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Buoyant plastics enter estuaries largely from urban streams and an unknown fraction is retained before further transport to the open ocean. Plastic drifters were launched in a well-mixed estuary to simulate the movement of surface buoyant plastics. Two experiments were conducted, one during spring tides and one during neap tides, both with similar river flows and winds. Stronger tidal currents during spring tides resulted in larger dispersion and further downstream transport of the drifters. Half of the drifters were grounded within two tidal cycles. During the neap experiment, even more of the drifters (87%) were retained in the estuary. The grounding of such a high proportion of drifters suggests that much of the plastic pollution in estuaries of this type remains close to the riverine source. These findings imply that local clean-up programs removing grounded litter can reduce over half of the plastic pollution input to these estuaries. • Between 50%–80% of drifters released in the upper estuary grounded within two tidal cycles. • Drifters dispersed more widely and travel further downstream during spring tides. • Drifters were more likely to ground during neap tides with less dispersion. [ABSTRACT FROM AUTHOR]

A three-year dataset (2007–2010) of shoreline and sandbar positions derived from video observations of an open sandy beach (Biscarrosse, France) is analyzed, to explore the impact of storms on the seasonal shoreline dynamics. The results indicate that a clear seasonality is observed in the offshore significant wave height and in the occurrence of ‘winter storm’ events that are defined as periods with significant wave height greater than 4 m lasting at least 12 h. Data indicate that the range of variation of the inner sandbar positions (120 m) is two and a half times larger than the range of variation of the shoreline position. Correlation analyses suggest that the offshore conditions do not conclusively explain the position of the inner bar. Shoreline positions show a clear seasonal pattern, displaying a stable position occurring in February and July, providing evidence of seasonal-recovery although analysis of storm activity indicates that the number and intensity of storms is highly variable over the three years. The Biscarrosse data show that rapid erosion can be observed also under moderate conditions, and that beach recovery after the storm season can be relatively rapid. [ABSTRACT FROM AUTHOR]

Sea-level rise has a strong influence on tidal systems, and a major focus of climate change effect studies is to predict the future state of these environmental systems. Here, we used a model to simulate the morphological evolution of tidal embayments and to explore their response to a rising sea level. The model was first used to reproduce the formation of channels and intertidal flats under a stable mean water level in an idealised and initially unchannelled tidal basin. A gradual rise in sea level was imposed once a well-developed channel network had formed. Simulations were conducted with different sea-level rise rates and tidal ranges. Sea-level rise forced headward erosion of the tidal channels, driving a landward expansion of the channel network and channel development in the previously non-inundated part of the basin. Simultaneously, an increase in channel drainage width in the lower part of the basin occurred and a decrease in the overall fraction of the basin occupied by channels could be observed. Sea-level rise thus altered important characteristics of the tidal channel network. Some intertidal areas were maintained despite a rising sea level. However, the size, shape, and location of the intertidal areas changed. In addition, sea-level rise affected the exchange of sediment between the different morphological elements. A shift from exporting to importing sediment as well as a reinforcement of the existing sediment export was observed for the simulations performed here. Sediment erosion in the inlet and the offshore transport of sediment was enhanced, resulting in the expansion of the ebb-tidal delta. Our model results further emphasise that tidal embayments can exhibit contrasting responses to sea-level rise. [ABSTRACT FROM AUTHOR]

The article presents a study that examined how incorporating restricted colonist dispersal decreases the range of spatial and temporal rates of disturbance under which benthic communities can persist, using model parameters representative of a New Zealand marine biogenic-structured community. Researchers used a spatially explicit patch dynamic model to show the interaction of the disturbance regime and colonization processes in regulating community dynamics and landscape structure in marine benthic systems. They concluded that the scale of the disturbance regime and dispersal processes are fundamentally coupled, and knowing the scales of both processes is important in predicting change in the structure and diversity of benthic communities threatened by cumulative change.

The article discusses diplomatic and political relations between Vatican City and Italy while the later was under a fascist regime. In particular, it discusses the roles during that period of Pope Pius XI, Cardinal Pacelli, who would become Pope Pius XII, and the college of cardinals in dealing with issues related to fascist Italy and the Catholic Church, Among other topics addressed are a 21 July 1931 meeting of the council of cardinals with the pope, the Italian Catholic political organization Azione Cattolica, and papal letters of the time.

Coastal sediments, where microplastics (MPs) accumulate, support benthic microalgae (BMA) that contribute to ecosystem functions such as primary production, nutrient recycling and sediment biostabilization. The potential interactions between MPs, BMA and associated properties and functions remain poorly understood. To examine these interactions, a survey of 22 intertidal sites was conducted. MP abundance, size and a suite of MP diversity indices (based on color and shape) were determined from surface sediments alongside biochemical and physical properties. MPs were detected at all sites and dominated by polypropylene (34%), polyester (18%) and polyethylene (11%). Fragment and fiber dominance (16–92% and 6–81% respectively) and color-shape category diversity varied significantly by site. Distance-based linear models demonstrated that estuary-wide, mean grain size and mud were the best predictors of MP abundance-diversity matrices, but variance explained was low (9%). Relationships were improved when the data was split into sandy and muddy habitats. In sandy habitats (<8% mud), physical properties of the bed (mean grain size, mud content and distance from the estuary mouth) were still selected as predictors of MP abundance-diversity (14% variance explained); but a number of bivariate relationships were detected with biochemical properties such as BMA associated pigments and organic matter. In muddy habitats (>8% mud), porewater ammonium was lower when fiber abundance and overall MP diversity were higher. The inclusion of porewater ammonium, organic matter content and pheophytins alongside physical properties explained a greater percentage of the variance in MP abundance-diversity for muddy habitats (21%). The results highlight the importance of examining plastic shapes and MP categories in addition to abundance and emphasize that functionally different habitats should be examined separately to increase our understanding of MP-biota-function relationships. [Display omitted] • Grain size was the main predictor for 'whole' estuary and sand habitats. • Including NH 4 + pools and organic matter (OM) improved predictions for muddy sites. • No. fragments increased with mud (up to 8%); No. fibers increased with grain size. • No. fragments higher in OM rich sites; fibers increased at low NH 4 + sites. • Interactions with sediment biochemical properties are an important consideration. Biochemical properties of field sediments influence the abundance and diversity of microplastics across sedimentary ecosystems. [ABSTRACT FROM AUTHOR]

Geography and Geographical education can learn much from and with science and science education. This article particularly looks at how new explanations of beach cusp development have recently emerged. There are clear messages for us on paradigm shifts and the development of transdisciplinary understandings -- using existing disciplines and knowledge in a new way to solve a real world problem and create new ways of seeing and understanding such problems. The context discussed here commences with science and science education, but could easily be read Geography and Geographical education. The environmental issue used as the example of how and why paradigm shifts are important in the knowledge economy will be in itself of direct interest to geographical educators. There are also important lessons with regard to the alignment of curriculum intent with classroom practice and the need of professional learning to support our students and their learning. To achieve international calls for the public understanding of science and geography, many educators are pointing to the important role that school education programs play in creating scientifically literate societies of the future. However research findings reveal that even when curricular goals promote discipline literacy they are rarely translated into classroom practice. Teachers' lack of understanding of the nature of science and the unavailability of appropriate teaching and learning resources have been identified as factors contributing to the nonachievement of these goals. This paper presents an account of contemporary scientific inquiry at work to highlight key aspects of the nature of such inquiry. In the context of earth sciences the story illustrates the part paradigms play in guiding scientific endeavour and how new scientific knowledge is generated. It is hoped that such narratives can facilitate teacher professional learning as well as teacher education and serve as useful learning contexts to motivate student interest and understanding of scientific inquiry. [ABSTRACT FROM AUTHOR]