Проблеми структурної модернізації регіонального ринку трудових ресурсів АПК в експертній оцінці працівників органів регіонального управління

Barriers and sandbars are ubiquitous natural coastal features, whose variability often determines nearshore morphological evolution. Wave-dominated beach profile evolution results from the interaction between wave non-linearities, wave-breaking induced turbulence, undertow, infragravity motions and swash processes. To explore each of these contributions to the sediment transport, the full-scale Barrier Dynamics Experiment (BARDEX II), performed in the Delta Flume in June 2012, provides a new dataset for the rigorous testing of the performance of beach profile evolution models in the case of steep beaches. This new experiment will improve our knowledge on (1) swash zone processes, including infiltration and exfiltration of water into the sand and subsequent groundwater table response, (2) bore-generated turbulence inducing suspend sediment transport, (3) surfzone sandbar dynamics and (4) overtopping/overwash impact on barrier dynamics. This study aims at testing the ability of the process-based beach profile model 1DBeach in the case of a steep beachface and a predominance of plunging breakers. In this context, we tested the model with a morphological sequence characterised by onshore and subsequent rapid offshore sandbar migration for time-invariant wave forcing and falling tide. A simulated annealing algorithm is used to calibrate the model. In this paper, we discuss the model configuration and associated results, as well as the need of intensive high-frequency full-scale data to further develop and improve process-based models

Extreme wave activity during 2013/2014 winter and morphological impacts along the Atlantic coast of Europe

Studies of coastal vulnerability due to climate change tend to focus on the consequences of sea level rise, rather than the complex coastal responses resulting from changes to the extreme wave climate. Here we investigate the 2013/2014 winter wave conditions that severely impacted the Atlantic coast of Europe and demonstrate that this winter was the most energetic along most of the Atlantic coast of Europe since at least 1948. Along exposed open-coast sites, extensive beach and dune erosion occurred due to offshore sediment transport. More sheltered sites experienced less erosion and one of the sites even experienced accretion due to beach rotation induced by alongshore sediment transport. Storm wave conditions such as were encountered during the 2013/2014 winter have the potential to dramatically change the equilibrium state (beach gradient, coastal alignment, and nearshore bar position) of beaches along the Atlantic coast of Europe

Comparative genomics in acid mine drainage biofilm communities reveals metabolic and structural differentiation of co-occurring archaea

Background Metal sulfide mineral dissolution during bioleaching and acid mine drainage (AMD) formation creates an environment that is inhospitable to most life. Despite dominance by a small number of bacteria, AMD microbial biofilm communities contain a notable variety of coexisting and closely related Euryarchaea, most of which have defied cultivation efforts. For this reason, we used metagenomics to analyze variation in gene content that may contribute to niche differentiation among co-occurring AMD archaea. Our analyses targeted members of the Thermoplasmatales and related archaea. These results greatly expand genomic information available for this archaeal order. Results We reconstructed near-complete genomes for uncultivated, relatively low abundance organisms A-, E-, and Gplasma, members of Thermoplasmatales order, and for a novel organism, Iplasma. Genomic analyses of these organisms, as well as Ferroplasma type I and II, reveal that all are facultative aerobic heterotrophs with the ability to use many of the same carbon substrates, including methanol. Most of the genomes share genes for toxic metal resistance and surface-layer production. Only Aplasma and Eplasma have a full suite of flagellar genes whereas all but the Ferroplasma spp. have genes for pili production. Cryogenic-electron microscopy (cryo-EM) and tomography (cryo-ET) strengthen these metagenomics-based ultrastructural predictions. Notably, only Aplasma, Gplasma and the Ferroplasma spp. have predicted iron oxidation genes and Eplasma and Iplasma lack most genes for cobalamin, valine, (iso)leucine and histidine synthesis. Conclusion The Thermoplasmatales AMD archaea share a large number of metabolic capabilities. All of the uncultivated organisms studied here (A-, E-, G-, and Iplasma) are metabolically very similar to characterized Ferroplasma spp., differentiating themselves mainly in their genetic capabilities for biosynthesis, motility, and possibly iron oxidation. These results indicate that subtle, but important genomic differences, coupled with unknown differences in gene expression, distinguish these organisms enough to allow for co-existence. Overall this study reveals shared features of organisms from the Thermoplasmatales lineage and provides new insights into the functioning of AMD communities.United States. Dept. of Energy. Genomics:GTL (Grant DE-FG02-05ER64134)National Science Foundation (U.S.). Graduate Research Fellowshi

Barred-beach morphological control on infragravity motion

A conceptual analysis of the coupling between bars and infragravity waves is performed combining laboratory experiments and numerical modeling. Experiments are carried out in a wave flume with a barred profile. The Boussinesq fully-nonlinear model SERR1D is validated with the laboratory data and a sensitivity analysis is performed next to study the influence on the infragravity wave dynamics of bar amplitude and location, and swash zone slope. A novel technique of incident and reflected motions separation that conserves temporal characteristics is applied. We observe that changing bar characteristics induces substantial variations in trapped energy. Interestingly, a modification of swash zone slope has a large influence on the reflected component, controlling amplitude and phase time-lag, and consequently on the resonant pattern. Variations of trapped infragravity energy induced by changes of swash zone slope reach 25 %. These changes in infragravity pattern consequently affect short-wave dynamics by modifying the breakpoint location and the breaking intensity. Our conceptual investigation suggests the existence of a morphological feedback through the action of evolving morphology on infragravity structures which modulates the action of short-waves on the morphology itself

Genomic resolution of a cold subsurface aquifer community provides metabolic insights for novel microbes adapted to high CO2 concentrations.

As in many deep underground environments, the microbial communities in subsurface high-CO2 ecosystems remain relatively unexplored. Recent investigations based on single-gene assays revealed a remarkable variety of organisms from little studied phyla in Crystal Geyser (Utah, USA), a site where deeply sourced CO2 -saturated fluids are erupted at the surface. To provide genomic resolution of the metabolisms of these organisms, we used a novel metagenomic approach to recover 227 high-quality genomes from 150 microbial species affiliated with 46 different phylum-level lineages. Bacteria from two novel phylum-level lineages have the capacity for CO2 fixation. Analyses of carbon fixation pathways in all studied organisms revealed that the Wood-Ljungdahl pathway and the Calvin-Benson-Bassham Cycle occurred with the highest frequency, whereas the reverse TCA cycle was little used. We infer that this, and selection for form II RuBisCOs, are adaptions to high CO2 -concentrations. However, many autotrophs can also grow mixotrophically, a strategy that confers metabolic versatility. The assignment of 156 hydrogenases to 90 different organisms suggests that H2 is an important inter-species energy currency even under gaseous CO2 -saturation. Overall, metabolic analyses at the organism level provided insight into the biochemical cycles that support subsurface life under the extreme condition of CO2 saturation

Morphodynamics of wave-dominated beaches

Abstract Wave-dominated sandy beaches are highly valued by societies and are amongst the world’s most energetic and dynamic environments. On wave-dominated beaches with unlimited sand supply and limited influence of tide and geology, beach change has long been conceptualised in the morphodynamic framework of Wright and Short (1984). Such framework describes the occurrence of beach types based on wave conditions and sediment characteristics across the complete reflective–dissipative spectrum. Building on theoretical work, field/laboratory measurements and monitoring programmes, the physical mechanisms underpinning this morphodynamic framework have been progressively unravelled. Cross-shore morphological changes are primarily controlled by equilibrium and beach memory principles with below (above) average wave conditions driving down-state (up-state) transitions associated with onshore (offshore) sediment transport. Such cross-shore behaviour mostly reflects the imbalance between the onshore-directed sediment transport driven by wave nonlinearities and the offshore-directed sediment transport driven by the undertow. Self-organised morphological instabilities resulting from different positive feedback mechanisms are primarily responsible for alongshore morphological variability and the generation of rhythmic morphological features, such as crescentic bars, rip channels and beach cusps. Critically, wave climate and changes in wave regimes are key in driving the coupled cross-shore and longshore behaviour that ultimately explains modal beach state and frequency-response characteristics of beach morphological time series.</jats:p

The influence of large-scale climate patterns on sediment loss from agricultural land – exploration using an instrumented field and catchment scale platform

Accelerated soil erosion and sediment delivery are threats to water quality. In western Europe, weather patterns are strongly influenced by large scale climate systems such as the North Atlantic Oscillation (NAOi). Recently, however, a new climate index has been developed, called the West Europe Pressure Anomaly (WEPAi), which may be more relevant for weather in northwestern Europe. Recent attempts have tried to link variability in weather patterns as described by hydro-climatic indices and amplifications in the degradation of water quality. However, to our knowledge, no previous work has been undertaken on investigating their effects on suspended sediment concentrations. A study was conducted in southwest England using long-term meteorological, monthly NAOi and WEPAi, and 15-min discharge and turbidity datasets collected from an instrumented field and catchment scale monitoring platform. Monthly winter precipitation totals, and air temperature were both found to be significantly positively related to NAOi, but not in the summer. Both variables were significant and more strongly related with the WEPAi for both seasons. Flow weighted mean suspended sediment concentrations calculated for both seasons over a 4-year period were compared to monthly NAOi and WEPAi. In winter months, no significant relationships were found at any scale for NAOi. However, significant positive relationships with the WEPAi were present regardless of catchment size. In the summer months there were no significant relationships with either climate indices. Large-scale climate drivers are important in the sediment responses of agricultural landscapes. An ability to forecast monthly climate scale drivers could enable farmers to better plan for those periods when hydro-sedimentological responses are likely to be elevated. More work is needed across a range of landscape typologies to confirm that the relationships observed hold true more widely

Modelling the alongshore variability of optimum rip current escape strategies on a multiple rip-channelled beach

Rip currents are a leading cause of drowning on beaches worldwide. How bathers caught in a rip current should attempt to escape has been a subject of recent debate. A numerical model of human bathers escaping from a rip current flow field is applied to a 2-km long section of the open beach of Biscarrosse, SW France. The study area comprises 4 rip channels that visually appear similar from the beach, but exhibit different morphologies. Simulations are run for 2 representative hazardous summer wave conditions. Results show that small changes in the bar/rip morphology have a large impact on the rip flow field, and in turn on the alongshore variability of the optimal rip current escape strategy. The overall flow regime (dominant surf-zone exits versus dominant recirculation), which is found to be influenced by the alongshore dimensions of the sand bars adjacent to the rip channel, is more important to rip current escape strategy than rip velocity. Flow regime was found to dictate the success of the stay afloat strategy, with greater success for recirculating flow. By comparison, the dominant longshore feeder current and rip-neck orientation determined the best direction to swim parallel toward. For obliquely incident waves, swim parallel downdrift then swim onshore with breaking waves was highly successful and can become a simple safety message for beach safety practitioners to communicate to the general public. However, in SW France where rip spacing is large (∼400 m), surf-zone eddies have large spatial scales of the order of 100+ m, requiring a large distance (100+ m) to swim to reach safety, therefore requiring good swimming ability. This also shows that in addition to rip current intensity, rip flow regime and the depth of adjacent sand bars, rip spacing is important for defining rip current hazard and the best safety message. Our results also indicate that for normal to near-normal wave incidence, rip current hazard and best rip current escape strategy are highly variable alongshore due to subtle differences in bar/rip morphology from one rip system to another. These findings challenge the objective of developing a universal rip current escape strategy message on open rip-channelled beaches exposed to normal to near-normal wave incidence, even for seemingly similar rip channels