Megabenthic assemblages at the southern Central Indian Ridge - Spatial segregation of inactive hydrothermal vents from active-, periphery- and non-vent sites.

Active hydrothermal vents are small-scale habitats hosting endemic fauna in a well-defined zonation around fluid effluents. The fauna of inactive hydrothermal vents and its relation to active vents and non-vent area is poorly known. Characterizing inactive areas is prerequisite to establish protected areas, especially in the context of potential seafloor massive sulfide mining, which targets inactive sites. Hierarchical clustering and Distance-based Redundancy Analysis revealed five assemblages, with significantly associated substrate types: I) active hydrothermal vent, II) periphery, III) inactive hydrothermal vent and IV) soft- and V) hard-substrate within the non-vent area. For the first time, a unique inactive faunal assemblage could be identified within the hydrothermally extinct inactive Gauss field and on adjacent hard substrates. The spatial separation from the active Edmond field and periphery and the non-vent area indicates the existence of an inactive assemblage.

[Challenges in the context of medical care during a naval research expedition. A case report]. / Herausforderungen im Rahmen der ärztlichen Begleitung einer Forschungsseereise. Ein Erfahrungsbericht.

Exploration for natural resources in the seabed of the Indian Ocean was undertaken by the German government institution of earth sciences and resources ("Bundesanstalt für Geowissenschaften und Rohstoffe", BGR) in November 2012. To provide for the medical safety of crew and scientists, a cooperation between the BGR and the trauma department of the Hannover Medical School was established. Research by physicians accompanying the naval expedition revealed that medical consultations mainly occur because of respiratory infections, abdominal discomfort, genitourinary discomfort and seasickness, with the rate of traumas being between 31% and 41%. Di Giovanna et al. stated that 97% of all emergencies on cruise ships are not critical and only 3% need an immediate emergency medical intervention. Consultations were already performed on the mainland prior to departure and included minor traumas due to non-appropriate footwear, otitis and respiratory infections. Seasickness was the main reason for consultation during the first days at sea. Strong seas resulted in some bruises. Minor injuries and foreign body injuries to the hands and feet also required consultation. First-degree sunburns resulted from exposure to the sun, while air-conditioning caused rhinosinusitis and conjunctivitis. A special consultation was a buccal splitting of tooth 36. An immediate emergency medical intervention was not necessary due to the relative low level of pain for the patient; however, due to the risk of further damage caused by nocturnal bruxism, a protective splint was formed using a small syringe. Other reasons for consultation were similar to those reported in the general literature. Medical activities at exotic locations may create the vision of a holiday character at first; however, intensive planning and preparation are needed. We recommend contacting police, customs, the federal institute for drugs and medical devices as well as the labour inspectorate, preferably in both the originating country and the destination, to prepare custom formalities and to obtain formal documents and approvals beforehand. It is advisable to be prepared not only for emergency situations, but also for general medical and dental problems. Improvisation in the treatment of special health problems is an unavoidable requisite.

Preliminary characterization and biological reduction of putative biogenic iron oxides (BIOS) from the Tonga-Kermadec Arc, southwest Pacific Ocean.

Sediment samples were obtained from areas of diffuse hydrothermal venting along the seabed in the Tonga sector of the Tonga-Kermadec Arc, southwest Pacific Ocean. Sediments from Volcano 1 and Volcano 19 were analyzed by X-ray diffraction (XRD) and found to be composed primarily of the iron oxyhydroxide mineral, two-line ferrihydrite. XRD also suggested the possible presence of minor amounts of more ordered iron (hydr)oxides (including six-line ferrihydrite, goethite/lepidocrocite and magnetite) in the biogenic iron oxides (BIOS) from Volcano 1; however, Mössbauer spectroscopy failed to detect any mineral phases more crystalline than two-line ferrihydrite. The minerals were precipitated on the surfaces of abundant filamentous microbial structures. Morphologically, some of these structures were similar in appearance to the known iron-oxidizing genus Mariprofundus spp., suggesting that the sediments are composed of biogenic iron oxides. At Volcano 19, an areally extensive, active vent field, the microbial cells appeared to be responsible for the formation of cohesive chimney-like structures of iron oxyhydroxide, 2-3 m in height, whereas at Volcano 1, an older vent field, no chimney-like structures were apparent. Iron reduction of the sediment material (i.e. BIOS) by Shewanella putrefaciens CN32 was measured, in vitro, as the ratio of [total Fe(II)]:[total Fe]. From this parameter, reduction rates were calculated for Volcano 1 BIOS (0.0521 day(-1)), Volcano 19 BIOS (0.0473 day(-1)), and hydrous ferric oxide, a synthetic two-line ferrihydrite (0.0224 day(-1)). Sediments from both BIOS sites were more easily reduced than synthetic ferrihydrite, which suggests that the decrease in effective surface area of the minerals within the sediments (due to the presence of the organic component) does not inhibit subsequent microbial reduction. These results indicate that natural, marine BIOS are easily reduced in the presence of dissimilatory iron-reducing bacteria, and that the use of common synthetic iron minerals to model their reduction may lead to a significant underestimation of their biological reactivity.