ALBERT

Description: Es wurden moderne Methoden auf ihre Eignung zur Bestimmung von Fischlarven untersucht. Als Vorbereitung auf die Bestimmung wurden Formen und proportionales Wachstum von Fischlarven der Nordsee und angrenzender Gebiete untersucht. Dazu wurden an 831 Fischlarven aus 33 Arten und 18 Familien die folgenden Messungen durchgeführt: Standardlänge, Präanallänge, Präorbitallänge, Präpektorallänge, Augendurchmesser, Orbitalhöhe, Pektoralhöhe, Analhöhe, Pektoralbreite und Analbreite. Aus den Messungen wurde das Volumen der Larven errechnet. Die Formen von Larven mit einem Volumen zwischen 3 und 5 μl wurden verglichen. Es ergaben sich vier deutlich getrennte Formgruppen: "eel-like", "fusiform", "deep + compressed" und "tadpole-like". Bis auf die Gruppe "fusiform" zeigten alle Gruppen allometrisches Wachstum bei bestimmten Körperproportionen. Die mögliche ökologische Bedeutung dieser Gruppen wird diskutiert. Es wurden drei computergestützte Bestimmungssysteme entwickelt und getestet: Ein numerisches System, ein Expertensystem und eine moderne Datenbank. Als Beispiel einer Methode der numerischen Taxonomie wurde die Quadratische Diskriminanzanalyse untersucht. Dazu wurden aus den durchgeführten Messungen die Diskriminanzfunktionen errechnet und unbekannte Larven zunächst einer Formgruppe und dann einer Art innerhalb der Formgruppe zugeordnet. Die richtige Zuordnung bei dieser Methode betrug 82 % . Die numerische Taxonomie scheint damit zur Bestimmung von Fischlarven grundsätzlich geeignet zu sein. Allerdings ist zweifelhaft, ob genügend Fischlarven (30 - 100 pro Art) zum Aufbau des Systems erhältlich sind. Aufbauend auf dem HALBEISEN-Schlüssel zur Bestimmung von Fischlarven der Nordsee und angrenzender Gebiete wurde das Expertensystem IDEXSYS entwickelt. Es kann als moderne Form traditioneller Bestimmungsschlüssel betrachtet werden. Expertensysteme erweisen sich damit als gut geeignet zur Bestimmung von Fischlarven. Mit einem modernen Datenbankprogramm wurde ein Such- und Eingabeformular mit etwa 80 Merkmalen entwickelt. Alle in der Nordsee und den angrenzenden Gebieten vorkommenden 126 Fischlarvenarten wurden auf diese Merkmale überprüft und in die Datenbank eingegeben. Der Test des Systems ergab, daß durchschnittlich nur drei Merkmale zur Bestimmung einer Fischlarve erforderlich waren. Bei einem Vergleich der Methoden wird für die Bestimmung von Fischlarven dem Datenbanksystem der Vorzug gegeben.

Description: Highlights • Development of an autonomous DIC analyzer based on Conductometric technique using a cell with 4 hollow brass electrodes. • CO2 extraction from seawater using a gas diffusion cell with a “Tube In A Tube” configuration and a gas permeable membrane. • Formulation of mathematical temperature and salinity correction to determine accurate DIC concentration. • Demonstration of the analyzer performance in the southwest Baltic Sea. Abstract Background The increase in anthropogenic CO2 concentrations in the Earth's atmosphere since the industrial revolution has resulted in an increased uptake of CO2 by the oceans, leading to ocean acidification. Dissolved Inorganic Carbon (DIC) is one of the key variables to characterize the seawater carbonate system. High quality DIC observations at a high spatial-temporal resolution is required to improve our understanding of the marine carbonate system. To meet the requirements, autonomous DIC analyzers are needed which offer a high sampling frequency, are cost-effective and have a low reagent and power consumption. Results We present the development and validation of a novel analyzer for autonomous measurements of DIC in seawater using conductometric detection. The analyzer employs a gas diffusion sequential injection approach in a “Tube In A Tube” configuration that facilitates diffusion of gaseous CO2 from an acidified sample through a gas permeable membrane into a stream of an alkaline solution. The change in conductivity in the alkaline medium is proportional to the DIC concentration of the sample and is measured using a detection cell constructed of 4 hollow brass electrodes. Physical and chemical optimizations of the analyzer yielded a sampling frequency of 4 samples h−1 using sub mL reagent volumes for each measurement. Temperature and salinity effects on DIC measurements were mathematically corrected to increase accuracy. Analytical precision of ±4.9 μmol kg−1 and ±9.7 μmol kg−1 were achieved from measurements of a DIC reference material in the laboratory and during a field deployment in the southwest Baltic Sea, respectively. Significance This study describes a simple, cost-effective, autonomous, on-site benchtop DIC analyzer capable of measuring DIC in seawater at a high temporal resolution as a step towards an underwater DIC sensor. The analyzer is able to measure a wide range of DIC concentrations in both fresh and marine waters. The achieved accuracy and precision offer an excellent opportunity to employ the analyzer for ocean acidification studies and CO2 leakage detection in the context of Carbon Capture and Storage operations.

Description: Vessel-mounted Acoustic Doppler Current Profilers (ADCPs) provide velocity profiles of the upper ocean along the ship track. They are a key tool in oceanographic research to study the oceanic circulation and the associated distribution of mass, heat, contaminants and other tracers. In order to obtain high-quality ocean current data from vessel-mounted ADCP measurements, a number of requirements must be met, from system installation and data acquisition measures to certain essential processing steps. Here, we present an open-source Python toolbox called OSADCP for scientists to convert, clean, calibrate and organize binary raw vessel-mounted ADCP data for scientific use. The toolbox is designed to process ADCP measurements in deep water by Teledyne RDI Ocean Surveyor ADCPs and the data acquisition software VMDAS.

Description: Der Biodiversitätsverlust schreitet in bedrohlichem Ausmaß voran. Mit dem Global Biodiversity Framework und voraussichtlich dem Nature Restoration Law bestehen nun auf internationaler und europäischer Ebene vielversprechende Ansätze, ihm Herr zu werden. Jetzt ist der Bundesgesetzgeber – nicht zuletzt aus verfassungsrechtlichen Erwägungen – aufgerufen, daran anzuknüpfen. Dazu bietet sich die Regelungsform eines Rahmen- und Politikplanungsgesetzes an, wie sie schon aus dem Klimaschutzgesetz und dem Klimaanpassungsgesetz bekannt ist. Der Aufsatz beleuchtet den internationalen, europa- und verfassungsrechtlichen Hintergrund eines solchen ‘Biodiversitätsschutzgesetzes’ und diskutiert – unter Zusammenarbeit sowohl rechts- als auch naturwissenschaftlicher Autor:innen – formale und materielle Ausgestaltungsmöglichkeiten.

Description: The expedition AL570 with the RV Alkor was carried out within the framework of the interdisciplinary DAM MGF-OSTSEE Project “Potential effects of closure for bottom fishing in the marine protected areas (MPAs) of the western Baltic Sea – baseline observations” funded by the Ministry of Education and Research (BMBF). Within MGF-OSTSEE a consortium of scientists from various institutions investigates how benthic ecosystems in Natura 2000 areas within the German exclusive economic zone develop after the exclusion of bottom trawling. Major goals of the project are i. the initial assessment of the environmental state and its variability in- and outside the three Natura 2000 areas Fehmarnbelt, Oder- and Rönnebank under the ongoing pressure of bottom trawling and ii. the general assessment of the effect of bottom trawling on benthic communities and benthic biogeochemical functioning as well as their development after fishery exclusion. The cruise AL570 concludes a series of three previous expeditions EMB238 (2020) and EMB267/268 (2021) and aimed to survey all components of the benthic food web including prokaryotes, protozoans, meiofauna and macrofauna, as well as sediment properties and biogeochemical processes in selected working areas in- and outside of the MPA. The working program comprised 156 station activities of various gears for biological and biogeochemical sampling of sediments. Solute exchange between the sediment and the water column was investigated using Landers and a novel underwater vehicle the Deep-Sea Rover (DSR) Panta Rhei. Investigations in the water column, seafloor observation and deployments of a dredge supplemented the station work. Due to stormy weather in situ solute fluxe measurements were not performed at the Rönnebank.

Description: In this deliverable, we perform Earth system model (ESM) simulations to assess the role of land-based and ocean-based negative emission technologies (NETs) for achieving the temperature target set by the 2015 Paris Agreement. The dataset provided from this work package will be used for investigating carbon sequestration potential, side-effects and potential constraints of combining oceanic and terrestrial NETs with the help of an earth system model, NorESM2. Two long NorESM2 coupled simulations with SSP5-3.4-OS scenario are conducted to check the CDR potential of terrestrial CDR, and terrestrial and marine CDR together by combining land-based Bioenergy for Carbon Capture and Storage (BECCS) and Ocean Alkalinization Enhancement (OAE) scenarios together. For the terrestrial BECCS simulation, the default land use distribution in the original CMIP6 SSP5-3.4 land use dataset is modified to accommodate more bioenergy crop in the future while keeping the total crop area of 2015 for food throughout the century and combining it with a bio-CCS system. For the second simulation we combined the above terrestrial BECCS simulation with 2030-high OAE scenario from Deliverable 4.6. A higher amount of carbon captured by making use of the carbon sequestration potential of land and ocean together.

Description: Geodetic data in plate boundary zones reflect the accrual of tectonic strain and stress, which will ultimately be released in earthquakes, and so they can provide valuable insights into future seismic hazards. To incorporate geodetic measurements of contemporary deformation into the 2022 revision of the New Zealand National Seismic Hazard Model 2022 (NZ NSHM 2022), we derive a range of strain-rate models from published interseismic Global Navigation Satellite Systems velocities for New Zealand. We calculate the uncertainty in strain rate excluding strain from the Taupō rift–Havre trough and Hikurangi subduction zone, which are handled separately, and the corresponding moment rates. A high shear strain rate occurs along the Alpine fault and the North Island dextral fault belt, as well as the eastern coast of the North Island. Dilatation rates are primarily contractional in the South Island and less well constrained in the North Island. Total moment accumulation derived using Kostrov-type summation varies from 0.64 to 2.93×1019 N·m/yr depending on method and parameter choices. To account for both aleatory and epistemic uncertainty in the strain-rate results, we use four different methods for estimating strain rate and calculate various average models and uncertainty metrics. The maximum shear strain rate is similar across all methods, whereas the dilatation rate and overall strain rate style differ more significantly. Each method provides an estimate of its own uncertainty propagated from the data uncertainties, and variability between methods provides an additional estimate of epistemic uncertainty. Epistemic uncertainty in New Zealand tends to be higher than the aleatory uncertainty estimates provided by any single method, and epistemic uncertainty on dilatation rate exceeds the aleatory uncertainty nearly everywhere. These strain-rate models were provided to the NZ NSHM 2022 team and used to develop fault-slip deficit rate models and scaled seismicity rate models.

Description: Highlights: • The interactions between vortices in a four-vortex flow field using a rotating water tank. • Driven by the strain field, non-ideal vortices stretch along the centerline, and manifest an asymmetric stretching pattern. • Non-ideal vortices disperse vorticity, accumulate filaments, and exhibit distinctive variations in anti-symmetric vorticity distribution, impacting respective merging efficiency. Abstract: Oceanic vortex merging is an important physical process for the vortex evolution and its impact on marine environment. However, limitation of the in-situ oceanic observational data of vortex merging inhabits its better understanding. This study investigates the interactions between non-ideal vortices in a four-vortex flow field in a rotating tank. We examine the merging stages of anticyclonic vortices, influenced by two other cyclonic vortices and their respective dynamical behaviors and quantify the effects of merging on vortex characteristics. The results indicate a strong shear flow between two counter-rotating vortices, which accelerates the motion of the anticyclonic vortex, while cyclonic ones exhibit greater stability. Subsequently, different stages of non-ideal vortex merging in a co-rotating framework are defined, primarily the encircling stage, rapid approaching stage, and merging vortex stage. In addition, we quantify and compare variations in morphological parameters and anti-symmetric vorticity distribution of non-ideal vortices across these stages. The stretching of vortices primarily occurs along the line connecting their centers due to the strain field exerted by neighboring vortices, resulting in an asymmetric stretching pattern in the interactions among non-ideal vortices. Furthermore, during the merging process, non-ideal vortices disperse vorticity outward and accumulate vortex filaments in the surrounding environment, leading to distinctive variations in anti-symmetric vorticity distribution, affecting their respective merging efficiency.

Description: During the last decades, the Chilean margin offshore Maule (34±S −36±S) had been reported as a highly locked and seismically quiet zone. The stress-accumulated state finished on the 27th of February 2010, when a megathrust earthquake (with Mw = 8.8) ruptured » 400 km of the Nazca-South America plate boundary. Unfortunately, up to now little was known about the seismic structure offshore Maule. In the frame of the third phase of the project SFB 574 “Volatiles and Fluids in Subduction Zones” of the Christan-Albrechts University of Kiel, seismic data was analyzed in order to obtain detailed images of the deep structure of the margin and of the outer rise. Here are presented constraints on the forearc and the subduction zone structure of the rupture area derived from seismic refraction and wide-angle data. The results show a wedge shaped body » 40 km wide with typical sedimentary velocities interpreted as a frontal accretionary prism (FAP). Landward of the imaged FAP, the velocity model shows an abrupt velocity-contrast suggesting a lithological change, which is interpreted as the contact between the FAP and the paleo accretionary prism (backstop). The backstop location is coincident with the seaward limit of the aftershocks, defining the updip limit of the co-seismic rupture and the seismogenic zone. Furthermore, the seaward limit of the aftershocks coincides with the location of the shelf break in the entire earthquake rupture area (33.5±S−38.5±S), which is interpreted as the location of the backstop along the margin. Published seismic profiles at the northern and southern limit of the rupture area also show the presence of a strong horizontal velocity gradient imaging the seismic backstop at a distance of » 30 km from the deformation front. The seismic wide-angle reflections from the top of the subducting oceanic crust constrain the location of the plate boundary offshore, dipping » 10±. The projection of the epicenter of the Maule earthquake onto our derived interplate boundary yielded a hypocenter around 20 km depth. This implies that the earthquake nucleated somewhere within the seismogenic zone, neither at its updip nor at its downdip limit. The second part of this thesis focuses on the dependency between the incoming plate’s bend faulting, lithospheric hydration and shallow outer rise seismic activity. To support the interpretation, are presented Vp and Vs seismic models obtained from wide angle seismic data and the derived 2D Poisson’s ratio distribution at the outer rise. The oceanic lithosphere shows a high degree of hydration, due to the water infiltration through the bending-related faults exposed to seawater. This process is presumably intensified bythe existence of a seamount in the area. It is concluded that the water infiltrates deep into the lithosphere, triggering shallow earthquakes in the outer rise and likely serpentinization in the mantle, estimated to be about 10%.