Quartz and zircon decoupling in sandstone: Petrography and quartz cathodoluminescence of the Early Triassic continental Buntsandstein Group in Germany

This study illustrates how decoupling of quartz and zircon can be used advantageously in provenance research. Thirty‐eight fine‐grained to coarse‐grained arkose samples of the Early Triassic intracontinental Buntsandstein Group from the Central European Basin in Germany were analysed for their petrography and 1200 grains in 23 of these for their detrital quartz cathodoluminescence characteristics. The samples represent the Hessian and Thuringian sub‐basins and the Eichsfeld–Altmark Swell separating them. The Hessian Sub‐basin includes more metamorphic lithoclasts with a larger content of plutonic grains than are found further east in the Thuringian Sub‐basin. More than 90% of the detrital quartz from the eastern Thuringian Sub‐basin produce medium to bright blue cathodoluminescence colours and corresponding spectra that are typical for igneous or high‐temperature metamorphic origin. Differently, the quartz from the Hessian Sub‐basin mostly luminesces brown and dark to medium blue, typical for a low‐temperature metamorphic origin. Quartz from the Eichsfeld–Altmark Swell and the western Thuringian Sub‐basin is a mixture between these origins. The quartz indicates different catchments for the sub‐basins, possibly the Bohemian Massif and the Massif Central, with converging transport routes on and close to the eastern fringe of the swell. Taking published zircon data from the same samples into account, light mineral‐zircon grain‐size shifts are up to 2 Φ units. That can be explained by mineral decoupling due to different transport modes for quartz and zircon and different zircon‐size availability in the source areas, exaggerated by combined aqueous–aeolian transport, as well as sample preparation‐induced sorting. This study concludes that submerged highs significantly can influence continental sediment transport. Hence, vast, flat continental areas with submerged morphological highs and a seemingly straightforward transportation pattern may be more complex than expected. The results also illustrate that analysis of detritus that has been affected by different dominating transport modes, and further sorting during sampling and preparation can reveal additional source information.     

The science of European marine reserves: Status,efficacy, and future needs

The ecologically and socio-economically important marine ecosystems of Europe are facing severe threats from a variety of human impacts. To mitigate and potentially reverse some of these impacts, the European Union (EU) has mandated the implementation of the Marine Strategy Framework Directive (MSFD) in order to achieve Good Environmental Status (GES) in EU waters by 2020. The primary initiative for achieving GES is the implementation of coherent networks of marine protected areas (MPAs). Marine reserves are an important type of MPA in which no extraction is allowed, but their usefulness depends upon a number of ecological, management, and political factors. This paper provides a synthesis of the ecological effects of existing European marine reserves and the factors (social and ecological) underlying their effectiveness. Results show that existing European marine reserves foster significant positive increases in key biological variables (density, biomass, body size, and species richness) compared with areas receiving less protection, a pattern mirrored by marine reserves around the globe. For marine reserves to achieve their ecological and social goals, however, they must be designed, managed, and enforced properly. In addition, identifying whether protected areas are ecologically connected as a network, as well as where new MPAs should be established according to the MSFD, requires information on the connectivity of populations across large areas. The adoption of the MSFD demonstrates willingness to achieve the long-term protection of Europe's marine ecosystems, but whether the political will (local, regional, and continent wide) is strong enough to see its mandates through remains to be seen. Although the MSFD does not explicitly require marine reserves, an important step towards the protection of Europe's marine ecosystems is the establishment of marine reserves within wider-use MPAs as connected networks across large spatial scales.     

Estimating reference evapotranspiration using numerical weather modelling

Evapotranspiration is an important hydrological process and its estimation usually needs measurements of many weather variables such as atmospheric pressure, wind speed, air temperature, net radiation and relative humidity. Those weather variables are not easily obtainable from in situ measurements in practical water resources projects. This study explored a potential application of downscaled global reanalysis weather data using mesoscale modelling system 5 (MM5). The MM5 is able to downscale the global data down to much finer resolutions in space and time for use in hydrological investigations. In this study, the ERA‐40 reanalysis data are downscaled to the Brue catchment in southwest England. The results are compared with the observation data. Among the studied weather variables, atmospheric pressure could be derived very accurately with less than 0·2% error. On the other hand, the error in wind speed is about 200–400%. The errors in other weather variables are air temperature (<10%), relative humidity (5–21%) and net radiation (4–23%). The downscaling process generally improves the data quality (except wind speed) and provides higher data resolution in comparison with the original reanalysis data. The evapotranspiration values estimated from the downscaled data are significantly overestimated across all the seasons (27–46%) based on the FAO Penman–Monteith equation. The dominant weather variables are net radiation (during the warm period) and relative humidity (during the cold period). There are clear patterns among some weather variables and they could be used to correct the biases in the downscaled data from either short‐term in situ measurements or through regionalization from surrounding weather stations. Artificial intelligence tools could be used to map the downscaled data directly into evapotranspiration or even river runoff if rainfall data are available. This study provides hydrologists with valuable information on downscaled weather variables and further exploration of this potentially valuable data source by the hydrological community should be encouraged. Copyright © 2010 John Wiley & Sons, Ltd.     

High-energy inundation events versus long-term coastal processes – room for misinterpretation

Coastal boulder deposits and chevrons are two features whose origin have triggered controversial discussions. Boulders are often used as indicators of past tsunamis and storms, with the former interpretation in many cases preferred due to the clast size. Chevrons, defined as large parabolic sand bodies, were previously attributed to (mega-)tsunami, potentially caused by oceanic impacts, because of their dimensions, height above sea level and alignment of the central axis. This study documents that chevrons along the Quobba coast in Western Australia are parabolic dunes and not related to tsunami inundation; their age is consistent with an arid period at about 3·9 to 2·3 ka when the sea level was 1 to 2 m higher than today. The internal age distribution proves an inland migration. Weakly developed soil horizons represent phases of intermittent dune stabilization and later reactivation. The calculated velocities required for wind transport and the prevailing wind directions are consistent with on-site meteorological parameters. The boulders at Quobba are most likely to be remnants of in situ platform denudation that produces shell hash, coral clasts and boulders. An unknown portion of the boulders was certainly moved by tropical cyclones. A previously proposed tsunami origin is unsustainable because the observed features can be explained by processes other than tsunamis. Boulders were tilted during gravitative platform collapse, standing water caused dissolution of the boulder bottoms, creating ‘pseudo-rockpools’, consequently not applicable as upside-down criteria, and ages of attached encrusting organisms document their colonization at higher sea level and (sub)recent frequent inundation by wave splash during rough seas.     

Long-term perspective on the relationship between phytoplankton and nutrient concentrations in a southeastern Australian estuary

Sixteen years (1997–2013) of physicochemical, nutrient and phytoplankton biomass (Chlorophyll-a (Chl-a)) data and a decade (2003-2013) of phytoplankton composition and abundance data were analyzed to assess how the algal community in a temperate southeastern Australian estuary has responded to decreased chronic point source nitrogen loading following effluent treatment upgrade works in 2003. Nitrogen concentrations were significantly lower (P < 0.05) following enhanced effluent treatment and Chl-a levels decreased (P < 0.05) during the warmer months. Temperature and nutrient concentrations significantly influenced temporal changes of Chl-a (explaining 55% of variability), while salinity, temperature, pH and nutrient concentrations influenced phytoplankton abundance and composition (25% explained). Harmful Algal Bloom (HAB) dynamics differed between sites likely influenced by physical attributes of the estuary. This study demonstrates that enhanced effluent treatment can significantly decrease chronic point source nitrogen loading and that Chl-a concentrations can be lowered during the warmer months when the risk of blooms and HABs is greatest.     

Climate change and other trends in streamflow observations in Australian forested catchments since 1970

The effect of climate change on water resources has been an area of continued research, especially in Australia. Previous studies have suggested significant trends in rainfall, and these are amplified causing larger changes in streamflow. However, most of the previous analysis was based on annual time scales or modelled data and did not account for changes in land cover, which could interact with changes in climate. Climate data and streamflow data between 1970 and 2010 from 13 mostly forested small catchments (<250 km²) in Australia were analysed for trends. Non-parametric Mann-Kendall trend analysis, generalized additive mixed modelling and rainfall-runoff modelling were combined for the analysis. This indicates consistent increases in maximum temperature and varied decreases in rainfall. The streamflow in the studied catchments indicated small decreases in streamflow, which amplified observed trends in the rainfall. In general, overall decreases are much smaller than suggested in earlier research.     

Exploring the effect of data assimilation by WRF‐3DVar for numerical rainfall prediction with different types of storm events

The mesoscale Numerical Weather Prediction (NWP) model is gaining popularity among the hydrometeorological community in providing high‐resolution rainfall forecasts at the catchment scale. Although the performance of the model has been verified in capturing the physical processes of severe storm events, the modelling accuracy is negatively affected by significant errors in the initial conditions used to drive the model. Several meteorological investigations have shown that the assimilation of real‐time observations, especially the radar data can help improve the accuracy of the rainfall predictions given by mesoscale NWP models. The aim of this study is to investigate the effect of data assimilation for hydrological applications at the catchment scale. Radar reflectivity together with surface and upper‐air meteorological observations is assimilated into the Weather Research and Forecasting (WRF) model using the three‐dimensional variational data‐assimilation technique. Improvement of the rainfall accumulation and its temporal variation after data assimilation is examined for four storm events in the Brue catchment (135.2 km²) located in southwest England. The storm events are selected with different rainfall distributions in space and time. It is found that the rainfall improvement is most obvious for the events with one‐dimensional evenness in either space or time. The effect of data assimilation is even more significant in the innermost domain which has the finest spatial resolution. However, for the events with two‐dimensional unevenness of rainfall, i.e. the rainfall is concentrated in a small area and in a short time period, the effect of data assimilation is not ideal. WRF fails in capturing the whole process of the highly convective storm with densely concentrated rainfall in a small area and a short time period. A shortened assimilation time interval together with more efficient utilisation of the weather radar data might help improve the effectiveness of data assimilation in such cases. Copyright © 2012 John Wiley & Sons, Ltd.     

Changes in North Sea macrofauna communities and species distribution between 1986 and 2000

The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes.The results showed that the large-scale spatial distribution of macrofauna communities in the North Sea hardly changed between 1986 and 2000, with the main divisions at the 50 m and 100 m depth contours. Water temperature and salinity as well as wave exposure, tidal stress and primary production were influential environmental factors on a large (North Sea-wide) spatial scale.The increase in abundance and regional changes in distribution of various species with a southern distribution in the North Sea in 2000 were largely associated with an increase in sea surface temperature, primary production and, thus, food supply. This can be most likely related to the North Sea hydro-climate change in the late 1980s influenced by the variability in the North Atlantic Oscillation (NAO). Only one cold-temperate species decreased in abundance in 2000 at most of the stations. Indications for newly established populations of offshore non-native species were not found.Differences in macrofauna community structure on localised spatial scales were predominantly found north of the 50 m depth contour off the British coast along the Flamborough Head Front towards the Dogger Bank, off the coast of Jutland and at the Frisian Front. These changes were most likely attributed to stronger frontal systems in 2000 caused by the increased inflow of Atlantic water masses in relation to the hydro-climate change in the late 1980s.     

Compositional variations of zirconolite from the Evate apatite deposit (Mozambique) as an indicator of magmatic-hydrothermal conditions during post-orogenic collapse of Gondwana

Mineralogy and Petrology - Zirconolite is documented from the Evate apatite-magnetite-carbonate deposit in the circular Monapo Klippe (eastern Mozambique)—a relic of Neoproterozoic nappe...     

KLENOT Project 2002–2008 contribution to NEO astrometric follow‐up

Abstract— Near‐Earth object (NEO) research plays an increasingly important role not only in solar system science but also in protecting our planetary environment as well as human society from the asteroid and comet hazard. Consequently, interest in detecting, tracking, cataloguing, and the physical characterizing of these bodies has steadily grown. The discovery rate of current NEO surveys reflects progressive improvement in a number of technical areas. An integral part of NEO discovery is astrometric follow‐up crucial for precise orbit computation and for the reasonable judging of future close encounters with the Earth, including possible impact solutions. The KLENOT Project of the Klet Observatory (South Bohemia, Czech Republic) is aimed especially at the confirmation, early follow‐up, long‐arc follow‐up, and recovery of near‐Earth objects. It ranks among the world's most prolific professional NEO follow‐up programs. The 1.06 m KLENOT telescope, put into regular operation in 2002, is the largest telescope in Europe used exclusively for observations of minor planets and comets, and full observing time is dedicated to the KLENOT team. In this paper, we present the equipment, technology, software, observing strategy, and results of the KLENOT Project obtained during its first phase from March 2002 to September 2008. The results consist of thousands of precise astrometric measurements of NEOs and also three newly discovered near‐Earth asteroids. Finally, we also discuss future plans reflecting also the role of astrometric follow‐up in connection with the modus operandi of the next generation surveys.