which exemplifies multi-phase landslide deposition from volcanic islands. The deposits reveal emplacement in multiple stages including two blocky volcanic debris avalanches, secondary seafloor failure and a late-stage erosive density current that carved channel-like incisions into the hummocky surface of the deposit about 15 km from the source region. The highly erosive density current potentially originated from downslope-acceleration of fine-grained material that was suspended in the water column earlier during the slide. Late-stage erosive turbidity currents may be a more common process following volcanic sector collapse than has been previously recognized, exerting a potentially important control on the observed deposit morphology as well as on the runout and the overall shape of the deposit. Key Points Landslide emplacement offshore Montserrat included volcanic flank collapses, sediment incorporation, and a late-stage erosive flow Highly erosive flows are likely to be common processes during volcanic flank collapse deposition Pre-existing topography plays a major role in shaping flank collapse-associated mass transport deposits Plain Language Summary Disintegration of volcanic islands can cause very large landslides and destructive tsunamis. To assess the tsunami hazard of such events, it is crucial to understand the processes that are involved in their formation. We present new insights from seismic data and drill cores from a landslide deposit offshore Montserrat, a volcanic island in the Lesser Antilles Arc in the Caribbean. Our analysis reveals the emplacement of landslide material in several stages, including multiple volcanic flank collapses, incorporation of seafloor sediments and an erosive flow that carved channels into the top of the deposit right after its emplacement. We suggest that highly erosive flows are a common process during volcanic flank collapse deposition and that they play a significant role in the shaping of the deposit's appearance.

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

Description: In the last decades, the slow-spreading Red Sea rift has been the objective of several geophysical investigations to study the extension of the oceanic crust, the thickness of the sedimentary cover, and the formation of transform faults. However, local seismology datasets are still lacking despite their potential to contribute to the understanding of the tectonic evolution of the Red Sea. The Zabargad Fracture Zone is located in the Northern Red Sea and significantly offsets the rift axis to the East. Thus, it is considered a key tectonic element to understand better the formation of the Red Sea rift. To fill the gap in the dataset availability, we deployed the first passive seismic network in the Red Sea, within the Zabargad Fracture Zone. This network included 12 Lobster OBSs from the DEPAS pool, 2 OBS developed and deployed by Fugro, and 4 portable seismic land stations deployed on islands and onshore on the Saudi Arabian coast. Our data-quality analysis confirms that the head-buoy cable free to strum, as well as other additional elements of the DEPAS OBSs, generate seismic noise at frequencies $〉$ 10 Hz. However, the Fugro OBSs show high-frequency disturbances even if they lack vibrating elements. Comparison between land and OBS stations reveals that noise between 1 and 10 Hz is due to ocean-generated seismic noise, and not due to resonance of the OBS elements. We also found that waveforms of teleseismic earthquakes recorded by the Fugro OBSs, islands, and onshore stations have comparable signal-to-noise ratios. Instead, differences in signal-to-noise ratio for local earthquakes are affected more by site and path effects than instrument settings.

Description: In this study we look beyond the previously studied effects of oceanic CO2 injections on atmospheric and oceanic reservoirs and also account for carbon cycle and climate feedbacks between the atmosphere and the terrestrial biosphere. Considering these additional feedbacks is important since backfluxes from the terrestrial biosphere to the atmosphere in response to reducing atmospheric CO2 can further offset the targeted reduction. To quantify these dynamics we use an Earth system model of intermediate complexity to simulate direct injection of CO2 into the deep ocean as a means of emissions mitigation during a high CO2 emission scenario. In three sets of experiments with different injection depths, we simulate a 100-year injection period of a total of 70 GtC and follow global carbon cycle dynamics over another 900 years. In additional parameter perturbation runs, we varied the default terrestrial photosynthesis CO2 fertilization parameterization by ±50 % in order to test the sensitivity of this uncertain carbon cycle feedback to the targeted atmospheric carbon reduction through direct CO2 injections. Simulated seawater chemistry changes and marine carbon storage effectiveness are similar to previous studies. As expected, by the end of the injection period avoided emissions fall short of the targeted 70 GtC by 16–30 % as a result of carbon cycle feedbacks and backfluxes in both land and ocean reservoirs. The target emissions reduction in the parameter perturbation simulations is about 0.2 and 2 % more at the end of the injection period and about 9 % less to 1 % more at the end of the simulations when compared to the unperturbed injection runs. An unexpected feature is the effect of the model's internal variability of deep-water formation in the Southern Ocean, which, in some model runs, causes additional oceanic carbon uptake after injection termination relative to a control run without injection and therefore with slightly different atmospheric CO2 and climate. These results of a model that has very low internal climate variability illustrate that the attribution of carbon fluxes and accounting for injected CO2 may be very challenging in the real climate system with its much larger internal variability.

Description: Processes taking place within the magma plumbing system can exert an important control on the composition of mid-ocean ridge basalts (MORB). Plagioclase ultraphyric basalts (PUBs) found at magma-poor mid-ocean ridges exhibit diverse disequilibrium characteristics, which can provide vital insights for distinguishing the complex effects of melt transport from those of source heterogeneity on the compositions of MORBs. Here, we present new insights into magmatic processes using integrated petrologic and geochemical studies of the PUBs from two zones (~ 50° and ~ 64°E longitude) along the ultraslow-spreading southwest Indian ridge (SWIR). The studied PUBs have complex mineral morphologies, including skeletal and acicular crystals, glomerocrysts with open and closed structure, reverse and normally zoned crystals and external and internal resorption even in single samples. Both low- and high-Fo olivine and An plagioclase crystals are in disequilibrium with their matrix glasses. Some plagioclase phenocrysts have repeated oscillatory zoning (An77–86) going from their core to rim and an abrupt decrease in An content toward the rim. Disequilibrium Sr isotopic compositions are present at several scales: between cores and rims of plagioclase crystals, between different plagioclase crystals and between plagioclase and their host lavas. Inferred pressures of magma storage range from 0.3 to 11.3 kbar. The textural and compositional diversity of crystals together with the variability in melt compositions reflect the combined influences of source heterogeneity and magmatic processes (e.g. crystallization, assimilation and magma mixing processes) taking place within crystal mushes. Our data combined with previous studies suggest that the magmatic processes within the SWIR magma plumbing system involve formation, disaggregation and juxtaposition of crystal-rich mush zones.

Description: The Atlantic meridional overturning circulation (MOC) is thought to have strong impact on climate.Here results from a pilot project to monitor fluctuations of the MOC in the tropical North Atlantic are presented. The backbone of the experiment design is an end point measurement method. One main aspect of this study comprises a technical performance assessment of the different measurement components (density,bottom pressure,current velocities) of the moored array. For the interpretation of the observed mean and time variable volume transports, comparisons to independent observational data and numerical model output have been carried out and spectral analysis as well as basic theoretical aspects of fluid dynamics have been applied. Rossby waves represent a major source of noise, which may mask the MOC signal. A verification of the experiment design using model simulations attest the transport signal observed to be moderately representative for MOC and meridional heat transport fluctuations. An eastward extension of the array into the eastern trough might lead to a drastic increase in the signal-to-noise ratio.

Description: Die Verbreitung der basaltischen Gesteine im Bereich des Pfahlberges wurde geologisch kartiert. Die verschiedenen Gesteinstypen werden detailliert beschrieben. Die geomagnetische Untersuchung des basaltischen Körpers wird an Hand von 7 Profilen erläutert. Mit Hilfe der Geomagnetik wurden einerseits die Ergebnisse der geologischen Kartierung bestätigt, zum anderen konnte eine Fortsetzung des Basaltes unter jüngerer Löß- und Bimsbedeckung nachgewiesen werden. Die Genese des Pfahlberges wird diskutiert. Der Basalt ist vermutlich vorwiegend als Lavastrom ausgetreten. Teilweise ist er lagergangartig zwischen seinen Tuff und das devonische Grundgebirge eingedrungen.

Description: Abstract: The distribution of the basaltic rocks within the region of the Pfahlberg was mapped geologically. The different rock types are described in detail. The geomagnetical investigation of the basaltic knob is illustrated by seven cross-sections. By support of the geomagnetics the results of the geological mapping are verified. It was also possible to prove the continuation of the basalt below the younger cover of loess and pumice. The genesis of the Pfahlberg is discussed. Probably the basalt is especially flown out as a lava river. Partly it is intruded dikelike between its tuff and the devonian basement.

Description: 1. Einleitung 2. Lage und Morphologie des Pfahlberges 3. Geologischer Überblick 4. Vulkanismus im Westerwald 5. Basaltvorkommen des Pfahlberges 5.1. Pyroklastische Gesteine 5.2. Basalt-Gesteine 6. Geomagnetische Untersuchungen6 7. Genese des Pfahlberges

Description: research

Description: Ein kurzer Abriß der paläobotanischen Forschungsgeschichte des saarpfälzischen Rotliegenden wird gegeben; ein Überblick über ältere Bestandsaufnahmen saarpfälzischer Rotliegendfloren schließt sich an. Einige der von Weiss (1868, 1869 bis 1872) und Florin (1938-1945) angegebenen Fundorte wurden in die von Boy & Fichter (1982) publizierte neue lithostratigraphische Gliederung des saarpfälzischen Rotliegenden eingestuft; ihre Floreninhalte sind aufgelistet. Sämtliche den Verfassern bekannte bzw. bekannnt gewordenen, heute noch zugänglichen Pflanzenlagerstätten sind ebenfalls in das Schema von Boy & Fichter (1982) stratigraphisch eingestuft worden, und ihre Floreninhalte sind in Tabellen angegeben. Zusätzlich wird eine aktualisierte Florenliste zu der (seit längerem bearbeiteten) Lokalität Sobernheim geliefert. Im Tafelteil werden die wichtigsten Florenelemente des saarpfälzischen Rotliegenden abgebildet, der Begleittext behandelt Fragen der Taxonomie und Nomenklatur.

Description: Abstract: The history of palaeobotanical investigations on the Rotliegendes of the Saar-Nahe area is briefly summarized. A review of previous inventories is given. A new lithostratigraphical subdivision of the Rotliegendes of the Saar-Nahe area was published by Boy & Fichter (1982). The stratigraphical positions of some of the localities mentioned by Weiss (1868, 1869-1872) and Florin (1938-1945) could be determined within this scheme. Their floral content is listed on tables. The occurrences of plant remains in a large number of localities, distributed over several lithostratigraphical units, are shown on tables. All the plant localities known to the authors, most of them still being accessible, are included. An updated list of the plant taxa of the locality Sobernheim is given separately. The most characteristic plant taxa are illustrated, some remarks on problems on taxonomy and nomenclature are included.

Description: 1. Einleitung 2. Zur Geschichte der paläobotanischen Forschung im saarpfälzischen Rotliegenden 3. Altere Bestandsaufnahmen saarpfälzischer Rotliegendfloren 4. Bemerkungen zu den Fundorten und Fundschichten 5. Stratigraphische und geographische Verbreitung der saarpfälzischen Rotliegendfloren 5.1. Unterrotliegendes 5.2. Oberrotliegendes Tabellen 1-19 Schriften Verzeichnis der Tafeln Tafeln 1-42

Description: research

Description: The present study revealed information on the foraging activity of breeding Imperial Cormorants. The analysis of the data allowed a precise quantification of the time budget underwater and showed that Imperial Cormorants partition their time underwater in a descent, bottom and ascent phase. Their percentage allocation of time to the different phases of the dive cycle varied substantially as a function of maximum dive depth so that foraging efficiency was highest at shallower depths and lowest at deeper depths. Imperial Cormorants foraged over the broad depth range of 5-70 m, despite a lower foraging efficiency when exploiting deeper waters. This observation intimates that there must be an advantage for them to do so. The results suggest that the foraging behaviour and ultimately the optimal foraging strategy employed by Imperial Cormorants is influenced by several environmental factors such as water depth, prey density and intraor inter-specific competition. Further investigations linking cormorants' feeding activity, prey distribution and environmental factors will undoubtedly help to clarify the foraging strategies employed by Imperial Cormorants.

Description: Meeresschutz in nächster Nähe: Ein Pilotprojekt soll Schulklassen für ihre Umwelt sensibilisieren

Description: Heutzutage und in der Vergangenheit hat sich gezeigt, dass der Dornenkronenseestern Acanthaster plancii in den weltweit verbreiteten Korallenriffen große Schäden durch Grazing verursacht. Es ist eine zentrale Frage herauszufinden, ob Fraßpräferenzen bestehen, und wenn, welche Korallenarten oder -gruppen bevorzugt durch Acanthaster plancii geschädigt werden. Um eine Einschätzung des ausgehenden Fraßdrucks und den daraus resultierenden Korallenschädigungen durch Acanthaster plancii durchführen zu können, wurde zunächst die natürliche Populationsdichte an Dornenkronen im Riff bestimmt. Man unterscheidet einerseits Korallenriffe, die vom Befall eines Dornenkronen-Outbreaks bedroht sind, und andererseits Riffe, die bereits von Dornenkronen befallen wurden, und welche, die nicht vom Ausbruch einer Dornenkronenpopulation bedroht sind. Die Anzahl an Dornenkronen an den beiden Riffen, an denen die Versuche stattgefunden haben, betrug auf je 5 000 m2 Riff an den Tripple Pools 145 Dornenkronen und somit einer Dichte von 29000 Dornenkronen km-2. und am Moray House 15 Dornenkronen. Das entspricht einer Dichte von 3000 Dornenkronen km-2. Die vorhandenen Korallenbeschädigungen an den Tripple Pools lag zwischen 21 % und 36 % Totalschädigung und am Moray House lag er bei 〈 10 %. Der Anteil der intakten Korallen betrug 〉 80 %. Durch die Kombination dieser Informationen ist das Riff Tripple Pools als ein von Dornenkronen befallenes Riff einzustufen und das Moray House wird als ein nicht von einem Dornenkronenausbruch bedrohtes Riff kategorisiert...

Description: Magnesium bewirkt eine Relaxation von Nerven- und Muskelzellen. Kalium weist dagegen eine antagonistische Wirkung auf. Mit dieser Arbeit konnte belegt werden, dass eine Erhöhung der Mg2+ - und K+-Konzentration im Hälterungswasser von Sepia officinalis das Wachstum der Tiere beeinflusst. Als Parameter wurde das Gewicht der Sepien bestimmt; außerdem wurden der Zuwa〈!hs, die Wachstumseffizienz und die Futteraufnahme der Tiere ermittelt. Die zu Beginn ca. 2g schweren Sepien wurden über vier Monate in einem geschlossenen Kreislaufsystem bei einer Wassertemperatur von 15° C gehältert. Die Sepien wurden ad libitum mit Palaemonetes varians gefüttert. Das natürliche Meerwasser besaß eine Mg2+ -Konzentration von 45mmol/r1 und eine K+ -Konzentration von 1 Ommolti-1. In diesem Zeitraum wurde die Mg2+ - Konzentration sukzessiv in jeweils dreiwöchigen Abständen auf 65mmol/r1 erhöht. Die K+ - Konzentration wurde auf 14mmol/r1 und 12,5mmoltr1 erhöht. Bei einer Mg2+ - Konzentration von 55mmoltr1 zeigte sich hinsichtlich des Gewichtes ein signifikanter Unterschied (p=0,001) zur Kontrollgruppe. Das Endgewicht der Kontrolltiere ereichte die Magnesiumgruppe bereits nach der zwölften Woche. Das Endgewicht der Magnesiumtiere lag 33% über dem Endgewicht der Kontrolltiere. Die Auswertung der weiteren Berechnungen ergaben keine Signifikanzen innerhalb dieses Konzentrationsabschnittes. Die Mg2+ -Tiere zeigten ein wesentlich geringeres Aktivitätsniveau auf als die Kontrolltiere. Die Verletzungs- und Sterblichkeitshäufigkeit lag weit unter den entsprechenden Raten der Kontrollgruppe. Bei der Erhöhung der K+ -Konzentration auf 14mmol/r1 wiesen die Tiere ein tendenziell geringeres Gewicht auf als die Kontrollgruppe; dies war jedoch nicht signifikant (p=O, 14). Die Tiere zeigten ein deutlich gesteigertes Aktivitätsniveau. Innerhalb dieses Zeitraumes lag die Verletzungs- und Sterblichkeitshäufigkeit über den Vergleichswerten der Kontrollgruppe. Bei einer K+Konzentration von 12,5mmol/r1 zeigten die Tiere in Verhalten und Gewicht (p=0,86) keinen signifikanten Unterschied zu den Kontrolltieren.

Description: Forscher von Geomar untersuchen Weltkriegsmunition in der Ostsee - Sie ist vielfältiger als gedacht

Description: Underwater vision systems have become popular in ocean research. However, imaging in the deep sea poses significant challenges. Firstly, cameras enclosed in waterproof housings must withstand extreme water pressure, while light undergoes refraction as it traverses multiple media layers. Secondly, light absorption and scattering in water degrade image quality. Additionally, artificial illumination in the deep sea creates unique visual effects. All these factors collectively contribute to the complexity and difficulty of visual 3D reconstruction in the deep sea. This dissertation provides comprehensive solutions to the challenges encountered in deep sea visual 3D reconstruction, encompassing both hardware and software components. To address geometric refraction effects, it thoroughly analyzes dome refractive geometry and proposes mechanical adjustments for centering cameras inside domes to mitigate refraction effects. Additionally, recognizing the wide use of flat port interfaces, the dissertation explores effective methods to correct flat refraction effects for underwater photogrammetry. Furthermore, the dissertation delves into radiometric issues arising from light absorption and scattering in water, especially concerning artificial illumination in deep-sea imaging. It explores physical models of underwater image formation and develops a general model suitable for restoring various types of underwater image, especially in environments with complex artificial illumination. This model enables the simultaneous removal of artificial lighting patterns and the restoration of true colors. Moreover, the dissertation demonstrates several successful applications of the techniques developed within its scope. It showcases their efficacy in various camera system designs, underwater 3D reconstruction, and improving complex illumination configurations within imaging systems.

Description: FS Maria S Merian – MSM129/2 07.06.2024 – 06.07.2024 St. John’s (Kanada) – Reykjavik (Island) 3. Wochenbericht (17.06. – 23.06.2024)

Description: In a 5x3 factorial crossing experiment paternal and maternal influences on early life history traits of haddock (Melanogrammus aeglefinus) were investigated. Female effects on egg size, dry weight, lipid content, survival and hatch rate were revealed. Paternal influence on egg traits was only evident through interaction with mother animal. Larvae on first and on fifth day post hatch were sampled to determine parental effects on morphometric traits (standard length, somatic area, yolk/yolk sac area, eye diameter, body depth and jaw length). From differences in somatic and yolk area between day O ph and day 5 ph yolk utilization efficiency was computed. For all morphometric traits maternal influences were evident, whereas paternal effects could only be demonstrated for body size related traits (standard length, somatic area, body depth). Coefficients of variation were largest for yolk related traits, possibly indicating an artefact attributable to preservation, as the shrinkage effect due to formalin preservation was most profound on yolk area. Growth rates for larval standard length were significantly influenced by both parental sides. Yolk utilization efficiency showed no direct parental effect, but a significant interaction between maternity and paternity was detected. Evidence for compensatory growth during the first five days of larval stage was not found, suggesting that size compensation demonstrated by other authors might take place during later life stages. Correlations between larval fitness determined as time to starvation and larval morphology were only significant for standard length.

Description: Ziel dieser Arbeit war es, mit Hilfe eines hochauflösenden Ozean-Modells die Dynamik des Subpolaren Wirbels und die damit verbundene Bildung von Wassermassen näher zu untersuchen. Im Vordergrund standen dabei die zwischenjährlichen langperiodischen Schwankungen im westlichen Randstrom und deren Mechanismen. Schließlich sollte der Einfluss dieser Schwankungen auf die meridionale Umwälzbewegung aufgezeigt werden. Da die durch Anomalien in den Antriebsfeldern hervorgerufenen Veränderungen im Subpolaren Wirbel im Mittelpunkt des Interesses standen, wurde auf den mittleren Zustand nur kurz eingegangen. Hierzu wurden zuerst die Modellergebnisse dahingehend untersucht, ob die Wassermassen des Subpolaren Wirbels im Nordatlantik nachvollziehbar wiedergegeben werden. Zu diesen Wassermassen gehört insbesondere das Labradorseewasser (LSW), das durch tiefreichende winterliche Konvektion in der Labradorsee gebildet wird und damit per se von den Anomalien in den Antriebsverh¨altnissen abhängig ist [The Lab Sea Group, 1998, Eden and Willebrand, 2001]. Wie sich jedoch zeigte, führen die verwendeten Randbedingungen des Modells zu veränderten Wassermasseneigenschaften [Dorow, 2001]. So sind die Salzgehalte im Nordatlantik zu hoch, was zu einer zu hohen Dichte führt. Die klassische Wassermasseneinteilung anhand von reinen Dichtekriterien [Mertens, 2000, Morsdorf, 2001] war somit nicht möglich. Ein Ausweg bot der direkte Vergleich der Salz- und Temperaturprofile mit den umgebenden Wassermassen und die Freonkonzentration, die im Modell als Tracer mitgerechnet wurde und stark von den Bildungsprozessen des LSW abhängt. Auch die Konvektion mit ihrer Deckschichtvertiefung selbst half, grobe Dichtebereiche festzulegen. Diese Bereiche unterteilen die Wassersäule in drei Schichten: Die obere Schicht mit dem leichten Wasser des Nordatlantischen Stroms und der Grönland- und Labrador-Ströme; die mittlere Schicht, die vornehmlich das Labradorseewasser repräsentiert und schließlich die unterste Schicht für das Tiefenwasser. Veränderte Modellkonfigurationen weisen indess eine bessere Darstellung des Salzgehaltes auf (Lars Czeschel, pers. Mitt.). So kann über die Schichtdickendiffusion der Wirbeltransport im Inneren der Labradorsee und durch einen offenen Nordrand die Randströme verbessert werden. Voraussichtlich wird hiermit eine noch genauere Untersuchung der Modell-Wassermassen im Subpolaren Wirbel möglich sein...

Description: In dieser Arbeit wurde die hydraulische Natur der Austausches in einer ideallisierten Meeresstraße unter dem Einfluss von Vermischung beschrieben. Alle Modelläufe zeigten in Übereinstimmung mit der theroretischen, reigungsfreien Lösung eine kontrollierte Strömung, bei geeigneter Berechnung der Froudezahl. Das System liess sich vereinfachen auf die Betrachtung eine einzige aktive Schicht, nämlich der unteren Wasserschicht. Es wurde untersucht, welche der vertikalen Vermischungsmodelle wieviel Vermischung verursachen. Die Vermischungsparamerisierung von Mellor-Yamada generiert im Vergleich zu Pakanowski-Philander den höheren Vemischungsgrad im Reservoir und an der Schwelle. Bei Pakanowski-Philander sieht man, dass eine unterschiedliche horizontale Vermischung den Vermischungsgrad stark ändern kann: die horizontale Vermischung auf Geopotentialflächen erzeugt am Bergabhang mehr Vermischung als die horizontale Vermischung auf Sigmaflächen. In allen Fällen werden die unteren, kalten Schichtdicken stromabärts der Schwelle durch Einschischung warmen Wassers aus der oberen Schicht, sehr viel dicker als die theroretische, vermischungsfreie Lösung vorhersagt. Die untere Schicht mischt bis über 50% (5° C) warmen Wassers ein, was die untere Schicht von 2° C auf teilweise bis zu 4° C erwärmt. An Hand der hydraulischen Theorie wurden die theoretischen, kontrollierten ransportraten an der Schwelle berechnet und auf die Schichtdicke der unteren Wasserschicht bezogen. Entdeckt wurde überraschenderweise, dass die Modelltransporte an der Schwelle trotz des hohen Vermischungsgrades von den theoretischen Transportwerten nicht sehr stark abweichen. Die grösste Abweichung der maximalen kontrollierten ransporte von den theoretischen Werten tritt bei dem Modell von Mellor-Yamada auf. Es wurden Volumentransporte und Schichtdicken an der Schwelle für unterschiedlichen Reservoirhöhen mit den theoretischen Werten verglichen. Es zeigte sich, dass die Modellvolumentransporte für Reservoir höhen grösser als 450m (die Höhe der Schwelle ist 350m) sehr ähnlich den kontrollierten theoretischen Transporten sind, d.h. es gilt die gleiche einfache Beziehung zwischen Transport auf der Schwelle und Reservoirhöhe wie in der Theorie. Die Beziehung zwischen Schichtdicke auf der Schwelle und Reservoirhöhe zeigte dieselbe lineare Abhängigkeit wie in der Theorie, allerdings mit einem gewissen konstanten Offset. In den Fällen mit Reservoir höhen kleiner als 420m (theoretische untere Schichtdicken von weniger als ca. 50m an der Schwelle) sind die Bedingungen für Stationarität und hydrostatische Kontrolle wegen der teilweisen Blockierung der Strömung am Unterwasserberg nicht mehr gegeben.

Description: Durch die Konstruktion eines mittleren Jahresganges für den Salzgehalt und somit für den Frischwassergehalt der zentralen Labradorsee anhand historischer und aktueller Daten konnte eine erstmals zeitliche Aufschlüsselung der Einträge in die Labradorsee erfolgen. Durch Vergleiche mit den berechneten Jahresgängen der Frischwassertransporte in den Randströmen konnte der Ursprung des Frischwasserjahresgangs gut erklärt werden. Die Frischwasserschichtung, die sich jährlich in der zentralen Labradorsee ausbildet, hat auf die Labradorsee als Konvektionsgebiet deutliche Auswirkungen. Die anfängliche Ausbildung unterbindet weitere Konvektion und die Stärke der Ausprägung im Laufe eines Jahres beeinflusst die Menge an Auftrieb, die der Wassersäule im Winter entzogen werden muss, bevor wieder Konvektion eintreten kann. Es wurde gezeigt, dass die Dichteschichtung in den oberen 300 m im Wesentlichen durch die Frischwasserschichtung bestimmt wird. Bei Untersuchung des mittleren Jahresgang für die zentrale Labradorsee zeigte sich, dass der Frischwassergehalt sich vorwiegend in zwei voneinander klar getrennten Einträgen aufbaut. Der erste Eintrag im Mai macht nur 20 % des gesamten Frischwassers am Ende des Sommers aus, sein Auftreten hängt jedoch direkt mit dem Beenden der Konvektion zusammen. Mehr als 60 % des Frischwassers, welches im September in der Labradorsee vorhanden ist, stammt aus dem zweiten Frischwasserimpuls zwischen Juli und August. Keine lokale Quelle ist groß genug, um für diese Einträge der Ursprung sein. Der Jahresgang des Frischwassertransports für den WGC, sowie Annahmen aufgrund von Drifterdaten (CUNY ET AL., 2002), zeigten, dass der WGC der Ursprung für den zweiten deutlich stärkeren Frischwassereintrag in die Labradorsee ist und somit auch für die Stärke der Ausprägung der Frischwasserschichtung. Der größte Teil des WGC dringt nicht in die Davis Strait ein, sondern speist zusammen mit dem BIC und dem Hudson Strait Ausstrom den LC. Über die Variabilitäten des BIC und des Hudson Strait Ausstroms ist bisher nur sehr wenig bekannt, doch speisen sie den LC mit einer wesentlich größeren Menge an Frischwasser als der WGC. Der Jahresgang im Frischwassertransport des LC zeigt ab Mai einen sprunghaften Anstieg und einen weiteren kleineren Anstieg im August. Der zweite Anstieg entspricht in der Größenordnung genau dem Frischwassertransport, die dem LC aus dem WGC zufliessen. Der erste stärkere Frischwasserimpuls im LC stimmt zeitlich gut mit dem Einsetzen der dünnen Frischwasserschicht in der zentralen Labradorsee überein. Dieser Frischwassereintrag kann mit der Annahme erklärt werden, dass etwa 7 % des Frischwassers den LC zwischen der Hudson Strait und Hamilton Bank verlassen. Dieses ist eine realistische Größenordnung, da aufgrund der Eisschmelze am Eisrand im Mai der LC mehr Frischwasser seewärts seines Kerns mit sich trägt als in den übrigen Monaten. Die Zuordnung des Ursprungs des Frischwassers der zentralen Labradorsee im September - 60 % WGC-Wasser und 20 % LC-Wasser - widerspricht der anderer Autoren, die ihre Berechnungen auf interannuale Variationen stützen. So schließen z.B. HOUGHTON UND VISBECK (2002) den WGC als Hauptquelle für interannuale Variationen des Salzgehalts in der zentralen Labradorsee aus. KHATIWALA ET AL. (2002) sehen, nach Analyse eines mittleren Jahresgangs, eher Schmelzwasser aus der Baffin Bay, Hudson Bay Region verantwortlich für die jährliche Versüßung der Labradorsee; doch untersuchen sie nur den Unterschied zwischen Winter und Sommersalzgehalten und schenken dem genaueren Jahresgang keine weitere Beachtung. Diese hier vorgenommenen genaueren Untersuchungen des Jahresgangs lassen zumindest für 60 % des Frischwassers der zentralen Labradorsee keine andere Quelle als den WGC zu. Für die interannualen Variationen lässt sich, bei dem Wissen über die sehr große Variabilität der Frischwasserquellen des WGC, auch eine deutliche Abhängigkeit vom WGC vermuten und interannuale Abhängigkeiten aus anderen Regionen als unwahrscheinlicher erscheinen. So wurde deutlich, dass für die anfängliche Ausprägung der salzarmen Deckschicht in der Labradorsee nur Frischwasser mit dem Ursprung in der Baffin Bay, Hudson Bay und im Meereis des LC verantwortlich ist. Eine Korrelation der Frischwassermenge im Sommer mit der Meereisschmelze in diesem zusammenhängenden Gebiet - welches die entscheidende Frischwasserquelle für die zentrale Labradorsee im Mai ist - kann jedoch nicht erwartet werden, da der Frischwassergehalt der zentralen Labradorsee nur zu einem Fünftel aus diesem Gebiet stammt. Da jedoch die Frischwassermenge der Labradorsee am Ende des Sommers zu zwei Dritteln aus dem WGC und dieser zu sehr großen Anteilen aus Schmelzwasser gespeist wird, ist eine Korrelation der Meereisschmelze östlich von Grönland mit dem Salzgehalt der zentralen Labradorsee zu erwarten.

Description: Aufgrund der Ergebnisse aus der Beschreibung der „Suit-Matrix" 2002 konnten Indizien gegen die gängige Meinung im ICES gefunden werden, dass sich die Größenselektionstheorie von Andersen und Ursin (1977) zur künstlichen Generierung einer „Suit-Matrix" eignet. Bei allen im Modell berücksichtigten Räuberarten wurde ein Anstieg des am meisten präferierten Räuber-Beute-Gewichtsverhältnisses mit dem Alter des Räubers in der „Suit-Matrix" 2002 beobachtet. Dies spricht gegen die Größenselektionstheorie von Andersen und Ursin. Weiterhin konnte gezeigt werden, dass die derzeitigen Annahmen in der MSVPA und MSFOR über Räuberpräferenz und Verfügbarkeit von Beuteorganismen in Form zeitlich konstanter Suits falsch sind. Die Suits weisen zwischen dem Magendatenjahr 1981 und 1991 große Unterschiede auf. Die Änderungen in den Suits scheinen dabei nicht nur zufällig zu erfolgen. Es sind wahrscheinlich systematische Prozesse dafür mitverantwortlich, die in der derzeitigen MSVPA nicht berücksichtigt werden (z.B. Prey-switching, variabler Overlap). Als weiterer Unsicherheitsfaktor für die Ergebnisse der MSVPA und von MSFOR konnte die Behandlung von „Other Food" identifiziert werden. In Sensitivitätsanalysen konnte im weiteren Verlauf dieser Arbeit dargestellt werden, dass die Ergebnisse der MSVPA und von MSFOR stark von der Wahl des Magendatensatzes abhängig sind. Das beweist, dass durch die falsche Annahme konstanter Suits die Ergebnisse der MSVPA sowie die Bestands- und Ertragsprognosen von MSFOR sehr unsicher sind. Auch der im derzeitigen Assessment praktizierte Kompromiss, nur den Mittelwert aus den in der MSVPA berechneten Koeffizienten der Prädationsmortalität in das „Single Species Assessment" zu übernehmen, erweist sich als gefährlich. Gleichzeitig ko,nnte am Beispiel des „Gadoid Recovery Plan" dargestellt werden, dass in der Zukunft das „Single Species Assessment" zu einem „Multi Species Assessment" erweitert werden muss. Das derzeitige „Single Species Assessment" kann durch das Ignorieren von dynamischen Veränderungen bei Räuber-Beute-Interaktionen falsche Prognosen über die Entwicklung der Fischbestände liefern. Es muss demnach ein vornehmliches Ziel sein, die MSVP A und MSFOR so zu verbessern, dass sichere Prognosen möglich sind. In dieser Arbeit konnte gezeigt werden, dass dafür ein prozess-basiertes dynamisches Nahrungswahlmodell die derzeitige Implementierung einer konstanten „Suit-Matrix" im Modell ersetzen muss.

Description: Die oberflächennahe Zirkulation des nördlichen tropischen Atlantiks wird anhand von hydrographischen und direkten Strömungsmessungen, die während der Fahrt Meteor 55 im Herbst 2002 entlang 10±N gewonnen wurden, sowie klimatologischer Daten untersucht. Die Auswertung der Strömungsdaten, die mit dem Schiffsadcp gemessen wurden, zeigt, dass die Datenqualität stark beeinträchtigt ist. Die Ursache hierfür liegt wahrscheinlich in einer sehr inhomogenen vertikalen Verteilung der Rückstreuer auf dem Schnittes. Daher ergibt sich eine eingeschränkte Einsatzmöglichkeit dieses Gerätes in solchen Gebieten. Durch einen Vergleich der Daten auf Station und während der Fahrt wurde eine bestmögliche teifenabhängige Korrektur der Daten durchgeführt. Die berechneten Ekmantransporte aus verschiedenen Winddatenquellen zeigen einheitlich eine nordwärtige Komponente von etwa 9 Sv. Der kumulative Transport wächst dabei monoton über das Becken an, mit einer abnehmenden Steigung zum östlichen Rand hin. Aus den Schiffsmessungen wird der ageostrophische Transport in der Deckschicht berechnet. Er ergibt sich aus der Differenz zwischen ADCP-Transport und geostrophischem Transport. Der kumulative Transport der ageostrophischen Strömung beträgt über das Becken 5,3 Sv und erklÄart nur teilweise den Ekmantransport, der aus Winddaten bestimmt wird. Die mittleren Pfade und Volumentransporte in der Sprungschicht werden für das Salzgehaltsmaximumwasser, das aus den Subtropen stammt und in die Tropen strömt, aus limatologischen Daten bestimmt. Im Mittel ergibt sich ein südwärtigen Transports über 10±N hinweg von 2,2 Sv. Im Jahresverlauf zeigt dieser Transport ein Maximum von 3,9 Sv im Sommer und ein Minimum von 1,1 Sv im FrÄuhjahr. Auch die Pfade, über die dieser Transport nach Süden erfolgt, zeigen saisonale Schwankungen. Für die zweite Jahreshälfte ereignet sich dieser Transport im Wesentlichen im Westteil des Beckens bis etwa 35°W. Für die erste Jahreshälfte zeigt sich auch östlich davon ein signifikanter Transport. Der Volumentransport, der sich für diese Schicht aus den ADCP-Messungen ergibt beträgt 4,3 Sv in Richtung Süden.

Description: Copepoden spielen im marinen Nahrungsnetz eine bedeutende ökologische Rolle. Bei der Nahrungsaufnahme ergreifen und zerkleinern sie die Nahrungspartikel mit den Gnathobasen ihrer Mandibeln. Die vorliegende Arbeit sollte die Bedeutung der Morphologie und der Stabilität dieser Mandibel-Gnathobasen für die Ernährungsweise antarktischer Copepodenarten klären. Dafür wurde die Morphologie der Mandibel-Gnathobasen von acht Copepodenarten aus dem Südpolarmeer detailliert untersucht. Es konnte ein Zusammenhang zwischen der Gnathobasen-Morphologie und der Ernährungsweise gezeigt werden. Calanus propinquus, Calanoides acutus und Ctenocalanus citer haben Gnathobasen mit relativ kurzen und sehr kompakten Zähnen. Sie fressen überwiegend Bacillariophyceen und können deren Silikatschalen mit ihren Mandibel-Gnathobasen durch gezielten Druck zerbrechen. Im Gegensatz dazu haben die Mandibel-Gnathobasen von Paraeuchaeta antarctica sehr lange spitze Zähne. Die Nahrung dieser Art setzt sich vorwiegend aus anderen Copepoden zusammen. Die bewegliche Beute kann durch Aufspießen mit den Gnathobasen festgehalten und anschließend zerkleinert werden. Paraeuchaeta antarctica hat im Vergleich zu den anderen untersuchten Copepodenarten besonders viele kleine Borsten an den Gnathobasen, die vermutlich mit Rezeptoren assoziiert sind und dem Orten der Beute dienen. Rhincalanus gigas und Metridia gerlachei ernähren sich sowohl von pflanzlichen als auch von tierischen Organismen. Sie besitzen eine Gnathobasen-Morphologie, die eine Übergangsform zwischen der von Paraeuchaeta antarctica und der von Calanus propinquus, Calanoides actutus und Ctenocalanus citer darstellt. Bei den Untersuchungen zeigte sich, daß Microcalanus pygmaeus überraschend lange und spitze Gnathobasen-Zähne besitzt und deshalb neben Phytoplankton mit großer Wahrscheinlichkeit auch tierische Organismen frißt. Auch für die Copepodenart Stephos longipes, in deren Magen-Darm-Trakt bisher ausschließlich Phytoplankton, vor allem Eisalgen, gefunden wurden, muß aufgrund der Gnathobasen-Morphologie angenommen werden, daß neben Phytoplankton auch tierische Organismen gefressen werden. Bei Fraßexperimenten mit Calanus propinquus und Metridia gerlachei während der „Polarstern"-Expedition ANT XIX/6 fraßen beide Arten die acillariophyceenart Fragilariopsis kerguelenis, die sehr stabile Silikatschalen besitzt. Untersuchungen der Kotballen zeigen, daß diese Silikatschalen von Metridia gerlachei im Vergleich zu Calanus propinquus beim Ingestieren nicht zerbrochen wurden. Dementsprechend konnte Metridia gerlachei wahrscheinlich die Fragilariopsis kerguelensis-Zellen nicht effektiv verwerten. Stabilitätsberechnungen an einem Finite-Elemente-Modell einer Mandibel-Gnathobase von Paraeuchaeta antarctica zeigen bei Simulationen theoretischer Belastungen der Gnathobase mit Fragilariopsis kerguelenis-Schalen, daß im ventralen Zahn theoretische Zugspannungen von bis zu 65 N mm-2 entstehen. Solche Werte liegen im für biologische Materialien kritischen Bereich und würden sehr wahrscheinlich zu Brüchen in den Zähnen der MandibelGnathobasen führen. Im kürzeren zweiten zentralen Zahn entstehen theoretische Zugspannungen, die deutlich niedriger sind. Es ist deshalb wahrscheinlich, daß Copepoden mit Mandibel-Gnathobasen wie denen von Calanus propinquus sehr viel stabilere Strukturen zerbrechen können als mit Mandibel-Gnathobasen, die denen von Paraeuchaeta antarctica ähnlich sind. Die Gnathobasen-Zähne von Calanus propinquus, Calanoides acutus, Rhincalanus gigas, Ctenocalanus citer, Stephos longipes, Microcalanus pygmaeus und Paraeuchaeta antarctica bestehen aus einem anderen Material als die restlichen Teile der Gnathobasen. Dabei handelt es sich sehr wahrscheinlich um Silikat, dessen Einlagerung in die Gnathobasen-Zähne vermutlich deren Härte erhöht. Bei Metridia gerlachei scheint kein Silikat in die Gnathobasen-Zähne eingelagert zu sein. Es ist vorstellbar, daß die Mandibel-Gnathobasen mit ihren komplexen Strukturen zusammen mit den Nahrungsorganismen eine Koevolution durchlaufen haben und dementsprechend gut an die Ernährungsweise der jeweiligen Copepodenarten angepaßt sind.

Description: In the present work, I investigated the breeding and foraging strategies of an endemic seabird species, the Humboldt Penguin (Spheniscus humboldtt), Meyen 1834, under the variable environment of the Humboldt upwelling ecosystem along the coast of north-central Chile. In this area, extending from 27 to 33°5, at least 12 seabird species breed, including the Humboldt Penguin with approximately 9,000 pairs. Breeding activity was monitored at the colony in Pajaro Nino Island (33°21' S; 71 °41' W) between 1995 and 2000. So as to access foraging behaviour, chick rearing adults were equlpped with data-loggers during the 2001-2002 spring breeding season at Pajaros Island (29°35' S; 71 °33' W). Relevant aspects of behavioural thermoregulation on land were evaluated through field observations at Pajaros and Chanaral Island (29°01' S; 71 °34' W) during the spring 2001-2002 and 2002 autumn breeding seasons, respectively. Aspects relevant to thermoregulation in water were assessed via respirometric experiments in the laboratory. Humboldt penguins in temperate central Chile (33° S) had a bi-modal breeding strategy, with two major breeding events in the year, one in spring (October) and the other in autumn (May). The spring event regularly produced offspring, but the autumn event was systematically affected by rains which flooded nests and severely compromised breeding success. After this, birds left the colony during winter and returned in September to resume breeding. Despite the low breeding success in autumn, Humboldt penguins maintain a bi-modal pattern, probably as a mechanism that provides additional offspring to those produced in spring, and thus maximise their life-time reproductive success. During the 1997-1998 El Nino, breeding was affected over three consecutive nesting events, where intense rainfall and likely, low prey availability, resulted in delayed onset of nesting, low numbers of birds breeding and attending the colony. Birds rapidly returned to the colony after El Nino and resumed breeding, with no mass adult mortality being evident...

Description: Im Rahmen dieser Diplomarbeit wurden Makrozoobenthosproben aus der Kieler Förde und aus der Schlei genommen und aufgearbeitet. Die ausgewerteten Daten wurden dann miteinander und mit historischen Daten verglichen. Besonderes Augenmerk wurde dabei auf die Artenzahl, die Abundanz und die Diversität der Gebiete gelegt. Die Ergebnisse wurden zum einen mittels Clusteranalyse und Multidimensionaler Skalierung, zum anderen mit Hilfe eines V-Tests diskutiert. Der Sauerstoffgehalt des Bodenwassers und der Salzgehalt wurden als wichtigste Faktoren für die Verteilung des Makrozoobenthos angesehen. Beim Vergleich der Daten aus der Kieler Förde mit jenen der Schlei, ergab der angewandte UTest zahlenmäßige Gleichheit der Artenzahl, der Abundanz und der Diversität. Die gefundenen Artenspektren unterschieden sich jedoch deutlich voneinander. Die Crustacea waren beispielsweise in der Kieler Förde kaum vertreten, während sie in der Schlei über 12% aller Individuen stellten. Unter Berücksichtigung der Tatsache, dass die Probennahme in der Kieler Förde im Winter, die der Schlei jedoch im Sommer stattfand, wurde die Kieler Förde als das Gewässer mit höherer Diversität beurteilt. Die Entwicklung des Makrozoobenthos in der Kieler Förde innerhalb der letzten zehn Jahre wird als positiv bewertet. Es fand eine Verbesserung der Bedingungen am Boden der Kieler Förde statt. Die Artenzahl lag im Jahr 2002/2003 deutlich höher als zehn Jahre zuvor. Die Zusammensetzung der Benthosgemeinschaft entwickelte sich von erstsiedelnden opportunistischen Polychaeten, vor allem Polydora sp., zu mehrjährigen Mollusken. RUMOHR (1996) beschreibt eine solche Entwicklung in seinem Ostsee-spezifischen Sukzessions-Modell, als eine Verbesserung der Lebensbedingungen am Boden der Ostsee von Stufe 3 auf Stufe 2 der Benthosgemeinschaft. Im inneren Teil der Schlei hat eine Diversitätserhöhung stattgefunden. STOTZ (1986 (371) stellte für die Schlei eine erhöhte Produktion in Gebieten mit oxidiertem Sediment fest. Die Faulschlammflächen breiteten sich im Laufe der Jahre immer weiter aus. Es fand eine Konzentration der Organismen auf immer kleiner werdenden Flächen mit oxischem Sediment statt. In dieser Arbeit wurden vor allem Hydrobiiden und Oligochaeten auf Faulschlammflächen gefunden. Diese Organismen waren früher nur auf oxidierten Sedimenten zu finden. Vermutlich durch die erhöhte Produktion auf oxischen Sedimenten, wichen Hydrobiiden und Oligochaeten auf Faulschlammflächen aus, was zu der erhöhten Diversität in der inneren Schlei führte. Im historischen Vergleich steht die Kieler F örde als positives Beispiel einer langfristigen Regeneration des Bodenlebens. Dagegen verschlammt die Schlei über die Jahre gesehen immer weiter und ihre Bodenfauna muss schon auf die fragilen Oberflächen der angrenzenden Faulschlammflächen ausweichen. Es hat sich gezeigt, dass wiederholte Untersuchungen im Dekadenrhythmus wichtig sind und Entwicklungen darzustellen vermögen, die im jährlichen Vergleich nicht aufgezeigt werden können.