Assessing anthropogenic impact on Mediterranean sand dunes from aerial digital photography

The Mediterranean region plays host to ca. 33% of the world’s tourism industry. This population of visitors (ca. 147 million in 1990) inevitably exerts an enormous impact on the natural resources of this coastal zone. In May 1997, a new generation Aerial Digital Photographic System [ADPS] configured with a Kodak Digital Science 460 CIR digital camera was used to acquire colour infrared digital photographs of the sand dune systems along the Mediterranean coast of France, from Le Barcares to St-Cyprien-Plage. These have been used to assess the condition of the dunes along this coast. A series of simple analytical techniques to identify and measure features indicative of public pressure using image processing software has been devised. The dune manager with basic computer skills can analyse such indicators as path length, vegetation cover (and conversely the extent of bare sand) to enable monitoring of the performance of their dune systems under particular management regimes. These photographs have been compared with similar digital photographs of dune sites in SW France to allow a comparison of dune degradation in a region with a different population pressure and climate regime. Dune systems sampled from the Mediterranean coastal zone showed more evidence of anthropogenically induced change than those sampled in SW France.     

STREAM QUALITY IMPACTS OF BEST MANAGEMENT PRACTICES IN A NORTHWESTERN ARKANSAS BASIN1

ABSTRACT: A variety of management options are used to minimize losses of nitrogen (N), phosphorus (P), and other potential pollutants from agricultural source areas. There is little information available, however, to indicate the effectiveness of these options (sometimes referred to as Best Management Practices, or BMPs) on basin scales. The objective of this study was to assess the water quality effectiveness of BMPs implemented in the 3240 ha Lincoln Lake basin in Northwest Arkansas. Land use in the basin was primarily forest (34 percent) and pasture (56 percent), with much of the pasture being regularly treated with animal manures. The BMPs were oriented toward minimizing the impact of confined animal operations in the basin and included nutrient management, dead bird composter construction, and other practices. Stream flow samples (representing primarily base flow conditions) were collected bi-weekly from five sites within the basin from September 1991 through April 1994 and analyzed for nitrate N (NO₃-N), ammonia N (NH₃-N), total Kjeldahl N (TKN), ortho-P (PO₄-P), total P (TP), chemical oxygen demand (COD), and total suspended solids (TSS). Mean concentrations of PO₄-P, TP, and TSS were highest for subbasins with the highest proportions of pasture land use. Concentrations of NH₃-N, TKN, and COD decreased significantly with time (35–75 percent/year) for all sub-basins, while concentrations of other parameters were generally stable. The declines in analysis parameter concentrations are attributed to the implementation of BMPs in the basin since (a) the results are consistent with what would be expected for the particular BMPs implemented and (b) no other known activities in the basin would have caused the declines in analysis parameter concentrations.     

Genetic variation of mitochondrial DNA in mussel (Mytilus edulis and M. galloprovincialis) populations from South West England and South Wales

Mitochondrial DNA (mtDNA) and allozyme variation were analysed in samples of mussels collected in 1984 and 1985 from four localities in South West England and one locality in South Wales, a region of Britain where the common mussel (Mytilus edulis) occurs sympatrically and hybridises with the Mediterranean mussel (M. galloprovincialis). Significant differences in mtDNA genotype frequencies for three restriction enzymes (BstEII, XbaI, and EcoRI) were observed between mussels from M. galloprovincialis populations (Padstow and Bude) and those from an M. edulis population (Swansea). Some mtDNA genotypes at high-frequency in M. galloprovincialis were not observed in M. edulis, although there was no indication that mtDNA variation provides greater overall diagnostic power than allozyme variation in distinguishing between the two forms of mussel. Construction of a phylogenetic tree of multiple mtDNA genotypes revealed small mutational distances between the genotypes characterising M. edulis and M. galloprovincialis. The results were consistent with predominant mtDNA flow from M. edulis to M. galloprovincialis. This can be explained by the dispersal of larvae to South West England from M. edulis regions to the north and east, but little dispersal in the opposite directions. Samples from two hybrid populations (Whitsand and Croyde) were analysed. mtDNA genotype frequencies at Croyde were in line with predictions made on the basis of two partially diagnostic allozyme loci (Est-D and Odh), mtDNA frequencies at Whitsand were not. Frequencies of some mtDNA genotypes at Whitsand were characteristic of M. edulis, others of M. galloprovincialis. Differential selective mortality or flow of different mtDNA genotypes and allozyme variation are proposed as possible causes of these results.     

Exceptionally high levels of multiple mating in an army ant

Most species of social insects have singly mated queens, although there are notable exceptions. Competing hypotheses have been proposed to explain the evolution of high levels of multiple mating, but this issue is far from resolved. Here we use microsatellites to investigate mating frequency in the army ant Eciton burchellii and show that queens mate with an exceptionally large number of males, eclipsing all but one other social insect species for which data are available. In addition we present evidence that suggests that mating is serial, continuing throughout the lifetime of the queen. This is the first demonstration of serial mating among social hymenoptera. We propose that high paternity within colonies is most likely to have evolved to increase genetic diversity and to counter high pathogen and parasite loads.     

Electrolytic treatment of an industrial wastewater from a hosiery plant.

Textile plant wastewater being treated in a facultative pond system had too high of a solids concentration to be reused in the dying and rinsing processes. Electrocoagulation was evaluated to further treat the pond effluent to remove turbidity, which was caused by dyes and microorganisms. A range of amperages were tested for removal of turbidity and chemical oxygen demand (COD). Electrocoagulation lowered the turbidity from 1400 NTU to below 50 NTU; and COD was lowered from 550 mg/L to approximately 250 mg/L, which was acceptable for reuse. In addition, a laboratory-scale sedimentation study was conducted on the electrocoagulated pond effluent, which indicated that a settling time of 35 minutes would provide for 80% removal of suspended solids, which was acceptable for reuse of the water in plant processes.     

Gaseous mercury capture by coir fibre coated with a metal-halide

ABSTRACT

Toxic gaseous elemental mercury (GEM) is emitted to the atmosphere through a variety of routes at rates estimated at over 5000 tonnes per annum, a large fraction of which is Anthropogenic. It is then widely disbursed atmospherically and eventually deposited, where it is subject to further biogeochemical cycling, including re-emission. Research into capture of point source mercury emissions revolves almost exclusively around the use of activated carbons, various catalytic oxidation substrates, or as a by-product of acidic treatments of flue gas during SOx and NOx reduction methods. GEM is very non-reactive in its native state, but capture rates are greatly enhanced if GEM is first oxidized, or at least where oxidation states play a role at the substrate GEM interface. Little research has been devoted to capture of GEM directly. However, presented here is a novel adaption of coir fibers for use as a substrate in capturing GEM emissions directly. Various coir modifications were investigated, with the most effective being fibers coated with CuI crystals dispersed in a non-crosslinked poly-siloxane matrix. Scanning electron microscopy was used to view surface morphologies, and sorption characteristics were measured using atomic absorption spectroscopy (AAS). These results indicate that coir fibers modified by CuI-[SiO₂] _n show great promise in their ability to efficiently sorb GEM, and could potentially be utilized in a variety of configurations and settings where GEM emissions need to be captured.     

The impact of angler groundbait on benthic invertebrates and sediment respiration in a shallow eutrophic reservoir

In an experiment to determine the impact of angler baits, cereal or maggots were added to areas of sediment in a eutrophic reservoir at realistic rates, over a 12-week period. The densities of benthic invertebrate taxa were estimated before treatment, immediately after treatment, and, finally, after a 4-month recovery period. All taxa except the tubificid Limnodrilus hoffmeisteri were reduced in density by cereal baiting, the most sensitive being naidid worms and cladocerans. Recovery of the benthic community was not apparent after 4 months, although cyclopoid copepods were significantly more abundant in treated areas. Baiting with maggots had a qualitatively similar effect. Laboratory experiments to determine the rate of oxygen consumption by sediments treated with cereal bait suggest that demand for oxygen can be increased 100-fold by a single application of bait. It is suggested that this demand for oxygen could result in local deoxygenation under warm, calm conditions, and that this is the probable mechanism of the impact of cereal bait on benthic invertebrates.     

Movement patterns of the limpet Cellana grata (Gould) observed over a continuous period through a changing tidal regime

Time-lapse videography of limpets mounted with light-emitting diodes was used to monitor the movements of a population of the non-homing Cellana grata on a vertical gully wall in Hong Kong. Animals were monitored for >7 days to examine spatial and temporal variation in their behaviour as the tides transited from a semi-diurnal to an almost diurnal pattern. Movement was synchronised with the tides, irrespective of the day–night cycles. Limpets rested low on the shore and were stimulated to move by the rising tide. Individuals moved up shore with the flooding tide, maintaining themselves in the awash zone, and then down shore on the ebbing tide, until they reached a resting height when the tide then fell beneath them, exhibiting ‘zonal shuttling’. A tight coupling of limpet position to tide height persisted through the changing tidal pattern, and almost all animals displayed the same organisation of activity over all tides. Initiation of activity and maximum height reached were probably controlled by the tides, but the cessation of activity may have been controlled by an internal clock. The pattern observed is consistent with the threat of attack from aquatic predators coupled with the need to minimise physical stresses while exposed. It is also consistent with the avoidance of grazing lower on the shore where interspecific competition may be more intense. Limpets showed two peaks of activity per tide, corresponding to when the rate of change of tide height was the greatest, except when tides became much reduced during the transit to a diurnal pattern. Movement was triphasic: an initial rapid phase, followed by a slower phase in the high shore and then a rapid phase before the limpets stopped moving. This structure is common in limpets and in this case is likely to be a consequence of animals maintaining themselves within the awash zone. Tide height appears to determine foraging activity, but with modifications in the behaviour in response to factors operating at more local temporal and spatial scales.     

建筑产品与生命周期思考

生命周期理念,在与建筑和建设部门的关系中,特别应该进行建筑产品分析、在提高建筑物能源效率并为经济繁荣有所贡献的时候,这些产品发挥着基本的作用,已经做出的要算披露,在从自然索取的物质资源和产生的垃圾总量中,有一半来自建筑部门,为了对建筑产品的影响进行和理并把综降到最低,就必须利用生命周期的方法对所产生的影响进生检测,本文评论了生命周期理念并思考了最新的发展.材料与可持续建筑,环境产品宣言,所体现的能源以及北方与南言建筑产品评估中产生的差异,都是要讨论的话题.     

Predicting tree species presence and basal area in Utah: A comparison of stochastic gradient boosting,generalized additive models,and tree-based methods

Many efforts are underway to produce broad-scale forest attribute maps by modelling forest class and structure variables collected in forest inventories as functions of satellite-based and biophysical information. Typically, variants of classification and regression trees implemented in Rulequest's^© See5 and Cubist (for binary and continuous responses, respectively) are the tools of choice in many of these applications. These tools are widely used in large remote sensing applications, but are not easily interpretable, do not have ties with survey estimation methods, and use proprietary unpublished algorithms. Consequently, three alternative modelling techniques were compared for mapping presence and basal area of 13 species located in the mountain ranges of Utah, USA. The modelling techniques compared included the widely used See5/Cubist, generalized additive models (GAMs), and stochastic gradient boosting (SGB). Model performance was evaluated using independent test data sets. Evaluation criteria for mapping species presence included specificity, sensitivity, Kappa, and area under the curve (AUC). Evaluation criteria for the continuous basal area variables included correlation and relative mean squared error. For predicting species presence (setting thresholds to maximize Kappa), SGB had higher values for the majority of the species for specificity and Kappa, while GAMs had higher values for the majority of the species for sensitivity. In evaluating resultant AUC values, GAM and/or SGB models had significantly better results than the See5 models where significant differences could be detected between models. For nine out of 13 species, basal area prediction results for all modelling techniques were poor (correlations less than 0.5 and relative mean squared errors greater than 0.8), but SGB provided the most stable predictions in these instances. SGB and Cubist performed equally well for modelling basal area for three species with moderate prediction success, while all three modelling tools produced comparably good predictions (correlation of 0.68 and relative mean squared error of 0.56) for one species.