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https://www.readbyqxmd.com/read/28188680/experimental-fossilization-of-mat-forming-cyanobacteria-in-coarse-grained-siliciclastic-sediments
#1
S A Newman, V Klepac-Ceraj, G Mariotti, S B Pruss, N Watson, T Bosak
Microbial fossils and textures are commonly preserved in Ediacaran and early Cambrian coarse-grained siliciclastic sediments that were deposited in tidal and intertidal marine settings. In contrast, the fossilization of micro-organisms in similar marine environments of post-Cambrian age is less frequently reported. Thus, temporal discrepancies in microbial preservation may have resulted from the opening and closing of a unique taphonomic window during the terminal Proterozoic and early Phanerozoic, respectively...
February 11, 2017: Geobiology
https://www.readbyqxmd.com/read/28185932/isolation-and-identification-of-chitin-from-heavy-mineralized-skeleton-of-suberea-clavata-verongida-demospongiae-porifera-marine-demosponge
#2
Hermann Ehrlich, Vasilii V Bazhenov, Cecile Debitus, Nicole de Voogd, Roberta Galli, Mikhail Tsurkan, Marcin Wysokowski, Heike Meissner, Esra Bulut, Murat Kaya, Teofil Jesionowski
Since the discovery of chitin in skeletal structures of sponges (Porifera) in 2007, studies on search of novel species which possess this structural aminopolysaccharide continue up today. The most potential source of chitin is suggested to be localized in the four families of sponges related to the order Verongida (Demospongiae) which nevertheless require further clarification. Here, we report for the first time the isolation and identification of α-chitin from the Suberea clavata demosponge (Aplysinidae: Verongida)...
February 6, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28182645/between-a-rock-and-a-soft-place-using-optical-ages-to-date-ancient-clam-gardens-on-the-pacific-northwest
#3
Christina M Neudorf, Nicole Smith, Dana Lepofsky, Ginevra Toniello, Olav B Lian
Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity...
2017: PloS One
https://www.readbyqxmd.com/read/28159791/microaerophilic-fe-ii-oxidizing-zetaproteobacteria-isolated-from-low-fe-marine-coastal-sediments-physiology-and-characterization-of-their-twisted-stalks
#4
K Laufer, M Nordhoff, M Halama, R E Martinez, M Obst, M Nowak, H Stryhanyuk, H H Richnow, A Kappler
: Microaerophilic Fe(II)-oxidizers are commonly found in habitats containing elevated Fe(II) and low O2 concentrations and often produce characteristic Fe mineral structures, so-called twisted stalks or tubular sheaths. Isolates originating from freshwater habitats are all members of the Betaproteobacteria, while isolates from marine habitats belong almost exclusively to the Zetaproteobacteria So far only few isolates of marine microaerophilic Fe(II)-oxidizers have been described, all of which are obligate microaerophilic Fe(II)-oxidizers and have been thought to be restricted to Fe-rich systems...
February 3, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28145706/ligand-promoted-photoreductive-dissolution-of-goethite-by-atmospheric-low-molecular-dicarboxylates
#5
Zhenzhen Wang, Hongbo Fu, Liwu Zhang, Weihua Song, Jianmin Chen
Recent evidences suggested that organic ligands in atmosphere water play an important role in the mobilization of iron from mineral aerosol. In this study, the dissolution of goethite (α-FeOOH) was investigated in the presence of three low-molecular dicarboxylates enriched in the atmosphere, as well as a reference organic acid of methanesulfonate (MSA), which is especially abundant in marine atmospheric boundary layer. Iron mobilized from α-FeOOH was promoted under the irradiation and the deaerated condition, and the soluble Fe(II) concentration was enhanced greatly in the ligand-containing suspensions exposed to light...
February 1, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28142089/effects-of-bioactive-extracellular-compounds-and-paralytic-shellfish-toxins-produced-by-alexandrium-minutum-on-growth-and-behaviour-of-juvenile-great-scallops-pecten-maximus
#6
REVIEW
Elodie Borcier, Romain Morvezen, Pierre Boudry, Philippe Miner, Grégory Charrier, Jean Laroche, Hélène Hegaret
Dinoflagellates of the genus Alexandrium are a major cause of harmful algal blooms (HABs) that have increasingly disrupted coastal ecosystems for the last several decades. Microalgae from the genus Alexandrium are known to produce paralytic shellfish toxins (PST) but also bioactive extracellular compounds (BEC) that can display cytotoxic, allelopathic, ichtyotoxic or haemolytic effects upon marine organisms. The objective of this experimental study was to assess the effects of PST and BEC produced by A. minutum upon juvenile great scallops Pecten maximus...
March 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28139676/glacier-advance-during-marine-isotope-stage-11-in-the-mcmurdo-dry-valleys-of-antarctica
#7
Kate M Swanger, Jennifer L Lamp, Gisela Winckler, Joerg M Schaefer, David R Marchant
We mapped six distinct glacial moraines alongside Stocking Glacier in the McMurdo Dry Valleys, Antarctica. Stocking Glacier is one of several alpine glaciers in the Dry Valleys fringed by multiple cold-based drop moraines. To determine the age of the outermost moraine, we collected 10 boulders of Ferrar Dolerite along the crest of the moraine and analyzed mineral separates of pyroxene for cosmogenic (3)He. On the basis of these measurements, the exposure age for the outermost moraine is 391 ± 35 ka. This represents the first documented advance of alpine glacier ice in the Dry Valleys during Marine Isotope Stage (MIS) 11...
January 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28131452/leaching-of-two-fungicides-in-spent-mushroom-substrate-amended-soil-influence-of-amendment-rate-fungicide-ageing-and-flow-condition
#8
Alba Álvarez-Martín, María J Sánchez-Martín, José M Ordax, Jesús M Marín-Benito, M Sonia Rodríguez-Cruz
A study has been conducted on the leaching of two fungicides, tebuconazole and cymoxanil, in a soil amended with spent mushroom substrate (SMS), with an evaluation of how different factors influence this process. The objective was based on the potential use of SMS as a biosorbent for immobilizing pesticides in vulnerable soils, and the need to know how it could affect the subsequent transport of these retained compounds. Breakthrough curves (BTCs) for (14)C-fungicides, non-incubated and incubated over 30days, were obtained in columns packed with an unamended soil (S), and this soil amended with SMS at rates of 5% (S+SMS5) and 50% (S+SMS50) under saturated and saturated-unsaturated flows...
January 25, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28129378/intensity-of-african-humid-periods-estimated-from-saharan-dust-fluxes
#9
Werner Ehrmann, Gerhard Schmiedl, Sarah Beuscher, Stefan Krüger
North Africa experienced dramatic changes in hydrology and vegetation during the late Quaternary driven by insolation-induced shifts of the tropical rain belt and further modulated by millennial-scale droughts and vegetation-climate feedbacks. While most past proxy and modelling studies concentrated on the temporal and spatial dynamics of the last African humid period, little is known about the intensities and characteristics of pre-Holocene humid periods. Here we present a high-resolution record of fine-grained eastern Saharan dust from the Eastern Mediterranean Sea spanning the last 180 kyr, which is based on the clay mineral composition of the marine sediments, especially the kaolinite/chlorite ratio...
2017: PloS One
https://www.readbyqxmd.com/read/28128836/substrate-specificity-and-copper-loading-of-the-manganese-oxidizing-multicopper-oxidase-mnx-from-bacillus-sp-pl-12
#10
Cristina N Butterfield, Bradley M Tebo
Manganese(ii) oxidation in the environment is thought to be driven by bacteria because enzymatic catalysis is many orders of magnitude faster than the abiotic processes. The heterologously purified Mn oxidase (Mnx) from marine Bacillus sp. PL-12 is made up of the multicopper oxidase (MCO) MnxG and two small Cu and heme-binding proteins of unknown function, MnxE and MnxF. Mnx binds Cu and oxidizes both Mn(ii) and Mn(iii), generating Mn(iv) oxide minerals that resemble those found on the Bacillus spore surface...
January 27, 2017: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/28123096/deep-conservation-of-bivalve-nacre-proteins-highlighted-by-shell-matrix-proteomics-of-the-unionoida-elliptio-complanata-and-villosa-lienosa
#11
Benjamin Marie, Jaison Arivalagan, Lucrèce Mathéron, Gérard Bolbach, Sophie Berland, Arul Marie, Frédéric Marin
The formation of the molluscan shell nacre is regulated to a large extent by a matrix of extracellular macromolecules that are secreted by the shell-forming tissue, the mantle. This so-called 'calcifying matrix' is a complex mixture of proteins, glycoproteins and polysaccharides that is assembled and occluded within the mineral phase during the calcification process. Better molecular-level characterization of the substances that regulate nacre formation is still required. Notable advances in expressed tag sequencing of freshwater mussels, such as Elliptio complanata and Villosa lienosa, provide a pre-requisite to further characterize bivalve nacre proteins by a proteomic approach...
January 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28118789/geotechnical-and-mineralogical-characterisations-of-marine-dredged-sediments-before-and-after-stabilisation-to-optimise-their-use-as-a-road-material
#12
L Saussaye, E van Veen, G Rollinson, M Boutouil, J Andersen, J Coggan
Dredging activities to extend, deepen and maintain access to harbours generate significant volumes of waste dredged material. Some ways are investigated to add value to these sediments. One solution described here is their use in road construction following treatment with hydraulic binders. This paper presents the characterisation of four sediments, in their raw state and after 90 days of curing following stabilisation treatment with lime and cement, using a combination of novel and established analytical techniques to investigate subsequent changes in mineralogy...
January 25, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28070312/investigation-of-nutritional-properties-of-three-species-of-marine-turban-snails-for-human-consumption
#13
Roslizawati Ab Lah, Joshua Smith, Dale Savins, Ashley Dowell, Daniel Bucher, Kirsten Benkendorff
Turban snails (family Turbinidae) are gastropod molluscs that are harvested for human consumption yet little is known about the nutritional properties of these snails, particularly from Australian waters. This study compares the proximate composition (ash, moisture, protein, and lipid content), fatty acid profiles, mineral, and trace element content of three species of turbinid snails; Turbo militaris, Lunella undulata, and Lunella torquata from northern New South Wales, Australia. They were all found to have relatively high protein in their flesh (16...
January 2017: Food Science & Nutrition
https://www.readbyqxmd.com/read/28069941/uranium-iv-adsorption-by-natural-organic-matter-in-anoxic-sediments
#14
Sharon E Bone, James J Dynes, John Cliff, John R Bargar
Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2+x) in anoxic sediments; however, studies now show that this is not often the case...
January 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28067268/regional-adaptation-defines-sensitivity-to-future-ocean-acidification
#15
Piero Calosi, Sedercor Melatunan, Lucy M Turner, Yuri Artioli, Robert L Davidson, Jonathan J Byrne, Mark R Viant, Stephen Widdicombe, Simon D Rundle
Physiological responses to temperature are known to be a major determinant of species distributions and can dictate the sensitivity of populations to global warming. In contrast, little is known about how other major global change drivers, such as ocean acidification (OA), will shape species distributions in the future. Here, by integrating population genetics with experimental data for growth and mineralization, physiology and metabolomics, we demonstrate that the sensitivity of populations of the gastropod Littorina littorea to future OA is shaped by regional adaptation...
January 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28065572/uneven-distribution-of-inorganic-pollutants-in-marine-air-originating-from-ocean-going-ships
#16
László Bencs, Benjamin Horemans, Anna Jolanta Buczyńska, René Van Grieken
The distribution of mass, water-soluble inorganic salts and mineral elements of size-segregated aerosols (PM1, PM2.5-1 and PM10-2.5), precursor gaseous pollutants, black carbon, and nanoparticles (10-300 nm size range) at the Southern Bight of the North Sea has been studied. The concentrations of air pollutants peaked over shipping lanes, open-water anchorage areas and frequently navigated waters, due to the presence of mobile emission sources. A considerable decrease in air pollutant levels was seen when diverting from these marine areas towards remote or coastal banks...
March 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28063184/biologically-agglutinated-eukaryotic-microfossil-from-cryogenian-cap-carbonates
#17
K R Moore, T Bosak, F A Macdonald, D J G Lahr, S Newman, C Settens, S B Pruss
Cryogenian cap carbonates that overlie Sturtian glacial deposits were formed during a post-glacial transgression. Here, we describe microfossils from the Kakontwe Formation of Zambia and the Taishir Formation of Mongolia-both Cryogenian age, post-Sturtian cap carbonates-and investigate processes involved in their formation and preservation. We compare microfossils from these two localities to an assemblage of well-documented microfossils previously described in the post-Sturtian Rasthof Formation of Namibia...
January 6, 2017: Geobiology
https://www.readbyqxmd.com/read/27991953/barium-and-its-importance-as-an-indicator-of-paleo-productivity
#18
Bianca T P Liguori, Marcelo G DE Almeida, Carlos E DE Rezende
Barium (Ba) is a trace element which occurs predominantly as barite mineral (BaSO4) in the marine environment. Previous work suggests that barite concentrations are related to the organic carbon flux and marine biological debris in the water column suggesting a direct or indirect involvement in the marine biological cycling. In addition, barite has a high preservation rate (~30%) in sediments and it is less affected by early diagenesis than other proxies for productivity such as carbonates (~10%) and organic carbon (~1%), for example...
October 2016: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/27986324/determination-of-sediment-metal-background-concentrations-and-enrichment-in-marine-environments-a-critical-review
#19
REVIEW
G F Birch
'Background' is the concentration of metals in pristine sediment, unaltered by human activity and 'enrichment' is the extent present-day sediment metal concentrations exceed pre-anthropogenic levels (the magnitude of human-induced change). Background and enrichment are becoming more frequently used for management measures to bring sediment and the environment back to near-pristine levels. Of the six empirical methods reviewed for determining background (global values, pristine marine and fluvial sediments, catchment soils and rocks), the use of sedimentary cores has the greatest advantage...
December 13, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27974830/stress-physiology-and-weapon-integrity-of-intertidal-mantis-shrimp-under-future-ocean-conditions
#20
Maya S deVries, Summer J Webb, Jenny Tu, Esther Cory, Victoria Morgan, Robert L Sah, Dimitri D Deheyn, Jennifer R A Taylor
Calcified marine organisms typically experience increased oxidative stress and changes in mineralization in response to ocean acidification and warming conditions. These effects could hinder the potency of animal weapons, such as the mantis shrimp's raptorial appendage. The mechanical properties of this calcified weapon enable extremely powerful punches to be delivered to prey and aggressors. We examined oxidative stress and exoskeleton structure, mineral content, and mechanical properties of the raptorial appendage and the carapace under long-term ocean acidification and warming conditions...
December 15, 2016: Scientific Reports
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