Tributyltin inputs to the North Sea from shipping activities, and potential risk of biological effects     

Davies  Ian M.; Bailey  Susan K.; Harding  Melanie J.C. 《ICES Journal of Marine Science》1998,55(1):34-43

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Validation of official erosion modelling based on high‐resolution radar rain data by aerial photo erosion classification          下载免费PDF全文

Franziska Katharina Fischer  Michael Kistler  Robert Brandhuber  Harald Maier  Melanie Treisch  Karl Auerswald 《地球表面变化过程与地形》2018,43(1):187-194

The universal soil loss equation (USLE) is the most frequently applied erosion prediction model and it is also implemented as an official decision‐making instrument for agricultural regulations. The USLE itself has been already validated using different approaches. Additional errors, however, arise from input data and interpolation procedures that become necessary for field‐specific predictions on a national scale for administrative purposes. In this study, predicted event soil loss using the official prediction system in Bavaria (Germany) was validated by comparison with aerial photo erosion classifications of 8100 fields. Values for the USLE factors were mainly taken from the official Bavarian high‐resolution (5 × 5 m²) erosion cadastre. As series of erosion events were examined, the cover and management factor was replaced by the soil loss ratio. The event erosivity factor was calculated from high‐resolution (1 × 1 km², 5 min), rain gauge‐adjusted radar rain data (RADOLAN). Aerial photo erosion interpretation worked sufficiently well and average erosion predictions and visual classifications correlated closely. This was also true for data broken down to individual factors and different crops. There was no reason to assume a general invalidity of the USLE and the official parametrization procedures. Event predictions mainly suffered from errors in the assumed crop stage period and tillage practices, which do not reflect interannual and farm‐specific variation. In addition, the resolution of radar data (1 km²) did not seem to be sufficient to predict short‐term erosion on individual fields given the strong spatial gradients within individual rains. The quality of the input data clearly determined prediction quality. Differences between USLE predictions and observations are most likely caused by parametrization weaknesses but not by a failure of the model itself. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Framing up the “Stretching” of Co-Management     

Leonie J. Pearson  Melanie Dare 《社会与自然资源》2019,32(4):363-381

Collaborative management, or co-management, is recognized as best practice for protected area management. A vast literature explores the benefits and challenges of implementing co-management, but more literature is not always better. We propose that the term co-management has been uncritically “stretched”, losing its original framing of actors working together collaboratively. Co-management has become a facade under which traditional hierarchical and market-based management regimes can occur. Conceptual stretching inhibits the capacity to critically articulate variations within models of collaborative governance. We investigate this stretching through a nuanced framework of co-management models with varying intensities. By considering participating actors, institutions and delivery objectives, the theoretically informed and empirically tested framework highlights the stretched implementation of co-management, enabling protected area managers an opportunity to align their practice with the promise of co-management.  相似文献   

Coral reef productivity and diversity—Contributions from enhanced photosynthesis via demand for carbohydrate from the host     

Melanie S. Adams  Barbara Demmig-Adams  Ruiqi Li  Daniel Zarate  Jingchun Li 《Marine Ecology》2020,41(6):e12618

Coral reefs’ high productivity has been attributed mainly to photosymbioses between the coral animal and algae of the family Symbiodiniaceae, with recognition that the host can increase algal photosynthesis by concentrating nutrients and enhancing the efficiency of light absorption. Here, we propose that an additional effect, consumption of carbohydrate by the host, may also enhance algal photosynthesis. We examine evidence from symbiosis between terrestrial plants and root fungi that indicates a link between carbohydrate consumption by the symbiotic partner and photosynthetic upregulation in the plant system. In addition, we review evidence from free-living algae manipulated to exude carbohydrate into the external medium, which was associated with strong upregulation of photosynthetic capacity. We offer suggestions on how host-induced carbohydrate release may increase photosynthesis rates in the symbionts in the intact photosymbiosis and how this relationship evolved.  相似文献   

Behavior of illite and chlorite during pressure solution of shaly limestone of the Kalkberg Formation, Catskill, New York     

Melanie E. Kreutzberger  Donald R. Peacor 《Journal of Structural Geology》1988,10(8)

Textural and chemical changes occurring in illite and chlorite concomitant with pressure solution of limestone were studied in samples from the Kalkberg Formation of Catskill, New York, using XRD and TEM/AEM. Samples on one limb of an anticline are massive shaly limestones, but those on the other have undergone extensive pressure solution and well-developed cleavage is present. Illite and chlorite from the uncleaved shaly limestone are found in small individual packets (100–800 Å thick) dispersed throughout the carbonate matrix with crystal morphologies characteristic of burial diagenesis. Phyllosilicates from the limb more affected by pressure solution occur in larger units (>1 μm thick) as stacks of subparallel packets (150–500 Å thick). Such stacks are inferred to represent coalescence of smaller packets. These data imply that the phyllosilicates are largely passive during pressure solution of limestone; however, localized solution-recrystallization is required by the coherent to semi-coherent packet boundaries and the crystal morphologies present in the pressure solution sample. The largely passive role is in contrast with the more active role of phyllosilicates in many shales and slates.XRD data for illite show an increase in crystallinity in the pressure solution sample under isothermal conditions. Differences in illite crystallinity are adequately explained in large part by differences in crystal size with some contribution due to strain. The data demonstrate that illite crystallinity cannot be unambiguously used in determining absolute or even relative temperatures.  相似文献   

Human occupation of the continental shelf during the late pleistocene/early Holocene: Methods for site location     

Melanie J. Stright 《Geoarchaeology》1986,1(4):347-363

Archaeological sites containing significant information not available from terrestrial sites occur along former land surfaces now submerged and buried on the continental shelf. Although sites may occur anywhere along these former land surfaces, factors essential to man's survival, such as fresh water and food resources, make site locations somewhat predictable. Landforms such as rivers, lakes, and bays represent locations where one or more of the basic subsistence factors are provided. These relict landforms on the continental shelf can be detected easily using high-resolution seismic profilers. Physical sampling of landforms targeted as potential site areas is usually the only method for confirming the presence of an archaeological site. Sediment samples from a potential site are subjected to a series of sedimentary analyses which discriminate between archaeological deposits and natural sedimentary deposits. These methods for locating inundated and buried archaeological sites on the continental shelf were tested in a Gulf of Mexico study funded by the United States Department of the Interior, Minerals Management Service. The study suggests that at least two locations sampled along the ancient Sabine River Valley represent archaeological deposits dating from the Late Wisconsinan period of lower sea stand.  相似文献   

New Reference Materials,Analytical Procedures and Data Reduction Strategies for Sr Isotope Measurements in Geological Materials by LA-MC-ICP-MS     

Jacob Mulder  Graham Hagen-Peter  Teresa Ubide  Rasmus Andreasen  Ellen Kooijman  Melanie Kielman-Schmitt  Yue-Xing Feng  Bence Paul  Andreas Karlsson  Christian Tegner  Charles Lesher  Fidel Costa 《Geostandards and Geoanalytical Research》2023,47(2):311-336

Laser ablation multi-collector mass spectrometry (LA-MC-ICP-MS) has emerged as the technique of choice for in situ measurements of Sr isotopes in geological minerals. However, the method poses analytical challenges and there is no widely adopted standardised approach to collecting these data or correcting the numerous potential isobaric inferences. Here, we outline practical analytical procedures and data reduction strategies to help establish a consistent framework for collecting and correcting Sr isotope measurements in geological materials by LA-MC-ICP-MS. We characterise a new set of plagioclase reference materials, which are available for distribution to the community, and present a new data reduction scheme for the Iolite software package to correct isobaric interferences for different materials and analytical conditions. Our tests show that a combination of Kr-baseline subtraction, Rb-peak-stripping using βRb derived from a bracketing glass reference material, and a CaCa or CaAr correction for plagioclase and CaCa or CaAr + REE²⁺ correction for rock glasses, yields the most accurate and precise ⁸⁷Sr/⁸⁶Sr measurements for these materials. Using the analytical and correction procedures outlined herein, spot analyses using a beam diameter of 100 μm or rastering with a 50–65 μm diameter beam can readily achieve < 100 ppm 2SE repeatability ("internal") precision for ⁸⁷Sr/⁸⁶Sr measurements for materials with < 1000 μg g^-1 Sr.  相似文献   

Twinned calcite as an indicator of high differential stresses and low shock pressure conditions during impact cratering     

Lina Seybold  Claudia A. Trepmann  Stefan Hölzl  Kilian Pollok  Falko Langenhorst  Fabian Dellefant  Melanie Kaliwoda 《Meteoritics & planetary science》2023,58(9):1287-1305

Shock-related calcite twins are characterized in calcite-bearing metagranite cataclasites within crystalline megablocks of the Ries impact structure, Germany, as well as in cores from the FBN1973 research drilling. The calcite likely originates from pre-impact veins within the Variscan metagranites and gneisses, while the cataclasis is due to the Miocene impact. Quartz in the metagranite components does not contain planar deformation features, indicating low shock pressures (<7 GPa). Calcite, however, shows a high density (>1/μm) of twins with widths <100 nm. Different types of twins (e-, f-, and r-twins) crosscutting each other can occur in one grain. Interaction of r- and f-twins results in a-type domains characterized by a misorientation relative to the host with a misorientation angle of 35°–40° and a misorientation axis parallel to an a-axis. Such a-type domains have not been recorded from deformed rocks in nature before. The high twin density and activation of different twin systems in one grain require high differential stresses (on the order of 1 GPa). Twinning of calcite at high differential stresses is consistent with deformation during impact cratering at relatively low shock pressure conditions. The twinned calcite microstructure can serve as a valuable low shock barometer.  相似文献