Status and outlook of hiking trails in the central part of the Low Tatra Mountains in Slovakia between 1980–1981 and 2013–2014

This study presents a methodology for assessment of the condition of hiking trails (HTs) and their impact zones in the central part of the Low Tatra mountain range, based on comparison of two complex data sets gathered in 33 years apart. The first field investigation was performed in 1980 and 1981, and the second in 2013 and 2014. The main goal was to perform a landscape typology in order to assess the susceptibility of landscape complexes to occurrence of anthropogenic and natural destruction processes and to assess the condition and prospects of HTs and their impacts on the adjacent alpine environment. Landscape complexes were characterised by selected abiotic, biotic and technical parameters of HTs and their impact zones. Due to the high variability of these parameters over the length of the HTs, we had to decide on how to map them. This was done using a square grid with 100 m-sized cells. For each cell with HT, the parameters were assigned the typical value within that cell. In total, 26.3 km of HT were studied, stretching over 266 grid cells. On comparison of the two data sets, it was seen that, 64% (171 grid cells) display a generally positive condition, with 54% (143 grid cells) even exhibiting significant improvement or continuously positive state of their condition. 36% (95 grid cells) were in bad condition, including 3% (9 grid cells) whose state had deteriorated, and 2% (6 grid cells) whose state had significantly deteriorated, in the time between the two assessments.     

Lignin phenols used to infer organic matter sources to Sepetiba Bay – RJ,Brasil

Lignin phenols were measured in the sediments of Sepitiba Bay, Rio de Janeiro, Brazil and in bedload sediments and suspended sediments of the four major fluvial inputs to the bay; São Francisco and Guandu Channels and the Guarda and Cação Rivers. Fluvial suspended lignin yields (Σ8 3.5–14.6 mgC 10 g dw⁻¹) vary little between the wet and dry seasons and are poorly correlated with fluvial chlorophyll concentrations (0.8–50.2 μgC L⁻¹). Despite current land use practices that favor grassland agriculture or industrial uses, fluvial lignin compositions are dominated by a degraded leaf-sourced material. The exception is the Guarda River, which has a slight influence from grasses. The Lignin Phenol Vegetation Index, coupled with acid/aldehyde and 3.5 Db/V ratios, indicate that degraded leaf-derived phenols are also the primary preserved lignin component in the bay. The presence of fringe Typha sp. and Spartina sp. grass beds surrounding portions of the Bay are not reflected in the lignin signature. Instead, lignin entering the bay appears to reflect the erosion of soils containing a degraded signature from the former Atlantic rain forest that once dominated the watershed, instead of containing a significant signature derived from current agricultural uses. A three-component mixing model using the LPVI, atomic N:C ratios, and stable carbon isotopes (which range between –26.8 and –21.8‰) supports the hypothesis that fluvial inputs to the bay are dominated by planktonic matter (78% of the input), with lignin dominated by leaf (14% of the input) over grass (6%). Sediments are composed of a roughly 50–50 mixture of autochthonous material and terrigenous material, with lignin being primarily sourced from leaf.     

Magnetic susceptibility logging of Chicxulub proximal impact breccias in the Santa Elena borehole: implications for emplacement mode

Magnetic susceptibility logging is used to study the impact breccias in the Chicxulub crater. The basic premise is that the high contrasts in magnetic properties can be used to characterize the breccias. The Santa Elena borehole was drilled 110 km radial distance from crater center and sampled a 172 m thick sequence of impact breccias, between 332 and 504 m depth. Breccia units are distinguished from differences in composition, size, and relative contents of clasts, type of matrix and textural and lithological assemblages, which can be resolved in the susceptibility logs. The whole-core log shows characteristic variation patterns with high, intermediate and low susceptibilities. High resolution logging of matrix and clasts records the heterogeneous nature of impactites, with higher variability at smaller spatial scales. Measurements confirm that diamagnetic susceptibilities characterize the carbonate clasts, high susceptibilities the basement granitic clasts and intermediate values the silicate melt-rich and silicate-poor matrix. Intermediate variable susceptibilities characterize breccias rich in melt particles. Correlation of matrix and clast logs with whole-core log shows that signal is controlled by the matrix. Logs for clast shows a discrete distribution with peaks of intermediate to high values, which correlate with large clast distributions. The ejecta blanket includes the fallback suevites rich in silicate melt particles and shocked minerals, the high temperature vapor deposits from ejecta curtain collapse and high velocity basal flows, and the carbonate rich deposits from lateral basal flows and secondary cratering. Late fallback suevites record minor turbulent conditions resulting from progressive cooling of the ejecta plume.     

Impact of pond aquaculture effluents on seagrass performance in NE Hainan,tropical China

The impact of pond aquaculture effluents on the distribution and performance of seagrasses was examined in NE Hainan, tropical China. Samples were taken along transects in three back-reef areas with different extent of aquaculture production in their hinterland. High δ¹⁵N in seagrass leaves and epiphytes (6–9‰) similar to values in pond effluents documented aquaculture as dominant nitrogen source in the back-reefs with decreasing impact with distance from shore. Seagrass species abundance, shoot density and biomass were lower and concentrations of nutrients, chlorophyll and suspended matter were higher at nearshore sites with high and moderate pond abundance than at the control site. High epiphyte loads and low δ³⁴S in seagrass leaves suggest temporal shading and sulphide poisoning of the nearshore seagrasses. Observed gradients in environmental parameters and seagrass performance indicate that the distance from the pond outlets and size of the adjacent pond agglomeration are major determinants of seagrass degradation.     

The credibility of volunteered geographic information

The proliferation of information sources as a result of networked computers and other interconnected devices has prompted significant changes in the amount, availability, and nature of geographic information. Among the more significant changes is the increasing amount of readily available volunteered geographic information. Although volunteered information has fundamentally enhanced geographic data, it has also prompted concerns with regard to its quality, reliability, and overall value. This essay situates these concerns as issues of information and source credibility by (a) examining the information environment fostering collective information contribution, (b) exploring the environment of information abundance, examining credibility and related notions within this environment, and leveraging extant research findings to understand user-generated geographic information, (c) articulating strategies to discern the credibility of volunteered geographic information (VGI), including relevant tools useful in this endeavor, and (d) outlining specific research questions germane to VGI and credibility.     

Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon

In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.     

Climate change projections for the Texas High Plains and Rolling Plains

Potential changes in future climate in the Texas Plains region were investigated in the context of agriculture by analyzing three climate model projections under the A2 climate scenario (medium–high emission scenario). Spatially downscaled historic (1971–2000) and future (2041–2070) climate datasets (rainfall and temperature) were downloaded from the North American Regional Climate Change Assessment Program (NARCCAP). Climate variables predicted by three regional climate models (RCMs) namely the Regional Climate Model Version3–Geophysical Fluid Dynamics Laboratory (RCM3-GFDL), Regional Climate Model Version3–Third Generation Coupled Global Climate Model (RCM3-CGCM3), and Canadian Regional Climate Model–Community Climate System Model (CRCM-CCSM) were evaluated in this study. Gaussian and Gamma distribution mapping techniques were employed to remove the bias in temperature and rainfall data, respectively. Both the minimum and maximum temperatures across the study region in the future showed an upward trend, with the temperatures increasing in the range of 1.9 to 2.9 °C and 2.0 to 3.2 °C, respectively. All three climate models predicted a decline in rainfall within a range of 30 to 127 mm in majority of counties across the study region. In addition, they predicted an increase in the intensity of extreme rainfall events in the future. The frost-free season as predicted by the three models showed an increase by 2.6–3.4 weeks across the region, and the number of frost days declined by 17.9 to 30 %. Overall, these projections indicate considerable changes to the climate in the Texas Plains region in the future, and these changes could potentially impact agriculture in this region.

     

Regional climate simulations for the European Alpine Region��sensitivity of precipitation to large-scale flow conditions of driving input data

The MM5 modelling system has been used to perform regional climate simulations over Western Europe on a 45-km grid for the years 1971 to 2000. We focus our analysis on the impact of the driving input data on simulated precipitation in the Alpine area. Using ERA40 reanalysis data, the MM5 climatology of precipitation compares reasonably well with an observational climatology for the Alpine region. Switching to an ECHAM5 climate simulation as driving data induces excessive overprediction by up to 80% in the colder seasons there, primarily over the Alpine slopes. The large-scale flow provided by the global datasets revealed moderate differences indicating an increased number of low-pressure systems travelling from the Atlantic into the Alpine region for ECHAM5 compared with ERA40. Mean seasonal 700-hPa wind speeds correspondingly showed higher values for the ECHAM5 driven simulation in the central Alps. Partitioning three-hourly 700-hPa winds according to direction and speed in the central Alps specifically revealed a distinct shift to stronger westerly and north-westerly winds. Furthermore, aggregating three-hourly rainfall amounts to the same wind direction and wind speed intervals as for the wind statistics revealed strongly intensified precipitation due to the overly intense westerly winds, implying too intense orographic precipitation enhancement.     

Ontology‐supported Querying of Geographical Databases

Querying geographical information systems has been recognized as a difficult task for non‐expert users. Furthermore, user queries are often characterized by semantic aspects not directly managed by traditional spatial databases or GIS. Examples of such semantic geospatial queries are the use of implicit spatial relations between objects, or the reference of domain concepts not explicitly represented in data. To handle such queries, we envisage a system that translates natural language queries into spatial SQL statements on a database, thus improving standard GIS with new semantic capabilities. Within this general objective, the contribution of this article is to introduce a methodology to handle semantic geospatial queries issued over a spatial database. This approach captures semantics from an ontology built upon the spatial database and enriched by domain concepts and properties specifically defined to represent the localization of objects. Some examples of the use of the methodology in the urban domain are presented.     

Climate and vegetation history from a 14,000-year peatland record, Kenai Peninsula, Alaska

Analysis of pollen, spores, macrofossils, and lithology of an AMS ¹⁴C-dated core from a subarctic fen on the Kenai Peninsula, Alaska reveals changes in vegetation and climate beginning 14,200 cal yr BP. Betula expansion and contraction of herb tundra vegetation characterize the Younger Dryas on the Kenai, suggesting increased winter snowfall concurrent with cool, sunny summers. Remarkable Polypodiaceae (fern) abundance between 11,500 and 8500 cal yr BP implies a significant change in climate. Enhanced peat preservation and the occurrence of wet meadow species suggest high moisture from 11,500 to 10,700 cal yr BP, in contrast to drier conditions in southeastern Alaska; this pattern may indicate an intensification and repositioning of the Aleutian Low (AL). Drier conditions on the Kenai Peninsula from 10,700 to 8500 cal yr BP may signify a weaker AL, but elevated fern abundance may have been sustained by high seasonality with substantial snowfall and enhanced glacial melt. Decreased insolation-induced seasonality resulted in climatic cooling after 8500 cal yr BP, with increased humidity from 8000 to 5000 cal yr BP. A dry interval punctuated by volcanic activity occurred between 5000 and 3500 cal yr BP, followed by cool, moist climate, coincident with Neoglaciation. Tsuga mertensiana expanded after ~ 1500 cal yr BP in response to the shift to cooler conditions.