Microbial ecology of biotechnological processes

The investigation of phylogenetic diversity and functionality of complex microbial communities in relation to changes in the environmental conditions represents a major challenge of microbial ecology research. Nowadays, particular attention is paid to microbial communities occurring at environmental sites contaminated by recalcitrant and toxic organic compounds. Extended research has evidenced that such communities evolve some metabolic abilities leading to the partial degradation or complete mineralization of the contaminants. Determination of such biodegradation potential can be the starting point for the development of cost effective biotechnological processes for the bioremediation of contaminated matrices. This work showed how metagenomics-based microbial ecology investigations supported the choice or the development of three different bioremediation strategies. First, PCR-DGGE and PCR-cloning approaches served the molecular characterization of microbial communities enriched through sequential development stages of an aerobic cometabolic process for the treatment of groundwater contaminated by chlorinated aliphatic hydrocarbons inside an immobilized-biomass packed bed bioreactor (PBR). In this case the analyses revealed homogeneous growth and structure of immobilized communities throughout the PBR and the occurrence of dominant microbial phylotypes of the genera Rhodococcus, Comamonas and Acidovorax, which probably drive the biodegradation process. The same molecular approaches were employed to characterize sludge microbial communities selected and enriched during the treatment of municipal wastewater coupled with the production of polyhydroxyalkanoates (PHA). Known PHA-accumulating microorganisms identified were affiliated with the genera Zooglea, Acidovorax and Hydrogenophaga. Finally, the molecular investigation concerned communities of polycyclic aromatic hydrocarbon (PAH) contaminated soil subjected to rhizoremediation with willow roots or fertilization-based treatments. The metabolic ability to biodegrade naphthalene, as a representative model for PAH, was assessed by means of stable isotope probing in combination with high-throughput sequencing analysis. The phylogenetic diversity of microbial populations able to derive carbon from naphthalene was evaluated as a function of the type of treatment.

Proceedings of the Seventeenth Annual Biochemical Engineering Symposium

This is the seventeenth of a series of symposia devoted to talks by students about their biochemical engineering research. The first, third, fifth, ninth, twelfth, and sixteenth were at Kansas State University, the second and fourth were at the University of Nebraska-Lincoln, the sixth was in Kansas City and was hosted by Iowa State University, the seventh, tenth, thirteenth, and seventeenth were at Iowa State University, the eighth and fourteenth were at the University of Missouri–Columbia, and the eleventh and fifteenth were at Colorado State University. Next year's symposium will be at the University of Colorado. Symposium proceedings are edited by faculty of the host institution. Because final publication usually takes place elsewhere, papers here are brief, and often cover work in progress. ContentsThe Effect of Polymer Dosage Conditions on the Properties of ProteinPolyelectrolyte Precipitates, K. H. Clark and C. E. Glatz, Iowa State University An Immobilized Enzyme Reactor/Separator for the Hydrolysis of Casein by Subtilisin Carlsberg, A. J. Bream, R. A. Yoshisato, and G. R. Carmichael, University of Iowa Cell Density Measurements in Hollow Fiber Bioreactors, Thomas Blute, Colorado State University The Hydrodynamics in an Air-Lift Reactor, Peter Sohn, George Y. Preckshot, and Rakesh K. Bajpai, University of Missouri–Columbia Local Liquid Velocity Measurements in a Split Cylinder Airlift Column, G. Travis Jones, Kansas State University Fluidized Bed Solid Substrate Trichoderma reesei Fermentation, S. Adisasmito, H. N. Karim, and R. P. Tengerdy, Colorado State University The Effect of 2,4-D Concentration on the Growth of Streptanthus tortuosis Cells in Shake Flask and Air-Lift Permenter Culture, I. C. Kong, R. D. Sjolund, and R. A. Yoshisato, University of Iowa Protein Engineering of Aspergillus niger Glucoamylase, Michael R. Sierks, Iowa State University Structured Kinetic Modeling of Hybidoma Growth and Monoclonal Antibody Production in Suspension Cultures, Brian C. Batt and Dhinakar S. Kampala, University of Colorado Modelling and Control of a Zymomonas mobilis Fermentation, John F. Kramer, M. N. Karim, and J. Linden, Colorado State University Modeling of Brettanomyces clausenii Fermentation on Mixtures of Glucose and Cellobiose, Max T. Bynum and Dhinakar S. Kampala, University of Colorado, Karel Grohmann and Charles E. Yyman, Solar Energy Research Institute Master Equation Modeling and Monte Carlo Simulation of Predator-Prey Interactions, R. 0. Fox, Y. Y. Huang, and L. T. Fan, Kansas State University Kinetics and Equilibria of Condensation Reactions Between Two Different Monosaccharides Catalyzed by Aspergillus niger Glucoamylase, Sabine Pestlin, Iowa State University Biodegradation of Metalworking Fluids, S. M. Lee, Ayush Gupta, L. E. Erickson, and L. T. Fan, Kansas State University Redox Potential, Toxicity and Oscillations in Solvent Fermentations, Kim Joong, Rakesh Bajpai, and Eugene L. Iannotti, University of Missouri–Columbia Using Structured Kinetic Models for Analyzing Instability in Recombinant Bacterial Cultures, William E. Bentley and Dhinakar S. Kompala, University of Colorado

Uranium concentrations and isotope ratios Bahamas seawater and ODP holes pore-water

The geometry, timing, and rate of fluid-flow through carbonate margins and platforms is not well constrained. In this study, we use U concentrations and isotope ratios measured on small volumes of pore-water from Bahamas slope sediment, coupled with existing chlorinity data, to place constraints on the fluid-flow in this region and, by implication, other carbonate platforms. These data also allow an assessment of the behaviour of U isotopes in an unusually well constrained water-rock system. We report pore-water U concentrations which are controlled by dissolution of high-U organic material at shallow depths in the sediment and by reduction of U to its insoluble 4+ state at greater depths. The dominant process influencing pore-water (234U/238U) is alpha recoil. In Holocene sediments, the increase of pore-water (234U/238U) due to recoil provides an estimate of the horizontal flow rate of 11 cm/year, but with considerable uncertainty. At depths in the sediment where conditions are reducing, features in the U concentration and (234U/238U) profiles are offset from one another which constrains the effective diffusivity for U in these sediments to be c. 1-2 * 10**-8 cm**2/s. At depths between the Holocene and these reducing sediments, pore-water (234U/238U) values are unusually low due to a recent increase in the dissolution rate of grain surfaces. This suggests a strengthening of fluid flow, probably due to the flooding of the banks at the last deglaciation and the re-initiation of thermally-driven venting of fluid on the bank top and accompanying recharge on the slopes. Interpretation of existing chlorinity data, in the light of this change in flow rate, constrain the recent horizontal flow rate to be 10.6 ( 3.4) cm/year. Estimates of flow rate from (234U/238U) and Cl[-] are therefore in agreement and suggest flow rates close to those predicted by thermally-driven models of fluid flow. This agreement supports the idea that flow within the Bahamas Banks is mostly thermally driven and suggests that flow rates on the order of 10 cm/year are typical for carbonate platforms where such flow occurs.

Ice and chlorophyll a concentration and mesozooplankton characteristics during two 'On Thin Ice' cruises, northern Svalbard waters

The spatial variation in mesozooplankton biomass, abundance and species composition in relation to oceanography was studied in different climatic regimes (warm Atlantic vs. cold Arctic) in northern Svalbard waters. Relationships between the zooplankton community and various environmental factors (salinity, temperature, sampling depth, bottom depth, sea-ice concentrations, algal biomass and bloom stage) were established using multivariate statistics. Our study demonstrated that variability in the physical environment around Svalbard had measurable effect on the pelagic ecosystem. Differences in bottom depth and temperature-salinity best explained more than 40% of the horizontal variability in mesozooplankton biomass (DM/m**2) after adjusting for seasonal variability. Salinity and temperature also explained much (21% and 15%, respectively) of the variability in mesozooplankton vertical distribution (ind./m**3) in August. Algal bloom stage, chlorophyll-a biomass, and depth stratum accounted for additional 17% of the overall variability structuring vertical zooplankton distribution. Three main zooplankton communities were identified, including Atlantic species Fritillaria borealis, Oithona atlantica, Calanus finmarchicus, Themisto abyssorum and Aglantha digitale; Arctic species Calanus glacialis, Gammarus wilkitzkii, Mertensia ovum and Sagitta elegans; and deeper-water inhabitants Paraeuchaeta spp., Spinocalanus spp., Aetideopsis minor, Mormonilla minor, Scolecithricella minor, Gaetanus (Gaidius) tenuispinus, Ostracoda, Scaphocalanus brevicornis and Triconia borealis. Zooplankton biomasses in Atlantic- and Arctic-dominated water masses were similar, but biological ''hot-spots'' were associated with Arctic communities.

Effect of the pulse trajectory on ultrasonic fluid velocity measurement

In a general situation a non-uniform velocity field gives rise to a shift of the otherwise straight acoustic pulse trajectory between the transmitter and receiver transducers of a sonic anemometer. The aim of this paper is to determine the effects of trajectory shifts on the velocity as measured by the sonic anemometer. This determination has been accomplished by developing a mathematical model of the measuring process carried out by sonic anemometers; a model which includes the non-straight trajectory effect. The problem is solved by small perturbation techniques, based on the relevant small parameter of the problem, the Mach number of the reference flow, M. As part of the solution, a general analytical expression for the deviations of the computed measured speed from the nominal speed has been obtained. The correction terms of both the transit time and of the measured speed are of M 2 order in rotational velocity field. The method has been applied to three simple, paradigmatic flows: one-directional horizontal and vertical shear flows, and mixed with a uniform horizontal flow.

Influência da configuração da célula combustível microbiana na geração de energia elétrica a partir da degradação de compostos orgânicos

Nessa pesquisa foram testadas tanto CCM com membranas e sem membranas que tinham por característica reproduzir sistemas de tratamento de esgoto sanitário. A etapa experimental desse trabalho foi dividida entre o Brasil (ensaios com CCM sem a MTP e utilizando esgoto sanitário) e Portugal (ensaios com CCM tradicionais de uma e duas câmaras, utilizando água residuária sintética e a bactéria Lactobacillus pentosus). A execução em dois locais diferentes resultou em um maior aprofundamento e desenvolvimento da pesquisa. As CCM foram avaliadas principalmente quanto ao potencial elétrico e eficiência da degradação de compostos orgânicos (esgoto sanitário e água residuária sintética). Para os dados obtidos no Brasil, as três configurações apresentaram maior diferença na potência em função do modo de operação. A operação intermitente apresentou a maior potência (11 mW/m2) para a CCM cilíndrica de fluxo ascendente, enquanto que operação continua a maior potência (4,2 mW/m2) foi obtida para a CCM retangular de fluxo horizontal, a qual também apresentava uma maior facilidade na manutenção quanto aos eletrodos (adição/remoção). A CCM cúbica de fluxo ascendente devido a sua concepção simples demandava um sistema complementar para o aumento da remoção de DQO. Apesar da baixa potência mensurada para os ensaios realizados no Brasil há de se pontuar que os mesmos foram obtidos para reatores sem membranas e utilizando o esgoto sanitário, o qual apresentou grande sazonalidade. Para a etapa realizada em Portugal, foi possível realizar quinze diferentes ensaios e mais um ensaio específico de crescimento. A maior potência (10,37 mW/m2) foi obtida para CCM de câmara dupla operada de modo contínuo para um tempo de detenção hidráulico (TDH) de 20 horas. A maior potência obtida para a CCM de câmara única foi de 5,53 mW/m2 quando houve a adição do extrato de levedura (função teórica de mediador). A potência da CCM, na maioria das vezes, esteve relacionada à proporção de sólidos voláteis e totais, SV/ST, quantidade de bactérias, pH, características de operação e por fim a configuração da CCM. O ensaio de crescimento revelou a correlação da potência em função da quantidade de bactérias inseridas da massa do biofilme (SV) e mostra-se como uma ferramenta na avaliação da potência das CCM.

Avaliação do antagonismo do efeito do sódio sobre o tratamento de água residuária de Charqueada com elevada salinidade em reator anaeróbio de manta de lodo (UASB)

As águas residuárias provenientes da indústria do charque são conhecidas por apresentarem elevado teor de cloreto de sódio, aliado a grandes concentrações de matéria orgânica proveniente do sangue liberado ao longo do processo industrial. Esse tipo de água residuária apresenta potencial para degradação biológica, contudo, o cloreto de sódio, em concentração elevada, pode inibir a atividade dos microrganismos e, em alguns casos, levar sistemas biológicos à falência. No presente trabalho, foi avaliada a viabilidade de degradação anaeróbia de efluente sintético de Charqueada contendo elevado teor de cloreto de sódio, em reator anaeróbio tipo UASB (Upflow Anaerobic Sludge Blanket), em escala de laboratório. Foram utilizados 4 reatores, alimentados com água residuária sintética com características similares à água residuária de Charqueada. O reator 1 foi utilizado como controle, o reator 2 recebeu NaCl e os demais (3 e 4) foram operados na presença de NaCl acrescidos de: betaína e potássio com cálcio, respectivamente. Os compostos citados são conhecidos como antagonizantes, por possuirem capacidade de minimizar o efeito inibitório do sódio sobre o processo de digestão anaeróbia. Os reatores foram inoculados com lodo de reator UASB e submetidos à concentração de 5000 mg/L de matéria orgânica, como DQO. A carga orgânica aplicada foi de 5 Kg/m3.d e os reatores não suportaram tal carga. Reiniciou-se a operação com aumento progressivo da DQO de 500 a 2000 mg/L resultando em cargas orgânicas de 0,5 a 2,0 Kg/m3.d, respectivamente. Após estabilização dos reatores, iniciou-se a fase de introdução de cloreto de sódio (1.500 a 13.500 mg/L) e antagonizantes com aumento progressivo a cada fase. Na presença ou ausência de antagonizantes, os reatores 2, 3 e 4 não tiveram o desempenho alterado até a concentração de NaCl de 6000 mg/L. Na presença de 9000 mg/L de NaCl, a betaína se mostrou pouco efetiva como soluto compatível no reator 3 e os antagonizantes do reator 4, potássio e cálcio, apresentaram efeitos estimulatórios. As morfologias encontradas ao longo do experimento foram cocos, víbrios, bacilos, sarcinas, além de morfologias semelhantes a Methanosarcina sp. e Methanosaeta sp. O aumento da concentração de cloreto de sódio provocou a redição da população de Arqueas.

Avaliação de um sistema descentralizado de tratamento de esgotos domésticos em escala real composto por tanque séptico e wetland construída híbrida

A concentração demográfica e de sistemas coletivos de esgotamento sanitário dentro do perímetro urbano da maioria dos municípios brasileiros, dificulta a viabilização do fornecimento de serviços de tratamento de esgotos domésticos à habitações e núcleos habitacionais isolados situados em áreas periurbanas e rurais, intensificando os danos provocados pela poluição de origem antrópica ao meio ambiente e à preservação da saúde pública. Para contribuir no equacionamento deste problema, o presente estudo teve por finalidade avaliar uma wetland construída híbrida em escala real, composta por uma unidade com fluxo contínuo subsuperficial vertical seguida por uma unidade de fluxo contínuo subsuperficial horizontal, cultivadas com capim Vetiver, para o tratamento de efluente proveniente de tanque séptico. A presente configuração experimental busca uma solução de baixo custo e simplificada para o tratamento descentralizado de esgotos domésticos. A estação experimental de tratamento de esgotos, parte integrante e um dos produtos da Rede Nacional de Tratamento de Esgotos Descentralizados RENTED, foi construída no Centro Tecnológico de Hidráulica CTH / Escola Politécnica EPUSP, campus Butantã da USP, em São Paulo. O esgoto bruto foi proveniente do Conjunto Residencial da USP e do restaurante central da Cidade Universitária. As vazões média e máxima de esgoto bruto, respectivamente, de 640L.d-1 e 1600L.d-1, foram aplicadas à entrada do TS de 5.000L e deste escoaram por gravidade à entrada da wetland construída híbrida, com TDH total de 2,8d e 1,1d, respectivamente, sob aplicação das vazões média e máxima de projeto. O monitoramento do experimento em campo, incluindo o período inicial de partida, durou 6 meses consecutivos. Foram avaliados os parâmetros físico-químicos e microbiológicos do esgoto bruto e do efluente do tanque séptico e das câmaras da wetland construída híbrida durante 97 dias consecutivos. Os resultados indicaram que tanto as mudas jovens quanto as adultas de capim Vetiver adaptaram-se bem às condições ambientais. As eficiências médias de remoção no efluente tratado final quanto à matéria orgânica carbonácea foram de 96 por cento para DBO5,20 e 90 por cento para DQO, 40 por cento para N-total, 23 por cento para N-amoniacal total, 60 por cento para P-total, 52 por cento para P-PO4, 74 por cento para SST, 96 por cento para SSV, 75 por cento para sólidos sedimentáveis, 44 por cento para SDV, 88 por cento para sulfeto total, e 97 por cento para óleos e graxas totais, variando entre 73 por cento a 100 por cento . Cerca de 80 por cento da fração orgânica da matéria nitrogenada presente no esgoto bruto foi removida. A remoção de coliformes termotolerantes foi, em média, de 2 e 3 unidades log, e de Escherichia Coli, média de 1 e 3 unidades log, respectivamente, sob aplicação das vazões máxima e média, Giardia sp, média de 99,995 por cento , Cryptosporidium sp, média de 98,7 por cento , Enterovírus, média de 99,6 por cento , e Ascaris sp, média de 0,10 ovo/L. A remoção de sulfetos propiciou a geração de efluente tratado sem odores desagradáveis. A diminuição da vazão aplicada e a elevação do TDH influenciaram positivamente no desempenho do sistema com relação às remoções dos parâmetros físico-químicos e microbiológicos. Com base no presente estudo, ficou evidente o benefício da associação de wetlands construídas com fluxo vertical e horizontal no tratamento de efluente de tanque séptico. O capim Vetiver apresentou bom potencial de utilização em wetlands 8 construídas para tratamento de esgotos domésticos. O sistema experimental de tratamento apresentou flexibilidade operacional, mantendo bom desempenho inclusive nos períodos de sobrecarga. A qualidade do efluente tratado final obtido no presente estudo atende às exigências de lançamento e aos padrões de emissão de efluentes líquidos em corpos dágua e em sistemas públicos de esgotamento sanitário definidos na legislação ambiental federal e do Estado de São Paulo. A tecnologia de wetlands construídas híbridas associada ao tratamento de efluentes de tanque séptico apresentou bom potencial para o tratamento descentralizado de esgotos domésticos, inclusive em regiões com pouca disponibilidade de área livre.

Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage

An integrated anaerobic-aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC = 100 mg/L and sulphate = 500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77-85% of TOC at HRT of 3 h and produce 70-90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3--N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.

DEVELOPMENT OF INTEGRATED BIOPROCESSING TECHNOLOGIES FOR THE PRODUCTION OF PECTIC OLIGOSACCHARIDES (POS) FROM AGRO-PROCESSING RESIDUES

This research deals with the production of pectic oligosaccharides (POS) from agro-industrial residues, with specific focus on development of continuous cross flow enzyme membrane reactor. Pectic oligosaccharides have recently gained attention due to their prebiotic activity. Lack of information on the continuous production of POS from agro-industrial residues formed the basis for the present study. Four residues i.e sugar beet pulp, onion hulls, pressed pumpkin cake and berry pomace were taken to study their pectin content. Based on the presence of higher galacturonic acid and arabinose (both homogalacturonan and rhamnogalacturonan) in sugar beet pulp and galacturonic acid (only homogalacturonan) in onion hulls, further optimization of different extraction methods of pectin (causing minimum damage to pectic chain) from these residues were done. The most suitable extractant for sugar beet pulp and onion hulls were nitric acid and sodium hexametaphosphate respectively. Further the experiments on the continuous production of POS from sugar beet pulp in an enzyme membrane reactor was initiated. Several optimization experiments indicated the optimum enzyme (Viscozyme) as well as feed concentration (25 g/L) to be used for producing POS from sugar beet pulp in an enzyme membrane reactor. The results highlighted that steady state POS production with volumetric and specific productivity of 22g/L/h and 11 g/gE/h respectively could be achieved by continuous cross flow filtration of sugar beet pulp pectic extract over 10 kDa membrane at residence time of 20 min. The POS yield of about 80% could be achieved using above conditions. Also, in this thesis preliminary experiments on the production and characterization of POS from onion hulls were conducted. The results revelaed that the most suitable enzyme for POS production from onion hulls is endo-polygalacturonase M2. The POS produced from onion hulls were present in the form of DP1 -DP10 in substituted as well as unsubstituted forms. This study clearly demonstrates that continuous production of POS from pectin rich sources can be achieved by using cross flow continuous enzyme membrane reactor.

Application of space-charge electrostatic precipitator for collection of oil mist from pyrolysis gases

A novel electrostatic precipitator CAROLA® is developed for collection of fine oil mists. It operates on the principle of unipolar particle charging in the corona discharge and particle precipitation under the field of space charge. The pilot precipitator was tested at different gas temperatures. It is shown that the increase of gas temperature changes the characteristics of the corona discharge and particle size distribution, especially for droplets sub-micron droplets. The CAROLA® precipitator was used for collection of oil mist from pyrolysis gases at the HALOCLEAN® plant. The flow rate of biomass in the HALOCLEAN® plant was 15-30 kg/h. The particle mass concentration in the raw gas was over 100 g/Nm. The operation voltage of the precipitator was 10-12 kV and corona current up to 0,1 mA. Single stage electrostatic precipitator ensured mass collection efficiency 97-99,5% for pyrolysis oil mist.

Verification and validation of numerical models of the transport of insulation debris

A combination of the two-fluid and drift flux models have been used to model the transport of fibrous debris. This debris is generated during loss of coolant accidents in the primary circuit of pressurized or boiling water nuclear reactors, as high pressure steam or water jets can damage adjacent insulation materials including mineral wool blankets. Fibre agglomerates released from the mineral wools may reach the containment sump strainers, where they can accumulate and compromise the long-term operation of the emergency core cooling system. Single-effect experiments of sedimentation in a quiescent rectangular column and sedimentation in a horizontal flow are used to verify and validate this particular application of the multiphase numerical models. The utilization of both modeling approaches allows a number of pseudocontinuous dispersed phases of spherical wetted agglomerates to be modeled simultaneously. Key effects on the transport of the fibre agglomerates are particle size, density and turbulent dispersion, as well as the relative viscosity of the fluid-fibre mixture.

Comparison of snail density, standing stock, and body size between Caribbean karst wetlands and other freshwater ecosystems

Synthesizing data from multiple studies generates hypotheses about factors that affect the distribution and abundance of species among ecosystems. Snails are dominant herbivores in many freshwater ecosystems, but there is no comprehensive review of snail density, standing stock, or body size among freshwater ecosystems. We compile data on snail density and standing stock, estimate body size with their quotient, and discuss the major pattern that emerges. We report data from 215 freshwater ecosystems taken from 88 studies that we placed into nine categories. Sixty-five studies reported density, seven reported standing stock, and 16 reported both. Despite the breadth of studies, spatial and temporal sampling scales were limited. Researchers used 25 different sampling devices ranging in area from 0.0015 to 2.5 m2. Most ecosystem categories had similar snail densities, standing stocks, and body sizes suggesting snails shared a similar function among ecosystems. Caribbean karst wetlands were a striking exception with much lower density and standing stock, but large body size. Disparity in body size results from the presence of ampullariids in Caribbean karst wetlands suggesting that biogeography affects the distribution of taxa, and in this case size, among aquatic ecosystems. We propose that resource quality explains the disparity in density and standing stock between Caribbean karst wetlands and other categories. Periphyton in Caribbean karst wetlands has high carbon-to-phosphorous ratios and defensive characteristics that inhibit grazers. Unlike many freshwater ecosystems where snails are key grazers, we hypothesize that a microbial loop captures much of the primary production in Caribbean karst wetlands.

Remote-Sensing Monitoring of Tide Propagation Through Coastal Wetlands

Tide propagation through coastal wetlands is a complex phenomenon affected by vegetation, channels, and tidal conditions. Generally, tidal flow is studied using stage (water level) observations, which provide good temporal resolution, but they are acquired in limited locations. Here, a remote-sensing technique, wetland InSAR (interferometric synthetic aperture radar), is used to detect tidal flow in vegetated coastal environments over broad spatial scales. The technique is applied to data sets acquired by three radar satellites over the western Everglades in south Florida. Interferometric analysis of the data shows that the greatest water-level changes occur along tidal channels, reflecting a high velocity gradient between fast horizontal flow in the channel and the slow flow propagation through the vegetation. The high-resolution observations indicate that the tidal flushing zone extends 2–3 km on both sides of tidal channels and can extend 3–4 km inland from the end of the channel. The InSAR observations can also serve as quantitative constraints for detailed coastal wetland flow models.

Geologie und Hydrogeologie im Raum Bad Pyrmont unter besonderer Berücksichtigung des Quellensystems

The hydrodynamics and hydrochemistry of salt and fresh water from solid rock aquifer systems in the Pyrmont area are described and interpreted on the basis of recent investigations including geoelectrics, isotope hydrology, soil air analysis. Theories on the source of the springs in this area are developed, which explain the different compositions of the springs and make it possible to protect them. Data from new and re-interpretated drill holes, borehole logs and outcrops suggest a revision of the geological structure of the Pyrmont dome. Bad Pyrmont is situated on a wide dome of Triassic rocks in the southern part of the Lower Saxony uplands. Inversion of the relief has caused the development of an erosional basin surrounded by prominent ridges. Deep faults developed at the crest of the dome as this part of the structure was subjected to the strongest tectonic stress. Subrosion of the Zechstein salts in the western part of the dome has caused the main salt bed to wedge out below the western part of the dome along a N-S striking structure; this structure is refered to as the „Salzhang“ (salt slope). West of the „Salzhang“, where subrosion has removed the salt bed that prevents gas rising from below, carbon dioxide of deep volcanic origin can now rise to the surface. Hydraulic cross sections illustrate the presence of extensive and deep-seated groundwater flow within the entire Pyrmont dome. While groundwater flow is directed vertically downwards in the ridges surrounding the dome, centripetal horizontal flow predominates the intermediate area. In the central part of the dome, groundwater rises to join the River Emmer, which is the main receiving water course in the central part of the eroded basin. The depth of the saltwater/freshwater interface is determinated by the weight of the superimposed freshwater body. Hydrochemical cross sections show the shape and position of the interface and document a certain degree of hydrochemical zonation of the gently mineralized fresh water. Genetic relationships between the two main water types and the hydrochemical zones of the freshwater body are discussed. The knowledge of the hydrogeological relationship in the Bad Pyrmont aquifer systems permits a spatially narrow coexistence of wells withdrawing groundwater for different purposes (medicinal, mineral, drinking and industrial water).