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  • 1
    Call number: ZSP-166-261
    In: Berichte aus dem MARUM und dem Fachbereich Geowissenschaften der Universität Bremen
    Type of Medium: Series available for loan
    Pages: 130, A41 S.
    Series Statement: Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen 261
    Classification:
    Oceanology
    Location: Lower compact magazine
    Branch Library: AWI Library
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  • 2
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    Pensoft Publishers
    Publication Date: 2024-04-05
    Description: Rhinophoridae are a small family of calyptrate flies commonly known as “woodlouse flies” due to their unique parasitoid habit of developing inside their isopod hosts (Oniscidea). Beside this peculiarity, the adult stage lacks unique family autapomorphies, sometimes making their identification challenging. However, their larvae are highly apomorphic and peculiar due to their unusual locomotive behaviour of leach-like crawling or even somersaulting. Until recently, woodlouse flies were considered an Old World group, with a peak in species diversity in the Turano-Mediterranean area. However, recent discoveries of new taxa in the tropics suggest that this was due to inadequate sampling of the Southern Hemisphere faunas. Confirming this lack of knowledge, four new genera and five new species are described here from both the Old and New World tropics, including a remarkable species endemic to the Mascarene Islands. Recent phylogenetic studies are helping us to better understand rhinophorid boundaries, and the family circumscription is adjusted accordingly. During the last decade, several taxa have been either included or excluded, and others have been proposed as new to science, making the compilation of this world catalogue highly needed. A richly illustrated key to the world woodlouse fly genera is provided.
    Keywords: QL1-991 ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSV Zoology and animal sciences
    Language: English
    Format: application/octet-stream
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  • 3
    Publication Date: 2012-04-15
    Description: Egg morphology of nine species of the cluster fly genus Pollenia Robineau-Desvoidy was studied with scanning electron microscopy. Funnel-shaped micropylar area, chorion covered with centrally depressed hexagons, well developed hatching pleats on the dorsal surface encompassing the median area were found in eggs of all species: P. amentaria (Scopoli), P. angustigena Wainwright, P. atramentaria (Meigen), P. labialis Robineau-Desvoidy, P. mayeri Jacentkovsky, P. pediculata Macquart, P. rudis (Fabricius), P. similis (Jacentkovsky), and P. vagabunda (Meigen). Untypical for Calliphoridae, a dual morphological structure of plastron-bearing area is described here for the first time. On the basis of our observations, all species studied share the presence of a plastron respiratory function on the entire surface between the hatching lines. Differences between species were found in the shape of the longitudinal hatching pleats and the proportion between ‘island pattern’ and ‘hexagonal pattern’ of their chorionic surface, and in the intensity of perforation of hexagons of the median area. Comparisons of Pollenia egg morphology with that of other representatives of Calliphoridae revealed its unique structure, allowing easy differentiation from other representatives of the family. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
    Print ISSN: 1059-910X
    Electronic ISSN: 1097-0029
    Topics: Natural Sciences in General
    Published by Wiley
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  • 4
    Publication Date: 2012-02-28
    Description: Egg morphology of nine species of the cluster fly genus Pollenia Robineau-Desvoidy was studied with scanning electron microscopy. Funnel-shaped micropylar area, chorion covered with centrally depressed hexagons, well developed hatching pleats on the dorsal surface encompassing the median area were found in eggs of all species: P. amentaria (Scopoli), P. angustigena Wainwright, P. atramentaria (Meigen), P. labialis Robineau-Desvoidy, P. mayeri Jacentkovsky, P. pediculata Macquart, P. rudis (Fabricius), P. similis (Jacentkovsky), and P. vagabunda (Meigen). Untypical for Calliphoridae, a dual morphological structure of plastron-bearing area is described here for the first time. On the basis of our observations, all species studied share the presence of a plastron respiratory function on the entire surface between the hatching lines. Differences between species were found in the shape of the longitudinal hatching pleats and the proportion between ‘island pattern’ and ‘hexagonal pattern’ of their chorionic surface, and in the intensity of perforation of hexagons of the median area. Comparisons of Pollenia egg morphology with that of other representatives of Calliphoridae revealed its unique structure, allowing easy differentiation from other representatives of the family. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
    Print ISSN: 1059-910X
    Electronic ISSN: 1097-0029
    Topics: Natural Sciences in General
    Published by Wiley
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  • 5
    Publication Date: 2014-05-04
    Description: Twelve submarine mud volcanoes (MV) in the Kumano forearc basin within the Nankai Trough subduction zone were investigated for hydrocarbon origins and fluid dynamics. Gas hydrates diagnostic for methane concentrations exceeding solubilities were recovered from MVs 2, 4, 5, and 10. Molecular ratios (C 1 /C 2 〈250) and stable carbon isotopic compositions (δ 13 C-CH 4 〉−40‰ V-PDB) indicate that hydrate-bound hydrocarbons (HCs) at MVs 2, 4, and 10 are derived from thermal cracking of organic matter. Considering thermal gradients at the nearby IODP Sites C0009 and C0002, the likely formation depth of such HCs ranges between 2,300 and 4,300 m below seafloor (mbsf). With respect to basin sediment thickness and the minimum distance to the top of the plate boundary thrust we propose that the majority of HCs fueling the MVs is derived from sediments of the Cretaceous to Tertiary Shimanto belt below Plio-/Pleistocene to recent basin sediments. With respect to sizes and appearances hydrates are suggested to be relicts of higher MV activity in the past, although the sporadic presence of vesicomyid clams at MV 2 showed that fluid migration is sufficient to nourish chemosynthesis-based organisms in places. Distributions of dissolved methane at MVs 3, 4, 5, and 8 pointed at fluid supply through one or few MV conduits and effective methane oxidation in the immediate subsurface. The aged nature of the hydrates suggests that the major portion of methane immediately below the top of the methane-containing sediment interval is fueled by current hydrate dissolution rather than active migration from greater depth.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 6
    Publication Date: 2011-09-17
    Description: The occurrence of gas hydrates at submarine mud volcanoes (MVs) located within the gas hydrate stability zone (GHSZ) is controlled by upward fluid and heat flux associated with MV activity. Determining the spatial distribution of gas hydrates at MVs is crucial to evaluate their sensitivity to known episodic changes in volcanic activity. We determined the hydrocarbon inventory and spatial distribution of hydrates at an individual MV structure. The Håkon Mosby Mud Volcano (HMMV), located at 1,250 m water depth on the Barents Sea slope, was investigated by combined pressure core sampling, heat flow measurements, and pore water chemical analysis. Quantitative pressure core degassing revealed gas–sediment ratios between 3.1 and 25.7, corresponding to hydrate concentrations of up to 21.3% of the pore volume. Hydrocarbon compositions and physicochemical conditions imply that gas hydrates incipiently crystallize as structure I hydrate, with a dissociation temperature of around 13.8°C at this water depth. Based on numerous in situ measurements of the geothermal gradient in the seabed, pore water sulfate profiles and microbathymetric data, we show that the thickness of the GHSZ increases from less than 1 m at the warm center to around 47 m in the outer parts of the HMMV. We estimate the total mass of hydrate-bound methane stored at the HMMV to be about 102.5 kt, of which 2.8 kt are located within the morphological Unit I around the center and thus are likely to be dissociated in the course of a large eruption.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 7
    Publication Date: 2013-07-31
    Description: Nature Geoscience 6, 647 (2013). doi:10.1038/ngeo1886 Authors: David Fischer, José M. Mogollón, Michael Strasser, Thomas Pape, Gerhard Bohrmann, Noemi Fekete, Volkhard Spiess & Sabine Kasten Methane, a potent greenhouse gas, is abundant in marine sediments. Submarine seepage of methane-dominated hydrocarbons is heterogeneous in space and time, and mechanisms that can trigger episodic seep events are poorly understood. For example, critical gas pressures have been predicted to develop beneath impermeable sediments that bear gas hydrates, making them susceptible to mechanical failure and gas release. Gas hydrates often occur in seismically active regions, but the role of earthquakes as triggers of hydrocarbon seepage through gas-hydrate-bearing sediments has been only superficially addressed. Here we present geochemical analyses of sediment cores retrieved from the convergent margin off Pakistan. We find that a substantial increase in the upward flux of gas occurred within a few decades of a Mw 8.1 earthquake in 1945—the strongest earthquake reported for the Arabian Sea. Our seismic reflection data suggest that co-seismic shaking fractured gas-hydrate-bearing sediments, creating pathways for the free gas to migrate from a shallow reservoir within the gas hydrate stability zone into the water column. We conservatively estimate that 3.26×108 mol of methane have been discharged from the seep site since the earthquake. We therefore suggest that hydrocarbon seepage triggered by earthquakes needs to be considered in local and global carbon budgets at active continental margins.
    Print ISSN: 1752-0894
    Electronic ISSN: 1752-0908
    Topics: Geosciences
    Published by Springer Nature
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  • 8
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    Springer Nature
    In: Nature
    Publication Date: 2016-09-15
    Description: Taxonomy: Species can be named from photos Nature 537, 7620 (2016). doi:10.1038/537307b Author: Thomas Pape As an international group of taxonomists who study a range of taxa, we consider that you misconstrued the case of a new insect species that was described on the basis of photographs (see Nature535, 323–324;10.1038/535323b2016).The species
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Springer Nature
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  • 9
    Publication Date: 2016-12-21
    Description: Characterizing and monitoring biodiversity and assessing its drivers require accurate and comparable data on species assemblages, which, in turn, should rely on efficient and standardized field collection. Unfortunately, protocols that follow such criteria remain scarce and it is unclear whether they can be applied to megadiverse communities, whose study can be particularly challenging. Here, we develop and evaluate the first optimized and standardized sampling protocol for megadiverse communities, using tropical forest spiders as a model taxon. We designed the protocol COBRA-TF (Conservation Oriented Biodiversity Rapid Assessment for Tropical Forests) using a large dataset of semiquantitative field data from different continents. This protocol combines samples of different collecting methods to obtain as many species as possible with minimum effort (optimized) and widest applicability and comparability (standardized). We ran sampling simulations to assess the efficiency of COBRA-TF (optimized, non-site-specific) and its reliability for estimating taxonomic, phylogenetic, and functional diversity, and community structure by comparing it with (1) commonly used expert-based ad hoc protocols (nonoptimized, site-specific) and (2) optimal protocols (optimized, site-specific). We then tested the performance and feasibility of COBRA-TF in the field. COBRA-TF yielded similar results as ad hoc protocols for species (observed and estimated) and family richness, phylogenetic and functional diversity, and species abundance distribution. Optimal protocols detected more species than COBRA-TF. Data from the field test showed high sampling completeness and yielded low numbers of singletons and doubletons. Optimized and standardized protocols can be as effective in sampling and studying megadiverse communities as traditional sampling, while allowing data comparison. Although our target taxa are spiders, COBRA-TF can be modified to apply to any highly diverse taxon and habitat as long as multiple collecting techniques exist and the unit effort per sample is comparable. Protocols such as COBRA-TF facilitate studying megadiverse communities and therefore may become essential tools for monitoring community changes in space and time, assessing the effects of disturbances and selecting conservation areas. We develop and evaluate the first optimized and standardized protocol—COBRA-TF (Conservation Oriented Biodiversity Rapid Assessment for Tropical Forests)—for collecting data on megadiverse tropical forest communities using spiders as a model taxon. After designing COBRA-TF using a large dataset of semiquantitative field data collected in different continents, we prove that it is as efficient as commonly used site-specific protocols. Optimized and standardized sampling protocols provide excellent quality data, are easy to develop and apply, are applicable to any taxon or system, and promote comparability across datasets or sites.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley
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  • 10
    Publication Date: 2016-12-30
    Description: The Niger Delta is one of the largest hydrocarbon basin offshore Africa and it is well known for the presence of active pockmarks on the seabed. During the Guineco-MeBo cruise in 2011, long cores were taken from a pockmark cluster in order to investigate the state of its current activity. Gas hydrates, oil and pore-water were sampled for geochemical studies. The resulting dataset combined with seismic data reveal that shallow hydrocarbon migration in the upper sedimentary section was focused exclusively within the pockmarks. There is a clear tendency for gas migration within the hydrate-bearing pockmarks, and oil migration within the carbonate-rich one. This trend is interpreted as a consequence of hydrate dissolution followed by carbonate precipitation in the course of the evolution of these pockmarks. We also demonstrate that Anaerobic Oxidation of Methane (AOM) is the main process responsible for the depletion of pore-water sulfate, with depths of the Sulfate-Methane Transition Zone (SMTZ) ranging between 1.8 and 33.4 m. In addition, a numerical transport-reaction model was used to estimate the age of hydrate-layer formation from the present-day sulfate profiles. The results show that the sampled hydrate-layers were formed between 21 and 3750 years before present. Overall, this work shows the importance of fluid flow on the dynamics of pockmarks, and the investigated cluster offers new opportunities for future cross-site comparison studies. Our results imply that sudden discharges of gas can create hydrate layers within the upper sedimentary column which can affect the seafloor morphology over few decades. This article is protected by copyright. All rights reserved.
    Electronic ISSN: 1525-2027
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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