Permeameter data verify new turbulence process for MODFLOW

A sample of Key Largo Limestone from southern Florida exhibited turbulent flow behavior along three orthogonal axes as reported in recently published permeameter experiments. The limestone sample was a cube measuring 0.2 m on edge. The published nonlinear relation between hydraulic gradient and discharge was simulated using the turbulent flow approximation applied in the Conduit Flow Process (CFP) for MODFLOW-2005 mode 2, CFPM2. The good agreement between the experimental data and the simulated results verifies the utility of the approach used to simulate the effects of turbulent flow on head distributions and flux in the CFPM2 module of MODFLOW-2005.     

A novel charge-transfer polymer for separating hydrocarbon fractions of crude oils

Hydrocarbon fractions in crude oil were separated by a new charge-transfer polymer in place of silver ions in Argentation TLC. The charge-transfer plates are cheaper than their silver nitrate equivalents, do not discolour, and store well. The polymer/silica gel mix can be re-used.     

Observation of high-frequency sound propagation in shallow waterwith bubbles due to storm and surf

An experiment was performed off the shore of Panama City, FL, to measure the spatial and temporal coherence of high-frequency signals that were transmitted between fixed towers. Transmission was along paths at mid depths in about 10 m of water. During the time of the experiment, there were two stormy days with breaking waves and nearby high surf. It was observed that pulse-to-pulse variations (over seconds) in travel times, over a range of frequencies, increased dramatically from those observed on quiet days. Average travel times also increased by about 3%. Dispersion was also observed. The distance between the source and the receiver towers was approximately 60 m. By assuming that bubbles were either generated by breaking waves and advected down ward and/or generated by surf and advected outward, these results are explained. Estimates of the average bubble density and bubble-density variations are made     

The climate of Scotland over the last 5000 years inferred from multiproxy peatland records: inter‐site correlations and regional variability

The mid to late‐Holocene climates of most of Scotland have been reconstructed from seven peat bogs located across north–south and east–west geographical and climatological gradients. The main techniques used for palaeoclimatic reconstruction were plant macrofossil, colorimetric humification, and testate amoebae analyses, which were supported by a radiocarbon‐based chronology, aided by markers such as tephra isochrons and recent rises in pine pollen and in spheroidal carbonaceous particles (SCPs). Field stratigraphy was undertaken at each site in order to show that the changes detected within the peat profiles were replicable. Proxy climate records were reconstructed using detrended correspondence analysis (DCA) of the plant macrofossil data and a mean water table depth transfer function on the testate amoebae data. These reconstructions, coupled with the humification data, were standardised for each site and used to produce a composite record of bog surface wetness (BSW) from each site. The results show coherent wet and dry phases over the last 5000 years and suggest regional differences in climate across Scotland, specifically between northern and southern Scotland. Distinct climatic cycles are identified, all of which record a millennial‐scale periodicity which can be correlated with previously identified marine and ice core Holocene cycles. The key role of the macrofossil remains of Sphagnum imbricatum, a taxon now extinct on many sites, is discussed in relation to the identified climatic shifts. Copyright © 2005 John Wiley & Sons, Ltd.     

Preserving the unpreservable: a lost world rediscovered at Christian Malford, UK

The small village of Christian Malford, Wiltshire (UK) is known to palaeontologists the world over because of the chance discovery of an astonishing fossil bonanza in the mid-nineteenth century. Pits in the Jurassic Oxford Clay yielded thousands of specimens of exquisitely preserved ammonites, fish and crustaceans, but became most famous for squid-like cephalopods and belemnites (collectively termed coleoids) with fossilized soft-parts. The precise location of the find has remained obscure, until now, and a new attempt is underway to understand the ancient environment that triggered this unusual preservation.     

Interactions between groundwater and surface water in a virginia coastal plain watershed. 1. Hydrological flowpaths

A field study of surface water and groundwater interactions during baseflow and stormflow conditions was performed at the Reedy Creek watershed in the Virginia Coastal Plain. Three estimates of the average saturated hydraulic conductivity (K_s) of the unconfined aquifer were in reasonable agreement (ranging from 0.0033 to 0.010 cm/s), indicating that baseflow in the creek is entirely from the drainage of shallow groundwater from the relatively thin (1–6 m thick) unconfined aquifer. This relatively permeable surficial aquifer was found to be underlain by dark, olive grey, clay-silt and diatomaceous Miocene deposits of low permeability known as the Calvert Formation, which is believed to function as a confining bed in the area. A chemical hydrograph separation technique was used to resolve the contributions of [old] (pre-event) and [new] (event) water to stormflow. Results from a major rainstorm indicated that old water dominated the stormflow response of the watershed, although the new water contribution approached 40% at the hydrograph peak. Stormflow at Reedy Creek appears to result from saturation overland flow from variable source areas which include the stream channels and a significant part of the riparian wetland area. This response appears to be attributable to the transient dynamics of the shallow groundwater flow system and to the formation of localized groundwater mounds which raise the water-table to the wetland surface.