Gravity flow is a key sedimentary process in deep-lacustrine environments, with transitional flow deposits commonly occurring in both distal and proximal zones of the turbidite systems. These deposits are crucial to understanding the sedimentary dynamics of fine-grained deep-water sediments. The transitional deposits between turbidity currents and mud-rich debris flows are particularly important for advancing our understanding of fine-grained sedimentation processes and have significant implications for unconventional oil and gas exploration.

The aim of this study is to describe transitional-flow facies, interpret their flow evolution and depositional processes, and assess their impact on the differential accumulation of organic matter in a fresh-water syn-rift deep-lacustrine system. Data were collected from the 111.39-m-thick Eocene  lacustrine oil-prone source rock succession, penetrated by the two wells in the Qibei Sub-sag, Bohai Bay Basin, China. Nine sedimentary facies were identified in the studied fine-grained succession, with various internal sedimentary structures (e.g., ripple cross lamination, low-angle cross lamination, wave lamination, parallel lamination, graded structure, deformed structure, and homogeneous structure) reflecting the dynamics of sedimentary processes in a deep-lacustrine depositional lobe distal environment. Millimeter-scale logging defined 5 bed types based on 2383 measured and recorded beds, with inferred transitional flow deposits exhibiting distinctive stacking patterns, from coarser grained turbidites to fine-grained debrites. A wide range of transitional-flow facies are recognized and can be assigned to turbulence-enhanced transitional flow, lower transitional plug flow, upper transitional plug flow and quasi-laminar plug flow. Despite the predominance of finning upward grain size trends, sedimentary structures in these heterolithic deposits may stack in varying orders, reflecting different flow dynamics.

The vertical facies trends of transitional flow deposit provide insights into the longitudinal flow evolution of flows, which were initially turbulent, but became increasingly laminar through deceleration and fine-grain entrainment. The assimilation of the lake-bottom mud into the density flows likely played a key role in modulating flow turbulence, helping to explain the common occurrence of transitional-flow facies indicated by sedimentological features such as sheared flame structures and deformed mud intrusions, which suggest interaction between the flow and the muddy lake floor.

Lacustrine organic matter was delivered to the lake floor by continuous settling, whereas terrestrial organic matter was transported via sediment density flows. The deep-lacustrine background mudstone is dominated by Type II₁ kerogen, whereas the quasi-laminar plug flow mudstone is dominated by Type II₁ and II₂ kerogen, turbulence-enhanced transitional flow and lower transitional plug flow mudstones are dominated by Type II₂ and III kerogen. These observations challenge the view that mud accumulates only from suspension fallout in distal basin-floor environments. This study suggests that composition, texture, and organic matter types of mud-dominated deep-lacustrine mudstones vary predictably in response to changes in depositional processes. The results have broader applicability to other deep-lacustrine sedimentary systems, highlighting the dynamic nature of transitional flows. Detailed microtextural and compositional analysis, combined with rigorous geochemical parameters, is essential for the understanding of the source-rock potential of basinal mudstones and fine-grained organic-rich sediments more general.

How to cite: Wang, J., Zhao, J., You, Z., Pu, X., Liu, K., Zhang, W., Shi, Z., Han, W., and Wang, Z.: Flow transformation processes recorded in the Eocene early syn-rift deep-lacustrine fine grained sedimentary rock in the Qibei Sub-sag, Bohai Bay Basin, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3094, https://doi.org/10.5194/egusphere-egu25-3094, 2025.

This study aims to simulate the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks and quantitatively analyze the impact of geological control factors on stratigraphic integrity. Most sedimentary strata exhibit discontinuities of different scales, represented by both temporal and spatial incompleteness. Defining and quantitatively characterizing "stratigraphic integrity" is of great importance for accurate stratigraphic correlation, reconstructing the depositional history of geological periods, and guiding oil and gas exploration.

2D physical water tank experiments can realistically simulate geological processes such as erosion, transport, deposition, and reworking of clastic materials. These experiments allow for the calculation of stratigraphic integrity at any given location. In this study, a narrow 3D water tank was used to approximate the 2D sedimentary processes, simulating the entire sedimentary sequence of marine (lake) to terrestrial transitional clastic rocks and calculating stratigraphic integrity.

A transparent glass water tank (1.5m×0.5m×0.05m) was chosen as the experimental setup. Based on a thorough review of relevant literature, multiple sedimentary bottom shapes were designed to replicate different real-world geological depositional environments. Specific time steps were set to quantitatively introduce different types of quartz sand, achieving visualization of the experimental results. A water level control curve was designed to change the water level over time, allowing for precise control of water height in the tank and effectively simulating the evolution of stratigraphic sequences. Finally, based on the experimental data, stratigraphic integrity was calculated for various depositional environments, enabling further analysis of the experimental results.

The experimental results clearly reveal the evolution of stratigraphy and depositional sequence features, which closely match actual geological conditions. This indicates that the experiment can realistically simulate the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks. From an overall perspective, erosion near the sediment source is more pronounced and frequent, while at the distal end, the strata remain more complete due to prolonged subaqueous conditions, and erosion is less noticeable. The depositional sequence shows a typical progradation pattern, with thin oblique and wavy bedding structures. Stratigraphic integrity studies show that the integrity increases from the proximal to distal end. A comparison of integrity at the same location shows that horizontal surface fluctuations have a much stronger impact on stratigraphic integrity than changes in the bottom shape, with frequency variations in the water level control curve having a greater effect than changes in amplitude.

This study uses 2D physical water tank experiments to simulate and reconstruct the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks. It also quantifies the influence of geological control factors on stratigraphic integrity. The results demonstrate that both the sedimentary bottom shape and water level change curves affect stratigraphic integrity, with water level changes having a more significant impact. This research is the first to combine 2D water tank simulations with stratigraphic integrity control factors, providing innovative experimental methods and technical tools for sedimentary physical modeling and stratigraphic integrity assessment.

How to cite: Fu, S. and Liu, J.: The Study of Stratigraphic Integrity of Marine (Lake) to Terrestrial Transitional Clastic Rocks Based on 2D Flume Experiments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7676, https://doi.org/10.5194/egusphere-egu25-7676, 2025.

Interplay between environmental drivers and antagonistic biotic interactions shape the niche of species. Understanding the extent to which species retain parameters of their ecological niches amid long-term environmental changes is crucial for numerous palaeoecological inferences applicable to conservation efforts, sequence stratigraphic reconstructions, and macroevolutionary theory. 

The Venus nux association of the Arda and Stirone River sections (Early Pleistocene, western Emilia, northern Italy) has been here analyzed from a systematic and a paleoecological point of view, resulting in the identification of 23 mollusc taxa. As the majority of the retrieved taxa is represented by living species, a comparison between their fossil and present-day environment has been carried out, focusing also on the Venus nux association during the Pliocene of the same region. This research aimed to assess whether the overall bathymetric range and dominance of the bivalve Venus nux have changed over the last 5 million years in the Adriatic basin. Preliminary results indicate a shift in the ecological niche of this common species during a time marked by increasingly pronounced climatic oscillations.

Indeed, currently, V. nux is rarely retrieved in the Adriatic basin, but it is common in the Alboran Sea and the Ibero-Moroccan Gulf (southern Spain), where it thrives in muddy to muddy-sandy substrates at depths between 30 and 350 meters (Salas, 1996), but typically is abundant within 60 and 120 m depth ranges. Conversely, during the Pliocene and Pleistocene geological intervals, V. nux was common in the sedimentary successions of the Adriatic Basin, though it exhibited dominance at different depths and a potentially different bathymetric range. Specimens of V. nux from the Lower Pleistocene Arda and Stirone River sections reveal a shallower bathymetric distribution (20-40 meters of water depth), as evidenced by the co-occurrence in the mollusc association of shallow-water species, like Mytilus edulis and Ostrea edulis. During the warm Pliocene (Zanclean-Piacenzian transition), its bathymetric distribution was slightly deeper than in the cold Early Pleistocene, possibly mirroring current conditions. Although further detailed studies are necessary, it seems that over the past few million years, this species has changed its niche parameters, possibly due to climate shifts.

Salas, C. 1996. Marine bivalves from off the southern Iberian Peninsula collected by the Balgim and Fauna 1 expeditions. Haliotis 25: 33–100.

How to cite: Crippa, G., Chiari, A., Lombardi, M., and Scarponi, D.: The Venus nux association during the Early Pleistocene of the Adriatic Sea: a comparative analysis with its Pliocene and Recent distribution, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16446, https://doi.org/10.5194/egusphere-egu25-16446, 2025.

Anthropogenic global change and environmental degradation lead to not only declines in biodiversity but also the simplification of trophic webs and fundamental changes in biotic interactions as taxa are removed from ecosystems. These changes are currently playing out over time scales of decades and centuries. Still, it would be instructional to understand the relationships between biotic interactions, diversity, and environmental change through deep time. Here, focusing on cephalopods, we quantify the relationships between antagonistic interactions and estimates of diversity, origination rates, and extinction rates. We have compiled a database of antagonistic biotic interactions preserved on fossil cephalopods composed of 279 species occurrences and 148,846 specimens ranging in age from Silurian to Quaternary. Predation occurrences were sparse in the Paleozoic, with peaks in the Jurassic and Cretaceous. We constructed a Generalized Linear Model comparing predation frequency and parasitism prevalence (for samples whose n ≥ 10) to mean standing genus diversity and three-timer origination and extinction rates using data from the Paleobiology Database and the Shareholder Quorum Subsampling methodology available on the FossilWorks website. A significant positive relationship exists between the frequency/prevalence of antagonistic interactions and mean standing diversity. Origination and extinction rates both have significant negative relationships with antagonistic interactions with much higher coefficients than mean standing diversity. We interpret this to mean that the intensity of antagonistic biotic interactions is higher when diversity is elevated but, more importantly, stable. We think this reflects that many of these interactions are obligate and taxon-specific. Ongoing work will include proxy data for temperature and CO2 concentration. As with modern ecosystems, we see evidence for links between diversity loss and the simplification of trophic webs in deep time.

How to cite: Burman, Z., De Baets, K., and Huntley, J. W.: Biodiversity loss and the simplification of trophic webs: Lessons from cephalopods in deep time, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21258, https://doi.org/10.5194/egusphere-egu25-21258, 2025.

The increasing frequency and magnitude of extreme weather events across the Earth's surface results in increasing pressure for living organisms and their habitats, including those in aquatic ecosystems. The main focus of this study is on the resilience of Mediterranean mussels (Mytilus galloprovincialis) against pronounced hydrodynamic stresses that may be experienced more frequently compared to the past. These mussels can be typically found in Mediterranean coasts and estuaries (such as in Greece, Spain, Italy, and Portugal), and they are also extensively farmed in the open sea using aquaculture practices. As such, they are of particular interest given their economic significance for Mediterranean countries, as well as their ecological role (offering significant ecosystem services as "ecosystem engineers", such as coastal protection).
The hydrodynamic stress of Mediterranean mussels is herein assessed indirectly using appropriately designed wave-flume experiments and analyzing video observations of the effects of wave motions of different characteristics on the Mediterranean mussels. For these experiments we embed specialised sensors to these mussels so they can record even minute displacements and changes in their orientation [1, 2]. Specifically, small, medium, and large mussels are exposed to two different configurations (similar to earlier studies [3]) on the surface of an artificial seabed, over which different wave fields are traversing. The movement of individual mussels was visually evaluated under varying wave intensities, transitioning from high to low energy and vice versa. These observations aim to determine the conditions and orientations under which these organisms drift relative to the wave flow direction or remain practically undisturbed. In the context of climate change and its impact on marine environments, this study may provide valuable insights into efforts to protect endangered marine species and enhance strategies for safeguarding aquaculture crops against damage caused by storms or significant wave fields.

References
[1] AlObaidi, K., & Valyrakis, M. (2021). Linking the explicit probability of entrainment of instrumented particles to flow hydrodynamics. Earth Surface Processes and Landforms, 46(12), 2448-2465.
[2] Al-Obaidi, K., & Valyrakis, M. (2021). A sensory instrumented particle for environmental monitoring applications: Development and calibration. IEEE Sensors Journal, 21(8), 10153-10166.
[3] Curley, E.A.M., Valyrakis, M., Thomas, R., Adams, C.E., & Stephen, A. (2021). Smart sensors to predict entrainment of freshwater mussels: A new tool in freshwater habitat assessment. Science of the Total Environment, 787, 147586.

How to cite: Karagianni, E. and Valyrakis, M.: Resilience of Mediterranean Mussels to Hydrodynamic Stresses: Insights for Climate Change Adaptation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2045, https://doi.org/10.5194/egusphere-egu25-2045, 2025.

The exploration of seabed topography is of paramount importance for a wide range of scientific and environmental applications. In deep water, sonar or multibeam technology among others are commonly used to map details of the sea floor, but applying these techniques in shallow waters is challenging due to the complex nature of the submerged terrain. Moreover, these techniques are costly and not accessible for small-scale projects. In recent years, underwater photogrammetry emerged as an effective solution for shallow water bathymetric mapping, bridging the gap between land topography and deep-water bathymetric measurements. Photogrammetry also enables a 3D or 4D visual representation of the submerged terrain, habitats, and objects.

Our research proposes a novel approach applying underwater photogrammetry to generate a 3D model of submerged terrain in shallow-waters over rocky coastline. Using underwater photographs and advanced land surveying techniques, we successfully generated a high-resolution, georeferenced 3D model with detailed geospatial maps covering 162 m² at depths ranging from 1 to 5 meters below sea surface of a submerged upper subtidal zone of a rugged, rocky-coast landscape.

The proposed method offers a practical and affordable tool for shallow water bathymetric mapping over subtidal zones in rocky coasts, providing scientists with geospatial maps, measurements and visual representations for applications in marine research, coastal management, habitat monitoring, or underwater archeology.

How to cite: Elias, A. R. and Khalil, A.: 3D Mapping of Submerged Landscapes: A Cost-Effective Approach to Shallow-Water Bathymetry Using Underwater Photogrammetry, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17381, https://doi.org/10.5194/egusphere-egu25-17381, 2025.

Geological sea-level proxies (e.g., fossil intertidal or foreshore deposits) preserve crucial data that enable the reconstruction of historical sea-level fluctuations. This information is essential for assessing the extension and volume of ice sheets during previous warm periods.

The work aims to present the results of a morpho-stratigraphic field campaign conducted along the southern Brazilian coast, from Osório (Rio Grande do Sul) to Paranaguá (Paraná). A classical geological and geomorphological approach was coupled with a literature review of the geological sea-level proxies related to Marine Isotope Stage (MIS) 5 from the coast of Uruguay to São Paulo. Samples from shallow-water marine sand and aeolian deposits have been analysed using granulometric and micropaleontological methods, in addition to direct dating with the Optically Stimulated Luminescence (OSL) technique. The elevation of each proxy was measured with centimetric precision using a GNSS RTK station and referenced to the local geoid model (MAPGEO2015), with an associated error margin of only a few centimetres.

Preliminary findings indicate that vertical land movements, both associated with glacial isostatic adjustment and sediment isostatic rebound, may have played a key role in the accumulation of Late Pleistocene marine and aeolian deposits, positioning them several meters above sea level at odds with global mean sea level position.

This presentation contributes to the WARMCOASTS project, which received funding from the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant agreement n. 802414).

How to cite: Cerrone, C., Lämmle, L., Perez Filho, A., Scicchitano, G., Jovane, L., Tagliaro, G. T., Mitrovica, J. X., Stocchi, P., and Rovere, A.: Pleistocene morpho-stratigraphy and vertical land motions on the South Brazil-Uruguay coastal plain, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12417, https://doi.org/10.5194/egusphere-egu25-12417, 2025.

Accurate assessment of coastal vulnerability is crucial for effective coastal risk management, especially in the context of increasing human pressure. One common approach to evaluating coastal erosion risk involves the use of geomorphological-based indices. These indices typically combine various physical factors such as: shoreline changes with historical and recent trends in coastline movement (erosion or accretion); dune and beach geometry (slope, dune height, and width); presence and type of vegetation, which can stabilize or destabilize the coastline; coastal infrastructure. the presence and type of human-made structures, such as seawalls and groins, which can impact coastal processes. These factors are often assigned weights or ranks to create a vulnerability classification, allowing for the identification of areas at higher risk of erosion. This approach provides a valuable framework for understanding the inherent susceptibility of a coastline to erosion. However, it is important to highlight that this is a simplified representation of complex coastal processes. Geomorphological indices offer a valuable tool for initial assessments of coastal vulnerability. Nevertheless, they should be used in conjunction with other data sources and analyses to gain a more comprehensive understanding of coastal processes. This study investigates coastal vulnerability along a coastline in Basilicata, southern Italy. The region faces significant coastal erosion due to a combination of natural factors and human impacts. To assess vulnerability, the study employs a multi-scale approach based on:  i) Coastal Erosion Susceptibility Index (CESI), this index evaluates the inherent susceptibility of the coastline to erosion based on factors like shoreline changes, dune and beach geometry, and vegetation. The results identified "hotspots" – areas with the highest level of susceptibility of coastal erosion; ii) High-resolution LiDAR Surveys, Unmanned Aerial Vehicles (UAVs) equipped with LiDAR sensors were used to create detailed 3D models of the coastline. By comparing LiDAR data from 2013 and 2023, we quantified the extent of coastal erosion and identified specific areas of significant change. This study demonstrates the effectiveness of integrating spatial data derived by indices with high-resolution LiDAR data for comprehensive coastal vulnerability assessment. This approach provides valuable insights for coastal managers in developing effective adaptation strategies to address the challenges posed by coastal erosion in the context of climate change and sea-level rise.

Founded by: Progetto PE 0000020 CHANGES, - CUP [B53C22003890006], Spoke 7, PNRR Missione 4 Componente 2 Investimento 1.3, finanziato dall’Unione europea – NextGenerationEU

How to cite: Minervino Amodio, A., Corrado, G., Di Paola, G., Rizzo, A., and Gioia, D.: Investigating Coastal Erosion Hotspots: A Multiscale Approach applied along the Basilicata Ionian coast (Southern Italy), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13498, https://doi.org/10.5194/egusphere-egu25-13498, 2025.

Quantitative analysis of drainage networks is one of the most used approaches for the investigation of the response of landscape to tectonic forcing and crustal deformation in different geodynamic setting. Recently, river profile inversion has largely been used for the reconstruction of spatial and temporal distribution of uplift in tectonically-active landscapes. The calibration of the erodibility coefficient of the river profile is particularly effective in coastal landscapes, due to the diffuse presence of independent geomorphic markers of the tectonic uplift such as the marine terraces. In this work, we estimated the uplift history of a large sector of the Ionian sector of South-Apennine chain by inverse modelling of river profiles. The landscape is dominated by the presence of several well-preserved orders of marine terraces, which are deeply incised by a trellis-type fluvial net. Several factors such as uniform lithology and well-constrained chronology of several orders of marine terraces provided a favourable setting for the robust application of the modeling of river profiles. The study area includes a large sector of the Ionian coast between Taranto and northern Calabria. southern Italy. From a geological viewpoint, the studied catchments transversally drain the outer zone of the chain to the south and the foredeep-foreland system to the north. Middle Pleistocene deformation in the external sector of the chain has been already demonstrated while the late Quaternary activity of the frontal thrust belt is more debated. Our reconstruction of the spatial and temporal increase of uplift rates to the south can contribute to unravel the recent/active deformation along the buried front of the chain.

How to cite: Gioia, D., Cerrone, C., Corrado, G., De Santis, V., Minervino Amodio, A., and Schiattarella, M.: Uplift history of the Taranto Gulf (southern Italy) from river profile inversion, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17790, https://doi.org/10.5194/egusphere-egu25-17790, 2025.

This research investigates the alongshore variability of shoreline and dune line responses to storm events and long-term changes on Culatra Island, located in the Algarve region of Portugal utilizing a combination of LiDAR data, satellite imagery, and numerical models (ShorelineS and SnapWave). Using a dune model based on Larson et al. (2016), integrated within the ShorelineS framework, to analyze the dynamic interactions between dune erosion, overwash by waves, and dune growth driven by aeolian (wind) transport. These interactions are critical in understanding the long-term and storm-induced changes in shoreline positions.

The calibrated ShorelineS model, supported by SnapWave's wave data, reveals that longshore transport gradients are the predominant drivers of shoreline change, significantly influenced by southeast prevailing waves, shallow active heights at the ebb delta, and the presence of the western breakwater.

By simplifying these processes into a 1D sand balance equation, where dune interactions are treated as source and sink terms, the model effectively captures several key dynamics of coastal morphology. However, certain idealizations, such as the assumed dune vegetation lines and simplified coastal profiles, result in some processes, like overwash, not being fully represented.

To ensure the accuracy and reliability of the model outputs, extensive sensitivity analyses were conducted with parameters such as impact coefficient Cs, median grain size d50, wave output points distances, and sediment transport factor (qscal). Validation of the ShorelineS model against 2011 DEM data and satellite trends reveals varying degrees of accuracy. For shoreline positions, the model demonstrates a strong positive correlation with DEM data (R² = 0.78) and even better alignment with satellite trends (R² = 0.85). However, the model's predictions for dune positions exhibit higher variability and weaker correlations with DEM data (R² = 0.47), indicating significant discrepancies. Interestingly, the model shows a stronger positive correlation with satellite trends for dunes (slope = 0.96).

The research identifies several key factors contributing to alongshore variability in dune and shoreline responses during storm events, including initial berm width, storm duration, wave height, and cumulative sediment transport due to dune erosion. Notably, dune responses exhibit higher sensitivity to these coastal parameters compared to shoreline responses, with cumulative sediment transport being a significant driver of dune change (Corr: -0.86).

Overall, this study highlights the critical need for integrating comprehensive modeling approaches with empirical data to inform coastal management practices. It offers a robust framework for future research aimed at enhancing the sustainability and resilience of coastal environments.

How to cite: Dabu, R., Roelvink, D., van Dongeren, A., and Garzon, J.: Alongshore Varying Dune Retreat at a Barrier Island, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-770, https://doi.org/10.5194/egusphere-egu25-770, 2025.

The EcoDaLLi project is an integrative initiative designed to contribute to the European Green Deal’s freshwater objectives by supporting the restoration, protection, and sustainable management of the Danube River Basin and its delta. As part of the broader mission "Restore Our Ocean, Seas & Waters by 2030," the project employs a systemic approach to ecosystem restoration through the implementation of innovative solutions and improved governance frameworks. By focusing on the Danube Basin, one of Europe’s most ecologically significant areas, EcoDaLLi aims to strengthen climate resilience, enhance biodiversity conservation, and promote sustainable water resource management. Additionally, Unitatea Executivă pentru Finanțarea Învățământului Superior, a Cercetării, Dezvoltării și Inovării (UEFISCDI) from Romania has awarded a special funding grant to support the present research.

A core scientific objective of the project is to document and analyze the dynamic behavior of the water surfaces in the Danube Basin. The present research relies on satellite radar imagery from the Sentinel-1 constellation, made available through the Copernicus Program. The radar data’s ability to penetrate cloud cover and record consistent surface reflections makes it highly suitable for long-term multi-temporal monitoring of water bodies, especially in a complex and variable environment such as the Danube Delta.

The initial phase involves the systematic collection of radar imagery, focusing on the VV polarization channel, which offers superior water isolation characteristics compared to other channels. In the second phase, a rigorous preprocessing workflow is applied to the raw imagery, including orbital corrections, radiometric normalization, and noise reduction. These steps are critical for ensuring data consistency and enabling precise extraction of water body extents. The processed data is then subjected to detailed geospatial analysis using advanced GIS tools, enabling the derivation of key hydrological metrics. These metrics include maximum and minimum water extent, presence and recurrence of water bodies, and seasonal variations.

The analysis will employ methodologies such as Continuous Change Detection and Classification (CCDC) to track and quantify spatial and temporal changes across the monitored lakes. Statistical models will further be used to correlate observed hydrological changes with climatic and environmental factors. The resulting datasets will provide a robust foundation for understanding the long-term hydrological dynamics of the Danube Delta’s lakes and their role in regional ecosystem functioning. Moreover, the results will offer guidelines for local and regional stakeholders, supporting evidence-based policy-making and adaptive management strategies.

Acknowledgments

This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS/CCCDI - UEFISCDI, project number PN-IV-P8-8.1-PRE-HE-ORG-2023-0089, within PNCDI IV.

How to cite: Toma, A. and Scrieciu, A.: Assessing Long-Term Water Dynamics in the Danube Delta Lakes using Sentinel-1 Radar Imagery, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8615, https://doi.org/10.5194/egusphere-egu25-8615, 2025.

The Portuguese spatial planning legislation includes legal restrictions to land use in order to preserve the ecosystems. These restrictions are framed by the legal structure called National Ecological Reserve (NER), and have associated a cartographic representation. Among the land use protection areas included in the NER are the Areas of High Risk of Soil Hydric Erosion (AHRSHE). Our goal is to improve the models and derived cartography and to use the enhanced maps as a basis to test and apply new and more advanced technologies, data and methods.

Currently, AHRSHE are determined based on USLE. The computation of the LS factor in this equation has been a challenging issue and, since this action is a legal responsibility of the municipalities, we could face a situation where different municipalities use different methodologies and, eventually, the results being not comparable. Thus, efforts have being made in order to produce a common methodology to standardise and enhance the cartographic representation of the LS, namely, by improving its accuracy and precision and by harmonizing and making it compatible with the other USLE factors. For this purpose, several methods of LS computation have been tested to evaluate soil loss risk in different geomorphic contexts. Based on the test results USLE's second revision, RUSLE2 (USDA, 2008), was selected together with imposing a maximum value to unorganised runoff length (L).

The results of using RUSLE2 might be affected by the lack of information on detailed soil properties caused by different geomorphological contexts and the lack of resolution of the Digital Terrain Model (DTM) to accurately identify the AHRSHE. The lack of DTM resolution affects the slope values (S), the shape of the hydrographic network and, above all, the delimitation of the disorganized flow domain, where AHRSHE are mapped.

In order to reach an acceptable solution, tests were made with varying maximum unorganized runoff length (L) and using different formulas to determine S, according hillslope values and rainfall regime. The test results show that the more accurate LS is obtained when L is limited to 305 m and S is calculated according to slope thresholds: below and above 9% (Panagos, et al., 2015) or above 18% (Liu, 1994; 2002), and excluding areas where the USLE is not applicable, like plane surfaces, water, or surfaces with high slopes.

Another conclusion was that small resolution DTM are inappropriate which lead us to use in the tests a 10m pixel DTM. Even so, and in order to prevent unjustified land use restrictions, we suggest the need to validate the results (by sampling), at least in specific geomorphologic contexts. Otherwise, the likelihood to get biased results, with adverse practical effects, will be high.

The shape and accuracy of AHRSHE depend on the methodologies and georeferenced data used. Thus, we intend to use, in the near future, a very-high resolution DTM derived from aerial LiDAR and to work on the identification of differentiated geomorphological contexts in each municipality in order to further improve the AHRSHE mapping, which have substantial impacts in the NER.

How to cite: Silva, A. and Reis, R.: Criteria to Map Areas of High Risk of Soil Hydric Erosion in Portugal using USLE, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20437, https://doi.org/10.5194/egusphere-egu25-20437, 2025.

As decision support methods (including as Artificial Intelligence supported decision making) progress, new ways and frameworks are emerging to enhance our understanding of sediment transport processes (via improved monitoring), but also better modeling those phenomena. This study offers a preliminary view of how deep learning models can link with real-time data from instrumented sediment particles, to predict the risk of bed surface destabilization in channels and rivers, which can lead to infrastructure scour. 
Specifically, three deep learning models are analyzed, herein: a) Long Short-Term Memory (LSTM), b) Gated Recurrent Units (GRU), and c) Transformers. These models were compared according to their accuracy, computational efficiency, and suitability for real-time applications.This study integrates data from specifically designed sediment stability monitoring sensors [1-3], with three deep learning models to predict the possibility that sediment is transported along the bed surface of the river [4], in real time. This is important for a series of applications, such as flood risk management, assessment of hazards to hydraulic infrastructure and water resource management, helping achieve resilient and sustainable development under a changing climate change. Future studies can explore further improving the efficiency of sensor enabled novel hydroinformatics approaches.

References
[1] Al-Obaidi, K., Xu, Y., & Valyrakis, M. (2020). The design and calibration of instrumented particles for assessing water infrastructure hazards. Journal of Sensor and Actuator Networks, 9(3), 36.
[2] AlObaidi, K., & Valyrakis, M. (2021). Linking the explicit probability of entrainment of instrumented particles to flow hydrodynamics. Earth Surface Processes and Landforms, 46(12), 2448-2465.
[3] Al-Obaidi, K., & Valyrakis, M. (2021). A sensory instrumented particle for environmental monitoring applications: Development and calibration. IEEE Sensors Journal, 21(8), 10153-10166.
[4] Valyrakis, M., Diplas, P., & Dancey, C. L. (2011). Prediction of coarse particle movement with adaptive neuro‐fuzzy inference systems. Hydrological Processes, 25(22), 3513-3524.

How to cite: Mavris, I. and Valyrakis, M.: Towards Enhancing River Bed Stability Assessment: A Comparative Study of LSTM, GRU, and Transformer Predictive Models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2032, https://doi.org/10.5194/egusphere-egu25-2032, 2025.

Coastal Zone Management Act (CZMA) areas in the United States are critical regions where coastal development and environmental conservation converge. Over 50 years, the CZMA has established a federal framework for state-level coastal management, fostering resilience to dynamic challenges. However, these regions increasingly face compounding risks from hazards such as sea-level rise, storm surges, and extreme precipitation, compounded by socio-economic vulnerabilities and geomorphological dynamics.

This study develops a geospatial framework for multi-hazard risk assessment in CZMA areas, integrating geomorphic and sedimentological characteristics with high-resolution datasets and socio-economic indicators to compute a detailed risk index. High-resolution datasets, including satellite-derived shoreline positions and wave and tidal records, are integrated with advanced geospatial and machine learning models, to enhance spatial and temporal projections. Future climate scenarios (2030, 2050, 2100) from CMIP6 datasets are used to assess long-term impacts of sea-level rise and extreme events, with scenario-based modeling addressing uncertainties across different emissions and socioeconomic pathways.

Preliminary findings reveal significant heterogeneity in risk distribution across CZMA areas, with low-elevation coastal plains, deltas, and lagoons identified as the most vulnerable due to geomorphic sensitivity and several challenges to protect them. Our comprehensive map highlights hotspots where erosion, flooding, and socio-economic disparities converge, enabling tailored adaptation strategies. This research bridges policy and science by integrating CZMA legal frameworks with geospatial and technological innovations, offering a scalable and transferable methodology for assessing and managing coastal multi-hazard risks globally.

How to cite: Poudel, S., Bista, S., and Talchabhadel, R.: Multi-Hazard Risk Assessment in CZMA Areas: A Geospatial Framework Integrating Future Climate Projections, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14644, https://doi.org/10.5194/egusphere-egu25-14644, 2025.

Glaciers have retreated since the maximum extent of the “Little Ice Age” around c. 1850. The barren forefields provide a unique opportunity to study the development of an emerging ecosystem from its early stages to better understand successional mechanisms, community assembly and underlying filtering processes. While previous studies have primarily focused on the Central Alps, there remains a knowledge gap regarding succession for the forefields in the Northern Limestone Alps. The aim of this new monitoring platform is to gain a more comprehensive understanding of vegetation dynamics in the context of ecosystem succession in glacier forefields of this region. To this end, the chronosequence approach is applied across four glacier forefields, namely Hallstätter Glacier, Great Gosau Glacier (both in Dachstein mountains, Austria), Watzmann Glacier and Blaueis (both in Berchtesgaden Alps, Germany). Integrated, interdisciplinary methods are used for long-term monitoring and assessment of succession processes. From Vegetation monitoring which follows GLORIA guidelines, selected trait measurements, analysis of ancient DNA pools in ice lake sediments, abiotic site characterization including temperature recording and substrate sampling, to remote sensing methods we want to provide a whole picture of this dynamic environment. First results shows that species richness, abundance increase with age. However, these trends occur at a much slower rate than observed in the Central Alps. Initial trait analyses based on database entries revealed only a few clear patterns along the age gradient. In-depth analyses using trait field measurements are still underway. Additionally, environmental parameters seem to play a role in shaping succession, indicating that abiotic factors may significantly influence the pace and pattern of ecosystem development in the glacier forefields of the Northern Limestone Alps.

How to cite: Hecht, C.: Monitoring and research on succession in glacier forefields of the Northern Limestone Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12335, https://doi.org/10.5194/egusphere-egu25-12335, 2025.

Due global warming, rock glaciers were increased after the glaciers retreated rapidly. Rock glaciers, as an important indicators of mountain permafrost, play a critical role in mountain hydrology. The Gaizi River Basin, located in Pamir plateau and even has the Muztag-Ata (7,509m) and Gongger (7,719m) massifs. Comprehensive studies on distribution characterizations of rock glaciers in this region are currently in the incipient stages. Using Chinese high spatial resolution GF-2 Satellite images and Google Earth, a total of 56 rock glaciers were identified. Their spatial distribution and relationship with local factors were studied. Following the guidelines of the International Permafrost Association, out of the 56 rock glaciers, 9 are glacier-connected, 16 are glacier-forefield connected, 19 are talus-connected, and 12 are debris-mantled slope-connected. The rock glaciers are situated at slopes of 12゜–37゜ and elevations between 3380 m and 5320 m a.s.l. and predominantly facing north, northwest, or northeast (54.5 %). The average annual precipitation ranges from 26 mm to 350 mm and annual air temperature of the rock glaciers ranges from -13.5 ^。C to 3.9 ^。C. The rock glaciers can be used to quantify water storages and investigate the extent of permafrost and therefore carry significance in study their response to climate change.

How to cite: Liu, Y.: The distribution characteristics of rock glaciers in the Gaizi River Basin, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12331, https://doi.org/10.5194/egusphere-egu25-12331, 2025.

Over the past 50 years, coral reefs have experienced a global decline due to the combined effects of human activities and climate change. Historical data on reef communities prior to significant human impacts in tropical regions is scarce, with only a few locations benefiting from long-term monitoring efforts. Pleistocene coral reefs, where preserved, provide valuable baselines for understanding the evolution of modern reef ecosystems. In this study, we compare the evolution of coral reef communities on the island of Curaçao (Leeward Antilles, Caribbean) between 1973 and 2023 with the dynamics of reef communities in Last Interglacial fossil reefs on the islands of Aruba, Curaçao, and Bonaire. Our findings reveal that modern reefs in the ABC islands, under increasing pressures from overpopulation, overfishing, coastal pollution, and invasive species, are being driven into uncharted territory, exhibiting conditions unmatched even by their fossil counterparts from the Last Interglacial period.

How to cite: Stocchi, P., Boyden, P. T., Rovere, A., Haas, A. F., El-Khaled, Y. C., Bejarano, S., Wild, C., Mijts, E., Scicchitano, G., and Vermeij, M.: Coral reefs of the Leeward Antilles (SouthernCaribbean) steered into unchartered waters byhuman impacts, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21691, https://doi.org/10.5194/egusphere-egu25-21691, 2025.