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.
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 effects of climate change in mountain regions are expected to be more intense and detectable than in many other regions of the world since climatic conditions vary sharply with elevation. The climatic impacts on fragile ecosystems of Nepal's Himalaya are no exception. It is increasingly being observed that biological systems are disrupted, migrations are starting earlier and species' geographic ranges are shifting. The overall goal of this research collaboration is to identify and analyze threats and opportunities related to climate change. In mountain regions, climate warming is generally considered to be correlated with a change in seasonal precipitation. Both changes will influence the way and intensity of human land use. In our project we therefore propose to study how different levels of land-use intensity (from primeval forests to arable fields) do affect biodiversity. We will investigate replicated land-use gradients at various altitudes in three regions with a different regional climate, and in particular, different levels of seasonal precipitation. Our core study region will be the Manasalu Conservation Area characterized by an oceanic climate and this region will be compared to a hyper-oceanic region in Annapurna Conservation Area and a semi-oceanic region of the Sagarmatha (Everest) region. By using a quasi-experimental landscape approach organisms will be investigated in six valleys covering different precipitation regimes, altitudinal gradients of 1600 m representing different temperatures, and four land use types ranging from closed forests to open landscapes. These organisms will include plants, lichens, mushrooms, butterflies and birds. Population data of Red Listed mammals (Flags
The hydrogeochemical dynamics in mountainous areas of the Korean Peninsula are mainly driven by a monsoon-type climate. To examine the interplay between hydrological processes and the mobilization and subsequent transport and export of nitrate and DOC from catchments, a field study was initiated in the Haean catchment in north-eastern South Korea under highly variable hydrologic conditions. In order to identify nitrate and DOC source areas, a subcatchment (blue dragon river) within the Haean basin, which includes different types of landuses (forest, dry land farming, and rice paddies), was selected. In 2009, high frequency surface water samples were collected at several locations during summer storm events. A similar but more comprehensive sampling routine was completed in 2010. In order to investigate the groundwater level fluctuations relative to the hydraulic potentials, a piezometer transect was installed across a second order stream of the subcatchment. The results so far suggest deep groundwater seepage to the aquifer with practically no base flow contributions to the stream in the mid-elevation range of the catchment. In 2009 the focus of research was within the subcatchment, in 2010 additionally a second piezometer transect was installed at a third order stream in the lower part of the catchment (main stem of the Mandae River) where more dynamic groundwater/surface water interactions are assumed due to expected higher groundwater levels in this part of the basin. In order to investigate these interactions piezometers equipped with temperature sensors and pressure transducers were installed directly into the river bed. Based on the observed temperature time series and the hydraulic potentials the water fluxes between the groundwater and the river can be calculated using the finite-difference numerical code, VS2DH. VS2DH solves Richard s equation for variably-saturated water flow, and the advection-conduction equation for energy transport. The field data collected at the second piezometer transect suggest that the investigated river reach exhibits primarily losing surface conditions throughout most of the year. Gaining groundwater conditions at the river reach are evident after monsoonal extreme precipitation events. At the transect streambed aggradation and degradation due to bedload transport was observed. Significant erosion has been reported throughout the catchment after extreme events. Results indicate that the event-based changes in streambed elevation, is an additional control on groundwater and surface water exchange. The streambed flux reversals were found to occur in conjunction with cooler in-stream temperatures at potential GW discharge locations. The export of nitrate and DOC were found to be variable in time and strongly correlated to the hydrologic dynamics, i.e. the monsoon and pre- and post-monsoon hydrological conditions. usw.
High-latitude and high-altitude forests are sensitive ecosystems that are more exposed to global warming in recent decades than forests of the temperate zones. As a result of the accelerating climate change, these forests may undergo severe changes regarding spatial distribution and species composition, the carbon, water and nitrogen cycles. This will have tremendous consequences for the sustainable functioning of the ecosystems and potential feedbacks to the atmosphere, such as increased release of greenhouse gases from soils. Insight into extreme past climate conditions and the response of Boreal and Alpine forests to these conditions provides an invaluable analogy for the potential future response. Trees from temperature-limited sites are known as sensitive proxies for climate reconstruction, while the availability of well-preserved wood in these regions enable the deciphering of past environmental conditions for centuries up to millennia. In this project, our main goal is to obtain a comprehensive description of the climatic and environmental changes during pronounced warm and cool periods of the past 1500 years. We want to achieve this goal by addressing the following three objectives: 1) we aim to better quantify the magnitude of temperature and precipitation variability for known periods of extreme climate conditions, focusing on the cold anomaly around 536AD, the Medieval optimum period, the 'little ice age' period and the last century, 2) we will use the combined analysis of tree-ring width, carbon and oxygen isotopes and physiological models to decipher the response of the trees in terms of photosynthesis and water-use during these periods, 3) and we want to determine the spatial and temporal coherence of large-scale climate events for Europe and northern Eurasia. We have access to unique dated tree-ring material from three sites in Northern Siberia and one site from the Alps that cover the investigation periods. We will use ring-width as a measure of growth and stable isotope ratios of carbon and oxygen of tree-ring cellulose as a measure of photosynthesis and water-use, while both isotopes are also related to temperature and precipitation. By applying a coupled photosynthesis-isotope fractionation model, which is driven by microclimate, photosynthesis, and soil water balance, we will be able to relate climatic to physiological changes. The results of the project will enable us to better understand the response of trees in temperature-limited environment to a changing climate.
Seasonal to annual quantitative reconstructions of spatially-explicit climate state variables for the last 1000 years are recognized as one of the primary targets for current climate research (IGBP-PAGES / WCRP-CLIWAR). The lack of adequate paleoclimate data series is strikingly evident for the southern hemisphere. This proposal will (i) explore systematically the potential of in-situ reflectance spectroscopy as a novel tool for quantitative high-resolution climate reconstructions in a variety of lakes in south-central Chile, and (ii) produce a number of temporally highly resolved temperature and/or precipitation reconstructions for the regional expression of climate variability during the past 1000 years. The project contributes to the international regional multi-proxy climate reconstruction in South America (IGBP-PAGES LOTRED-SA).
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.
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