Abstract. This study presents high-resolution hydroacoustic datasets covering over 7000 km2 of Polish Marine Areas in the Southern Baltic, acquired between April 2022 and December 2023 as part of a national initiative to map benthic habitats using advanced sonar technologies. Utilizing a fleet of seven vessels and the expertise of approximately 250 personnel, the project collected bathymetric and side-scan sonar data along more than 95 000 km of survey lines, adhering to International Hydrographic Organization S-44 Order 1a standards. The resulting datasets include detailed bathymetric grids at 50 cm×50 cm resolution and side-scan sonar backscatter mosaics at 20 cm×20 cm resolution, with robust quality control ensuring at least 95 % data completeness per grid cell. These data provide unprecedented insight into the underwater topography and sediment characteristics of the region, supporting applications in scientific research, environmental management, offshore wind farm planning, and underwater archaeology. The datasets, available at DOI: https://doi.org/10.26408/southern-baltic-hydroacoustic-datasets (Janowski et al., 2025), lay a solid foundation for future studies and the development of science-informed policies to promote sustainable and resilient marine ecosystems in the Baltic Sea.

The article analyzes ritual ceramics from Lake Amatitlan, decorated with Teotihuacan glyphs. Amatitlan is a freshwater lake located in the Republic of Guatemala. For a long peri-od of time, Lake Amatitlan was a site of pilgrimage and various water rituals for the ancient Maya. Ritual ceramics and other offerings to the lake's waters dating from the Preclassic to the Postclassic periods have been discovered on the bottom of the lake by underwater ar-chaeologists. Many of these objects are made in the Teotihuacan style, reflecting the cultural and economic connections between Teotihuacan and the Guatemalan Highlands. Of par-ticular interest to this study is the archaeological site Mejicanos, located on the southern shore of Lake Amatitlan. Mejicanos was an important center of Teotihuacan culture during the Classic period. Ceramics discovered at the Mejicanos site are often decorated with iconographic elements in Teotihuacan style. Some incense burners feature Teotihuacan-style glyphs, including “Reptile’s Eye” and “Tlaloc” glyphs.

This article presents the typological and chemical analysis of a small glass assemblage recovered from a, likely Dutch, early 17th-century shipwreck known as Barco de las Pipas, found off the coast of the Province of Montecristi, Dominican Republic. All fifteen glass fragments recovered during underwater excavation were typologically characterised, sampled, and analysed using Electron Micro-Probe Analysis (EMPA) for major and minor elements and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) for trace elements to determine their provenance. The results of this analysis are compared with existing datasets of 16th- and 17th-century European glass, and their potential raw ingredients and technology are assessed. In addition, arguments are presented to challenge several long-held assumptions concerning glassmaking on the European continent during the seventeenth century, including the poorer quality of some Western European plant ashes, compared to Levantine ones. Finally, the paper highlights the potential of the approach for future studies investigating the nature of transatlantic trade in the Early Modern Period.

New Book Chronicle: Maritime and underwater archaeology

Abstract. The study and preservation of fragile organic artefacts represent an ongoing challenge in cultural heritage conservation, particularly when traditional physical reconstruction is unfeasible due to degradation or fragmentation. This paper provides a state-of-the-art review of digital documentation and reconstruction practices for organic materials such as leather, textiles, and wood, with an emphasis on their material characteristics, conservation risks, and computational potential. Central to this discussion is a case study of a 12th-century leather bag recovered from an underwater excavation in the port of Rhodes Island. The study combines close-range photogrammetry, laser scanning, and recent AI-driven methods, including Neural Radiance Fields (NeRF) and Gaussian Splatting, to propose a replicable and transparent workflow for the non-invasive documentation and digital reassembly of fragile artefacts. The paper also explores the role of interdisciplinary collaboration, semantic annotation, and interactive visualization in enhancing interpretative accuracy and public accessibility. The findings underscore the need for methodological transparency, data traceability, and ethical considerations in the digital management of vulnerable cultural heritage.

Abstract. Photogrammetry has become a widely adopted method in underwater archaeology worldwide and is increasingly used in Korean land-based archaeological investigations. However, its application in Korean underwater sites has been challenging due to strong currents and low visibility. This study examines photogrammetric applications in two Korean underwater sites: Jeju Sinchang-ri, where relatively clear visibility allowed for the creation of detailed site maps, and Gunsan Seonyudo, where sedimentation and low visibility required experimental approaches. At Sinchang-ri, a photogrammetric survey was conducted with a Double Grid method and 10-meter grid units, enabling the production of plan before and after dredging and an artifact distribution map. High-resolution data was acquired using Metashape, resulting in 3D models and orthophotos that effectively visualized site distribution. In contrast, at Seonyudo, the presence of 1-meter-thick sediment made high-resolution artifact mapping difficult. To address this, experimental approaches were tested, including adjusting survey timing based on tidal changes and using underwater lighting for stratigraphic recording. This resulted in the creation of plan of trenches and stratigraphic cross-sections, distinguishing artifact-bearing layers from non-artifact-bearing ones. These case studies highlight the need to refine photogrammetric techniques to suit different underwater environments. As more shipwrecks are discovered, the advancement of photogrammetric methodologies will contribute to more effective underwater surveys and documentation.

Underwater archeology faces significant challenges in sampling sunken ships and buried artifacts, including high operational risks, low efficiency, high deployment costs, and potential damage to underwater cultural heritage. To address these issues, this paper presents the design and development of a biomimetic peristaltic robot inspired by the motion of earthworms. The robot comprises three primary components: a drilling mechanism, a peristaltic mechanism, and a transmission mechanism. The peristaltic mechanism features a multi-segment, serially connected Sarrus linkage module, with motion transmission achieved through a cylindrical cam mechanism. The profile of the cylindrical cam groove is precisely calculated based on the planned motion sequence. Additionally, an optimization scheme incorporating a dual-roller follower configuration for each slider unit is proposed to minimize sliding resistance at the ring slider of the Sarrus linkage module. To enable passive bending and passive steering, the cylindrical cam is segmented and connected via flexible shafts, bellows, and compression springs. A static analysis of key components is performed to ensure structural integrity and reliability. Finally, prototype experiments validate the robot’s capabilities in peristaltic motion, bending, and burrowing.

The objective of this article is to provide a critical analysis of maritime heterotopia as a category for reinterpreting ships, shipwrecks and maritime landscapes between the 16th and 18th centuries. Through an interdisciplinary approach combining history, underwater archaeology, heritage theory and literary analysis, it explores the ways in which maritime spaces, especially ships and shipwrecks, functioned as ‘other spaces’–following Foucault’s concept of heterotopia–in the articulation of imperial projects, power relations, experiences of transit and narratives of memory. A particular focus has been placed on the examination of shipwreck accounts, which are regarded as microhistories of human behaviour in contexts of crisis. These accounts have been shown to offer insights into alternative social structures, dynamics of authority, and manifestations of violence or solidarity. A review of the legal framework and practices related to shipwrecks in the Spanish Carrera de Indias is also undertaken, with particular emphasis on their impact on maritime legislation and international law. This article proposes a reading of maritime heritage as a symbolic and political device in constant dispute, where material remains and associated narratives shape collective memories, geopolitical tensions and new forms of cultural appropriation. Shipwrecks thus become sites of rupture and origin, charged with utopian, dystopian and heterotopic potential.

Underwater images frequently experience significant color distortion, diminished contrast, and decreased visibility. These issues arise due to the selective absorption and scattering of light in aquatic environments. This study introduces an innovative method for enhancing the quality of underwater images through the implementation of adaptive color correction and detail-preserving fusion techniques. The approach addresses the attenuation of red and blue color channels, followed by an adaptive fusion process that enhances contrast and texture while maintaining intricate image details. The findings reveal notable advancements compared to current state-of-the-art techniques, as assessed by widely recognized metrics including the Perceptual Color Quality Index (PCQI), the Underwater Image Quality Measure (UIQM), and the Underwater Color Image Quality Evaluation (UCIQE). Specifically, the method achieves a PCQI score of 1.00 on test shipwreck images, demonstrating a significant improvement in color quality. The enhanced images exhibit more accurate color representation, improved sharpness, and higher contrast, making them suitable for both human observation and further computer vision applications. Additionally, the segmentation performance, as measured by the Geodesic Active Contours (GAC++) algorithm, is markedly improved on the enhanced images, demonstrating the practical utility of the proposed approach for underwater image analysis and object detection. This work sets a new standard for underwater image enhancement, facilitating its application in fields such as marine biology, underwater archaeology, and robotic vision systems.

Subterranean exploration in submerged granular media (GM) presents significant challenges for robotic systems due to high drag forces and the complex physics of GM. This paper introduces a robotic system that combines water-jet-based fluidization for self-burrowing in submerged environments and an untethered, volume-change mechanism for burrowing out. The water-based fluidization approach significantly reduces drag on the robot, allowing it to burrow into GM with minimal force. To burrow out, the robot uses a soft, inflatable bladder that undergoes periodic radial expansion, inspired by natural systems such as razor clams. Experimental results demonstrate that increased water flow rates accelerate the burrowing process, while the unburrowing mechanism is effective at varying depths. Comparisons between pneumatic and hydraulic untethered systems highlight trade-offs in terms of operational time and unburrowing speed. This work advances the capabilities of robots in underwater environments, with potential applications in environmental monitoring and underwater archaeology.

Obtaining high-quality images of Limulidae in amphibious environments is a challenging task due to insufficient light and the complex optical properties of water, such as light absorption and scattering, which often result in low contrast, color distortion, and blurring. These issues severely impact applications like nocturnal biological monitoring, underwater archaeology, and resource exploration. Traditional image enhancement methods struggle with the complex degradation of such images, but recent advancements in deep learning have shown promise. This paper proposes a novel method for amphibious low-light image enhancement based on hybrid Mamba, which integrates wavelet transform, Discrete Cosine Transform (DCT), and Fast Fourier Transform (FFT) within the Mamba framework. Wavelet transform effectively decomposes images at multiple scales, capturing feature information at different frequencies and excelling in noise removal and detail preservation, whereas DCT concentrates and compresses image energy, aiding in the restoration of high-frequency components and improving clarity. FFT provides efficient frequency domain analysis, accurately locating key information in the image spectrum and enhancing image quality. Mamba, as an emerging optimization strategy, offers unique computational characteristics and optimization capabilities, making it well suited for this task. The main contributions include the construction of the amphibious low-light image dataset (ALID) in collaboration with the Beibu Gulf Key Laboratory of Marine Biodiversity Conservation and the introduction of the hybrid Mamba method. Extensive experiments on the ALID dataset demonstrate that our method outperforms state-of-the-art approaches in both subjective visual assessment and quantitative analysis, achieving superior results in brightness enhancement and detail reconstruction, thus paving new paths for amphibious low-light image processing and promoting further development in related industries and research.

Underwater image enhancement (UIE) technology plays a vital role in marine resource exploration, environmental monitoring, and underwater archaeology. However, due to the absorption and scattering of light in underwater environments, images often suffer from blurred details, color distortion, and low contrast, which seriously affect the usability of underwater images. To address the above limitations, a lightweight transformer-based model (LITM) is proposed for improving underwater degraded images. Firstly, our proposed method utilizes a lightweight RGB transformer enhancer (LRTE) that uses efficient channel attention blocks to capture local detail features in the RGB domain. Subsequently, a lightweight HSV transformer encoder (LHTE) is utilized to extract global brightness, color, and saturation from the hue–saturation–value (HSV) domain. Finally, we propose a multi-modal integration block (MMIB) to effectively fuse enhanced information from the RGB and HSV pathways, as well as the input image. Our proposed LITM method significantly outperforms state-of-the-art methods, achieving a peak signal-to-noise ratio (PSNR) of 26.70 and a structural similarity index (SSIM) of 0.9405 on the LSUI dataset. Furthermore, the designed method also exhibits good generality and adaptability on unpaired datasets.

Abstract. Underwater archaeology has historically depended on geophysical and remote sensing technology to identify and document submerged archaeological sites and shipwrecks. Acoustic remote sensing for seabed archaeology developed from sonar systems originally designed for military use and geological exploration. These systems assess the physical characteristics of the seafloor, particularly backscatter and water depth, by emitting acoustic energy towards the bottom and capturing the arrival times and directions of the returning acoustic signals. These methods are efficient in data acquisition and yield results that are both repeatable and quantifiable.In recent decades, significant advancements in marine geophysical techniques have afforded the maritime archaeological community remarkable opportunities to redefine site mapping, evaluation, and monitoring procedures. The introduction of very-high resolution sonar systems has made it possible to determine the three-dimensional shapes of submerged objects, providing an invaluable resource for identifying and characterizing archaeological assets on the seabed.In this work we present the preliminary results of an acoustic remote sensing survey conducted with the latest generation of ultra-high resolution (UHR) multibeam echo-sounders (MBES) in the Baia submerged park (southern Italy). These systems integrates advanced acoustic array geometry, high-precision inertial navigation and positioning systems that can rapidly generate massive point clouds of millions of individual bathymetric measurements with unprecedented resolution and accuracy. The exceptionally high density of these measurements lead to the development of multiresolution models, which can be effectively utilized for interactive 3D visualization on digital platforms.

Abstract. 3D reconstructions in underwater environments face significant challenges due to poor image quality, caused by blurring, reduced contrast, color distortion, and inadequate lighting. This study investigates the impact of various image enhancement techniques on underwater 3D reconstruction, focusing on Contrast Limited Adaptive Histogram Equalization (CLAHE), RGB Histogram Stretching (RGHS), and a combined approach integrating RGB stretching with CLAHE. Three real-world underwater datasets were analyzed to assess the effectiveness of these methods in improving the accuracy and completeness of reconstructed 3D models. Notably, the RGB-CLAHE combination achieved the most substantial improvements, increasing reconstructed points by 7.60%, detected features by 7.56%, and reconstructed features by 12.94% on average across the datasets. However, the enhancement methods did not improve performance in certain cases, underscoring the need for a robust evaluation methodology to determine the most suitable technique for each dataset. These findings support the design and development of adaptive evaluation frameworks alongside advanced enhancement strategies, enabling more accurate and detailed analysis of submerged environments. Such approaches have the potential to benefit a wide range of scientific and industrial applications, including marine research, underwater archaeology, and inspection tasks.

The North American Great Lakes offer a dynamic case study of inundated cultural landscapes. These bodies of water and the life around them have never been static. While submerged lands offer avenues for archaeological research, it is essential to first understand that these cultural landscapes have also been flooded with invasive power dynamics through settler colonialism. For example, the land and water systems in Anishinaabe Akiing (the northern Great Lakes) have fundamentally shifted from flourishing life systems to poisoned areas and now struggle to deal with invasive species. When seeking to learn from or otherwise engage Indigenous knowledge, it is essential to work from a perspective that takes all these changes into consideration. There are Indigenous communities who are interested in these inundated landscapes, and in this research, but a pause, naandamo, is needed to ethically consider the ongoing process of settler colonialism and Indigenous perspectives. Here we address ethical considerations for researchers participating in, or interested in participating in, submerged site research. By incorporating settler colonialism as a methodology of understanding, we will provide an ethical starting place for working with Indigenous communities and inundated landscapes.

In cutter suction dredger (CSD) operations, direct visual assessment of underwater soil composition and terrain is unavailable to operators. This limitation necessitates reliance on indirect indicators, such as concentration meter readings, interpreted through the operator’s accumulated experience. However, concentration meters are typically installed at the stern of CSDs rather than near the cutter head, introducing significant time delays in the recorded signals. Consequently, these signals fail to provide real-time feedback on the cutter head’s excavation states. To address this challenge, this paper proposes a novel framework based on long sequence time-series forecasting for multi-step prediction of dredged slurry concentration. The framework aims to enable early assessment of underwater excavation states, thereby supporting timely decision making by operators. The study begins by identifying characteristic indicators related to slurry concentration through a detailed analysis of the excavation process. These indicators are then screened to construct a subset of relevant features. Furthermore, a velocity-integrated time compensation method is used to temporally align concentration data with other feature data. The proposed ITCNet model is evaluated against four baseline models using real-world construction data from CSD operations. Results demonstrate that the ITCNet delivers consistent multi-step predictions with minimal errors over a 15 s horizon, providing operators with ample time to respond to dynamic changes. Compared to baseline models, the ITCNet achieves superior accuracy across key metrics, empowering operators to make proactive and informed decisions.

Underwater image quality often deteriorates, posing significant challenges in extracting underwater information and affecting advanced visual tasks, for instance, tasks in various fields such as oceanography, marine biology, underwater exploration, underwater archaeology, environmental monitoring, and marine engineering. To overcome these issues, many recent methods have attempted various techniques. Most of them focus solely on a single factor, such as visibility recovery or contrast enhancement, while neglecting the overall improvement of image quality. In this paper we propose a multi-task hybrid fusion method (MHF-UIE) for real-world underwater image enhancement by tackling problems such as color distortion, poor visibility, and low contrast. This is achieved through color correction using the gray world assumption, visibility recovery via type-II fuzzy sets, and contrast enhancement with curve transformations. Our experimental results indicate that MHF-UIE outperforms 12 state-of-the-art underwater image enhancement algorithms across three datasets, showing exceptional performance in applications like geometric rotation estimation and edge detection. The proposed MHF-UIE method, making it more desirable for various complex underwater scenarios.

This article developed an archaeometric examination of the brass sheathing remains recovered from two mid-19th-century shipwrecks, in Mexico: El Ángel site and the Black Warrior (1858), studied by the Vice-Directorate of Underwater Archaeology (SAS) of the National Institute of Anthropology and History (INAH) in collaboration with scholars from other research centres. The main aim of this research was twofold: on the one hand, to obtain compositional and microstructural data of brass sheets produced by the Muntz company in different periods and shed light on its features; on the other hand, to provide new data that help to assess the El Ángel site. Although the vessel’s identity has not been defined yet, the analysed evidence links it to the mid-19th-century logwood british trade. The Black Warrior was thus far preliminarily explored, but it has provided valuable data to compare with. Based on historical research and archaeometric analyses using XRD and XRF, a discussion on the manufacturing processes, materials, and patents associated with Muntz company’s brass sheathings is developed. The information obtained has contributed to the study of both wreck sites and is significant for assessing other unidentified sites.

Abstract In 2017, British shock-artist Damien Hirst released a coffee-table book with photographs from his Venice Biennale exhibition, Treasures from the Wreck of the Unbelievable, featuring artifacts retrieved from a Roman-era shipwreck in the Indian Ocean. The following year, a “documentary” was released on Netflix featuring the backstory of the wreck's excavation, showing how all those coral-encrusted antiquities made their way from the seafloor to the art scene. At this same time and elsewhere in Britain, a practitioner of art history, art, and maritime archaeology was in the process of developing the concept of “hauntography” as an object-oriented artistic method that represents (visually or otherwise) the ontological absent-presence of shipwrecks, that is, as objects that defy complete phenomenological access, while inspiring speculation into the uncanniness of being a thing of anthropogenic origin, but which persists beyond anthropos. Because both hauntography and Hirst's project make claims regarding epistemological and phenomenological limits pertaining to underwater wreckage, this article answers the question first posed by the author's students as to whether Hirst's satirical take on shipwreck archaeology ought to be considered the first hauntograph. By examining the relationships between two contemporary art projects, underwater archaeology, and object-oriented philosophies, this article considers how art objects might nudge epistemological limits without resorting to a post-truth dismissal of objective reality.

Abstract The importance and impact of subsoil quality is discussed with regard to the safety and reliability of underwater pipelines. Non-classical operational analysis is employed to define generalised dynamic systems. A model incorporating loading of the subsoil acting on a pipeline immersed in an underwater excavation is a specific case of a generalised dynamic system. This paper justifies the incorporation of the analytical method of generalised dynamic systems into the selected model. An innovative, non-standard and effective method is proposed to compact and improve the subsoil for underwater pipeline foundations using blasting charges.