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Eddy Hunter: A Data Mining System for High-Resolution Eddy Signals, Leveraging Spatio-Temporal Similarities in the SWOT Satellite Data
No full textThe SWOT mission opened a new chapter in understanding ocean dynamics, yielding constantly growing amounts of high-resolution Sea Surface Height (SSH) observations. However, this extremely valuable data source is still not fully exploited by researchers, due to technical reasons and novelty. In particular, long orbit cycles and KaRIn altimeter’s limited spatial coverage impose challenges for eddy detection and tracking using SWOT. Conversely, traditional satellite altimeters served as the backbone of mesoscale research for over 30 years, providing wide spatio-temporal coverage. The integration of such satellites and SWOT could offer possible solutions to some of the aforementioned challenges. We aim to provide a system capable of overcoming the limitations of KaRIn altimetry data, leveraging the integration between SWOT and conventional SSH altimetry. Adopting an information retrieval approach, we identify and index high-resolution eddy signals similar to a low-resolution counterpart. To do so, the Eddy Hunter System (EHS) integrates the Mesoscale Eddy Trajectory Atlas (META) and SWOT Level-3 products, by leveraging the spatio-temporal similarities in the SSH signals. The EHS extracts a spatio-temporal Region Of Interest (ROI) from every eddy observation present in the META and computes the SWOT passages that could possibly contain related signals. The introduction of “Marine Data Science” topics in the similarity-search community can provide new problems and challenges regarding information retrieval and data mining. The deployment of our system could foster advancements both in oceanographic and applied ML/AI research, providing a powerful data mining tool to build high-resolution eddy repositories and unveil previously unseen ocean phenomena
Artificial light at night shapes marine early hard-bottom communities in Madeira Island, NE Atlantic
No full textHighlights:
• ALAN altered the composition of marine hard-bottom communities.
• The hydrozoan Pennaria disticha dominated ALAN-exposed communities regardless of light colour.
• Exposure to ALAN led to increased species richness, particularly under white light.
• Evenness decreased under both white and yellow artificial light.
• Both yellow light and white light increased total cover and community biomass.
Abstract
Artificial light at night (ALAN) is increasingly recognised as a pollutant that modifies natural light conditions and negatively impacts terrestrial and aquatic ecosystems. Marine hard-bottom communities are important components of coastal ecosystems, supporting diverse sessile organisms and early successional processes that can reveal community-level responses to environmental changes. This study investigated the influence of ALAN on early successional marine hard-bottom communities in a field experiment conducted in Madeira, Portugal. Simulated outdoor LED lighting systems were used to expose submerged PVC settlement panels to white and yellow light in order to assess their effects on the establishing communities over a three-month period. Light of both colours significantly altered community composition and the abundances of colonisers such as the hydrozoan Pennaria disticha and the red alga Polysiphonia sertularioides in comparison to assemblages that simultaneously established on non-illuminated surfaces. In general, ALAN-exposed communities exhibited a higher species richness but a lower evenness compared to non-exposed assemblages. Our results reveal the potential of ALAN to alter the biodiversity and structure of shallow-water, benthic communities and underscore the need for further research to assess the consequences of anthropogenic light emissions for coastal marine ecosystems
Global ocean indicators: Marking pathways at the science-policy nexus
No full textOcean knowledge is crucial for shaping policies that enable sustainable development, adaptation, and well-being at all levels, as everyone—either directly or indirectly—depends on the ocean, which today faces escalating threats from climate change, pollution, and biodiversity loss, pushing us beyond critical planetary boundaries. Ocean indicators are crucial for translating ocean science and data into practical metrics, guidance, and tools informing on the state and health of the ocean that can be directly applied by policymakers, practitioners, and the public. Despite their critical importance, ocean indicators trail behind those for continental areas, limiting effective monitoring and policy integration. Developing reliable, comparable, and regularly updated ocean indicators, backed by a unified international framework, is essential for delivering coherent, actionable insights that can guide global goals and protect the ocean's future. This paper establishes a scientific foundation for ocean indicators through international and multidisciplinary collaboration, presenting defined criteria and a set of pilot indicators for the ocean’s physical, biogeochemical, biodiversity, and ecosystem aspects. The proposed framework offers a solid foundation for generating indicators that not only track the ocean state but also provide outputs for application in informing policy and decision-making
Pollen transport to deep-marine environments: Considerations for reconstructing past vegetation from marine sediment cores
No full textHighlights
• New 135 ka deep-marine pollen record from turbidite-rich core IODP-U1520D from eastern Aotearoa-New Zealand.
• Three offshore pollen records compared across Marine Isotope Stage 6–5 and Marine Isotope Stage 2–1 to assess impacts of pollen and sediment transport on palaeovegetation records.
• Pollen assemblages show strong interglacial similarity but diverge in glacial periods.
• Fine-grained, turbidite-dominated records from active margins can be used to create reliable palaeovegetation records.
Abstract
Deep-marine sedimentary records provide a unique opportunity to investigate long-term vegetation changes in response to climate through pollen analysis. In contrast to pollen records from terrestrial sites which capture a local vegetation signature, deep-marine records typically capture a regional vegetation signature, with pollen often taking long and complex transport pathways before depositing on the seafloor. To use deep-marine pollen records to their full potential, we need to understand how pollen is reaching deep-marine sites and whether different transport processes (i.e. ocean currents or gravity flows) impact or bias the final palaeovegetation record. We compare three deep-marine pollen records from offshore eastern Aotearoa-New Zealand from different depths, proximities from land and sedimentary settings to understand whether these different factors influence the final palaeovegetation records. We focus on the glacial-interglacial transitions from Marine Isotope Stages 6-5 and 2-1, and present a new 135 ka pollen record from the turbidite-dominated sediment core IODP-U1520D. We find that pollen assemblages in the three cores show consistent changes over glacial-interglacial cycles, with pollen assemblages showing greater similarities in interglacial periods and varying during glacial periods. The general consistency in pollen assemblages is surprising given the vastly different nature of the three sediment cores and shows that deep-marine records, including fine-grained turbidite-dominated records from active margins, can yield reliable palaeovegetation records
New species in Galeommatoidea (Bivalvia) from Namibia
No full textFour new species in the superfamily Galeommatoidea (Bivalvia) were found in sediment samples from the continental shelf and upper bathyal slope off Namibia, SW Africa: Kurtiella namibiensis n. sp., Bornia walvisensis n. sp., Scacchia aartseni n. sp. and Scacchia huberi n. sp. One live specimen of Bornia walvisensis n. sp. was brooding. A commensal relationship is likely between Bornia walvisensis n. sp. and the decapod host Kraussillichirus kraussi (Stebbing, 1900)
Constraining the drivers of barium isotope composition in marine barite: Insights from Pliocene-Holocene Eastern Mediterranean sapropels
No full textThe stable isotopic composition of barium in marine barite (δ138/134Babarite) has been proposed as a proxy for reconstructing past Ba cycling in the oceanic water column. However, whether δ138/134Babarite can also be a proxy for export productivity remains uncertain, particularly in semi-enclosed basins such as the Eastern Mediterranean (EMed). Here we present the first record of δ138/134Babarite extracted from EMed Pliocene to Holocene sapropels from six Ocean Drilling Program (ODP) Sites. Despite strong variability in Ba concentrations (∼400–4000 ppm) and organic carbon content (∼3–25 %)—reflecting varying export productivity levels—the δ138/134Babarite values show limited variation (ranging between 0.02 to −0.16 ‰), even during periods of exceptionally high inferred export productivity (e.g., during late Pleistocene sapropel S5). Consistent δ138/134Babarite values are also observed in sapropel S1 sites located at a wide range of water depths (∼900–3600 m). Well-preserved pelagic barite crystal textures (observed under scanning electron microscopy) and barite sulphur isotope composition similar to seawater (∼21 ‰; Paytan et al., 2004) in the sapropels, suggest that neither partial dissolution in bottom waters nor postdepositional Ba ion-exchange significantly altered the δ138/134Babarite signal. These results suggest that fluctuations in marine productivity had a limited impact on the dissolved Ba pool and its isotopic composition in the EMed upper water column during sapropel deposition. Instead, the EMed δ138/134Ba was likely controlled primarily by the Ba isotope composition of Atlantic Water inflow and local dissolved Ba sources, such as riverine and groundwater inputs, rather than by productivity-driven barite fluxes. This finding highlights that δ138/134Babarite in sedimentary records should not be interpreted as a straightforward proxy for export productivity, particularly in semi-restricted basins
2nd Submarine Volcanism Workshop
No full textIntegrating Geophysics, Sampling and Ocean Floor Imaging for a better Understanding of Submarine Volcanoe
Multi-phase intra-plate rifting and deformable plate modelling of the Northeast Atlantic back to the Permian
No full textThe Northeast Atlantic was one of the last regions of the Pangea supercontinent to undergo complete break-up, experiencing over 200 million years of episodic continental stretching before final separation. This prolonged tectonic evolution has been studied using recent geological and geophysical data obtained from the mid-Norwegian and East Greenland margins, which provide constraints on the timing, location, amount, and direction of extension. To analyse these parameters, we adopt a basin-to-plate scale approach and develop a deformable plate reconstruction. We implement four discrete phases of rifting: Phase I (264–247 Ma), Phase II (166–140 Ma), Phase III (125–110 Ma), Phase IV (80–56 Ma), with a progressive shift in extension direction from east-west to southeast-northwest. A key component of our methodology is the restoration of basin hinges for each rift episode. These hinges mark the outermost rigid boundaries of the deforming region and provide essential structural constraints. Over time, the width of the rifting domain narrows from approximately 300 km to 220 km, depending on margin location. Our model predicts cumulative stretching ranging from 240 km in the north to 310 km in the south of the domain. Extension rates and amounts vary by phase; for a mid-margin location, Phase I accounts for approximately 90 km of extension at 0.5 cm/yr, Phase II for 30 km at 0.13 cm/yr, Phase III for 90 km at 0.58 cm/yr, and Phase IV for 80 km at 0.32 cm/yr. By comparing forwards- and backwards-in-time crustal thickness reconstructions, our results suggest an initial crustal thickness exceeding 35 km before the onset of Permian rifting, and that lateral variations of non-linear stretching were likely. Our framework indicates that both rigid and deforming reconstructions should be developed in tandem with regional basin-scale constraints. Our model will form the basis for additional regional temporal and structural investigations including the Barents Sea, North Sea, and Northwest North Atlantic