ALBERT

Description: Das Alfred-Wegener-Institut in der Geschichte der Polarforschung : Einführung und Chronik

Description: The emerald mineralization in the Habachtal (Austria) is geologically and tectonically complex, and previous investigators have identified fluid inclusion evidence for a hydrothermal/metamorphic origin for the emeralds. In this paper we report the discovery of emeralds with a distinctly different inclusion population including melt inclusions, which demonstrates that at least some and probably most of the emerald mineralization in the Habachtal occurred from an extremely fluid-rich pegmatite-like aluminosil- icate melt under supercritical conditions, at high temperatures and moderate pressures (~700 °C, 5 kbar). This conclusion is based on the presence of very highly-ordered graphite, and extremely water-rich melt inclusions in emerald. The Lorentz distribution of MgCO3 against the water concentration is a very robust proof for the supercritical state. We suggest that the purely metamorphic model, based on the extrapolation of fluid inclusion data to the regional metamorphic conditions (550 °C and 5 kbar) by some previous investigators are inconsistent with our finding of high-temperature indications (well-ordered graphite, high-temperature fluid inclusions and melt inclusions). This apparent conflict suggests a more complex situation and requires a re-investigation of the emerald genesis in the Habachtal deposit.

Description: The continental silicon (Si) cycle, including terrestrial and freshwater ecosystems (lakes, rivers, estuaries), acts as a filter and modulates the amount of Si transported to the oceans. In order to link the variation in the terrestrial Si cycle to aquatic ecosystems, knowledge on changes in vegetation cover, soil disturbance and the impact of human activity are required. This study on varved lake sediments from Tiefer See near Klocksin (TSK) in northeastern Germany investigates Si isotope variations in diatom frustules (δ30Sidiatom) over the last ∼4300 years. δ30Sidiatom values vary between 0.37 and 1.63‰. The isotopic signal measured in centric (mostly planktonic) and pennate (mostly benthic) diatoms shows the same trend through most of the record. A decrease in δ30Sidiatom coinciding with early deforestation between 3900 and 750 a BP in the catchment area, points to an enhanced export of isotopically light dissolved silica (DSi) from adjacent soils to the lake. The burial flux of biogenic silica (BSi) observed in the lake sediments increases with cultivation due to enhanced nutrient supply (N, P and Si) from the watershed and nutrient redistribution caused by wind-driven increased water circulation. When the cultivation intensifies, we observe a shift to higher δ30Sidiatom values that we interpret to reflect a diminished Si soil pool and the preferential removal of the lighter 28Si by crop harvesting. Human activity influences the DSi supply from the catchment and appears to be the primary driver controlling the Si budget in TSK. Our data shows how land use triggers variations in continental Si cycling on centennial timescales and provides important information on the underlying processes.

Description: Report of Opening Session. Report of Governing Council. Report of the Finance and Administration Committee. Reports of Science Board and Committees. Report of the Climate Change and Carrying Capacity Scientific Program. Reports of Expert Groups. Session Summaries. Participants. PICES Members. PICES Acronyms.

Description: The geomagnetic Kp index is one of the most extensively used indices of geomagnetic activity, both for scientific and operational purposes. This article reviews the properties of the Kp index and provides a reference for users of the Kp index and associated data products as derived and distributed by the GFZ German Research Centre for Geosciences. The near real-time production of the nowcast Kp index is of particular interest for space weather services and here we describe and evaluate its current setup.

Description: In eastern Africa, there are few long, high-quality records of environmental change at high altitudes, inhibiting a broader understanding of regional climate change. We investigated a Holocene lacustrine sediment archive from Lake Garba Guracha, Bale Mountains, Ethiopia, (3,950 m a.s.l.), and reconstructed high-altitude lake evaporation history using δ18O records derived from the analysis of compound-specific sugar biomarkers and diatoms. The δ18Odiatom and δ18Ofuc records are clearly correlated and reveal similar ranges (7.9‰ and 7.1‰, respectively). The lowest δ18O values occurred between 10 and 7 cal ka BP and were followed by a continuous shift towards more positive δ18O values. Due to the aquatic origin of the sugar biomarker and the similar trends of δ18Odiatom, we suggest that our lacustrine δ18Ofuc record reflects δ18Olake water. Therefore, without completely excluding the influence of the ‘amount-effect’ and the ‘source-effect‘, we interpret our record to reflect primarily the precipitation-to-evaporation ratio (P/E). We conclude that precipitation increased at the beginning of the Holocene, leading to an overflowing lake between ~10 and ~8 cal ka BP, indicated by low δ18Olake water values interpreted as reduced evaporative enrichment. This is followed by a continuous trend towards drier conditions, indicating at least a seasonally closed lake system.

Description: Various species of Alexandrium can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised bioactive extracellular compounds (BECs). The latter metabolites are released into the environment and affect a large range of organisms (from protists to fishes and mammalian cell lines). These compounds mediate allelochemical interactions, have anti-grazing and anti-parasitic activities, and have a potentially strong structuring role for the dynamic of Alexandrium blooms. In many studies evaluating the effects of Alexandrium on marine organisms, only the classical toxins were reported and the involvement of BECs was not considered. A lack of information on the presence/absence of BECs in experimental strains is likely the cause of contrasting results in the literature that render impossible a distinction between PSTs and BECs effects. We review the knowledge on Alexandrium BEC, (i.e., producing species, target cells, physiological effects, detection methods and molecular candidates). Overall, we highlight the need to identify the nature of Alexandrium BECs and urge further research on the chemical interactions according to their ecological importance in the planktonic chemical warfare and due to their potential collateral damage to a wide range of organisms.

Description: Since the early ages of humankind, safety and security has been a critical issue against the forces of nature. However, history has always proven the power of nature over humankind in certain regions on Earth for centuries. Indeed, this is a never-ending war between Earth and its inhabitants, namely us, human beings. Humankind’s organization (cities, roads, lifelines etc.) in the nature has never been perfect within the view of environmental pollution and excessive consumption of the resources. Particularly, the quality of civil engineering design and practice is strongly affected from the social and economic background of the country. The societies in rapid development claim excessive demands in terms of housing and transportation. Such demands may create vulnerable urban areas if the economic and social conditions are not in balance or harmony. Thus, nature should not be blamed as the scapegoat in the regions where disasters claim human and economic losses. In fact, the reason for the losses is nothing else than humankind itself. A rational question arises then about how to overcome human and economic loss due to natural disasters. The idea of determining the most vulnerable items in urban areas and reconstructing with the most reliable equivalents may seem very challenging. Even though the macroeconomic implications are very complex, reconstructing the items in densely populated areas is the most effective mitigation action against disasters in the short term. Having learnt lessons from the major earthquake disasters in the heart of the industry and mostly dense urban areas, Turkish government has drawn a long strategic road map in the risk perception and the disaster mitigation strategy for almost all the community services and the infrastructure. The development of awareness against disasters has become part of formal education at all ages. The National Disaster Management system was reorganized from scratch and the capabilities improved by providing additional financial and human resources. All school and hospital buildings in İstanbul were assessed in terms of seismic safety. Those found inadequate were demolished and then reconstructed. In addition, a law on urban renewal of the seismic risk areas was enacted in 2012 allowing the licensed engineering offices to assess the seismic risk of residential buildings at the request of the house owners. If the assessment report is approved by the local municipality, the building is set to demolish within 60 days following the legal notice to the property owners. Disagreeing owners have the right to get the assessment re-evaluated by the independent peer reviewers. In the case of demolition, the house owners are eligible to receive 12 months of rental support from the government. During the time period 2012 to 2019, more than 120 000 buildings were assessed and 74% of them were demolished, the majority of the latter were in İstanbul area where a major earthquake is expected within the following decades. This chapter is intended to explain one of the most comprehensive and challenging disaster mitigation strategies being applied in Turkey based on experience since the 1999 earthquakes.

Description: Published

Description: 19-42

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: This open access book summarizes peer-reviewed articles and the abstracts of oral and poster presentations given during the YOUMARES 9 conference which took place in Oldenburg, Germany, in September 2018. The aims of this book are to summarize state-of-the-art knowledge in marine sciences and to inspire scientists of all career stages in the development of further research. These conferences are organized by and for young marine researchers. Qualified early-career researchers, who moderated topical sessions during the conference, contributed literature reviews on specific topics within their research field.