Underwater Archaeological Sites Research Articles

An updated reconstruction of Campi Flegrei caldera (southern Italy) ground deformation history and its interaction with the human sphere since Roman time

Since the 19th century, many scientists have tried to reconstruct the ground motions that occurred in the Campi Flegrei caldera, one of the most dangerous volcanos in the Mediterranean area. This study aims to assess the joint effects of vertical ground movements and anthropic forcing along the coasts of this volcanic area. A huge dataset of hundreds of archeo-stratigraphic boreholes was coupled with direct and indirect surveys of the main underwater archaeological sites scattered along the whole coastal sector and with the reinterpretation of bibliographic sources. Clear evidence of a differential volcano-tectonic behaviour (highlighted for the first time in this study) led us to divide the study area into three coastal stretches with homogeneous vertical ground movements. In each sector, a new relative sea-level (RSL) curve was reconstructed, by interpreting our stratigraphic and archaeological data in terms of SL markers covering a wider timespan compared to the previous studies, from the first Roman urbanization to the present day. The comparison between RSL curves and GIA models allowed estimating vertical ground movements (See Supplementary material 2) that occurred along the coast with decimetres accuracy. For each of the 5 recognized phase of uplift or subsidence, we also studied the subsequent effects in terms of coastal geomorphological change, and advantages or negative impacts on ancient human activities. We measured an overall subsiding trend that brought the RSL from −12 ± 1 m (4th century BC) to 7 ± 0.2 m during three different episodes between 5th and 15th centuries (1450–450 y BP), which was interrupted by short-lived falls (less of 100 years) of RSL. During the phases of RSL fall and/or volcano-tectonic stability, detected for the first time in the eastern and western part of the caldera (1st-2nd century AD and 3rd-4th century AD), a basinward shift of the coastline created newly emerged land even at the base of the local sea cliffs, where shore platforms emerged, favouring intense phases of urbanization on them along the Baia – Miseno sector and at the footslope of Rione Terra. This trend also favoured the closure of the Lucrino lagoon with an extended spit bar during the 2nd century BC, allowing the establishment of a large oyster farming system belonging to Sergio Orata. On the contrary, the subsiding phases resulted in the flooding of coastal areas and anthropic structures such as villas, nymphaea and ports inducing the construction of coastal protection structures. In the extreme case of Portus Julius, subsidence led to the abandonment of the military port and its move to nearby Miseno.

What kind of corrosion products are “black spots”? —Effects of reduced sulfur compounds on corrosion of bronze artefacts

While deterioration due to the generation of “black spots” is reported, consensus on the specific corrosion products comprising black spots and underlying deterioration mechanisms is lacking. This study investigated the deterioration of copper objects by analysing the black spots that appeared on them and proposes environmental conditions to suppress the appearance of black spots. Bronze artefacts excavated from a marine archaeological site, on which black spots were generated, were closely observed, and investigated. First, X-ray fluorescence and micro-X-ray diffraction analyses were performed on a bronze artefact, from which the black spots were removed, to determine the composition of the artefact. Second, to investigate the composition of the black spots, fine structure analysis of the black spots on the fine fragments of the bronze artefacts was conducted using scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron diffraction (ED) analysis. The results indicate that the black spots were partially composed of metallic copper and a fine particle mixture of Cu2S and CuSO4. These results imply that the transformation of copper sulfide to metallic copper may have played an important role in the initiation and propagation of black spots. In this study, ED analysis was performed on the microscopic area of the black spots; no amorphous phases were detected, and all observed phases were identified as crystalline materials. To determine the sources of gas-phase sulfur compounds that cause black spots, H2S and carbonyl sulfide (COS) emissions from a spherical clay artefact (a cannon ball with gunpowder excavated from an underwater archaeological site) which was exhibited in the same showcase with the bronze artefacts were analysed via gas chromatography. The concentrations of H2S and COS were 0.462 and 8.636 ppb, respectively; these are significantly higher than those in the lower troposphere. These results indicate that deterioration by black spots occurred because of H2S and COS, which were emitted from the spherical clay artefact excavated from an underwater archaeological site in the exhibition case. In addition, it was confirmed that the inclusion of deoxygenating and dehumidifying agents (RP-AN) in the plastic bag in which the spherical clay artefact was inserted resulted in a significant decrease in the concentration of H2S and COS.

Environmental stimulant-responsive hydrogels based on polyethylene glycol-derived polymer for underwater bonding and extraction of fragile wooden relics: Synthesis, characterization, and preliminary application

It has become widely acknowledged that certain underwater cultural relics, in a state of severe decay, should be salvaged for further protection. Underwater temporary reinforcement materials provide the possibility for such protection. These materials can achieve both the reinforcement of cultural relics underwater, as well as their reversible removal after extraction, without causing damage to the cultural relics in either process. In this context, two kinds of hydrogels based on polyethylene glycol-derived polymers were developed in this study. They are denser than water and can undergo gelatinization by UV-induced or oxidant-induced reactions in the underwater environment. Additionally, they possess enough mechanical strength to provide the necessary support in the bonding process. Both hydrogels have been successfully used to extract fragile underwater archaeological wooden artifacts in situ under laboratory conditions. The experimental results revealed that, in the case of UV-induced hydrogels, the compression strength was 115 kPa with a tensile strength of 20 kPa. For oxidant-induced hydrogels, the compression strength was 382 kPa, while the tensile strength was 8.2 kPa. During the actual extraction processes, the UV-induced hydrogel exhibited a lower water absorption ratio, maintained a more stable mechanical property underwater, and was easier to remove after extraction. On the other hand, the oxidant-induced hydrogel could complete the gelation process quickly through a rather convenient operation; however, it tended to absorb surrounding water and swell, thereby reducing its mechanical property. These two methods would be adapted to different underwater archaeological sites as convenient, environmentally friendly, and cost-effective novel methods for extracting fragile underwater wooden relics.

Predictive Modelling in Underwater Archaeology. A Case Based on Mesolithic Coastal Settlements in Denmark

Abstract Research on underwater archaeological sites has been adversely affected by various socioeconomic (specialized equipment, lack of know-how, legal framework, etc.) and environmental (weather conditions, site formation processes, etc.) challenges. Interdisciplinary approaches, especially technology integration, can help introduce a methodology to evaluate these factors and mitigate limitations to enhance the information retrieved and assist the interpretation process. One such approach may be predictive modelling while developing methodologies based on predictive models can be assets in research. The work presented in this article is based on this approach and assesses the use of predictive models based on six case studies. It is an effort to evaluate whether targeting sub-areas when excavating on limited time and budget can help clarify the interpretation of the information collected from these areas.

GPR survey on underwater archaeological site: A case study at Jenipapo stilt village in the eastern Amazon region, Brazil

In this work we present and discuss the results of a pioneering Ground Penetrating Radar (GPR) survey performed at the underwater archaeological stilt village called Jenipapo in the eastern Amazon region. Jenipapo stilt village is located on the Turiaçu River, Maranhão State, Northeast of Brazil. The region is known as the Maranhense wetland where settlements were built by indigenous populations that inhabited this region during the pre-colonial period (∼AD 1 – 1100). These settlements were built on the margin of rivers and lakes, being supported by wooden pillars, corresponding to prehistoric stilt houses. The objectives of this research are to refine the wooden pillars location at the Turiaçu River bottom and guide the search for underwater archaeological artifacts. A total of twelve GPR profiles were acquired with 270 MHz antennas using a rubber boat. The GPR results indicated clear signal reflection from the river bottom and several diffraction hyperbolas suspended over the river bottom related to the top of the wooden pillars. To support the interpretation of the results, a GPR numerical modeling was performed to simulate the diffraction hyperbolas suspended in the water related to the wooden pillars. The synthetic result presented a good agreement with real data. Finally, the location of several diffraction hyperbolas can guide the divers to find and collect archaeological artifacts around the underwater wooden pillars that are the best evidence of the stilt houses of indigenous settlements found in the eastern Amazon region. Several archaeological artifacts were found during previous work, including ceramic materials. The results of this research show the capability of the GPR method to map an underwater wooden pillar and increase the probability of finding archaeological artifacts on the river bottom, which contributes to improve the knowledge of the Amazonian archaeology in Brazil.

A Smart System for Environmental Parameter Monitoring in Underwater Archaeological Sites

In this paper, we present a prototype for the remote monitoring of underwater archaeological sites. The system aims to provide autonomous and real-time data collection from environmental probes and also includes biofouling detection based on image processing. The monitoring system is equipped with sensors to measure various parameters of interest, including temperature, pH, conductivity, dissolved oxygen, and oxidation-reduction potential. To detect biofouling, a camera is integrated into the system, and an analysis is performed on the captured images utilizing indices such as the Normalized Difference Vegetation Index (NDVI) and the PYM method. The system consists of a subsea node placed near the monitoring site, connected to a surface buoy through an umbilical cable. The surface buoy contains an LTE router for data transmission to a remote web platform for data storage and visualization. The hardware of the underwater node includes an embedded computer, responsible for providing functionalities for image processing and interfacing with the web platform, and a micro-controller board to read the sensor measurements. The developed remote monitoring system has been tested in a marine environment and offers a comprehensive solution for long-term environmental parameter analysis, biofouling detection, and real-time data access. It holds great potential for applications in marine research, environmental monitoring, and ecosystem studies.

Stone artefacts on the seabed at a submerged freshwater spring confirm a drowned cultural landscape in Murujuga, Western Australia

We report the discovery and identification of five ancient stone artefacts associated with a submerged freshwater spring at the underwater archaeological site WH1 in Murujuga (Dampier Archipelago), Western Australia. A limiting date applied to the site based on timing of inundation suggests it was occupied in the Late Pleistocene or Early Holocene. The site is situated well below the intertidal zone having been recorded at 14 m depth in Flying Foam Passage. This discovery highlights the high potential of these submerged springs as archaeological survey targets. We discuss results of a recent survey that expands the number of confirmed artefacts located at WH1 and the geomorphological context in a large calcareous depression associated with a freshwater source. This study demonstrates how submerged landscape research using a suite of technologies can reveal archaeological assemblages in this tropical geomorphological environment, and that adapted techniques could be applied to other tropical conditions such as mangrove coasts, large deltaic plains, or reef-building environments. There are likely thousands of drowned archaeological sites on the continental shelf of the tropics, extending from the intertidal zone to the lowest point of the culturally occupied landmass, at approximately 130 m below modern sea level.

Sunken landscapes and settlement areas. On the reconquest of underwater archaeological sites

Prehistoric lake dwellings around the Alps have been of great interest to researchers and are now part of the UNESCO World Heritage List. These sites offer challenging but favourable building locations around a lake with constantly changing water levels, which likely resulted in a lot of movement from people and nature over time. When water levels rose, these sites were taken over by aquatic plants and animals. But owing to climate change, neozoa and neophytes are spreading quickly into new habitats. It is important to document and monitor these developments in order to understand the extent and potential threat of these species in different areas.

Application of Parametric Sub-Bottom Profilers for Responsible in Situ Management of Underwater Shallow-Buried Archaeological Materials

The application potential of parametric sub-bottom profilers (SBPs) to in situ management of underwater archaeological sites at risk from degradational loss of shallow-buried materials is presented. This approach is based on the process-driven in situ preservation and research frameworks advocated by the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage and provides a basis for greater uptake by the archaeological community. Results from research at a purposely prepared sub-seabed site and on the adjoining James Matthews (1841) wreck site in Western Australia demonstrate how noninvasive SBP-derived data support responsible management of underwater cultural heritage (UCH) sites by: (1) identifying and/or confirming the presence of sub-seabed UCH material, (2) identifying the potential level of risk of further material loss from ongoing degradation, (3) providing key information with which to make a sound in situ management or site-research plan for the sub-seabed material, and (4) delivering monitoring feedback regarding the success of in situ management actions.

Objects of Antique and Medieval Cultural Heritage as a resource of the geoecosystems of the Northern Black Sea Coast and of the Black Sea Shelf in the area of the Bug Estuary

This article is a continuation of the author’s series of publications devoted to the study of the resource potential of archaeological artifacts — sites of ancient and medieval heritage as anthropogenic components of modern geoecosystems of the Northern Black Sea coast (GESNBSC) and the nearby Black Sea shelf including the estuaries. These sites are currently partially or fully located in the transitional part of the Black Sea Geoecosystem (BSG) space and associated geoecological subsystems of estuaries, where modern natural aerial, aquatic and geological environmental subsystems interface with each other. The article presents the results of research, characterization and typification of archaeological sites of the cultural heritage of ancient and medieval times, which are located in the space of geoecosystems that were formed in this region. Among them are the underwater archaeological sites dis- covered in the space of ancient coastal and littoral paleogeoecosystems of the Bug Estuary, their connection with the most significant archaeological sites that were once formed as part of geoecosystems of the land. A preliminary reconstruction of the borders of the Bug Estuary in ancient and medieval times is made; there is demonstrated the resource archaeological potential of GESNBSC spaces and the adjacent zone of the Black Sea shelf with estuaries, including the ancient and medieval archaeo- logical sites of cultural heritage, which were created and for some time belonged to the spaces of cer- tain paleo-GESNBSC, but are now located in the space of modern geoecosystem of the Bug Estuary. The article gives a brief description of the already known archaeological, partially submerged sites of ancient and medieval cultural heritage, some other interesting underwater archaeological artifacts, and shows the feasibility of expanding their study with reference to bathymetric and geomorphological features of the boundaries between modern natural BSG environmental subsystems. Such knowledge is important both for solving the issues related to a more profound understanding of the causes and consequences of changes in the paleogeoecological and modern geoecological conditions of the shelf of Azov-Black Sea basin and GESNBSC, predicting their dynamics and directions of development, and for historical and archaeological reconstructions, in particular, to identify new cultural heritage sites. The results of geoarchaeological (that is, a complex of geoecological and archaeological) studies published in the article are important not only for understanding the formation and functioning of transitional geoecosystems with their resources, which include archaeological artifacts as anthropogenic components, but also for the development of public culture, historical memory population and expansion of its historical consciousness. In addition, such knowledge is necessary to consciously and competently address a number of economic problems in the development of communities in the Northern Black Sea region. In particular, to attract investment in the development of coastal and underwater tourism, to predict the impact of many geo-environmental processes inherent in the research region under specific conditions of the search, identification, use and preservation of the historical and archaeological potential of ancient and medieval cultural heritage located in the space of modern GESNBSC and BSG as their components. These anthropogenic components are objective evidence of the impact of natural geo-environ- mental conditions and their dynamics on the peculiarities of life and migration of the region’s inhabitants from ancient times up to the present.

Different approaches to the protection and enhancement of underwater archaeological sites: Acquirements and Aspirations

This paper presents aspects of underwater cultural heritage management in Greece, focusing mainly on accessibility to the diving community and the general public. More specifically, it discusses different approaches to the protection and enhancement of Underwater Archaeological Sites, already put into practice over the last years (2018-2021) by the Ephorate of Underwater Antiquities, the public service of the Hellenic Ministry of Culture and Sports responsible for the management of underwater heritage. Moreover, it analyses the aspirations for the future, as these took shape already at the beginning of 2021. Lately, cultural management has turned into a fast-growing sector with multilevel developmental prospects. In order to tap into the underwater cultural heritage potential, we must always take into consideration the identity and special characteristics of each underwater site as well as the different possibilities of access — physical or virtual — that are rapidly changing because of new technological achievements. All these parameters affect significantly decision making and the undertaking of relevant initiatives. Examples of the pilot implementation of the opening of underwater archaeological/cultural sites to the public will be presented. Through them, preliminary conclusions concerning the efficacy of the selected managerial approaches can be drawn, while at the same time domains where more should be done will be highlighted.

Of time and tide: the complex impacts of climate change on coastal and underwater cultural heritage

The Intergovernmental Panel on Climate Change has documented wide-ranging changes to the world's coasts and oceans, with significant further change predicted. Impacts on coastal and underwater heritage sites, however, remain relatively poorly understood. The authors draw on 30 years of research into coastal and underwater archaeological sites to highlight some of the interrelated processes of deterioration and damage. Emphasising the need for closer collaboration between, on one hand, archaeologists and cultural resource managers and, on the other, climate and marine scientists, this article also discusses research from other disciplines that informs understanding of the complexity of the interaction of natural and anthropogenic processes and their impacts on cultural heritage.

Potential of antique and medieval cultural heritage in the space of geoecosystems of the Northern Black Sea area and the Black Sea shelf from the Danube to the Berezan estuary

The article examines the typification and gives a brief description of underwater archaeological sites of ancient and medieval cultural heritage, the main types of ancient shores, as well as the most significant objects studied so far in the space of the geoecosystems of the Northern Black Sea (GESNBS) and the marine geoecosystem (MGES) of the shelf from the Danube delta to the Berezan estuary and the island of Berezan. The results of research on archaeological sites located in this territory are presented. A preliminary reconstruction of the shores that existed in this part of the Northern Black Sea Coast has been made. Nowadays, these archaeological sites are partially or completely located in the areas of the Black Sea shelf and its basin subsystems of a lower level (bays, ducts, estuaries, deltas, etc.), mainly at the boundary of their aquatic (from the Latin aqua — water) (AQESUS) and geological (GEOESUS) subsystems of the MGES shelf. The main objective of this article, which the authors set while writing it, was to show the potential of antique and medieval cultural heritage, which was formed in the relevant ancient times in the space of paleogeoecosystems of the Northern Black Sea but is now preserved in the MGES space of the modern Black Sea shelf from the Danube River to the Berezan estuary. Among the main tasks of this article is a brief description of the already known archaeological, in particular underwater, sites of antique and medieval cultural heritage, some other interesting underwater archaeological artifacts, and their future imposition on the modern geological, geographical and bathymetric framework with reference to certain AQESUS and GEOESUS of MGES of the Black Sea. This is important not only for historical and archaeological reconstructions but also for solving the problems of in-depth knowledge of the causes and consequences of changes in the paleogeological and modern geoecological conditions of the Azov-Black Sea basin and GESNBS shelf, dynamics and directions of their development. Such research is also important both for the development of public culture, expansion of the historical consciousness of the population of Ukraine and for solving some economic problems in the development of communities in the Northern Black Sea region by attracting investment to the development of coastal and underwater tourism, predicting the impact of many geoecological processes inherent in this studied region on the peculiarities of the conditions of search, identification, use and preservation of the historical and archaeological potential of antique and medieval cultural heritage located in the space of GESNBS and MGES of the modern Black Sea shelf as their anthropogenic component, affecting the lives of residents of the region under consideration, from ancient times until the present.

Getting Your Feet Wet

AbstractThere is a lack of broad representation in archaeology generally, and in a specialized field such as underwater archaeology, this issue is only exacerbated. Underwater archaeological sites are often “out of sight, out of mind,“” creating a general lack of awareness of underwater cultural heritage and career prospects in many communities. Coupled with a lack of education and the additional demands of working in a submerged environment (e.g., scuba diving), there is a striking lack of diversity in underwater archaeology. Overall, underwater archaeologists are a largely homogeneous group, particularly along the lines of race and wealth—categories that often overlap. In the context of asking broader questions such as “Why are there so few underwater archaeologists of color?” and “How can we do better?” this article outlines the barriers to inclusivity writ large in underwater archaeology and provides solutions for increasing diversity and accessibility in the field, including specific opportunities and resources for underrepresented groups to “get their feet wet.”

Dive in the Past: A Serious Game to Promote the Underwater Cultural Heritage of the Mediterranean Sea

In the last decades, the popularity of video games has been increasing thanks to their unique ability to engage their audience and create empathy. Among them, serious games have additional purposes besides entertainment, such as learning and behaviour change. Serious games, in fact, have been successfully applied to different fields, including education, health, tourism, and cultural heritage. In this context, the paper describes a novel serious game developed for increasing awareness and promoting the Underwater Cultural Heritage (UCH). In particular, the paper focuses on the Dive in the Past Serious Game which allows users to simulate a virtual dive into the Mediterranean Sea to explore accurate and life-sized 3D reconstructions of underwater archaeological sites. The purpose of the game is twofold: to engage diver and non-diver tourists into a virtual interactive exploration of underwater sites through digital storytelling and challenges; to increase awareness and knowledge on Mediterranean UCH. This work has been carried out in the context of the MeDryDive project, an EU co-funded under the COSME Programme, which aims to create personalized dry dive experiences for the promotion of Mediterranean UCH sites as distinctive tourism destinations.

Study on Distortion Compensation of Underwater Archaeological Images Acquired through a Fisheye Lens and Practical Suggestions for Underwater Photography - A Case of Taean Mado Shipwreck No. 1 and No. 2 -

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180o) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.

BENTHIC COMMUNITY DIVERSITY AT MARINE ARCHAEOLOGICAL SITE, PULAU BIDONG, SOUTH CHINA SEA

An artificial structure on the seafloor will affect the structure of the benthic community. This structure may include a sunken ship or a century-old building that becomes an underwater heritage site. Benthic communities at underwater archaeological sites have been studied around the world, though it is lacking in Malaysia. This study aimed to determine the benthic community composition and diversity in sediment and on an artifact (small ceramic pot) at the marine “Bidong shipwreck” archaeological site. SCUBA divers collected samples (sediment and artifact) from an 18 m depth archaeological site in October 2017. Then, all samples were fixed with 10% buffered formalin and preserved in 80% ethanol prior to identification analysis. Most benthic organisms were identified until class taxon, except for class Polychaeta until family. A total of 2711 benthic organisms which belonged to eight phyla, and 17 classes were recorded, of which 638 are polychaetes. In the archaeological site, Syllidae was the most abundant family in the sediment, and the family Nereididae dominated in artifact while Capitellidae was dominant at the control site. Shannon-Weiner diversity index showed variation and ranged from 1.5 to 2.1, while the evenness index value ranged from 0.56 to 0.77. The benthic community in sediment on both sites were more diverse and even compared to the artifact. Simultaneously, Jaccard’s similarity test discovered that the benthic community’s composition in sediment at the control site was highly similar to the archaeological site (0.80) comparatively to the artifact (0.65). It is suggested that the benthic community at the archaeological site has reached an equilibrium state similar to the control site. The scouring process may influence the lower benthic community composition on the artifact than sediments in its surroundings. These findings provide an overview of benthic community’s post-disturbance resilience and reveal a marine archaeological site’s ecological status.

Exploration and reconstruction of a medieval harbour using hydroacoustics, 3‐D shallow seismic and underwater photogrammetry: A case study from Puck, southern Baltic Sea

AbstractExploration of the marine environment using underwater remote‐sensing methods is the most reasonable method for investigating submerged archaeological heritage sites, preserving their current condition and maintaining them for future generations. While non‐invasive recognition of heritage sites is one of the main objectives of underwater archaeology, the nearshore environment of the small Polish town of Puck hides one of the biggest medieval harbours in the Baltic Sea. The following research objectives were met in this study: (a) exploration of underwater archaeological heritage harbour in Puck using high‐resolution hydroacoustics, 3‐D shallow seismics and underwater photogrammetry; (b) reconstruction of the submerged Puck medieval port by the combining of hydroacoustics, 3D shallow seismics, underwater photogrammetry and archival documentation; (c) estimation of the rate at which the bottom sediments containing the archaeological objects are being destroyed. The underwater archaeological site of Puck harbour was explored using multiple surveying methods, including multibeam echosounder, parametric sub‐bottom profiler, underwater photogrammetry, aerial photography and comparison with archival documentation. Very high‐resolution bathymetry from a multibeam echosounder allowed seabed features such as piles, stones and horizontal structural elements to be identified, along with other archaeological artefacts, boat wrecks and boat‐building artefacts. The 3‐D shallow seismic datasets allowed us to distinguish, for example, several outcropping structures, a previously unknown buried shipwreck, past excavation trenches, the harbour boundary and a palaeochannel of the Płutnica River. Fusing datasets from multiple sources in the geographic information system (GIS) environment allowed for a combined visualization of the heritage sites, providing a broad archaeological demonstration of the underwater structure. By comparing with archival documentation, we calculated that 43% of biogenic layers containing archaeological objects eroded over 26 years. Our results demonstrated that without any doubt, underwater remote‐sensing methods are the most appropriate for exploration and investigation of underwater heritage sites while maintaining their original value.

Making the Invisible Visible: Underwater Malta—A Virtual Museum for Submerged Cultural Heritage

The seabed can be considered as the world’s largest museum, and underwater sites explored and studied so far provide priceless information on human interaction with the sea. In recognition of the importance of this cultural resource, UNESCO, in its 2001 Convention on the Protection of the Underwater Cultural Heritage, determined that objects/sites should be preserved in situ, whilst also advocating for public access and sharing. The implementation of these principles is not without difficulties. Some states have opened up underwater sites to the public—mainly through diving, yet the vast majority of the world’s population does not dive. In Malta, 7000 years of human occupation is reflected in and on the landscape, and recent offshore surveys show that the islands’ long and complex history has also left an indelible mark on the seabed. Besides difficulties related to their protection and management, these sites also present a challenge with regard to sharing and communicating. Recent advances in underwater imaging and processing software have accelerated the development of 3D photogrammetry of submerged sites and the idea for a virtual museum was born. The virtual museum, UnderwaterMalta, was created out of a need to share the plethora of underwater sites located on the seabed of the Maltese Islands. A multitude of digital tools are used to share and communicate these sites, offering visitors a dry dive into submerged sites that would otherwise remain invisible to the vast majority of the public. This paper discusses the basic principle of the sharing of underwater cultural heritage and the difficulties that beset the implementation of such a principle. A detailed explanation and evaluation of the methods used to gather the raw data needed is set in the context of the particular and unique working conditions related to deep water sites. The workings of this paper are based on first-hand experiences garnered through the recording of numerous wrecks over the years and the creation and launch of The Virtual Museum-Underwater Malta—a comprehensive virtual museum specifically built for “displaying” underwater archaeological sites that are otherwise invisible to the general public.

Technique of Temporary Undisturbed Reinforcement Extraction of Fragile Lacquerware from Shipwrecks

A subject of continuous discussion in the field of underwater archaeology is how to safely extract fragile waterlogged artifacts while maintaining their best condition. In this study, lacquerware with fragile wooden body was simulated and extracted, using a triple-package reinforcement technique. Using veratraldehyde as a temporary consolidant, SH-MWCNTs@PU sponge/epoxy resin composite materials as free-form reinforced layers, and double-sided self-adhesive bandages wrapped around the outer layer, the safe underwater extraction and the layer-by-layer removal of the simulated artifacts were studied. The method maximized the preservation of the artifacts’ state and information and minimized their damage during removal and transport. This method can be used as a technique for the extraction of fragile artifacts from underwater archaeological excavation sites.