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Fisheries management in the Baltic Sea – two failed models
No full textManagement of fisheries in the Baltic Sea has generally failed to meet its objectives. Two recently published scientific articles dive deeper into the reasons. A new calculation showing a decline in the abundance of eels in northern European coastal waters and calls into question the effectiveness of the decentralized management of eels based on national eel management plans. Another article analyzes serious deficiencies in the EU's centralised management of key commercial fish stocks, such as cod, herring and sprat, and proposes an alternative, more precautionary and ecosystem-based approach
Artificial light at night has the potential to alter the structure and functioning of shallow water benthic ecosystems: results from globally replicated experiments
No full textResolving Sharper Fronts of the Agulhas Current Retroflection Using SWOT Altimetry
No full textAs a cutting‐edge altimetry product, the Surface Water and Ocean Topography (SWOT) satellite observations require validation against in situ measurements and existing satellite data sets. During the fast‐repeat phase of the mission, daily SWOT altimetry retrievals capture submesoscale ocean eddies (30 km) amidst larger mesoscale (100–200 km) structures in the dynamic Agulhas Current Retroflection region. Our results reveal that SWOT significantly enhances the resolution of the Agulhas Current's frontal features, producing sea surface height gradients that are 28% sharper compared to conventional altimetry products. Comparisons with in situ velocity observations from an underwater glider and surface drifters, further demonstrate SWOT's unparalleled capability to detect the strongest velocities and velocity gradients. These findings mark a pivotal step forward in resolving fine‐scale ocean circulation from satellite altimetry, with promising implications for unveiling horizontal and vertical dynamics in western boundary currents and beyond.
Plain Language Summary
The Surface Water and Ocean Topography (SWOT) satellite provides a groundbreaking view of sea surface height across a 120 km‐wide swath, resolving features nearly 10 times smaller than those detected by previous altimeter missions. These high‐resolution observations offer new opportunities to study fine‐scale ocean variability and improve the accuracy of ocean models. However, before SWOT data can be widely used, its measurements must be validated against well‐established observations. In this study, we compare daily SWOT data over the Agulhas Current region with a commonly used gridded altimetry product. SWOT reveals small‐scale ocean eddies embedded within the larger‐scale circulation of the Agulhas Current Retroflection and detects oceanic fronts that are 28% sharper than those captured by conventional altimetry. Comparisons with surface currents measured by drifters and an underwater glider further confirm that SWOT accurately represents ocean variability, particularly for velocities exceeding 0.5 m . These findings highlight SWOT's potential to significantly improve our ability to observe mesoscale and submesoscale ocean circulation, especially in highly dynamic regions such as western boundary currents.
Key Points
Surface Water and Ocean Topography (SWOT) captures stronger velocities than previous altimetry products, with velocities higher than 1.8 m being on average 50% larger
SWOT's superior spatial resolution reveals submesoscale circulations and sharper fronts associated with the Agulhas Retroflection
In situ drifter and glider velocity observations 0.5 m are more closely correlated to SWOT compared to previous altimetry product
Uncrewed surface vehicles in the Global Ocean Observing System: a new frontier for observing and monitoring at the air-sea interface
No full textObserving air-sea interactions on a global scale is essential for improving Earth system forecasts. Yet these exchanges are challenging to quantify for a range of reasons, including extreme conditions, vast and remote under-sampled locations, requirements for a multitude of co-located variables, and the high variability of fluxes in space and time. Uncrewed Surface Vehicles (USVs) present a novel solution for measuring these crucial air-sea interactions at a global scale. Powered by renewable energy (e.g., wind and waves for propulsion, solar power for electronics), USVs have provided navigable and persistent observing capabilities over the past decade and a half. In our review of 200 USV datasets and 96 studies, we found USVs have observed a total of 33 variables spanning physical, biogeochemical, biological and ecological processes at the air-sea transition zone. We present a map showing the global proliferation of USV adoption for scientific ocean observing. This review, carried out under the auspices of the ‘Observing Air-Sea Interactions Strategy’ (OASIS), makes the case for a permanent USV network to complement the mature and emerging networks within the Global Ocean Observing System (GOOS). The Observations Coordination Group (OCG) overseeing GOOS has identified ten attributes of an in-situ global network. Here, we discuss and evaluate the maturation of the USV network towards meeting these attributes. Our article forms the basis of a roadmap to formalise and guide the global USV community towards a novel and integrated ocean observing frontier
Wind-triggered Antarctic sea ice decline preconditioned by thinning Winter Water
No full textAbstract:
Between 2015 and 2017, Antarctic sea ice underwent a drastic change, transitioning from a period of record high sea ice area to a period of record low sea ice area. While both an intensified atmospheric circulation and warmer ocean temperatures in 2016 have been invoked as possible causes for this sea ice regime shift, a detailed process understanding is still missing. Using ~110,000 hydrographic profiles from the seasonally ice-covered Southern Ocean and atmospheric reanalysis, we show that this change of the sea ice state was preconditioned by a gradual thinning of Antarctic Winter Water over the period 2005 to 2015, reducing the barrier between the warmer deep water and the surface. As a result, the reservoir of warmer deep water moved closer to the surface and sea ice. Throughout 2015, anomalously strong winds enhanced mixing across the thin Winter Water layer, which broke down stratification over the upper ocean and enhanced connectivity between the ocean mixed layer and deeper interior. Combined, the reduced stratification and stronger winds allowed upwelling of warmer deep waters to melt the sea ice. Our findings thus show that an oceanic preconditioning was a prerequisite for the recent drastic sea ice regime shift that was ultimately triggered by strong wind-driven mixing in 2015
A roadmap for equitable reuse of public microbiome data
No full textScience benefits from rapid open data sharing, but current guidelines for data reuse were established two decades ago, when databases were several million times smaller than they are today. These guidelines are largely unfamiliar to the scientific community, and, owing to the rapid increase in biological data generated in the past decade, they are also outdated. As a result, there is a lack of community standards suited to the current landscape and inconsistent implementation of data sharing policies across institutions. Here we discuss current sequence data sharing policies and their benefits and drawbacks, and present a roadmap to establish guidelines for equitable sequence data reuse, developed in consultation with a data consortium of 167 microbiome scientists. We propose the use of a Data Reuse Information (DRI) tag for public sequence data, which will be associated with at least one Open Researcher and Contributor ID (ORCID) account. The machine-readable DRI tag indicates that the data creators prefer to be contacted before data reuse, and simultaneously provides data consumers with a mechanism to get in touch with the data creators. The DRI aims to facilitate and foster collaborations, and serve as a guideline that can be expanded to other data types
Analysing a Multi-Criteria Analysis to Prioritise Munition Piles in the German Baltic Sea for Remediation
No full textIn the aftermath of World War II, significant
amounts of munitions were dumped into the German
coastal waters. These unremedied munitions harbour
various risks. The Multi-Criteria Analysis for Dumped
Munition Prioritisation (MCA-DuMP) was developed as
part of the efforts of the CONMAR project and enables
the prioritisation of these munitions for remediation. To
better understand the formation and structure of these
prioritisation results, a Sensitivity Analysis (SA) was
conducted. As part of this analysis, two approaches to
SA, VARS and PAWN, were applied to three input/output
series obtained using different sampling strategies. The
results of this SA were used to identify influential factors
and to rank the factors according to their influence on the
prioritisation results. Both aspects are helpful to decision
makers as they enable them to better assess and categorise
the prioritisation results, thus allowing them to utilise
the findings as best as possible in their decision-making
process. They can also be utilised by the developers of
MCA-DuMP to verify its behaviour
Atlantic wide detection of marine heatwaves beyond the surface in a high-resolution model
No full textProlonged periods of anomalously high ocean temperatures, known as marine heatwaves (MHWs), can have devastating effects on ecosystems. MHWs have been extensively studied in the near-surface ocean, but little is known about MHWs at depth.
As continuous observations in space and time are very sparse away from the surface, basin wide studies on MHWs at depth have to rely on models. This comes with several challenges as models are often subject to spurious trends and require sufficiently high resolution to realistically simulate temperature gradients, currents and mesoscale variability.
Therefore, a basin wide detection of MHWs requires extensive model experiments and a large amount of data to be processed.
In oder to enable comprehensive studies on MHWs, this dataset provides information about the presence of MHWs and their key characteristics (duration and intensity) throughout the entire Atlantic Ocean. MHWs were detected in the high-resolution ocean model configuration VIKING20X following the commonly applied definition of Hobday et al. (2016). A 30-year fixed baseline (1980-2009) was applied. To ensure that the ocean has adjusted to the initial conditions, the model was spun-up for more than 300 years
Wohin mit dem CO2? Das Meer soll helfen
No full textDer Ozean: Klimaanlage, Sauerstofffabrik und - wichtige Kohlenstoffsenke. Lange haben wir versucht, den Klimawandel vor allem mit einem Ziel zu bekämpfen: weniger CO₂ ausstoßen. Weniger fliegen, sauberer produzieren, erneuerbare Energien nutzen. All das ist wichtig - aber es reicht nicht mehr. Wie das Meer uns dabei helfen kann, CO₂ zu binden, das weiß Forscherin Dr. Nadine Mengis vom GEOMAR-Institut in Kiel
