Marine sediment contamination of an industrial site at Port of Bagnoli, Gulf of Naples, Southern Italy

For almost one century an important steel plant has been active at the Bagnoli industrial area (Naples, Southern Italy). The environmental survey of near shore and offshore sediments has been carried out as fundamental part of a clean up project. The characteristics of the area, supposed type of pollution, national and international protocols in force were taken into consideration in designing sampling schemes and selecting analytical parameters. For this work, sediment grain size, PAHs, PCBs, trace elements, total hydrocarbons and organic matter were considered. Factor analysis evidenced two main types of pollution in the proximity of the industrial plant, both probably attributable to the activity of the industrial site. The first one, due to Cd, Pb, Zn and Mn seems determined by localised activities at the southern part of the plant. The second one, due to Fe and Mn, appears directly linked to the whole contaminated area.     

Responses to salt stress in the halophyte Plantago crassifolia (Plantaginaceae)

General responses to salt stress have been investigated in the halophyte Plantago crassifolia. Seed germination was strongly inhibited by NaCl, although seed viability and germination capacity were not affected by salt pre-treatments. A concentration-dependent inhibition of plant growth was observed in the presence of NaCl, which was accompanied by the accumulation of Na⁺ ions in the leaves, as determined by cation exchange HPLC. A 20-fold increase of proline content in leaves was observed when plants were treated with 500 m NaCl, suggesting a protective role against high salinity stress for this amino acid, whose possible mechanism of action is discussed.     

甘肃北山地区榴辉岩的变质年龄：来自锆石的U-Pb同位素定年证据

北山造山带地处塔里木-中朝板块与哈萨克斯坦板块的交汇部分,主造山时期被认为是早古生代。榴辉岩产在北山造山带的南带,带中榴辉岩与大量基性超基性洋壳岩石和俯冲碰撞有关的花岗岩等伴生,反映该带有可能代表板块的边界。北山榴辉岩的锆石SHRIMP U-Pb同位素定年表明,榴辉岩相的变质年龄为(819±21)Ma,原岩年龄为(1007±20)Ma,表明北山地区存在新元古代一次重要的板块裂解和俯冲碰撞事件。与北山相邻的祁连山南部柴北缘地区近年也报道存在新元古代板块裂解和蛇绿岩洋壳形成事件,表明中国西部存在区域上的新元古代洋盆裂解事件,或称之为罗德尼亚大陆裂解事件。需强调的是,北山榴辉岩相变质事件发生在新元古代,柴北缘榴辉岩的原岩虽为新元古代洋壳岩石,但榴辉岩相变质作用则发生在早古生代,反映北山新元古代俯冲碰撞事件之后的又一次俯冲碰撞事件。     

Direct evidence of imbalanced seagrass (Posidonia oceanica) shoot population dynamics in the Spanish Mediterranean

Direct census of shoots tagged in permanent plots was used to assess the present (2000–2002)Posidonia oceanica population dynamics in 25 meadows along the Spanish Mediterranean Coast. Shoot density ranged from 154±8 to 1,551±454 shoots m⁻², absolute shoot mortality from 5±0 to 249±53 shoots m⁻² yr⁻¹, and absolute shoot recruitment from <5 ±1 to 62±42 shoots m⁻²yr⁻¹. Specific shoot mortality and recruitment rates, which are mathematically and statistically (p>0.05) independent of shoot density, varied from 0.015±0.006 to 0.282±0.138 yr⁻¹ and 0.018±0.005 to 0.302±0.093 yr⁻¹, respectively. Absolute shoot mortality rate was scaled to shoot density (Pearson correlation, r=0.78, p<0.0001), and variability in specific shoot recruitment rate was partially due to differences in the percentage of growing apexes, which produce most of the recruits within the population (Pearson correlation, r=0.50, p<0.001), demonstrating the existence of structural constraints on shoot demography. Shoot half-life was estimated to range from 2.5 to 60.4 yr and meadow turnover times between 6.7 yr and more than a century, provided current estimates of shoot mortality, recruitment rates, and density remain uniform. There were differences in shoot mortality and recruitment at the regional scale, with the meadows developing along the coast of the Spanish mainland experiencing the highest shoot mortality (Tukey test, p<0.05) and tending to exhibit the highest shoot recruitment. The low shoot recruitment did not balance shoot mortality in most (60%) of the meadows, showing a prevalence of declining populations among the 25 meadows studied (Wilcoxon ranked sign test, p<0.0005). This study demonstrates the power of direct census of seagrass shoots in permanent plots to evaluate the present status of seagrass meadows, to detect on-going population decline, and to provide some insight onto the possible factors involved. The incorporation of direct census of seagrass meadows to monitoring programs will help provide the early-warning signals necessary to support management decisions to conserve seagrass meadows.     

Targeted GOES Satellite Observations to Improve Hurricane Track Forecast: A Case Study of Hurricane Floyd

This study performs a set of Observing System Simulation Experiments (OSSEs) using Geostationary Operational Environmental Satellite (GOES) soundings. The primary objective of the OSSEs is to demonstrate that targeted observations can improve forecast accuracy by enhancing the initial conditions and mitigating their uncertainties. Hurricane Floyd (1999) is chosen as a study case. The main reason for choosing hurricane Floyd as a test case is that the movement of the storm was dictated by a mid-level complex polar jet steering flow region. This well-defined feature allowed us to examine the inaccuracy of analysis over the steering flow area using GOES soundings as targeted observations and its impact on the forecast track error. The set of experiments starts from a baseline forecast of hurricane Floyd using the Operational Multiscale Environment model with Grid Adaptivity (OMEGA). From GOES satellite soundings, atmospheric vertical profiles were extracted to simulate targeted observations. These data extracts were assimilated in the initial conditions to simulate new forecasts of hurricane Floyd which were then compared against both the baseline track and observed track. It was found that targeted observations in a forecast sensitive area can help to reduce hurricane forecast track error. Assimilation of only the subset of data (about 50 soundings) from the subjectively chosen fully sampled target region produced a considerable reduction of the track forecast errors (about 30%) within the first critical three days of the forecast.     

The Oka Belt (Southern Siberia and Northern Mongolia): A Neoproterozoic analog of the Japanese Shimanto Belt?

Abstract   The Oka Belt, composed of clastic rocks and greenschists, extends for approximately 600 km in the South-Siberian Sayan region and adjacent northern Mongolia. For a long time the Oka Belt's age and tectonic setting were the most controversial problem in the region. We argue that the belt was formed in Late Neoproterozoic as an accretionary prism. The Oka Belt shows imbricated thrust structure, which had originally seaward vergence and reflected the Neoproterozoic accretion process. The Early Paleozoic orogeny had minor effect on its structural style. The belt contains tectonic slivers of mid-ocean ridge basalts, some oceanic-island basalts and possible pelagic sediments. In several localities they are associated with gabbro and serpentinite. All these rocks represent the oceanic lithosphere subducting beneath the Oka prism and trapped within it. In the inner zone of the Oka Belt are the blueschists exhumed from the deeper prism level. The northern Oka Belt includes mafic intrusions geochemically similar to normal mid-oceanic ridge basalt and felsic volcaniclastic rocks. This segment of the belt is very similar to the Tertiary portion of northern Shimanto Belt, in Japan, and has also experienced the subduction of orthogonal oceanic ridge beneath the prism. This event dates back to 753 ± 16 Ma (the U-Pb zircon discordia). The Oka prism started accreting in Mid-Neoproterozoic after the subduction had initiated under the Japan-like South-Siberian continental terrain. The prism existed through the second half of Neoproterozoic and accumulated a huge volume of sialic material to enlarge the nearby continent. Currently, the Oka Belt remains poorly studied and is very promising for further investigation and discoveries.     

Transfer zones and fault reactivation in inverted rift basins: Insights from physical modelling

Carbonate mylonites with varying proportions of second-phase minerals were collected at positions of increasing metamorphic grade along the basal thrust of the Morcles nappe (Helvetic nappes, Switzerland). Variations of temperature, stress, and strain rate, changes in chemistry of solid and fluid phases, and differing degrees of strain localization and annealing were tracked by measuring the shapes, mean sizes, and size distributions of both matrix and second-phase grains, as well as crystal preferred orientation (CPO) of the matrix. Field structures suggest that strain rate was constant along the fault. The mean and distribution of the calcite grain sizes were affected most profoundly by temperature: Increased temperature, presumably accompanied by decreased stress, correlated with larger mean sizes and wider size distributions. At a given location, the matrix grains in mylonites with more second-phase particles are, on average, smaller, have narrower size distributions, and have more elongate shapes. For example, mylonites with 50 vol.% of second phases have matrix grain sizes half that of pure mylonites. Changes in calcite chemistry and the presence of synkinematic fluids seemed to influence microfabric only weakly. Temporal variations in conditions, such as exhumation-induced cooling, apparently provoke changes in temperature, stress, and strain rate along the nappe. These changes result in further strain localization during retrograde conditions and cause the grain size to be reduced by an additional 50%. The matrix CPO strengthens with increasing temperature or strain, but weakens and rotates with increasing second-phase content. These fabric changes suggest differing rates of grain growth, grain size reduction, and development of CPO owing to variations in the deformation conditions and, perhaps, mechanisms. To interpret natural mylonite structures or to extrapolate mechanical data to natural situations requires careful characterization of the microfabric, and, in particular, second-phase minerals.     

Two-dimensional Non-linear Alfvén Wings Generated by the Electrodynamic Interaction between Callisto and the Jovian Magnetosphere

When a highly conducting magnetized plasma passes an object with lower conductivity, or a body with inhomogeneous conductivity, 2-D structures are formed, the so-called `Alfvén wings'. These structures may arise, for example, at a Jovian moon without an intrinsic magnetic field (Callisto). In this case, Alfvén wings could be generated in the magnetized Jovian magnetospheric plasma flow owing to the in homogeneity of the moon's ionosphere/atmosphere conductivity. Such Alfvén wings may be considered as a satellite magnetosphere; the satellite magnetospheric magnetic field is a disturbed field of the Jovian magnetospheric plasma flow. An analytical solution is obtained in a simple proposed model. This revised version was published online in July 2006 with corrections to the Cover Date.     

Elicitation of Expert Judgments of Climate Change Impacts on Forest Ecosystems

Detailed interviews were conducted with 11 leading ecologists to obtainindividualqualitative and quantitative estimates of the likely impact of a2 × [CO₂] climate change onminimally disturbed forest ecosystems. Results display a much richer diversityof opinion thanis apparent in qualitative consensus summaries, such as those of the IPCC.Experts attachdifferent relative importance to key factors and processes such as soilnutrients, fire, CO₂fertilization, competition, and plant-pest-predator interactions. Assumptionsand uncertaintiesabout future fire regimes are particularly crucial. Despite these differences,most of the expertsbelieve that standing biomass in minimally disturbed Northern forests wouldincrease and soilcarbon would decrease. There is less agreement about impacts on carbon storagein tropicalforests. Estimates of migration rates in northern forests displayed a rangeof more than fourorders of magnitude. Estimates of extinction rates and dynamic response showsignificantvariation between experts. A series of questions about research needs foundconsensus on theimportance of expanding observational and experimental work on ecosystemprocesses and ofexpanding regional and larger-scale observational, monitoring and modelingstudies. Results ofthe type reported here can be helpful in performing sensitivity analysis inintegrated assessmentmodels, as the basis for focused discussions of the state of currentunderstanding and researchneeds, and, if repeated over time, as a quantitative measure of progress inthis and other fieldsof global change research.