Groundwater discharges in the Baltic Sea: survey and quantification using a schlieren technique application

Groundwater seeps are known to occur in Eckernförde Bay, Baltic Sea. Their discharge rate and dispersion were investigated with a new schlieren technique application, which is able to visualize heterogeneous water parcels with density anomalies down to Δσ_t = 0.049 on the scale of millimeters. With the use of an inverted funnel, discharged fluids can be captured and the outflow velocity can be determined. Overall, 46 stations could be categorized by three different cases: active vent sites, seep‐influenced sites, and non‐seep sites. New seep locations were discovered, even at shallow near‐shore sites, lacking prominent sediment depression, which indicate submarine springs. The detection of numerous seeps was possible and the groundwater‐influenced area was defined to be approximately 6.3 km². Flow rates of between 0.05 and 0.71 l m^?2 min^?1 were measured. A single focused fluid plume, which was not disturbed by the funnel was recorded and revealed a flux of 59.6 ± 20 ml cm^?2 min^?1 and it was calculated that this single focused plume would be strong enough to produce a flow rate through the funnel of 1.32 ± 0.44 l m^?2 min^?1. The effect of different seep‐meter funnel sizes is discussed.     

The significance of pockmarks to understanding fluid flow processes and geohazards

Underwater gas and liquid escape from the seafloor has long been treated as a mere curiosity. It was only after the advent of the side‐scan sonar and the subsequent discovery of pockmarks that the scale of fluid escape and the moon‐like terrain on parts of the ocean floor became generally known. Today, pockmarks ranging in size from the ‘unit pockmark’ (1–10 m wide, < 0.6 m deep) to the normal pockmark (10–700 m wide, up to 45 m deep) are known to occur in most seas, oceans, lakes and in many diverse geological settings. In addition to indicating areas of the seabed that are ‘hydraulically active’, pockmarks are known to occur on continental slopes with gas hydrates and in association with slides and slumps. However, possibly their potentially greatest significance is as an indicator of deep fluid pressure build‐up prior to earthquakes. Whereas only a few locations containing active (bubbling) pockmarks are known, those that become active a few days prior to major earthquakes may be important precursors that have been overlooked. Pockmark fields and individual pockmarks need to be instrumented with temperature and pressure sensors, and monitoring should continue over years. The scale of such research calls for a multinational project in several pockmark fields in various geological settings.     

H. L. Hunley Revealed: documentation,deconcretion, and recent developments in the investigation of an American Civil War submarine from 1864

Since 2014, the conservation staff at Clemson University's Warren Lasch Conservation Center in Charleston, South Carolina have been removing the concretion from the hull of H. L. Hunley, an American Civil War submarine lost 1864. In parallel, the archaeological team has been documenting the condition of the hull, the concretion layers, and the hull features revealed by the deconcretion process. This involved photography, direct measurements, and 3D scanning. This article will discuss the strategy for recording the concretion, the techniques used to document the newly revealed hull and its unique features, and the preliminary analysis of their archaeological significance.     

Neutrality and submarine warfare: Germany and Spain during the First World War

The Spanish government maintained official neutrality during the Great War because deviating from neutrality would supposedly endanger the nation’s already limited political and social stability and even threaten the survival of the monarchic regime. In August 1914 there were no direct Spanish interests in the conflict and no benefit to be obtained from any intervention by Spain, which was very weak in military terms and in the international arena. Nevertheless, Spain’s geographic location and its commercial dependence on the Entente made it especially vulnerable to the pressures of France and Great Britain, both of which attempted to take advantage of the services that Spain could offer in the economic war; Spain’s importance increased with the prolongation of the fight. Germany, in contrast, could not hope for more from Spain than its strict neutrality because of its highly important political and economic ties with the Entente and its defencelessness before England and France, from which Germany could not protect it. Because Germany could not wait for Spain’s participation next to her, the primary target of German diplomacy had to be to resist the influence of the Entente and maintain Spanish neutrality while preventing Spain from inclining towards favouring the Allies. To achieve this objective, Berlin fed, with vague promises, the idea that a Spanish collaboration would be rewarded with the annexation of some territories. On this basis, we can begin to study German–Spanish relations during the Great War, which came to be determined by incidents that were caused by the submarine war. The dependence on the Entente also helps to explain the last evolution of the relations between Germany and Spain, which could follow no other policy than that imposed by the final development of the war: taking up a position near the winners and distancing from, and nearly rupturing ties with, Germany. Using both Spanish and German documentation allows us to reach different conclusions that aim to contribute substantially to understanding the relationship between Spain and Germany during the Great War.     

Analysis of the Aft Ballast Pump Onboard the American Civil War-era Submarine H.L. Hunley

Since its discovery and raising offshore of Charleston, Warren Lasch Conservation Center scientists have conducted extensive research on the contents and components of the American Civil War submarine H.L. Hunley, the first successful combat submarine. Recent conservation of the aft ballast pump has led to greater focus on the function and configuration of the ballast system and how it pertains to the submarine's sinking. This article relays the latest interpretation on design and use of the ballast system onboard the Hunley; findings from historical research on the components, operation and design of the aft pump, and avenues for further research. Understanding the ballast system and pump may prove highly relevant in answering questions regarding the loss of the vessel and her crew.     

The Wire: Progress,Paradox, and Disaster in the Strategic Networking of China, 1881–1901

This study of the introduction of telegraphy to China in the late-nineteenth century tells three interrelated stories: China’s pursuit of telegraphic sovereignty with its strategic networking of the empire in the period 1881–99; the functioning of China’s hybrid express courier-telegraphic communications infrastructure; and the international communications crisis during the Boxer Uprising and the “Siege of the Legations” in 1900. The material reality of two inter-connected networks—the privately owned Imperial Telegraph Administration network and the government-run telegraph network—allowed Qing-era Beijing and its provincial governors to communicate with much greater speed. The materiality of these networks—how this new communications technology affected the practical realities of government communications, including the ease of lateral communications between provincial governors—is explored in the context of the communications crisis of 1900. In May and June of 1900 all telegraph lines to Beijing, and throughout much of North China, were cut or otherwise destroyed. While these blinded Western governments are no longer able to exchange telegrams with their Beijing-based envoys, the Qing express courier system continued to operate. Moreover, both the court and provincial officials quickly improvised ad hoc telegraphic communication protocols through the use of “transfer telegrams” (zhuandian) that relied on mounted express couriers between Beijing and those North China telegraph stations with working network connections. This assessment of real-time secret imperial communications between the Qing court and the provinces is based on the documentary register Suishou dengji (Records of [documents] at hand) maintained by communications managers in the Grand Council. China lost its telegraphic sovereignty in the capital region when Allied troops occupied the Beijing-Tianjin line of communications in the summer and fall of 1900. Moreover, Western dreams of laying, landing, and controlling submarine cables on the China coast were finally realized in North China by the end of 1900. The British, therefore, were able to add a critical section to their planned global network of secure telegraphic communications. China’s recognition of the Western and Japanese right of protecting the Beijing-Tianjin line of communications was codified in Article 9 of the Boxer Protocol of September 1901. These losses of China’s telegraphic sovereignty would not be completely reversed until after 1949.     

Archaeological Reconnaissance of the 1865 American-Built Sub Marine Explorer at Isla San Telmo, Archipielago de las Perlas, Panama

A wrecked submarine lying in the inter-tidal zone of Isla San Telmo, off Panama's coast, has been identified as Sub Marine Explorer , a rare surviving example of a mid-19th-century submersible. One of the world's first successful lock-out dive-chambers, the craft had a fatal design aspect that ultimately harmed its crew and may have killed the builder through the effects of pressure. Documentation of the submarine provides a detailed understanding of this technologically advanced but flawed craft.
© 2006 The Author     

Conservation and Management Strategies Applied to Post-Recovery Analysis of the American Civil War Submarine H. L. Hunley (1864)

The 12-m long submarine H. L. [Horace Lawson] Hunley was successfully recovered from the Atlantic in August 2000 after nearly 140 years of immersion, and immediately brought to the Warren Lasch Conservation Center to be excavated in a controlled environment. In 2001 a multi-disciplinary team excavated the crew compartment and uncovered numerous fragile artefacts and human remains. This paper describes the conduct of the excavation and technological advancements developed to work with this complex and unstable iron vessel. Impressed current technologies, automated tank controls and water monitoring systems; laser mapping; fibre-optics; database management; in situ x and gamma rays; moulding and protection of fragile archaeological features; and protocols for moving artefacts to the laboratory will also be discussed.
© 2004 The Nautical Archaeology Society