Earth Sciences

Aim Many intercontinental disjunctions, especially among spore-producing plants, are shaped by long-distance dispersal (LDD) via wind currents. Amphitropical disjunctions are most commonly explained through LDD, but other vectors and dispersal scenarios must also be considered. To interpret the New World amphitropical disjunction in the dung-moss genus Tetraplodon, we compared stepwise migration along the Andes, direct LDD and ancient vicariance. Location Global, specifically high-latitude and high-elevation localities, with a focus on the New World. Methods Phylogenetic relationships were inferred from four loci sampled from 124 populations representing the global range of Tetraplodon, and analysed using maximum-likelihood and Bayesian optimality criteria, with divergence dates estimated in beast. Results The monophyletic T. mnioides complex diversified between the early Miocene and early-to-mid Pliocene into three well-supported clades, each with a unique geographical distribution: Laurasian, primarily high-elevation tropical, and amphitropical. Populations from southernmost South American were reconstructed as a monophyletic lineage that diverged from high-latitude Northern Hemisphere populations around 8.63 Ma [95% highest posterior density (HPD) 3.07-10.11 Ma]. Main conclusions Direct LDD has resulted in the American amphitropical disjunction in Tetraplodon. A lack of modern or historical wind connectivity between polar regions and the poor resistance of Tetraplodon spores to the conditions associated with wind-dispersal suggest that bird-mediated LDD provides the best explanation for the establishment of amphitropicality.

Temperature and pressure changes associated with the cyclic steam stimulation (CSS) used in heavy oil production from sands are accompanied by significant deformation. Inversion of induced reservoir pore-pressure changes from deformation measurements may provide a potentially powerful reservoir-monitoring tool if the issues of measurement noise, uncertainty in model parameterization, and numerical accuracy and stability can be resolved. We discuss inverting injection-induced reservoir pressure changes from observable surface deformations using a linear poroelastostatic model of a heavy oil reservoir. We also present results of inversion from surface tilt measurements taken at a production site undergoing CSS. We demonstrate that a stable inversion of the reservoir pore-pressure change can be achieved from sparse and noisy surface tilt measurements using constrained regularized optimization. The results provide an insight into the heterogeneity of reservoir stimulation and could help with optimizing well locations and stimulation protocols.

Lagenaria vulgaris (LV) shell was used as a biosorbent for the removal of heavy metal ions, Pb 2+ , Cd 2+ and Zn 2+ , from aqueous solutions. Experiments were carried out under batch conditions. The effects of contact time, initial pH, temperature and stirring speed on removal efficiency are presented. Sorption of the investigated metals was fast, reaching equilibrium after about 5 to 10 min, depending on the metal. Biosorption was highly pH-dependent, and the optimal pH for investigated metals was in the range of 4.5 to 6.0. The effects of temperature demonstrated that biosorption of the metals is a chemical process. SEM analysis revealed interesting morphological changes after acid refinement of the raw biosorbent and metal uptake that is related to the chemical nature of the biosorption process. EDX analysis of Lagenaria vulgaris biosorbent (LVB) before and after metal sorption revealed that the ion exchange mechanism was the principal sorption process. Fourier transform infrared spectroscopy (FTIR) analysis has shown that major functional groups (carboxyl and hydroxyl) on the biosorbent surface took part in the metal ion uptake process as active sites. The results obtained showed that Lagenaria vulgaris based biosorbent could be used as an effective and low-cost pre-treatment step for removal of toxic metals from wastewaters.

Over the past few years, fog studies have been introduced as part of courses in Earth system science for both university students and high school teachers at Seattle Pacific University. In the undergraduate course, about three hours are devoted to the study of fog starting with a discussion on sustainable water systems. This is followed by presentations on types of fog, the role of fog in the biosphere, biogeochemical cycles and fog, human influences on fog and fog intensity, and remote sensing of fog. We end with a description of fog collection. Fog education efforts increased for students when our campus was able to obtain fog collecting equipment from Richard Jagels at the University of Maine. The equipment included active and passive fog collectors as well as infrared-beam fog detectors. Two graduating students took on fog collection as their senior project. After setting up the newly acquired equipment, the students designed a fog collection project for the University's Whi...

Aim  Cuckoo‐shrikes and allies (Campephagidae) form a radiation of birds widely distributed in the Indo‐Pacific and Africa. Recent studies on the group have been hampered by poor taxon sampling, causing inferences about systematics and biogeography to be rather speculative. With improved taxon sampling and analyses within an explicit spatiotemporal framework, we elucidate biogeographical patterns of dispersal and diversification within this diverse clade of passerine birds.Location  Africa, Asia, Australo‐Papua, the Pacific, the Philippines and Wallacea.Methods  We use model‐based phylogenetic methods (MrBayes and garli) to construct a phylogenetic hypothesis of the core Campephagidae (Campephagidae with the exclusion of Pericrocotus). The phylogeny is used to assess the biogeographical history of the group with a newly developed Bayesian approach to dispersal–vicariance analysis (Bayes‐diva). We also made use of a partitioned beast analysis, with several calibration points taken fr...

Water stress is likely the most important factor that adversely affects plant growth and development. In this study two wheat cultivars Gemmieza-7 (sensitive) and Sahel-1 (tolerant) were subjected to water stress and compared in terms of growth parameters (growth vigor of root and shoot), water relations (relative water content and saturation water deficit ) and protein as well as nucleic acids (DNA and RNA) content in flag leaves of both cultivars. In general, water stress caused noticeable reduction in almost all growth criteria of root, shoot and flag leaf which was consistent with the progressive alteration in water relations, protein and nucleic acids content of both cultivars during grain filling. Furthermore, degree of leaf succulence and degree of leaf sclerophylly were severely affected by water stress in both wheat cultivars. In relation to wheat cultivar, the sensitive was more affected by water stress than the tolerant one. Generally, the application of salicylic acid, t...

Icebergs plough through unconsolidated lake/sea sediments gouging out kilometre long grooves, 100s of metres wide and tens of metres deep. Although the surface morphology of iceberg scours is well documented, little is known about what scours look like in stratigraphic section, particularly where surface characteristics are absent (e.g. through deterioration or burial). This is exacerbated by their inaccessibility in modern

We studied the coarsening behavior of two lyotropic liquid-crystal systems by static light scattering. The samples were quenched from the isotropic phase into either the nematic phase or a region of coex- istence between nematic and isotropic phases. In the coexistence region, we observed, in both two and three dimensions, Porod power-law tails of the scattering intensity. Such a behavior is described by S(q) -q '"+" in the limit of large wave vectors q, where S is the scattering intensity, q is the wave vec- tor, and d is the dimension of the system. In addition, the nernatic phases displayed novel power-law scaling behavior at large q, namely, S(q)-q ", where u=4 in two dimensions and u=6 in three dimen- sions. These results will be compared to recent theoretical predictions.

Environmental contextAmmonium ion, an inorganic pollutant in agricultural land, can induce eutrophication, impacting on water quality. We investigate the adsorption of ammonium ion on surfactant-modified alumina and demonstrate highly efficient removal of ammonium ions by the alumina from two agricultural water samples. Adsorption mechanisms are also proposed based on adsorption isotherms, surface modification and the change in surface charge. The adsorptive removal of ammonium ions (NH4+) from aqueous solution using surfactant-modified alumina (SMA) was investigated. The optimum NH4+ adsorption removal conditions on SMA were systematically studied and found to be pH 4, contact time 180min, adsorbent dosage 30mgmL–1 and ionic strength 1mM NaCl. The equilibrium concentration of NH4+ was measured by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) and spectrophotometry. Surface modification of α-Al2O3 with the anionic surfactant sodium do...

Intensively managed grazed grasslands in temperate climates are globally important environments for the exchange of the greenhouse gases (GHGs) carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ). We assessed the N and C budget of a mostly grazed and occasionally cut and fertilised grassland in SE Scotland by measuring or modelling all relevant imports and exports to the field as well as changes in soil C and N stocks over time. The N budget was dominated by import from inorganic and organic fertilisers (21.9 g N m -2 a -1 ) and losses from leaching (5.3 g N m -2 a -1 ), N 2 emissions (2.9 g N m -2 a -1 ), and NO x and NH 3 volatilisation (3.9 g N m -2 a -1 ), while N 2 O emission was only 0.6 g N m -2 a -1 . The efficiency of N use by animal products (meat and wool) averaged 9.9 % of total N input over only-grazed years (2004)(2005)(2006)(2007)(2008)(2009)(2010). On average over 9 years (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), the balance of N fluxes suggested that 6.0 ± 5.9 g N m -2 a -1 (mean ± confidence interval at p > 0.95) were stored in the soil. The largest component of the C budget was the net ecosystem exchange of CO 2 (NEE), at an average uptake rate of 218 ± 155 g C m -2 a -1 over the 9 years. This sink strength was offset by carbon export from the field mainly as grass offtake for silage (48.9 g C m -2 a -1 ) and leaching (16.4 g C m -2 a -1 ). The other export terms, CH 4 emissions from the soil, manure applications and enteric fermentation, were negligible and only contributed to 0.02-4.2 % of the total C losses. Only a small fraction of C was incorporated into the body of the grazing animals. Inclusion of these C losses in the budget resulted in a C sink strength of 163 ± 140 g C m -2 a -1 . By contrast, soil stock measurements taken in May 2004 and May 2011 indicated that the grassland sequestered N in the 0-60 cm soil layer at 4.51 ± 2.64 g N m -2 a -1 and lost C at a rate of 29.08 ± 38.19 g C m -2 a -1 . Potential reasons for the discrepancy between these estimates are probably an underestimation of C losses, especially from leaching fluxes as well as from animal respiration. The average greenhouse gas (GHG) balance of the grassland was -366 ± 601 g CO 2 eq. m -2 yr -1 and was strongly affected Published by Copernicus Publications on behalf of the European Geosciences Union. 2070 S. K. Jones et al.: The nitrogen, carbon and greenhouse gas budget of a grassland by CH 4 and N 2 O emissions. The GHG sink strength of the NEE was reduced by 54 % by CH 4 and N 2 O emissions. Estimated enteric fermentation from ruminating sheep proved to be an important CH 4 source, exceeding the contribution of N 2 O to the GHG budget in some years. * LSU stands for livestock units; 1 LSU has a standard live weight of 600 kg head -1 (Scottish Agricultural College, 1995).

Adequately designed fishways mitigate the negative effects of barriers in rivers, restoring longitudinal connectivity. To do so, they must present suitable hydraulic conditions, with velocity and turbulence fields adequate for multiple fish species. In the present study, numerical modelling was used to compare the hydrodynamics of two widely used vertical slot fishways (VSF) configurations and three multi slot fishway (MSF) configurations. The MSF configuration needs a lower discharge to operate than the VSF, while keeping similar flow depths, which is vital in regions where water availability is limited, such as most Mediterranean regions. By reducing the discharge, the velocity, turbulent kinetic energy, and Reynolds shear stress values in the studied MSF configurations are much lower than the values for VSF configurations. Thus, besides requiring smaller discharges than similar VSF geometries, the MSF additionally could be less selective for fish species, particularly smaller-sized individuals, and individuals with weaker swimming capacities, and a better option for a multiple-species fishway. 2007). To achieve the goal of good ecological status, the European

Chapter 3. Mitigating hydropeaking impacts on fish through direct measures under a 1D-based modelling approach Chapter 3. Mitigating hydropeaking impacts on fish through direct measures under a 1D-based modelling approach 3.1. New insights into hydropeaking mitigation assessment from a diversion hydropower plant: the GKI project (Tyrol, Austria) Paper published in Ecological Engineering

Chapter 3. Mitigating hydropeaking impacts on fish through direct measures under a 1D-based modelling approach Chapter 3. Mitigating hydropeaking impacts on fish through direct measures under a 1D-based modelling approach 3.1. New insights into hydropeaking mitigation assessment from a diversion hydropower plant: the GKI project (Tyrol, Austria) Paper published in Ecological Engineering

Adequately designed fishways mitigate the negative effects of barriers in rivers, restoring longitudinal connectivity. To do so, they must present suitable hydraulic conditions, with velocity and turbulence fields adequate for multiple fish species. In the present study, numerical modelling was used to compare the hydrodynamics of two widely used vertical slot fishways (VSF) configurations and three multi slot fishway (MSF) configurations. The MSF configuration needs a lower discharge to operate than the VSF, while keeping similar flow depths, which is vital in regions where water availability is limited, such as most Mediterranean regions. By reducing the discharge, the velocity, turbulent kinetic energy, and Reynolds shear stress values in the studied MSF configurations are much lower than the values for VSF configurations. Thus, besides requiring smaller discharges than similar VSF geometries, the MSF additionally could be less selective for fish species, particularly smaller-sized individuals, and individuals with weaker swimming capacities, and a better option for a multiple-species fishway. 2007). To achieve the goal of good ecological status, the European

Developing and testing new fishway designs is important to improve these facilities. Discharge-efficient passage systems are required in Mediterranean regions and other areas with dry climates. The present study compares the passage performance of the Iberian barbel, Luciobarbus bocagei (Steindachner, 1864), a potamodromous cyprinid, negotiating two different types of vertical slot fishways (VSF): a standard VSF and a multi-slot VSF (MSF). Results show that differences exist between configurations in the number of fish movements through the first slot. The I. barbel performed a significantly higher number of movements in the MSF. However, no differences were found in the entrance time and entry efficiency. The performance was similar between configurations in terms of successes, suggesting that both fishways could be used to restore longitudinal connectivity. Nevertheless, the MSF is a more discharge-efficient configuration, since it requires 31% less water to operate for the same water depth in the pools. Consequently, the velocity and turbulence have lower magnitudes which generally favour the negotiation by smaller individuals. Since it is a more discharge-efficient and cost-efficient configuration, future studies should focus on the passage performance of smaller species to determine if MSF is a useful solution for the whole fish community.

We measured diel migration with 11 acoustic Doppler current meter profilers and consistently found diel and lunar cycles of vertical migration from 250 m down to the bathypelagic (. 1000 m). These measurements come from year-long deployments in eight locations within the Gulf of Mexico. Diel vertical migration could be characterized, in depth and time, by a pulse of maximum vertical migration activity (PMV), which has a nearly fix phase relation to sunrise and sunset modulated by the lunar cycle. The vertical velocity of migrating biota is in the same direction as the PMV propagation, but it is significantly slower. This difference in velocity implies that the PMV cannot represent the migration pattern of one single population. The lunar cycle is evident down to 1000 m, where the upward migration delays in phase with the full moon. The extension of the diel and lunar cycles over 1000 m depth together with the difference in vertical migration velocity indicate that the surface irradiance signal is transmitted to bathypelagic depth by synchronized depth-tiered populations. A model in which particulate organics are recycled at different depths, similar to a bucket brigade, is consistent with these observations. This daily vertical connectivity is expected to affect the vertical transport of carbon down to the bathypelagic.

Ethiopia has made significant progress in extending access to improved water sources under its Universal Access Plan (UAP). Although data are contested, all sources confirm the strong upward trajectory. However, the ability of the country to sustain progress is difficult to predict. One key challenge is ensuring that investment translates into sustainable services that continue to meet users' needs in terms of water quantity, quality, ease of access, and reliability. Although data are limited, available evidence suggests that many schemes provide unreliable services or fail completely. Service sustainability is not a new issue in Ethiopia, or elsewhere in sub-Saharan Africa (SSA). The available evidence suggests that perhaps 40 per cent of handpumps are non-functional in SSA; in Ethiopia, official data suggest that 20-30 per cent of schemes have failed, or experience frequent outages. But a long-standing emphasis on capital investment and new infrastructure, coupled with weak monitoring and evaluation (M&E), has tended to obscure the problem, and few rigorous studies have been carried out on this topic. In this chapter, we review the evidence from Research-inspired Policy and Practice Learning in Ethiopia and the Nile Region (RiPPLE) research in two Ethiopian woredas (districts) -Halaba Special woredas and Mirab Abaya -looking at water coverage, the number of non-functioning water schemes, and the factors that determine service sustainability, focusing particularly on rural water supply. Drawing on Ethiopian and wider regional research, we then highlight lessons and recommendations for addressing the problem at different decision-making levels.

This paper presents the main outcomes of a study within the RiPPLE project, to identify appropriate and scalable approaches to strengthen local water governance and planning in the context of the Universal Access Plan planning framework. This study assessed the functionality and service level of water supply schemes in two woredas in SNNP Regional State, Ethiopia to get insight in the current status of water service delivery and the main impacting factors and thus the main challenges to reach the UAP target of providing 15 litres per person per day within 1.5 km. The functionality rate of water schemes as well as coverage appeared to be below the official figures. Lack of clear accountability and responsibility, insufficient budget, manpower and material capacity, poor coordination and communications, absence of specialized spare-parts suppliers and low sense of ownership contributed to the high rate of scheme non-functionality in the study areas.

This study presents a bioeconomic analysis of artificial shelter performance in a fishery targeting a spiny lobster meta-population, with spatially allocated, individual exclusive benthic property rights for shelter introduction and harvest of species. Insights into fishers’ short-run decisions and fishing strategies are also provided. Spatiotemporal bioeconomic performance of shelters located in ten fishing areas during four seasons was compared using two-way ANOVAs and Pearson correlations. Results show that there was spatiotemporal heterogeneity in bioeconomic variables among fishing areas, with mean catch per unit effort (CPUE, kg shelter–1) ranging from 0.42 kg to 1.3 kg per trip, mean quasi-profits of variable costs per shelter harvested ranging from USD6.00 to USD19.57 per trip, and mean quasi-profits of variable costs ranging from USD338 to USD1069 per trip. Positive moderate correlations between shelter density and CPUE (kg shelter–1 km–2) were found. Bioeconomic performanc...

Across the coastal zone, rates of carbon and nutrient exchange are defined by the spatiotemporal heterogeneity of individual estuarine systems. Elemental stoichiometry provides a mechanism for simplifying overlapping physical, chemical, and biological drivers into proxies that can be used to compare and monitor estuarine biogeochemistry. To this end, the seasonal and tidal variability of estuarine stoichiometry was examined over an annual cycle in North Inlet (NI), South Carolina. Surface samples for dissolved and particulate carbon (C), nitrogen (N), and phosphorus (P) were collected every 20 days (August 2014 to August 2015) over a semidiurnal tidal cycle. Dissolved nutrient flux estimates of an individual tidal creek were also made. Overall, the results demonstrated the dominance of seasonal versus tidal forcing on water column C:N:P stoichiometry. This seasonal behavior mediated the relative exchange of N and P into and out of the tidal creek and influenced the nutrient status index (NSI) of NI plankton communities. These communities were largely N deficient with the magnitude of this deficiency impacted by assumptions of inorganic versus organic plankton P demand and nutrient supply. Persistent N deficiency appeared to help drive the net import of N, while temporary P surplus likely drives its seasonal export. Combined, these results indicate that material delivery must be considered on seasonal time frames, as net annual fluxes do not reflect the short-term deliveries of C and nutrients into nearshore ecosystems. Keywords Stoichiometry . Tidal exchange . Nutrient status . Salt marsh tidal creek . NERRS * Douglas W. Bell

Ha estat un camí llarg però finalment aquesta tesi doctoral és una realitat. Avui escric aquestes línies recordant la multitud de bons moments viscuts al costat de persones que han fet que no només aquesta tesi hagi arribat a bon port, sinó que també han fet que gaudís del camí fent que el trajecte fos d'allò més excitant, divertit i gratificant. First of all I want to thank my PhD supervisors, Pere and Claudia. I started to work with both of you when I was still doing my Bachelors. I was sent to participate on my first research cruise and I instantaneously fell in love with the world of oceanographic research. Since then, there have been many more expeditions, but I am still passionate about going to sea; no matter what regions, there is always something new to explore. I think part of that enthusiasm is due to having you as supervisors, since both of you are extremely active and exited about a wide variety of topics. You have fed my passion of going to sea and always supported me, even when you probably thought it was not the smartest decision if one was planning to finish a PhD thesis, and for that I will be eternally grateful. I know the academic world is competitive and papers seem to be the only thing that matters nowadays, but you have always been patient and supportive, clearly valuing other aspects of research that had a much deeper impact on me as a person. Thanks for giving me the opportunity to work with you, for all the support, knowledge and advice provided. It has been a great pleasure and hopefully it will not finish here. Em sento extremadament afortunada per haver tingut els companys de grup que he tingut. Heu estat una peça clau del meu dia a dia, heu fet de tots aquests anys un record inoblidable. Gràcies a vosaltres he tirat endavant quan el que em venien ganes de fer era plegar veles i triar l'opció cocotero. Moltes gràcies pel recolzament, per tots els moments fantàstics compartits i per la vostra amistat. Sé que acabar el doctorat no implicarà perdre el contacte amb vosaltres perquè sou molt més que companys de laboratori. Vull començar donant les gràcies al Jordi perquè tu vas ser el que em vas iniciar en el món de la radioactivitat ambiental i ets el culpable que els radioisòtops es convertissin en la meva passió aquell curs 2005/06 (si si, ara fa 10 anys!!!). Sempre has estat disponible i ajudant quan ha fet falta, amb la millor de les actituds i amb bon humor. Gràcies per ser un jefe que aporta tan bon ambient al grup, amb tanta motivació i tan involucrat en tot, fins i tot quan ja no queden més minuts lliures per res. Moltes gràcies Joan Manuel per tot el suport que m'has donat durant tots aquests anys, en el lab (amb les depos i mesurant discs de Pb-Po del dret i del revés tantes vegades com ha fet falta amb molta paciència), com preparant campanyes com fins i tot participant-ne en una. Saps que sense tu donant un cop de mà quan fes falta, arribar fins aquí microphytoplankton. Thus, and although different food web regimes led to similar export of carbon, the sinking particle pools differed in their composition north and south of the Antarctic Polar Front (aggregates of small particles in the north vs fast-sinking large particles in the south), resulting in two different scenarios regarding the amount of exported carbon that reached greater depths. Finally, estimates of particle flux and export efficiency were examined in a semi-enclosed basin (Gulf of California and the surrounding waters of the Eastern Tropical North Pacific), with a strong seasonality that leads to changes in the planktonic community. Export estimates were assessed using the 234 Th approach in combination with surface-tethered sediment traps. Data on size fractionation and high vertical resolution of in situ pump deployments allowed a comparison of the C/ 234 Th ratios attenuation with depth between small (1-53 μm) and large (>53 μm) particles. Results indicate that, under dominance of pico-and nanoplankton and with presence of diazotrophs, small particles play and important role in carbon export and that this export might be more efficient than that resulting from a diatom dominated planktonic community in the study area.

Few long-term environmental records are available for southern Africa where shifts in atmospheric circulation and changes in sea surface temperatures interact to influence regional climate dynamics. We present downcore grain size and inorganic geochemistry data covering the last ~23,000 years from a peatland on the east coast of South Africa and examine links between shifts in regional wind activity and palaeoclimatic variability. Our record documents substantial variations in aeolian flux associated with changes in regional climate and wind patterns that reflect larger scale atmospheric circulation patterns. Substantially higher fluxes observed during the Last Glacial Maximum (LGM) are linked to widespread aridification and an expansion in local source areas brought about by a clear shift to dry and cool conditions. Variations in grain size distribution reveal that the aeolian record from Mfabeni comprises two dominant end-members; locally-derived coarse-grained material and a more fine-grained dust component. Marked changes in composition and modal grain size suggest that hydrological shifts in the region during the LGM were accompanied by an increase in storm frequency and wind strength that we link to a northward displacement in the westerly wind belt and a strengthening in wind intensity.

The oceans are an important global reservoir for mercury (Hg), and marine fish consumption is the dominant human exposure pathway for its toxic methylated form. A more thorough understanding of the global biogeochemical cycle of Hg requires additional information on the mechanisms that control Hg cycling in pelagic marine waters. In this study, Hg isotope ratios and total Hg concentrations are used to explore Hg biogeochemistry in oligotrophic marine environments north of Hawaii. We present the first measurements of the vertical water column distribution of Hg concentrations and the Hg isotopic composition in precipitation, marine particles, and zooplankton near Station ALOHA (22°45′N, 158°W). Our results reveal production and demethylation of methylmercury in both the euphotic (0-175 m) and mesopelagic zones (200-1,000 m). We document a strong relationship between Hg isotopic composition and depth in particles, zooplankton, and fish in the water column and diurnal variations in Δ 199 Hg values in zooplankton sampled near the surface (25 m). Based on these observations and stable Hg isotope relationships in the marine food web, we suggest that the Hg found in large pelagic fish at Station ALOHA was originally deposited largely by precipitation, transformed into methyl-Hg, and bioaccumulated in situ in the water column. Our results highlight how Hg isotopic compositions reflect abiotic and biotic production and degradation of methyl-Hg throughout the water column and the importance of particles and zooplankton in the vertical transport of Hg.

Underground seepage and the sediment-water interface are important pathways for transporting concentrated pore water solutes through permeable sediments. In this study, we utilized radium-224/thorium-228 disequilibria to examine solute transport throughout shallow sediments (depth < 30 cm) of a tidal marshland, North Inlet, South Carolina, over a seasonal cycle. Distinct 224 Ra-228 Th disequilibria patterns indicate that significant pore water exchange occurred both directly across the sediment-water interface and at depth as underground seepage. Temporal variations in phosphorus (P), iron (Fe), and manganese (Mn) pore water concentrations also support this two-layer transport model. Solute transport across the interface was influenced by seasonal bioirrigation, with highest exchange rates occurring in the late spring. Interfacial flux of dissolved Fe ranged over two orders of magnitude, from 0.5 mmol m -2 d -1 to 134 mmol m -2 d -1 , and fluxes of soluble reactive phosphate (SRP) and dissolved Mn varied from 0.01 mmol m -2 d -1 to 0.72 mmol m -2 d -1 and from 0.04 mmol m -2 d -1 to 2.7 mmol m -2 d -1 , respectively. Seepage occurs year-round, with fluid exchange rates related to the distance from the tidal creek. SRP transport via seepage ranged from 0.98 mmol m -2 d -1 to 5.0 mmol m -2 d -1 , one order of magnitude higher than across the sediment-water interface. Reduction/oxidation reactions at depth diminished trace metal concentrations in deep pore water, and lowered the transport efficiency of Fe and Mn along seepage paths. Although an appreciable fraction of exported solutes likely returns to marsh sediments during tidal circulation, our results indicate that organic-rich sediments provide a potentially large source of nutrients and trace elements to the coastal ecosystem.

The Laurentian Great Lakes (LGL) constitute one of the largest freshwater systems in the world while providing social and economic value to two powerful nations. The spatial scale of these inland seas falls between two endpoints: small lakes and oceans. Lacustrine in many characteristics, the LGL often require a scientific approach with attributes similar to those of oceanography. There is a strong sense that within the LGL support for scientific research has not kept pace with the need for process‐oriented research and that we lack basic information needed to forecast change, mitigate impacts and restore and preserve the LGL. Consequently, 58 researchers met in September 2014 and identified five “Grand Challenges for Research in the LGL”: (1) How has this vast inland freshwater system responded to shifting climate in the past, and how will it respond in the future? (2) What is the current status of the most important ecosystem processes, including their variability in space and tim...

Multiple-point Geostatistics is a well-known general statistical framework by which complex geological phenomena have been modeled efficiently. Pixel-based and patch-based are two major categories of these methods. In this paper, the optimization-based category is used which has a dual concept in texture synthesis as texture optimization. Our extended version of texture optimization uses the energy concept to model geological phenomena. While honoring the hard point, the minimization of our proposed cost function forces simulation grid pixels to be as similar as possible to training images. Our algorithm has a self-enrichment capability and creates a richer training database from a sparser one through mixing the information of all surrounding patches of the simulation nodes. Therefore, it preserves pattern continuity in both continuous and categorical variables very well. It also shows a fuzzy result in its every realization similar to the expected result of multi realizations of other statistical models. While the main core of most previous Multiple-point Geostatistics methods is sequential, the parallel main core of our algorithm enabled it to use GPU efficiently to reduce the CPU time. One new validation method for MPS has also been proposed in this paper.

Toxicological assessment of inhaled aerosols and their effects on respiratory tissue cells requires accurate measurements of particle delivery, properties, evolution, and deposition in the human respiratory tract. These measurements are affected by both anatomical features and physiological factors, such as thermal conditions in the respiratory system. We constructed a segmented cast model, based on a realistic geometry of the human respiratory tract, equipped with features to control the temperature of the air flow. We then evaluated the thermal equilibrium of the air flow through the cast using both experimental measurements and computational fluid dynamics modeling. Uniform temperature distribution in the cast shell was achieved using parallel connection of the cast segments to a thermal bath by flow splitter. Air temperature inside the cast was shown to require <1 min to equilibrate with the temperature of the cast during internal circulation of hot water. Air flow temperature was shown to equilibrate with the cast temperature in the mouth-throat region, and a uniform temperature distribution was achieved in the other segments, resembling the thermal conditions of respiratory flow in the human lung. We showed that the cast successfully represents the physiological thermal conditions of the human respiratory system.

Necessity of underground storage for natural gas have increased because of progressive request for suitable and low-pollution fuel as supersede of oil, increasing use for natural gas, more economic and safety than pipe lines and tanker trucks. This matter control worldwide energy and economic markets such as Iran industry. In this study, it is tried to assessment and introduces several suitable sites for underground gas storage in central Iran (Semnan and Kuh-e-gugerd) with regard to geology and structural geologic setting of tertiary salt domes. In this area, salt domes have a core from massive and pure gypsum belong to Eocene-Oligocene. These domes deposited in marine environment and covered by newer salts belong to Miocene (evaporates sections of URF formation) that deposited in playa and lake environments. Based on geological setting, satellite images, topographic sections and other data, salt domes in central Iran can consider as suitable choices for underground gas storage. Co...

The evolution of SARS-CoV-2 virus has resulted in variants likely to be more readily transmitted through respiratory aerosols, underscoring the increased potential for indoor environmental controls to mitigate risk. Use of tight-fitting face masks to trap infectious aerosol in exhaled breath and reduce inhalation exposure to contaminated air is of critical importance for disease control. Administrative controls including the regulation of occupancy and interpersonal spacing are also important, while presenting social and economic challenges. Indoor engineering controls including ventilation, exhaust, air flow control, filtration, and disinfection by germicidal ultraviolet irradiation can reduce reliance on stringent occupancy restrictions. However, the effects of controls-individually and in combination-on reducing infectious aerosol transfer indoors remain to be clearly characterized to the extent needed to support widespread implementation by building operators. We review aerobiologic and epidemiologic evidence of indoor environmental controls against transmission and present a quantitative aerosol transfer scenario illustrating relative differences in exposure at close-interactive, room, and building scales. We identify an overarching need for investment to implement building controls and evaluate their effectiveness on infection in well-characterized and real-world settings, supported by specific, methodological advances. Improved understanding of engineering control effectiveness guides implementation at scale while considering occupant comfort, operational challenges, and energy costs. Emerging variants of SARS-CoV-2 have led to increased infectivity by the aerosol inhalation mode and increasing infection incidence. Even in the absence of symptoms, people infected with respiratory viruses can exhale infectious aerosols that can be inhaled, deposit in the respiratory tract, and initiate infection. Indoor environments are the predominant settings for respiratory infection transmission because people spend most of their time indoors, and because concentrations of infectious aerosols can accumulate, resulting in hazardous inhalation exposure at close-interactive, room (even at distances much greater than two meters), and building scales. We illustrate the relative respiratory aerosol transfer and exposure at these scales, provide an overview of the scientific basis of engineering controls that can be deployed in buildings to reduce transfer between people, and outline priority research directions to guide widespread implementation of controls in buildings.

The substantial, global disease burden attributed to seasonal influenza and the threat of pandemic influenza demand improved preparedness. Each year influenza has caused up to 650 000 respiratory deaths globally, and as many as 960 000 hospitalizations and over $11 billion in economic burden in the United States. Efforts to develop and improve vaccines (related to possible differential immunity stimulated by infection initiation in lung vs upper respiratory mucosa) and other prevention strategies are hindered by deficient understanding about the competing risk contributions of contact, large droplet, and droplet nuclei (ie, aerosol or airborne) transmission modes. Influenza virus has been detected in exhaled breath droplet nuclei, 4 and there is evidence supporting airborne transmission as a driver of epidemics and severe illness. Quantifying airborne risk is widely accepted as a necessary step for quelling outbreaks.

This paper presents a complete exact analytical solution of steady gravity flow between two reservoirs containing fluids of different densities and levels and connected by a channel of slowly varying depth. The flow over sill is similar to the flow through a contraction. If the level of denser fluid is equal or higher than the level of lighter fluid, δ≤0, then the lighter fluid is at rest depends on δ and ε; the approximate formula q 2apr (0,δ)=2(1-6δ+2(2δ) 3/2 )/ 27 is shown be valid. The comparison of the solutions of exchange flows over a sill and through a contraction is made. Some examples of application of the theory for prediction of a mass and volume transport through a estuary with silled entrance are given in the last section.

An electrokinetic strengthening process is investigated in this study using a large-scale experimental facility. The results of experiments conducted on a marine sediment recovered from the Korean coast showed that the undrained shear strength, preconsolidation pressure and undrained modulus of the sediment were increased considerably in areas surrounding electrodes after the application of voltage gradients in the range of 9.5 to 28.2 V/m for 22 to 34 days. It was also evidenced that improvement of soil properties is further enhanced with time after the voltage was withdrawn. This paper presents the design, execution and results of the experimental program. The discussion covers practical issues such as the layout of electrodes and prefabricated vertical drains, application of intermittent current, power consumption and anode corrosion, monitoring of soil deformation and pore water pressure during treatment, and the geotechnical, physical and chemical properties of the sediment before and after treatment. The process developed in this research has potential applications of strengthening soil around foundations for new offshore structures as well as for the rehabilitation of existing platforms under various loading conditions.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Copyright

Several studies on the prevalence of allergic conditions have identified that allergic conditions are on the increase worldwide. The aim of this study was to study the effect of classroom humidity and temperature levels on schoolchildren in Malta. Our cohort included 191 children. Standardised ISAAC health questionnaires were answered by the children’s parents.  Lung function tests, acoustic rhinometry, exhaled NO, exhaled CO and nasal lavage were performed on the participating children. School building characteristics were also studied. A significant association was noted between a high relative humidity exposure and nasal cross-sectional areas (p=0.003), and doctor diagnosed allergic rhinitis (p=0.002), indicating the presence of allergic rhinitis, as was increased indoor temperature (p=0.003). Increased indoor temperature was also associated with increased exhaled nitric oxide (FeNO) (p&lt;0.001) indicating uncontrolled asthma.  In conclusion, increased classroom temperatures and...

A paleomagnetic study was undertaken on samples collected from seven sites of the exhumed and eroded Ait-Abdallah and Kerdous antiforms in the Moroccan Anti-Atlas of the West African craton. These sites are located in the Adoudounian Formation considered as of Neoproterozoic-Cambrian age. The magnetic mineralogy is represented essentially by magnetite and titanohematite. Magnetization is carried by three components respectively of high-temperature (500-670°C), medium-temperature (350-470°C) and low- temperature (NRM-300°C). Plotted in Gondwana Apparent Polar Wander Path, the high and medium temperature components close to the Permian pole and determine Permian overprint directions. The low temperature component closes to the present day field and corresponds to the present overprint day. This study shows that Permian overprint largely affect the Anti-Atlas area.

Aboveground tree biomass (bole, branches and foliage), M, plays a key role in the conventional and sustainable management of forest communities. The standard approach to assess tree or plot M is harvesting trees, developing and fitting allometric equations to trees or forest inventory plot data. In the absence of local tree allometry, it is usually recommended to fit off site allometric equations to evaluate tree or plot M. This research aims: (a) to develop an updated on site allometric equation (b) to fit available off site allometric equations to destructively harvested trees and (c) to fit available allometric equations to plot M of Mexico’s Sinaloan tropical dry forests to understand sources of inherent tree and plot M variability. Results showed that: (a) the improved on site allometric equation increases precision in contrast to the conventional biomass equation previously reported as well as to off site tree M equations, (b) off site allometry projects tree and plot M deviat...

The Badain Jaran Desert is the second-largest area of shifting sands in China. Our first measurements of the energy components and water vapor fluxes on a megadune using eddy covariance technology were taken from April 2012 to April 2013. The results indicate that the longwave and shortwave radiative fluxes exhibited large fluctuations and seasonal dynamics. The total radiative energy loss by longwave and shortwave radiation was greater on the megadune than from other underlying surfaces. The radiation partitioning was different in different seasons. The land-atmosphere interaction was primarily represented by the sensible heat flux. The average sensible heat flux (40.1 W/m 2 ) was much larger than the average latent heat flux (14.5 W/m 2 ). Soil heat flux played an important role in the energy balance. The mean actual evaporation was 0.41 mm/d, and the cumulative actual evaporation was approximately 150 mm/a. The water vapor would transport downwardly and appear as dew condensation water. The amount of precipitation determined the actual evaporation. The actual evaporation was supposed to be equal to the precipitation on the megadune and the precipitation was difficult to recharge the groundwater. Our study can provide a foundation for further research on land-atmosphere interactions in this area.

Probabilistic seismic hazard analysis (PSHA) is now established practice as the basis for determining seismic design ground motions for important nuclear facilities. Consistent with this practice, PSHAs for ground motion and fault displacement have been performed for the Yucca Mountain site . The methodology used for the PSHAs incorporated multiple expert evaluations of seismic sources, the potential for fault displacement, and ground motion estimation. The experts provided weighted alternative evaluations to characterize uncertainties in their interpretations. Based on these alternative interpretations, hazards were calculated and expressed as the annual frequency at which levels of ground motion or fault displacement are expected to be exceeded. The objective of the PSHAs was to provide ground motion and fault displacement hazard results for both determining preclosure (up to 300 years) seismic design requirements and for postclosure (10,000 years or more) assessment for long-term waste containment and isolation performance of the potential repository. The governing regulation requires consideration of two categories of design basis events. Category-1 events are expected to occur 1 or more times during the preclosure operational period of the facility. For ground motion, the target hazard for Category-1 events has been established at 10 -3 annual frequency of exceedance. For Category-2 events, ground motion will be based on hazard at an annual exceedance frequency of 10 -4 . For postclosure assessment, annual exceedance frequencies as small as 10 -7 may need to be considered.

The population of (Haliaeetus vocifer (Daudin)) at Lake Naivasha, Kenya, was censused over a 13-year period (1987-99). During this time it declined by over half, to a low of 70 birds, by 1996. Breeding effectively ceased, with no courtship or nesting observed for most of the 1990s. The reason seemed to be a food shortage, which provided enough to stay alive but not enough to breed. Declines in the main prey items -fish species and red knobbed coot (Fulica cristata), occurred during the early 1990s and feeding conditions were worsened by a combination of increased turbidity in the lake, floating mats of exotic vegetation and the loss of shallow lagoons behind fringing Cyperus papyrus. This explanation was confirmed when heavy rains, following the strong ENSO event in 1997-98, caused a rapid lake level rise of 3 m vertically, flooding new lagoons behind formerly stranded C. papyrus. Breeding re-commenced, leading to 17-24 fledged juveniles in a population exceeding 100, by 1999. This population of H. vocifer is a valuable index of both the health of the lake and of its littoral ecotone.

Antarctica holds a great number of inland lakes whose characteristics vary from ultra-oligotrophic to hypereutrophic, and from freshwater to hypersaline. The harsh conditions in these ecosystems (extremely low temperatures, large annual variation in solar radiation, light limitation below the ice) account for adaptive strategies of the selected phytoplankton species; some of them are mixotrophy, formation of resistant cysts, starch accumulation, pigment adaptation and motility. Algal richness is comparatively lower than in other parts of the world, although molecular studies are now revealing a biodiversity much higher than that previously based on morphological identifications. Many lakes are permanently stratified, such as perennially ice-covered or saline meromictic, whereas shallow lakes in coastal regions are usually ice-free in summer, accounting for contrasting patterns in their phytoplankton temporal dynamics. Simple and short food webs are characteristic of Antarctic lakes, where phytoplankton fraction [ 2 lm is usually dominated by nanoflagellates. In this review, we provide an overview of the current knowledge about phytoplankton of Antarctic lakes, including information on biodiversity (morphologicalbased, functional and molecular), and the main ecological aspects (colonization, endemism, ecological strategies, temporal dynamics, biotic interactions). We compared ecosystems of different trophic status and from Continental and Maritime Antarctica, including own data from manipulative experiments.