Biotic and abiotic parameters and cynobacteria abundance during an experimental set-up with varying pCO2 conditions

Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2) concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C) and dinitrogen (N2) fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 µatm), mid (median 353 µatm), and high (median 548 µatm) CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2) and 40 ± 25% (mid vs. high pCO2), as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low) and 44% (high vs. mid) at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP) was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the Baltic Sea are discussed.

Radio-echo sounding investigation of the western Dronning Maud Land and north-eastern Coats Land, East Antarctica (Scale 1:2 500 000)

During two Antarctic field seasons, western Dronning Maud Land and eastern Coats Land were covered by airborne radio-echo sounding surveys, conducted in combination with magnetic and gravity measurements along the 50 NW-SE-directed tracks, totaling about 11200 km and spaced 20 km apart. The data were collected in analogue form and then processed to compile ice surface, ice thickness and bedrock topography maps in I : 2 500 000 scale which gave a new and/or more detailed information on the region than previous compilations. The maps show that western Dronning Maud Land is dominated by a large mountainous area with altitudes up to 2800 m including rock outcrops of Annandagstoppane, Borgmassivet, Kirwanveggen and Heimefrontfjella. Upland terrains of Vestfjella and Mannefallknausane have an isolated position and are surrounded by a plain with bedrock depressions of 600 m deep below sea level. A narrow strip of north-eastern Coats Land studied by radio-echo soundings exhibits a smooth subice relief with altitudes close to sea level. The structural style of bedrock topography was mostly determined by extensional tectonics.

Wave height (regular and irregular waves) reduction in 2m water depth over a 40-m-long salt marsh test section in a large scale laboratory flume

Coastal communities around the world face increasing risk from flooding as a result of rising sea level, increasing storminess, and land subsidence. Salt marshes can act as natural buffer zones, providing protection from waves during storms. However, the effectiveness of marshes in protecting the coastline during extreme events when water levels and waves are highest is poorly understood. Here, we experimentally assess wave dissipation under storm surge conditions in a 300-m-long wave flume that contains a transplanted section of natural salt marsh. We find that the presence of marsh vegetation causes considerable wave attenuation, even when water levels and waves are high. From a comparison with experiments without vegetation, we estimate that up to 60% of observed wave reduction is attributed to vegetation. We also find that although waves progressively flatten and break vegetation stems and thereby reduce dissipation, the marsh substrate remained remarkably stable and resistant to surface erosion under all conditions.The effectiveness of storm wave dissipation and the resilience of tidal marshes even at extreme conditions suggest that salt marsh ecosystems can be a valuable component of coastal protection schemes.

Large-Scale smart grids as system of systems

Smart Grids are advanced power networks that introduce intelligent management, control, and operation systems to address the new challenges generated by the growing energy demand and the appearance of renewal energies. In the literature, Smart Grids are presented as an exemplar SoS: systems composed of large heterogeneous and independent systems that leverage emergent behavior from their interaction. Smart Grids are currently scaling up the electricity service to millions of customers. These Smart Grids are known as Large-Scale Smart Grids. From the experience in several projects about Large-Scale Smart Grids, this paper defines Large-Scale Smart Grids as a SoS that integrate a set of SoS and conceptualizes the properties of this SoS. In addition, the paper defines the architectural framework for deploying the software architectures of Large-Scale Smart Grid SoS.

The Role of ICT in Scaling Up the Impact of Social Enterprises

Information and Communication Technologies (ICT) can help social enterprises and other organizations working on global sustainability issues and in the human development sector in general scale their social impact. The flexibility, dynamism, and ubiquity of ICTs make them powerful tools for improving relationships among organizations and their beneficiaries, multiplying the effects of action against many, if not all, aspects of global unsustainability, including poverty and exclusion. The scaling of social impact occurs in two different dimensions. On one hand, ICTs can increase the value proposition of a program or action (depth scaling) in different ways: providing accurate and fast needs recognition, adapting products and services, creating opportunities, building fairer markets, mobilizing actions on environmental and social issues, and creating social capital. On the other hand, ICTs can also increase the number of people reached by the organization (breadth scaling) by accessing new resources, creating synergies and networks, improving organizational efficiency, increasing its visibility, and designing new access channels to beneficiaries. This article analyzes the role of ICT in the depth and breadth scaling of social impact.

Multiple Hashing Integration for Real-Time Large Scale Part-to-Part Video Matching

A real-time large scale part-to-part video matching algorithm, based on the cross correlation of the intensity of motion curves, is proposed with a view to originality recognition, video database cleansing, copyright enforcement, video tagging or video result re-ranking. Moreover, it is suggested how the most representative hashes and distance functions - strada, discrete cosine transformation, Marr-Hildreth and radial - should be integrated in order for the matching algorithm to be invariant against blur, compression and rotation distortions: (R; _) 2 [1; 20]_[1; 8], from 512_512 to 32_32pixels2 and from 10 to 180_. The DCT hash is invariant against blur and compression up to 64x64 pixels2. Nevertheless, although its performance against rotation is the best, with a success up to 70%, it should be combined with the Marr-Hildreth distance function. With the latter, the image selected by the DCT hash should be at a distance lower than 1.15 times the Marr-Hildreth minimum distance.

Rapid prototyping of multi-scale biomedical microdevices by combining additive manufacturing technologies

The possibility of designing and manufacturing biomedical microdevices with multiple length-scale geometries can help to promote special interactions both with their environment and with surrounding biological systems. These interactions aim to enhance biocompatibility and overall performance by using biomimetic approaches. In this paper, we present a design and manufacturing procedure for obtaining multi-scale biomedical microsystems based on the combination of two additive manufacturing processes: a conventional laser writer to manufacture the overall device structure, and a direct-laser writer based on two-photon polymerization to yield finer details. The process excels for its versatility, accuracy and manufacturing speed and allows for the manufacture of microsystems and implants with overall sizes up to several millimeters and with details down to sub-micrometric structures. As an application example we have focused on manufacturing a biomedical microsystem to analyze the impact of microtextured surfaces on cell motility. This process yielded a relevant increase in precision and manufacturing speed when compared with more conventional rapid prototyping procedures.

Guidelines for the design of an environmental flow regime program at the regional scale: Application of the ELOHA framework in the Ebro River basin

La gestión de los recursos hídricos se convierte en un reto del presente y del futuro frente a un panorama de continuo incremento de la demanda de agua debido al crecimiento de la población, el crecimiento del desarrollo económico y los posibles efectos del calentamiento global. La política hidráulica desde los años 60 en España se ha centrado en la construcción de infraestructuras que han producido graves alteraciones en el régimen natural de los ríos. Estas alteraciones han provocado y acrecentado los impactos sobre los ecosistemas fluviales y ribereños. Desde los años 90, sin embargo, ha aumentado el interés de la sociedad para conservar estos ecosistemas. El concepto de caudales ambientales consiste en un régimen de caudales que simula las características principales del régimen natural. Los caudales ambientales están diseñados para conservar la estructura y funcionalidad de los ecosistemas asociados al régimen fluvial, bajo la hipótesis de que los elementos que conforman estos ecosistemas están profundamente adaptados al régimen natural de caudales, y que cualquier alteración del régimen natural puede provocar graves daños a todo el sistema. El método ELOHA (Ecological Limits of Hydrological Alteration) tiene como finalidad identificar las componentes del régimen natural de caudales que son clave para mantener el equilibrio de los ecosistemas asociados, y estimar los límites máximos de alteración de estas componentes para garantizar su buen estado. Esta tesis presenta la aplicación del método ELOHA en la cuenca del Ebro. La cuenca del Ebro está profundamente regulada e intervenida por el hombre, y sólo las cabeceras de los principales afluentes del Ebro gozan todavía de un régimen total o cuasi natural. La tesis se estructura en seis capítulos que desarrollan las diferentes partes del método. El primer capítulo explica cómo se originó el concepto “caudales ambientales” y en qué consiste el método ELOHA. El segundo capítulo describe el área de estudio. El tercer capítulo realiza una clasificación de los regímenes naturales de la cuenca (RNC) del Ebro, basada en series de datos de caudal mínimamente alterado y usando exclusivamente parámetros hidrológicos. Se identificaron seis tipos diferentes de régimen natural: pluvial mediterráneo, nivo-pluvial, pluvial mediterréaneo con una fuerte componente del caudal base, pluvial oceánico, pluvio-nival oceánico y Mediterráneo. En el cuarto capítulo se realiza una regionalización a toda la cuenca del Ebro de los seis RNC encontrados en la cueca. Mediante parámetros climáticos y fisiográficos se extrapola la información del tipo de RNC a puntos donde no existen datos de caudal inalterado. El patrón geográfico de los tipos de régimen fluvial obtenido con la regionalización resultó ser coincidente con el patrón obtenido a través de la clasificación hidrológica. El quinto capítulo presenta la validación biológica de los procesos de clasificación anteriores: clasificación hidrológica y regionalización. La validación biológica de los tipos de regímenes fluviales es imprescindible, puesto que los diferentes tipos de régimen fluvial van a servir de unidades de gestión para favorecer el mantenimiento de los ecosistemas fluviales. Se encontraron diferencias significativas entre comunidades biológicas en cinco de los seis tipos de RNC encontrados en la cuenca. Finalmente, en el sexto capítulo se estudian las relaciones hidro-ecológicas existentes en tres de los seis tipos de régimen fluvial encontrados en la cuenca del Ebro. Mediante la construcción de curvas hidro-ecológicas a lo largo de un gradiente de alteración hidrológica, se pueden sugerir los límites de alteración hidrológica (ELOHAs) para garantizar el buen estado ecológico en cada uno de los tipos fluviales estudiados. Se establecieron ELOHAs en tres de los seis tipos de RNC de la cuenca del Ebro Esta tesis, además, pone en evidencia la falta de datos biológicos asociados a registros de caudal. Para llevar a cabo la implantación de un régimen de caudales ambientales en la cuenca, la ubicación de los puntos de muestreo biológico cercanos a estaciones de aforo es imprescindible para poder extraer relaciones causa-efecto de la gestión hidrológica sobre los ecosistemas dependientes. ABSTRACT In view of a growing freshwater demand because of population raising, improvement of economies and the potential effects of climate change, water resources management has become a challenge for present and future societies. Water policies in Spain have been focused from the 60’s on constructing hydraulic infrastructures, in order to dampen flow variability and granting water availability along the year. Consequently, natural flow regimes have been deeply altered and so the depending habitats and its ecosystems. However, an increasing acknowledgment of societies for preserving healthy freshwater ecosystems started in the 90’s and agreed that to maintain healthy freshwater ecosystems, it was necessary to set environmental flow regimes based on the natural flow variability. The Natural Flow Regime paradigm (Richter et al. 1996, Poff et al. 1997) bases on the hypothesis that freshwater ecosystems are made up by elements adapted to natural flow conditions, and any change on these conditions can provoke deep impacts on the whole system. Environmental flow regime concept consists in designing a flow regime that emulates natural flow characteristics, so that ecosystem structure, functions and services are maintained. ELOHA framework (Ecological Limits of Hydrological Alteration) aims to identify key features of the natural flow regime (NFR) that are needed to maintain and preserve healthy freshwater and riparian ecosystems. Moreover, ELOHA framework aims to quantify thresholds of alteration of these flow features according to ecological impacts. This thesis describes the application of the ELOHA framework in the Ebro River Basin. The Ebro River basin is the second largest basin in Spain and it is highly regulated for human demands. Only the Ebro headwaters tributaries still have completely unimpaired flow regime. The thesis has six chapters and the process is described step by step. The first chapter makes an introduction to the origin of the environmental flow concept and the necessity to come up. The second chapter shows a description of the study area. The third chapter develops a classification of NFRs in the basin based on natural flow data and using exclusively hydrological parameters. Six NFRs were found in the basin: continental Mediterranean-pluvial, nivo-pluvial, continental Mediterranean pluvial (with groundwater-dominated flow pattern), pluvio-oceanic, pluvio-nival-oceanic and Mediterranean. The fourth chapter develops a regionalization of the six NFR types across the basin by using climatic and physiographic variables. The geographical pattern obtained from the regionalization process was consistent with the pattern obtained with the hydrologic classification. The fifth chapter performs a biological validation of both classifications, obtained from the hydrologic classification and the posterior extrapolation. When the aim of flow classification is managing water resources according to ecosystem requirements, a validation based on biological data is compulsory. We found significant differences in reference macroinvertebrate communities between five over the six NFR types identified in the Ebro River basin. Finally, in the sixth chapter we explored the existence of significant and explicative flow alteration-ecological response relationships (FA-E curves) within NFR types in the Ebro River basin. The aim of these curves is to find out thresholds of hydrological alteration (ELOHAs), in order to preserve healthy freshwater ecosystem. We set ELOHA values in three NFR types identified in the Ebro River basin. During the development of this thesis, an inadequate biological monitoring in the Ebro River basin was identified. The design and establishment of appropriate monitoring arrangements is a critical final step in the assessment and implementation of environmental flows. Cause-effect relationships between hydrology and macroinvertebrate community condition are the principal data that sustain FA-E curves. Therefore, both data sites must be closely located, so that the effects of external factors are minimized. The scarce hydro-biological pairs of data available in the basin prevented us to apply the ELOHA method at all NFR types.

Benthic–pelagic links and rocky intertidal communities: Bottom-up effects on top-down control?

Insight into the dependence of benthic communities on biological and physical processes in nearshore pelagic environments, long considered a “black box,” has eluded ecologists. In rocky intertidal communities at Oregon coastal sites 80 km apart, differences in abundance of sessile invertebrates, herbivores, carnivores, and macrophytes in the low zone were not readily explained by local scale differences in hydrodynamic or physical conditions (wave forces, surge flow, or air temperature during low tide). Field experiments employing predator and herbivore manipulations and prey transplants suggested top-down (predation, grazing) processes varied positively with bottom-up processes (growth of filter-feeders, prey recruitment), but the basis for these differences was unknown. Shore-based sampling revealed that between-site differences were associated with nearshore oceanographic conditions, including phytoplankton concentration and productivity, particulates, and water temperature during upwelling. Further, samples taken at 19 sites along 380 km of coastline suggested that the differences documented between two sites reflect broader scale gradients of phytoplankton concentration. Among several alternative explanations, a coastal hydrodynamics hypothesis, reflecting mesoscale (tens to hundreds of kilometers) variation in the interaction between offshore currents and winds and continental shelf bathymetry, was inferred to be the primary underlying cause. Satellite imagery and offshore chlorophyll-a samples are consistent with the postulated mechanism. Our results suggest that benthic community dynamics can be coupled to pelagic ecosystems by both trophic and transport linkages.

Linking genome and proteome by mass spectrometry: Large-scale identification of yeast proteins from two dimensional gels

The function of many of the uncharacterized open reading frames discovered by genomic sequencing can be determined at the level of expressed gene products, the proteome. However, identifying the cognate gene from minute amounts of protein has been one of the major problems in molecular biology. Using yeast as an example, we demonstrate here that mass spectrometric protein identification is a general solution to this problem given a completely sequenced genome. As a first screen, our strategy uses automated laser desorption ionization mass spectrometry of the peptide mixtures produced by in-gel tryptic digestion of a protein. Up to 90% of proteins are identified by searching sequence data bases by lists of peptide masses obtained with high accuracy. The remaining proteins are identified by partially sequencing several peptides of the unseparated mixture by nanoelectrospray tandem mass spectrometry followed by data base searching with multiple peptide sequence tags. In blind trials, the method led to unambiguous identification in all cases. In the largest individual protein identification project to date, a total of 150 gel spots—many of them at subpicomole amounts—were successfully analyzed, greatly enlarging a yeast two-dimensional gel data base. More than 32 proteins were novel and matched to previously uncharacterized open reading frames in the yeast genome. This study establishes that mass spectrometry provides the required throughput, the certainty of identification, and the general applicability to serve as the method of choice to connect genome and proteome.

Mineral surfaces and bioavailability of heavy metals: A molecular-scale perspective

There is a continual influx of heavy metal contaminants and pollutants into the biosphere from both natural and anthropogenic sources. A complex variety of abiotic and biotic processes affects their speciation and distribution, including adsorption onto and desorption from mineral surfaces, incorporation in precipitates or coprecipitates, release through the dissolution of minerals, and interactions with plants and microbes. Some of these processes can effectively isolate heavy metals from the biosphere, whereas others cause their release or transformation to different species that may be more (or less) bioavailable and/or toxic to organisms. Here we focus on abiotic adsorption and precipitation or coprecipitation processes involving the common heavy metal contaminant lead and the metalloids arsenic and selenium in mine tailings and contaminated soils. We have used extremely intense x-rays from synchrotron sources and a structure-sensitive method known as x-ray absorption fine structure (XAFS) spectroscopy to determine the molecular-level speciation of these elements at concentrations of 50 to several thousand ppm in the contaminated environmental samples as well as in synthetic sorption samples. Our XAFS studies of As and Pb in the mine tailings show that up to 50% of these contaminants in the samples studied may be present as adsorbed species on mineral surfaces, which makes them potentially more bioavailable than when present in sparingly soluble solid phases. Our XAFS studies of Se(VI) sorption on Fe2+-containing sulfates show that this element undergoes redox reactions that transform it into less bioavailable and less toxic species. This type of information on molecular-level speciation of heavy metal and metalloid contaminants in various environmental settings is needed to prioritize remediation efforts and to assess their potential hazard to humans and other organisms.

The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory

We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60 degrees, detected at the Pierre Auger Observatory. the geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the similar to 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for.

Mechanical annealing of metallic electrodes at the atomic scale

The process of creating an atomically defined and robust metallic tip is described and quantified using measurements of contact conductance between gold electrodes and numerical simulations. Our experiments show how the same conductance behavior can be obtained for hundreds of cycles of formation and rupture of the nanocontact by limiting the indentation depth between the two electrodes up to a conductance value of approximately 5G0 in the case of gold. This phenomenon is rationalized using molecular dynamics simulations together with density functional theory transport calculations which show how, after repeated indentations (mechanical annealing), the two metallic electrodes are shaped into tips of reproducible structure. These results provide a crucial insight into fundamental aspects relevant to nanotribology or scanning probe microscopies.

Electrochemical synthesis at pre-pilot scale of 1-phenylethanol by cathodic reduction of acetophenone using a solid polymer electrolyte

The pre-pilot scale synthesis of 1-phenylethanol was carried out by the cathodic hydrogenation of acetophenone in a 100 cm2 (geometric area) Polymer Electrolyte Membrane Electrochemical Reactor. The cathode was a Pd/C electrode. Hydrogen oxidation on a gas diffusion electrode was chosen as anodic reaction in order to take advantage of the hydrogen evolved during the reduction. This hydrogen oxidation provides the protons needed for the synthesis. The synthesis performed with only a solid polymer electrolyte, spe, has lower fractional conversion although a higher selectivity than that carried out using a support–electrolyte–solvent together with a spe. However, the difference between these two cases is rather small and since the work-up and purification of the final product are much easier when only a spe is used, this last process was chosen for the pre-pilot electrochemical synthesis of 1-phenylethanol.

Water reduction in waste-activated sludge by resettling and filtration in batch. Phase (1): pilot-scale experiments to optimize performance

This article describes an effective procedure for reducing the water content of excess sludge production from a wastewater treatment plant by increasing its concentration and, as a consequence, minimizing the volume of sludge to be managed. It consists of a pre-dewatering sludge process, which is used as a preliminary step or alternative to the thickening. It is made up of two discontinuous sequential stages: the first is resettling and the second, filtration through a porous medium. The process is strictly physical, without any chemical additives or electromechanical equipment intervening. The experiment was carried out in a pilot-scale system, consisting of a column of sedimentation that incorporates a filter medium. Different sludge heights were tested over the filter to verify the influence of hydrostatic pressure on the various final concentrations of each stage. The results show that the initial sludge concentration may increase by more than 570% by the end of the process with the final volume of sludge being reduced in similar proportions and hydrostatic pressure having a limited effect on this final concentration. Moreover, the value of the hydrostatic pressure at which critical specific cake resistance is reached is established.