Arsenic-contaminated ground- and drinking water is a global environmental problem with about 1-2Prozent of the world's population being affected. The upper drinking water limit for arsenic (10 Micro g/l) recommended by the WHO is often exceeded, even in industrial nations in Europe and the USA. Chronic intake of arsenic causes severe health problems like skin diseases (e.g. blackfoot disease) and cancer. In addition to drinking water, seafood and rice are the main reservoirs for arsenic uptake. Arsenic is oftentimes of geogenic origin and in the environment it is mainly bound to iron(III) minerals. Iron(III)-reducing bacteria are able to dissolve these iron minerals and therefore release the arsenic to the environment. In turn, iron(II)-oxidizing bacteria have the potential to co-precipitate or sorb arsenic during iron(II)- oxidation at neutral pH followed by iron(III) mineral precipitation. This process may reduce arsenic concentrations in the environment drastically, lowering the potential risk for humans dramatically.The main goal of this study therefore is to quantify, identify and isolate anaerobic and aerobic Fe(II)-oxidizing microorganisms in arsenic-containing paddy soil. The co-precipitation and thus removal of arsenic by iron mineral producing bacteria will be determined in batch and microcosm experiments. Finally the influence of rhizosphere redox status on microbial Fe oxidation and arsenic uptake into rice plants will be evaluated in microcosm experiments. The long-term goal of this research is to better understand arsenic-co-precipitation and thus arsenic-immobilization by iron(II)-oxidizing bacteria in rice paddy soil. Potentially these results can lead to an improvement of living conditions in affected countries, e.g. in China or Bangladesh.
Water is an intrinsic component of ecosystems acting as a key agent of lateral transport for particulate and dissolved nutrients, forcing energy transfers, triggering erosion, and driving biodiversity patterns. Given the drastic impact of land use and climate change on any of these components and the vulnerability of Ecuadorian ecosystems with regard to this global change, indicators are required that not merely describe the structural condition of ecosystems, but rather capture the functional relations and processes. This project aims at investigating a set of such functional indicators from the fields of hydrology and biogeochemistry. In particular we will investigate (1) flow regime and timing, (2) nutrient cycling and flux rates, and (3) sediment fluxes as likely indicators. For assessing flow regime and timing we will concentrate on studying stable water isotopes to estimate mean transit time distributions that are likely to be impacted by changes in rainfall patterns and land use. Hysteresis loops of nitrate concentrations and calculated flux rates will be used as functional indicators for nutrient fluxes, most likely to be altered by changes in temperature as well as by land use and management. Finally, sediment fluxes will be measured to indicate surface runoff contribution to total discharge, mainly influenced by intensity of rainfall as well as land use. Monitoring of (1) will be based on intensive sampling campaigns of stable water isotopes in stream water and precipitation, while for (2) and (3) we plan to install automatic, high temporal-resolution field analytical instruments. Based on the data obtained by this intensive, bust cost effective monitoring, we will develop the functional indicators. This also provides a solid database for process-based model development. Models that are able to simulate these indicators are needed to enable projections into the future and to investigate the resilience of Ecuadorian landscape to global change. For the intended model set up we will couple the Catchment Modeling Framework, the biogeochemical LandscapeDNDC model and semi-empirical models for aquatic diversity. Global change scenarios will then be analyzed to capture the likely reaction of functional indicators. Finally, we will contribute to the written guidelines for developing a comprehensive monitoring program for biodiversity and ecosystem functions. Right from the beginning we will cooperate with four SENESCYT companion projects and three local non-university partners to ensure that the developed monitoring program will be appreciated by locals and stakeholders. Monitoring and modelling will focus on all three research areas in the Páramo (Cajas National Park), the dry forest (Reserva Laipuna) and the tropical montane cloud forest (Reserva Biologica San Francisco).
This project will provide quantitative estimates of the flow of low-salinity warm water through the Indonesian Gateway on suborbital timescales during MIS 2 and 3 (focusing on Dansgaard Oeschger (D-O) oscillations) and will assess the Indonesian Throughflow (ITF) s impact on the hydrography of the eastern Indian Ocean and global thermohaline circulation during this critical interval of high climate variability. ITF fluctuations, associated with sea level change, temperature and salinity variations in the West Pacific Warm Pool (WPWP) strongly influence precipitation over Australia, the strength of the southeast-Asian summer monsoon, and the intensity of warm meridional currents in the Indian Ocean. We will test the hypothesis that increased ITF is associated with warm interstadials of MIS 3, whereas a strong reduction in ITF occurred during stadials. We will use as main proxies planktonic and benthic foraminiferal isotopes in conjunction with Mg/Ca temperature estimates and radiogenic isotopes (mainly Nd) as tracers of Pacific water masses along depth transects in the Timor Passage and the eastern Indian Ocean. This project will provide the paleoceanographic framework that will be crucial to validate and refine circulation models of D-O events and high-frequency climate variability on a global scale.
Phosphorus is one of the most needed elements for soil fertilization and a strategic resource to ensure food security. Presently an important part of applied fertilisers originates from mineral resources. Almost no phosphorus rock resources exist in Europe, so that Europe strongly depends on imports. It is further expected that the phosphorus rack price will increase and the quality will decrease in the future. At the same time, most of the wastewater treatment plants (WWTP) remove phosphorus from the wastewaters, transferring it first to the sludge and later on part of it to the sludge liquor after dewatering. Therefore, sewage sludge is an attractive secondary resource for fertilizer production. In the whole of Europe the yearly produced sewage sludge (11.1 million tons) contains 310000 tons of phosphorus (assuming 28 gP/kg dry matter) which corresponds to 20Prozent of the total European phosphorus demand. New technologies are being developed for its recovery from the sludge, but only few examples of industrially implemented processes exist. Struvite precipitation is one of the most promising and among the few being implemented in full scale up to now. The application of struvite precipitation for phosphorus recovery from the sludge liquor is ecologically and economically beneficial. This project will study four innovations related to this process: Struvite precipitation in microbial fuel cells, struvite precipitation initiated by air stripping, struvite crystals agglomeration by addition of natural coagulants and flocculants and the application of low cost seawater concentrate, which is locally available in the main study site Burgas. The project will go deeper into the process design, namely by developing innovative techniques for phosphorus dissolution from the sludge matrix. To achieve this, the application of microbial fuel cells, high osmotic salt solution and waste acids will be studied experimentally. Furthermore, research will be carried out on nanofiltration for metal separation to control and improve the product quality. The technologies under study will be applied on model waste sludges originating from several waste water treatment chains with different technological levels in Bulgaria and Switzerland. The project will be complemented by a quantification of available phosphorus from existing WWTPs in Bulgaria and Switzerland as well as an assessment of the application potential of the developed technologies including a membrane process to provide high concentrated magnesium and sodium chloride solutions, respectively, for application in low cost struvite precipitation and osmotic shock treatment of sludge.
PI Trachte. Predicting future climate change is in itself already difficult, especially in such complex ecosystems as the Andean mountain rain and dry forest as well as the Paramo. The common tools to simulate global climate change are global circulation models (GCM). Because of their coarse resolution they are not able to capture atmospheric processes affecting the local climate. For this reason a dynamical downscaling approach will be used to develop a highly resolved spatial and temporal Climatic Indicator System (hrCIS) to derive ecologically relevant climate change indicators affecting the ecosystems of South Ecuador. A local-limited area model (LAM) will be used to (i) generate a highly resolved gridded climatology for present day (hrCISpr) based on reanalysis data and (ii) to generate a highly resolved gridded climatology for projected future (hrCISpf) based on the new Representative Concentration Pathways (RCP) scenario data. The output of the LAM for present day will be validated with in-situ measurement data and satellite-derived products to ensure the accuracy of the model for the simulations of the projected future. On the basis of statistical analysis of both climatologies changes in climate indicators such as air temperature and precipitation regime will be described. PI Bendix. The proper storage, curation and accessibility of environmental data is of crucial importance for global change research particularly for monitoring purposes. C 12 offers an adequate data management system for the Platform for Biodiversity and Ecosystem Monitoring and Research. This is achieved by extending the web-based information management system FOR816DW (a data warehouse for collaborative ecological research units) with features like - an automatic upload interfaces - a workbench for integrative analysis - a user defined alert system, to facilitate environmental monitoring for scientist as well as stakeholders. A further objective is the transfer of knowledge and information (know how, source code, and collection data) to our partners in Ecuador. We cooperate with university and non-university parties in the joint establishment of a Data access platform for environmental data of the region. This includes the long-term accessibility, which is envisaged by a data transfer to the planned German national data infrastructure GFBio.
Proposed research: This research programme proposes to analyze the predictability of the hydrologic behaviour of Alpine ecosystems at the spatio-temporal scales relevant for water management, i.e. at spatial scales of between 200 km2 (e.g. a hydropower production catchment) and around 5000 km2 (e.g. flood management of the Swiss Rhone catchment) and at temporal scales ranging from hours to seasons. Research context: Quantitative stream flow predictions are essential for the sustainable management of our natural and man-made environment and for the prevention of natural hazards. Despite of ever better insights into the involved physical processes at the point scale, many existing catchment scale runoff prediction models still show a lack of reliability for stream flow prediction. The present research programme addresses this foremost issue in Alpine environments, which are the source of many major European rivers and play a dominant role for hydropower production and flood protection. Stream flow prediction in such environments is particularly challenging due to the high spatial variability of the meteorological driving forces opposed to notorious data scarcity in remote and high elevation areas. Project context: The present proposal is a follow-up proposal of the Ambizione project Hydrologic Prediction in Alpine Environments. During the main phase of the project (3 years), certain essential research objectives could not be reached, due namely to the maternity leave of the principal investigator (PI), but also due to additional research questions that emerged at the very beginning of this research. The present follow-up project proposes to complete the research programme during a complementary project phase (2 years). Objectives: The main objective of this research programme is to assess under which conditions simple hydrological models can give reliable stream flow predictions in Alpine environments. This objective will be reached based on an analysis of the variability of natural flow generation processes and of the variability of corresponding state-of-the-art hydrological model outputs. During the main phase of the project, the research was concentrated on the analysis of flow generation processes related to snowmelt, which in Alpine areas dominate the hydrological response over a large part of the year. The achieved results include a new hourly snowmelt model combined to a spatially-explicit precipitation-runoff model, an improved snowfall-limit prediction method for hydrological models and a weather generator that produces coupled temperature and prediction scenarios to analyze how these two meteorological variables integrate to the snow-hydrological response.(...)
Bacteria can trigger mineral formation by their metabolic activity or by provision of sorption and nucleation sites on cell surfaces. Sulfide minerals occur in marine and freshwater sediments primarily as the result of dissimilatory sulfate reduction which is mediated by a phylogenetically diverse group of Prokaryotes that gain their energy by anaerobic respiration with sulfate as terminal electron acceptor. In principle it is the reversal process of pyrite oxidation which generates acidic metal-rich waters causing severe environmental pollution in coal and metal ore mining areas. The formation of iron sulfides is a major process in controlling global element cycling, besides, it is the target process during the treatment of acid mine drainage by the use of dissimilatory sulfate reduction. The sustainability of bioremediation depends on the extent and stability of iron sulfides formed. However, so far little is known about iron sulfide formation under acidic conditions and the role that bacteria play in this process. The objectives of this project are i) to investigate the formation of iron sulfide minerals in sulfate-reducing enrichment cultures under low pH-conditions, ii) to analyse and characterise mineral structures and cell-mineral interactions, iii) to elucidate community structure and its response to varying pH values, and iv) to find out whether the involved bacteria benefit from iron sulfide precipitation. This study may contribute to our general understanding of biomineral formation and sulfate reduction under acidic conditions and may help us to further improve bioremediation strategies.
In the South-Indian city of Chennai (formerly called Madras), disastrous tropical monsoon linked with excessive precipitation frequently lead to wide-flat floods in the coastal plains. Caused by rapid urbanisation, the population in urban and periurban areas is more and more affected by these events. Besides the marginalised population living in disfavoured areas, increasingly also the more wealthy population that settles in flood prone areas is affected. Interdisciplinary assessments are needed to explain the complex causes of floods. The project analysed environmental aspects of risk exposure as well as socioeconomic aspects of risk perceptions and response strategies. By combining natural-scientific with socio-scientific approaches, a holistic perspective of the complex reasons and impacts of flooding could be covered. The project consisted of the following steps: 1. Analysis of flood risk exposure: Physio-geographic, hydrological and meteorological realities in risk areas were assessed using remote sensing (RS) data and geographical information systems (GIS). 2. Analysis of risk perception and management: Affected marginalised poor segments of the population, affected middle class groups as well as local planning authorities were interviewed to analyse local perceptions of floods and dominant management strategies. 3. Development of a flood risk map: The results of the risk assessment were integrated in an interactive flood risk map. The map - using several different layers - functions as a flood risk management tool including often neglected socioeconomic and socio-cultural parameters which reflect local vulnerability. 4. Holding of two workshops: A policy workshop with different stakeholders involved in flood management and affected by floods was held in Chennai in August 2007. This workshop was to foster communication and dialogue between different stakeholders and to create awareness on the current situation and problems in the area. A roundtable with the partners from India and organisations dealing with flood management and flood relief measures took place in October 2007 in Freiburg in order to present and discuss the findings and to strengthen future co-operation, communication and networks.
Surface exposure dating has become an important tool for glacial and climate reconstructions in recent years. Especially in arid mountain areas, where organic material for radiocarbon dating is scarce, it is now possible to establish precise glacial chronologies from moraine deposits. In previous and ongoing SNF-projects, we have mapped moraines in many parts of the Central Andes. Only recently we started to apply surface exposure dating using in-situ 10Be in the Cordillera Real and Cochabamba, Bolivia (ca.15 S), and in the Andes of Central Chile/Argentina (30-40 S). We expect to get important insights into past changes of the tropical and the ek-tropical atmospheric circulation, i.e. the westerlies in the south and the South American Summer Monsoon in the north. First results from northern Chile (ca.30 S) show that glaciers advanced ca.30 ka BP and again between ca.14 and 12 ka BP. Moisture advection during the temperature minimum of the global LGM (last glacial maximum: 18-20 ka BP) seems to have been insufficient to allow considerable glacial extents. Preliminary exposure ages indicate that glaciers in the Cordillera Real and Cochabamba did not only advance during the LGM, triggered by temperature reductions, but also during the Late Glacial and the Early Holocene - likely due to increased precipitation during the 'Tauca' and 'Coipasa' wet phases (18-14 and 13-11 ka BP). Although our preliminary results are promising and show the high potential of surface exposure dating for Late Quaternary glacier and climate reconstruction, three aspects are evident that currently limit the paleoclimatic interpretations: I.) our preliminary chronologies in Bolivia are based on too few exposure ages II.) there is a gap of glacial chronologies in NW-Argentina and South Bolivia III.) up to now there is a complete absence of calibration sites in the Central Andes In order to further assess the role of temperature and the tropical and ek-tropical moisture sources, respectively, on the glaciation history in the Central Andes, we intend to apply surface exposure dating in six selected research areas in NW-Argentina (4) and Bolivia (2). In combination with the glacier-climate model, which has previously been developed in our working group, the exposure age chronologies will allow the quantitative reconstruction of temperature and precipitation conditions for the dated glacial stages. An important focus of the proposed project is to carry out calibration studies. This implies the necessity to independently date glacial deposits using for example radiocarbon dating of lake sediments. This is the only way to minimize the systematic uncertainties of the exposure ages and thus to confirm the paleoclimatic interpretations.
In rivers and streams, biofilms are major sites of carbon cycling. They retain large amounts of dissolved organic carbon (DOC) and consequently are most important for the development of aquatic organisms on higher trophic levels. Besides autochthonous primary production, which supports heterotrophic production in biofilms, large amounts of organic carbon (OC) are derived from the surrounding catchment areas. More precipitation and more frequent and severe floods due to climate change will increase the transport of material into streams. Moreover, catchment characteristics including vegetation affect the transport and nature of DOC into aquatic ecosystems. Thus, carbon dynamics depend on how a stream is embedded within and interacts with its surrounding terrestrial environment. Despite its importance for carbon cycling it is not understood to which extent autochthonous or allochthonous carbon is used in biofilms and how increased addition of allochthonous carbon determines the relative use of both carbon sources. The combined application of 13C and 14C analysis on differently labeled DOC sources intend to answer to which extent DOC from different sources is used by bacteria in biofilms and finally transported to higher trophic levels. The use of 13C and 14C signals on carbon compounds and biomarkers is an excellent method to determine carbon sources for microorganisms and the transport of labeled material within the food web.
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