Evolution of Mid-Atlantic Coastal and Back-Barrier Estuary Environments in Response to a Hurricane: Implications for Barrier-Estuary Connectivity

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m³ of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.     

The distribution of iodine and chlorine in soils over lead-zinc mineralisation,East of Glogfawr,mid-Wales

The potential pathfinder elements iodine, as total (I_tot) and watersoluble (I_aq), chlorine (Cl_tot and Cl_aq) together with F, As, Pb, Zn and Cu have been determined in B horizon soils over proved lead-zinc mineralisation east of the disused Glogfawr mine, Dyfed, Wales. Pb and Cu are anomalous in soils over this occurrence while Zn fails to reflect underlying mineralisation. Total and water soluble I and Cl show anomalously high values over the proved mineralisation and also indicate extensions along the trend of the mineralised fracture system to the south-southwest and the north-northeast; these anomalies are more extensive than those formed by Pb or Cu.In the soils analysed there is a strong correlation between I_tot and I_aq and Cl_tot and Cl_aq and it is possible that a simple water-extractable method could be of use in geochemical prospecting.     

Groundwater-pumping optimization for land-subsidence control in Beijing plain,China

Hydrogeology Journal - Beijing, in the North China plain, is one of the few megacities that uses groundwater as its main source of water supply. Groundwater accounts for about two-thirds of the...     

Deglaciation and meltwater events in hudson strait and the Eastern Canadian Arctic

Stable isotope measurements on molluses from raised marine deposits, and on foraminifera in a piston core, define a series of light isotope events. A major event is¹⁴C dated at ca. 10.3 ka and is correlated with a marked isotopic excursion in HU77-021-156. This event is followed by a dramatic rise in diatom and, slightly later, in benthic foraminiferal abundances. Molluses record another light event around 8 ka. Major fluctuations in both ¹⁸O and ¹³C around 10.3 ka suggests that the Hudson Strait ice stream may have responded to the Younger Dryas climatic oscillation.     

The implications of laboratoryRn flux measurements to the radioactivity in groundwaters: the case of a karstic limestone aquifer

Laboratory time-scale experiments were conducted on Carboniferous Limestone gravels from the Mendip Hills area, England, with the purpose of evaluating the release of²²²Rn to the water phase. The specific surface areas of the samples were 4.14 and 1.69 cm² g⁻¹ , which provided, respectively, values of 50.6 and 12.7 pCi for the released Rn. These results allowed the calculation of the emanation coefficient of this rock matrix with respect to the release of Rn, where completely different values corresponding to 23% and 6% were found, suggesting that the extent to which grain boundaries or imperfections in aggregates of micro-crystals of calcite intersect the particle surface certainly affects the Rn release. They also permitted the evaluation of models for the generation of Rn in rocks and transfer to water, in order to interpret the radioactivity due to this gas in groundwaters from the karstic aquifer of the Mendip Hills area, where the calculated activities in groundwater based on the values of 23% and 6% for the emanation coefficient were about 51 and 15 times higher than actually measured in groundwater. Therefore, the emanation coefficient in nature is considerably smaller than in the lab experiment, and another factork (0 < k < 1) may be introduced into the equations related to the modelling, with the aim of adjusting the theoretical-practical results.     

Urban climate and clues of heat island events in the metropolitan area of Rio de Janeiro

This paper aims to map the thermal field in the metropolitan region of Rio de Janeiro (MARJ) considering the atmospheric characteristics and the land use that contribute to understanding the urban heat island. Three thermal maps are defined through the use of Landsat5-TM satellite images for three winter events chosen for the decades of 1980, 1990, and 2000, respectively. The results reveal a concentration of warmer cores in urban central areas as well as some local warmer areas in suburban region. Sites with lower temperatures correspond to vegetated areas which are away from the central part of the MARJ, including points of suburban areas. This work emphasizes the importance of the combined analysis of surface temperature with land use and atmospheric conditions, depicting a distinct pattern of heat islands for tropical climate.