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.
The goal of this study was to enable a prognosis on the future rainfall conditions of the Nile Equatorial Lakes regions by delivering time-series of monthly rainfall sums for the time-period from 2021 to 2050 that can be used for all kinds of applications. One example might be the dimensioning of hydraulic structures. In these very long lasting investments, future climatic conditions have to be considered during present planning and construction.The principal sources of information on future climate conditions are General Circulation Models (GCMs). These are physically based atmospheric models that resemble a numerical weather prediction system but on a much coarser scale. This forecast cannot be perfect. Especially, it cannot predict single values, e. g. if January 2050 will be rather wet or dry, but only climatic references, i.e. state, if Januaries in general will become wetter or dryer in the future. Even if the predictions of a GCM were perfect, its output could not be used directly for hydrological purposes, due to its coarse resolution. The monthly precipitation values that are provided by the GCM present the spatially averaged precipitation over a grid cell of several thousand square kilometres. This 'block rainfall' can differ significantly from rainfall measured at the ground. Rain gauges are influenced by local effects like micro climatic conditions or orographic effects of mountain ranges that GCMs are not able to resolve.This study combined the information from different data sources. As global trend information, monthly precipitation values from two GCMs (ECHAM5 and HadCM3) were used. Three CO2-emission scenarios (A1b, A2 and B1) were considered in this data. As local ground reference observed monthly rainfall sums from several rain gauges in East Africa as well as from three reanalysis projects (Climate Research Unit, University of Delaware and GPCC) were used.At each rain gauge or observation point in the reanalysis a technique called 'Quantile-Quantile-Transformation' was applied to establish a relationship between the Cumulative Distribution Function (CDF) of the GCMs and that of the ground references during the calibration period from 1961-1990. The CDFs were fitted by non-parametric Kernel-Smoothing. To account for potential shifts in the annual cycles of GCMs and ground references, the transformations was done separately for each month.Assuming that the relation between Global Model and local response will be constant in the future, the global predictions of the GCM can be downscaled to local scale, leading to future rainfall scenarios that are coherent with observed past rainfall.Combining the data from three CO2-emission scenarios of two GCM with three reanalysis data sets, an ensemble of 18 different rainfall time-series was created for each observation point. The range of this ensemble helps to estimate the possible uncertainties in the prognosis of future monthly precipitation sums from 2021 to 2050.
As an isolated marginal sea, the Black Sea reacted particularly sensitive to paleoclimatic and paleoenvironmental changes and on both global and regional scales. In spite of its unique potential for high resolution paleoclimate reconstructions, late Quaternary sediment sequences of the Black Sea have only subordinately been studied with respect to paleoclimatic questions. This is somewhat surprising considering the key-geographic location of the Black Sea, where climate is strongly affected by two major climate systems; the North Atlantic/Siberian pressure system in winter and the Indian monsoon in summer. Highly-resolved and precisely dated paleoclimate records are crucial for reconstructing past regional climate variability, which can then be compared to paleoclimate records from the North Atlantic, Europe and the Indian monsoon domain. Several core sites in the Black Sea along the North-Anatolian rim can provide records of vegetation dynamics and changing precipitation regimes in the Anatolian hinterland as well as paleoceanographic/ paleolimnologic data of environmental changes in the marine/limnic Black Sea system itself. Uranium-series dated stalagmites from Sofular Cave located at the Black Sea coast in north-western Turkey will provide, as terrestrial counterpart, long complementary paleorecords of changes in vegetation and precipitation. When combined, such records will allow us to better quantify the far-field effects of North Atlantic climate and Indian monsoon during the Holocene, Eemian and the last two glacial/interglacial transitions (T1 and T2).
The proposed research contributes to the following overarching goals: (i) better understanding of the complex hydro-biogeochemical and biological interactions in tropical montane forest systems under natural and altered conditions; (ii) the integration of this knowledge in an integrated modeling system that will be tested to long-term and spatially dense datasets; and (iii) prognosis of the likely impact of climate change scenarios on the hydro-biogeochemical and biological processes considering for each process the uncertainty range on the prediction. A main deliverable of the project will be the expanded CMF modeling tool enabling the simulation of the combined impact of land use and climate change on hydro-biogeochemical processes and biological interaction. The project follows the general philosophy of cooperative researchers between experimentalists and modelers, thereby facilitating the implementation of state-of-the-art system understanding into simulation tools. The integrated modelframework developed in D4 will therefore allow to assess the likely impacts of global change on tropical montane rainforest ecosystems of Ecuador.
The Antarctic ice sheet and ice shelves cover an area of ca. 14 million km2, over 300 times the area of Switzerland. An additional 19 million km2 of winter sea ice expands the overall southern cryosphere to greater than 6 percent of the Earths surface. With ca. 15 million km2 of that sea ice melting away each summer, the Southern Ocean sea ice cover is one of the largest annual changes on the Earths surface. These large numbers underscore the importance of the Antarctic to global climate processes, and challenge our ability to accurately represent the Antarctic in global climate models. Switzerlands long history of involvement in Antarctic climate and paleoclimate research became grounds for its advancement to full membership in the Scientific Committee on Antarctic Research in 2004. In recognition of growing Swiss interest in the Antarctic, field research described in this proposal will be an international collaborative effort, using logistics and environmental permits issued by Australia, Belgium and Germany. Three distinct lines of research will be pursued with the support requested from SNF and with the assistance of facilities and graduate students provided by the EPFL-ENAC-IIE-CRYOS Laboratory. These research topics will contribute to an increased understanding of oceanic and atmospheric processes influencing the mass balance of the Antarctic sea ice and ice sheet. 1) Field measurements of precipitation, blowing snow, and snow thickness distribution in the Antarctic sea ice zone. International research cruises into Antarctic sea ice fields in consecutive austral winters (September - October 2012 and June - August 2013) will measure blowing snow transport, precipitation, and snow accumulation patterns on sea ice. A PhD student whose dissertation research focuses on snow distribution on sea ice will participate in this work. 2) Numerical modeling of precipitation, blowing snow, and accumulation of snow over sea ice and coastal regions of the Antarctic ice sheet. Precipitation, blowing snow and related measurements obtained during these expeditions will be used in the validation of a high-resolution numerical model of blowing snow transport. That model will in turn be used in larger-scale studies of precipitation enhancement of blowing snow processes, sublimation and riming of atmospheric ice crystals, and the recycling of moisture between the sea ice zone and the Antarctic ice sheet. 3) Time-series oceanographic measurements in a remote area of the east Antarctic coastline, in collaboration with Belgian and EU research programs on ice sheet stability and sea level rise. This study will focus on coastal ocean processes that have been largely overlooked in recent assessments of ice sheet mass balance and the potential contribution of the East Antarctic ice sheet to near-term sea level rise.
A crucial vulnerability faced by the international community in the near future will be access to fresh water in sufficient quantity and of adequate quality to meet increasing and more diverse needs of a growing world population. Mountains have always held a privileged relationship with water, as the sources of the world's greatest rivers and as the home of the great reserves of water held in glaciers.Major global forces nevertheless threaten these mountain reservoirs. Climate change is predicted to modify quantities of water available as well as shift its seasonality. It is likely that even greater challenges will come from the dynamics of human behavior. Population growth is perhaps the most obvious threat to sufficient water supply but it goes hand in hand with changing norms and evolving activities, leading to increasing competition among use for agriculture, industry, leisure, and domestic activities. Influencing production and distribution are societal rules and norms such as pricing schemes, regulations, and property rights that determine who gets how much water and when. Appropriate solutions to oversee water use will contribute to efficient and equitable distribution. Poor management can aggravate shortages, increase social and economic disparities, and is a potential source of deadly international conflict.Mountain regions are generally considered to be the 'water towers of the world' not only because they receive important quantities of precipitation, but also because this water is then stored there in the form of snow and ice. Populations living in mountains have a very long history of overseeing this precious resource and can be the source of important knowledge about solving the dilemmas of managing a public good that knows no boundaries and can therefore be diverted and traded. Resources governed by natural processes in this way become inextricably linked with political and economic forces. (...)
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.
The emission of anthropogenic CO2 from the combustion of fossil fuels has led to an increase in the concentration of CO2 in the atmosphere from a pre-industrial level of ca. 280 ppm to its current level of ca. 380 ppm. This significant increase in CO2 concentration is almost certainly linked to long-term climate change. Considering that the use of coal is projected to increase by ca. 80 Prozent over the next 20 years, it is imperative to find ways of using coal which limit the release of CO2 into the atmosphere. However, the currently available CO2 capture technology, i.e. amine scrubbing, comes with a large penalty on plant efficiency. Therefore, advanced CO2 capture techniques that utilise calcium-based solid sorbents have been proposed. Calcium-based sorbents possess a high theoretical up-take of CO2, however, the capacity of natural calcium-based sorbents to capture CO2 decreases markedly with the number of cycles of carbonation and calcination. Thus, the development of synthetic CO2 sorbents with high cyclic stability and reactivity is an important research objective in the development of efficient and sustainable energy cycles. The overall objective of this proposal is the development of novel, synthetic, calcium-based sorbents for CO2 capture. These sorbents shall possess high cyclic reactivity and capacity, tolerance towards sulphur and a low tendency for attrition. Two advanced particle preparation techniques, i.e. co-precipitation and sol-gel, which offer the possibility to tailor key structural parameters of the sorbent, such as pore size distribution, which in turn influence the overall CO2 uptake strongly, will be applied. To improve the understanding of the underlying structure mechanisms during carbonation and calcination such as sintering, pore blockage and product layer formation nanometre-scale, advanced 3D tomographic measurements of the structure of the sorbents and changes thereof during repeated cycles of calcination and carbonation shall be developed. We propose the novel application of: (i) advanced electron microscopy techniques, i.e. High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM) and (ii) Laser Local Electrode Atom Probe (LEAP), to provide such detailed measurements on a nanometre-scale. It is hoped that, based on a detailed, fundamental understanding of the preparation method and the underlying structural changes occurring during reaction, this research will enable the rational design of highly efficient CO2 sorbents. The successful completion of this project would be an important step towards the design of highly efficient particles that would pave the way for a process for capturing CO2 with a small energy penalty. The detailed 3D tomographic measurements of chemical and structural changes in the nano- and micrometre scale are not only important in the field of CO2 sorbents, but will aid a better understanding of gas-solid reactions in general.
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