Environmental features of deep-sea habitats linked to the genetic population structure of a crustacean species in the Mediterranean Sea

The deep-sea habitat, from 200 to 2000 m depth, has long been thought as an ecosystem where biotic and abiotic factors vary very little and consequently species are not disturbed by processes and phenomena which could promote fast evolutionary mechanisms. Unfortunately, biological information relating to deep water is limited, especially regarding the population genetics of species inhabiting the Mediterranean Sea, and general patterns cannot be inferred. In this study we report data on the population genetic structure of Aristeus antennatus , a deep-sea decapod crustacean species which has been widely studied due to its important economic value. We surveyed and examined the variation in a 369-bp fragment of the mtDNA control region from individuals caught by Spanish and Italian trawlers in eight localities. High levels of mitochondrial control region haplotypic diversity (ranging from 0.884 to 0.989) were observed. AMOVA showed a high level of genetic variation, more within than between populations, and a low but significant Φ_ST value was recovered. Minimum spanning network did not separate any haplotype group and haplotype distribution does not mirror the geographic origin of the samples. The absence of population substructuring was also observed with a principal coordinates analysis, which uses an individual-by-individual comparison. These results revealed extensive gene flow among populations. Information on demographic history based on mismatch analysis revealed an unstable population, showing an alternate pattern of growth and decline. Our results indicated that in the western and central Mediterranean basins A. antennatus is a large panmictic population with a fluctuating abundance. The absence of deep-sea barriers and adult migration may prevent the structuring of the species into genetically differentiated populations.     

Low-cost port competitiveness index: Implementation in the Spanish port system

Spanish Port Authorities currently face a wide range of complexities in their decision-making processes, as they have to satisfy several port management objectives that may conflict with one another. This paper examines these circumstances by using decision theory methodology with multiple objectives, which, through the Promethee method, makes the design of an index possible. This index combines different decision factors that shape the competitiveness of a port to rank the Spanish Port Authorities. This ranking serves as an alternative to the traditional ranking system by easily providing more information about port traffic.     

Salt marsh plants (Juncus maritimus and Scirpus maritimus) as sources of strong complexing ligands

This work aimed to evaluate, in vitro, the capability of roots of salt marsh plants to release strong Cu-complexing ligands and to ascertain whether Cu contamination would stimulate ligands' exudation or not. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location and spiked with Cu²⁺ in the range 0–1600 nM to obtain plant exudates. In the final solutions as well as in sediment pore water total dissolved Zn and Cu, Cu-complexing ligand concentrations and the respective conditional stability constants (K_CuL^′) values were determined by voltammetry. This study demonstrated that plants are able to release, in a short period of time, relatively high amounts of strong Cu-complexing ligands (56–265 nmol g_root⁻¹), which differed among plants and sampling site but were independent of the season. Cu contamination did not stimulate exudation of Cu-complexing ligands. On the other hand, in media contaminated with Cu both plants accumulated relatively high amounts (29–83%) of the initially dissolved Cu, indicating that they have alternative internal mechanisms for Cu detoxification. Cu exchange between roots and medium (either accumulation in contaminated medium or release in the absence of Cu) was more intense for S. maritimus than for J. maritimus. It was observed that exudate solutions obtained in the absence of added Cu and sediment pore water (the densities of roots observed inside the salt marsh where comparable to those used in the in vitro experiments), displayed similarities in terms of total dissolved metals, Cu-complexing ligands concentrations, values of K_CuL^′ (12 < log K_CuL^′ < 14), as well as patterns of variation among seasons (only observed for Zn). These results are novel and point out that salt marsh plants may be the source at least partially of the strong organic ligands found in the sediment pore water in shallow marginal areas. The capability of salt marsh plants to release strong organic ligands into the environment, conjugated with their known capacity to oxidize anaerobic sediment around roots, indicate that these plants can play a role in controlling metal speciation in the water/sediment interface.     

Experimental study on the hydrodynamic forces induced by a twin-propeller ferry during berthing

The paper presents the experimental study on the influence of wall effect on the hydrodynamic forces induced by the propellers and thrusters of a ferry during the berthing. The program of the model tests was developed for the twin-propeller, twin-rudder, man-manned model of a car–passenger ferry in 1:16 scale, equipped with two bow thrusters. The different combinations of the operational settings of bow thrusters and propellers operating in the push–pull mode allowed to observe and quantify the variation of the hydrodynamic forces due to the changes of the water depth to draft ratios and distances to the quay. The results of model tests are introduced and discussed in the paper. The difference between the measured total hydrodynamic force and superposition of the component forces induced by the propellers and thrusters has been investigated. According to the structure of the generally accepted modular manoeuvring model, the proposition of the weight factors for the component forces comprising the interaction effects has been introduced and discussed.     

A Moon-borne electromagnetic calorimeter

We discuss an electromagnetic sampling calorimeter for the detection of very high energy gamma-rays on the Moon, which is based on the use of scintillating cylinders and plates imbedded in the lunar soil. The use of lunar soil as a calorimeter radiator reduces the weight of the material to be transported to the Moon and minimises environmental impact. Plastic scintillator bars inserted into the regolith about 1.5 m are the active elements of this instrument: at the surface, each bar is terminated by a plastic scintillator plate to veto high energy charge particles. The readout system for the scintillator bars and plates are based on recently developed single photon solid state detectors (Silicon Photomultiplier, SiPM), extremely compact, sturdy and sensitive devices suited for detecting small light pulses in a space experiment. The performance of a regolith-scintillator calorimeter is evaluated and the relevant parameters are optimised using a GEANT4 simulation.     

Can industrial pollution cause intersexuality in the amphipod, Echinogammarus marinus?

Following recent studies, in which intersex and/or reproductive abnormalities have been observed in a number of crustaceans in association with pollution, the prevalence of intersexuality in the amphipod, Echinogammarus marinus was monitored at sites receiving industrial discharges for one year in 2002/2003. Based upon reports of intersexuality occurring in amphipods due to feminising microsporidian parasites, the occurrence, and role of microsporidian parasites in causing intersex was investigated through histological examination. Results demonstrate a significantly higher prevalence of intersex organisms was found at sites receiving industrial discharges throughout the year when compared to a reference site, with the phenotype of intersex (intersex male and intersex female) varying in its dominance between impacted sites. Intersex specimens were significantly more likely to be infected with microsporidian parasites at sites receiving discharges than reference sites, however relatively few specimens (normal or intersex) were infected at reference sites suggesting parasitism is not the only cause of intersex. The direct/indirect role of pollution in the observed intersexuality is discussed.     

Refined timing and kinematics for Baltica–Avalonia convergence based on the sedimentary record of a foreland basin

The Caledonian foreland basin of Poland onlaps the SW slope of the East European Craton and is elongated in a NW–SW direction along the margin of the Baltica palaeocontinent. The base of the synorogenic clastic wedge rises in age from Llandovery to Ludlow between NW and SE Poland, respectively. As the initial influx of orogen‐derived detritus can be unequivocally identified, this diachronism documents a southeastward migration of the basin depocentre, parallel to the present‐day Caledonian Deformation Front. Our best‐fit plate model shows an oblique collision of Baltica and Avalonia, the latter initially indenting the Baltica margin in the NW. Afterwards, Baltica was progressively underthrust beneath Avalonia towards the SE in response to the oblique soft‐mode closure of the Tornquist Ocean. The final deformation event within the Caledonian foreland took place in the earliest Devonian as a far‐field effect of sinistral orogen‐parallel displacements along the Iapetus suture.     

Multidecadal biological monitoring and abatement program\ assessing human impacts on aquatic ecosystems within the Oak Ridge Reservation in eastern Tennessee,USA

Human activities can be powerful drivers of ecosystem change within catchments. While most long-term catchment studies have been conducted at pristine sites, such studies are less common from sites more impacted by human activity. The Oak Ridge National Laboratory's Biological Monitoring and Abatement Program (BMAP) was developed in the mid-1980s to (1) assess compliance with environmental regulations, (2) identify causes of adverse ecological impacts, (3) provide data for human and ecological risk assessments, and (4) evaluate the effectiveness of remedial actions taken to mitigate the impacts of contaminants in soils, groundwater, and surface water by documenting ecological recovery on the Oak Ridge Reservation (ORR), a federally owned 33 476-acre site in eastern Tennessee, managed by the US Department of Energy. The ORR is composed of multiple watersheds containing many small to mid-size streams. BMAP uses an integrated approach for determining stream health; its databases include long-term seasonal records of contaminant concentrations in water and biota, data from aquatic toxicity testing, and surveys of macroinvertebrate and fish assemblages from impacted and reference streams. These long-term data provide valuable records of degradation and recovery in catchment ecosystems. Our objective here is to describe our study system and data series in order to increase awareness of the availability of these long-term data to the catchment science community.     

Multi-criteria spatial screening and uncertainty analysis applied to direct-use geothermal projects

ABSTRACT

The focus of this work is general methods for prioritization or screening of project sites based on the favorability of multiple spatial criteria. We present a threshold-based transformation of each underlying spatial favorability factor into a continuous scale with a common favorability interpretation across all criteria. We compare several methods of computing site favorability and propagating uncertainty from the data to the favorability metrics. Including uncertainty allows decision makers to determine if seeming differences among sites are significant. We address uncertainty using Taylor series approximations and analytical distributions, which are compared to computationally intensive Monte Carlo simulations. Our methods are applied to siting direct-use geothermal energy projects in the Appalachian Basin, where our knowledge about any particular site is limited, yet sufficient data exist to estimate favorability. We consider four factors that contribute to site favorability: the thermal resource described by the depth to 80°C rock, natural reservoir productivity described by rock permeability and thickness, potential for induced seismicity, and the estimated cost of surface infrastructure for heat distribution. Those factors are combined in three ways. We develop favorability uncertainty propagation and sensitivity analysis methods. All methods are general and can be applied to other multi-criteria spatial screening problems.