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Sensitivity of the tropical Atlantic to vertical mixing in two ocean models (ICON-O v2.6.6 and FESOM v2.5)
No full textOcean general circulation models still have large upper-ocean biases, including in tropical sea surface temperature, that are possibly connected to the representation of vertical mixing. In earlier studies, the ocean vertical mixing parameterization has usually been tuned for a specific site or only within a specific model. We present here a systematic comparison of the effects of changes in the vertical mixing scheme in two different global ocean models, ICON-O and FESOM, run at a horizontal resolution of 10 km in the tropical Atlantic. We test two commonly used vertical mixing schemes: the K-profile parameterization (KPP) and the turbulent kinetic energy (TKE) scheme. Additionally, we vary tuning parameters in both schemes and test the addition of Langmuir turbulence in the TKE scheme. We show that the biases of mean sea surface temperature, subsurface temperature, subsurface currents, and mixed layer depth differ more between the two models than between runs with different mixing scheme settings within each model. For ICON-O, there is a larger difference between TKE and KPP than for FESOM. In both models, varying the tuning parameters hardly affects the pattern and magnitude of the mean state biases. For the representation of smaller-scale variability like the diurnal cycle or inertial waves, the choice of the mixing scheme can matter: the diurnally enhanced penetration of equatorial turbulence below the mixed layer is only simulated with TKE, not with KPP. However, tuning of the parameters within the mixing schemes does not lead to large improvements for these processes. We conclude that a substantial part of the upper-ocean tropical Atlantic biases is not sensitive to details of the vertical mixing scheme
Blue Carbon potential in Germany: Status and future development
No full textHighlights:
• Collection of knowledge on the Blue Carbon potential of marine habitats in Germany.
• Identification of crucial open research questions for future management measures.
• Review of current political momentum on national, sub- and supra-national level.
• Blue Carbon Restoration Plan to strengthen conservation, restoration and mitigation.
• Case study of practical implementation on salt marsh restoration strategies.
Climate change and biodiversity loss are global challenges that need to be addressed through a combination of measures. However, political and societal action has not yet kept pace with the urgency of these challenges. Marine carbon sequestering habitats (“Blue Carbon habitats”) are globally recognized for their role in climate change mitigation and for their co-benefits and ecosystem functions, e.g., as habitat providers. In Germany, research on the Blue Carbon potential of coastal and marine ecosystems has gained momentum in recent years. However, a synergistic approach with an inclusive decision-making process is crucial to ensure political action. Current challenges are considerable knowledge gaps and the limited accessibility and transferability of existing data. Funding of research projects at different administrative levels impacts coordination, output and visibility. Here, we present a general overview of existing knowledge and identified knowledge gaps in Blue Carbon research and focus on potential Blue Carbon ecosystems (BCEs) of the German coast. Furthermore, we identify windows of opportunity and provide actionable recommendations at the science-policy-society interface by examining the current framework for Blue Carbon in Germany. Based on this, ongoing research can be further prioritized and funded in order to simultaneously strengthen the political decision-making process. The results of this study, supported by the lessons learned from a case study on the German coast, recommend a two-pronged strategy to not only avoid additional release of already stored carbon through ecosystem conservation and sustainable governance and management, but also to increase net carbon storage through (re-)establishing BCEs
Editorial: ICYMARE – early career researchers in marine science
No full textThis Research Topic is a collection of original research, review, and perspective articles produced in the frame of the ICYMARE initiative. ICYMARE – the ‘International Conference for Young MArine REsearchers’ – is an annual international conference and networking meeting for young marine scientists (www.icymare.com)
Investigation of offshore freshened groundwater using marine controlled–source electromagnetic: Insights from Gozo, Maltese Islands
No full textHighlights
• Bayesian inversion improves offshore freshened groundwater (OFG) characterization.
• Two resistivity anomalies identified offshore Gozo suggest potential OFG.
• Shallow resistive body shows landward rising resistivity, suggesting fresher pore water.
• Deeper resistive anomaly indicates uncertainty in OFG presence or lithological changes.
• Uncertainty analysis enhances CSEM data reliability for mapping OFG.
Abstract
Carbonate margins form a significant portion of the world's coastlines, contain substantial freshwater resources, and play a vital role in global hydrogeological processes. These regions are promising reservoirs for offshore freshened groundwater (OFG), a potential resource for coastal and island populations. Mapping OFG within continental margins using marine controlled–source electromagnetic (CSEM) data relies on electrical resistivity as a proxy, requiring sophisticated inversion techniques. Given the ambiguity in deriving discrete resistivity distributions from CSEM data, understanding uncertainty is essential for reliable OFG inference. The conventionally used two–dimensional deterministic inversion provides a best–fit solution but does not assess resistivity uncertainties, limiting OFG characterization. To address this, we apply trans–dimensional Bayesian inversion on marine CSEM data from a semi–arid carbonate setting off eastern Gozo (Maltese Islands, Mediterranean Sea). Here, we integrate deterministic and trans–dimensional inversion results with seismic reflection data to identify two distinct, continuous resistivity anomalies within the Lower Coralline Limestone formation. The first, shallower resistive body starts ~4 km from the coast, appearing across all the CSEM profiles at 210–250 m below sea–level, with resistivity increasing landward. This anomaly may suggest an OFG body. The second, deeper anomaly starts at 350–400 m below sea–level and extends deeper. Whether it represents a second OFG unit or geological changes remains uncertain. Our findings offer new insights into resistivity distributions within carbonate margins, highlighting their OFG potential and the value of trans–dimensional sampling. This study augments CSEM research, underlining the need to extend coastal hydrogeological studies offshore for improved environmental conservation and resource management
UN-Ozeankonferenz - Mehr Schutz für die Meere
No full textAuf der UN-Ozeankonferenz gab es überraschend Fortschritte: 51 Staaten ratifizierten das Hochseeabkommen – neun fehlen noch. Fast 100 Länder fordern ein Plastikabkommen. Die USA blieben praktisch fern, China überraschte mit einer KI-Initiative
Seasonal cycles in a seaweed holobiont: A multiyear time series reveals repetitive microbial shifts and core taxa
No full textMunition in der Ostsee: "Wir müssen uns beeilen"
No full textKieler Toxikologe Edmund Maser mahnt eine schnelle Bergung an - Spuren von TNT in Muscheln und Fischen nachgewiese
Research Software Engineering Research: RSE Research & RSE Metascience
No full textThis presentation explores Research Software Engineering Research (RSE Research), a field focused on understanding and enhancing the development of software for research purposes. It also considers whether software engineering can be viewed, in some sense, as a form of metascience applied to software
Asymmetric continental crust stretching and seafloor spreading of the southwestern South China Sea: New insights from wide-angle seismic data
No full textAlong-strike heterogeneity of pre-existing Mesozoic structures have caused different rift-to-drift
features from east to west of the South China Sea (SCS). The southwestern margins have
undergone prolonged extension and propagating seafloor spreading, leading to crustal structures
significantly different from the northeastern SCS margin. The geodynamic mechanism of the
termination of seafloor spreading in the SCS is still enigmatic.
In this study, we present a ~780 km long P-wave velocity model across the two conjugate
continental margins and the oceanic basin at the southwestern propagating tip in the SCS from a
wide-angle seismic refraction profiling. We use joint refraction and reflection seismic tomographic
inversion and a layer-stripping approach to obtain the velocity structure. We show that the crustal
thickness varies from ~6–23 km in the extended continental domain to <5 km in the oceanic basin.
Significant asymmetry in velocity structures is observed in both the continental and oceanic
domains, across the mid-ocean ridge. The continental crust of the Nansha Block in the
southwestern SCS margin has a velocity structure and a mid-crustal layer (Vp=6.0-6.5 km/s)
comparable to those of the Xisha Block. In contrast, the conjugate continental crust in the
northern margin features a thinner upper crust with a high velocity gradient and lacks a midcrustal
layer. Stretching factors show that the upper and lower crusts of the southern continental
margin are uniformly extended. However, the upper crust of the northern continental margin is
much more stretched than its lower crust. The fault-driven stretching factor calculated on the
coincident multi-channel seismic profile is much smaller than the stretching factors of the upper
crust calculated from crustal thinning, suggesting that the initial crustal thickness may be much
less than 32 km. In the ocean basin, we observe high P-wave velocities with high gradient at 2-3 km
below the top of the sedimentary basement, and they increase to 7.5 km/s at a depth of 6 km
below the basement. Our results suggest that a highly serpentinized mantle underlies a thin
oceanic crust at the southwestern tip of the SCS basin, and the magmatic budget was inadequate
near the end of the southwestward spreading propagation of the SCS
