Early Jurassic phytotoxicity due to Hg-remobilization

2021 ◽  
Author(s):  
Remco Bos ◽  
Sofie Lindström ◽  
Hamed Sanei ◽  
Irene Waajen ◽  
Appy Sluijs ◽  
...  
Keyword(s):  
Dominant Role ◽  
Early Jurassic ◽  
Intermediate Step ◽  
Terrestrial Vegetation ◽  
Volcanic Emissions ◽  
Ecological Stress ◽  
Alternative Sources ◽  
Initial Deposition ◽  
Local Impacts ◽  
Extreme Seasonality

<p>The Central Atlantic Magmatic Province (CAMP) eruptions are generally regarded as the main driver of major environmental change and mass-extinction across the Triassic-Jurassic (TJ) boundary (~201.3 Ma), but the exact mechanisms linking volcanism and extinction, resilience, and recovery remain poorly constrained. Volcanogenic mercury (Hg) has been implicated as the cause for mutations in spores/pollen indicating severe ecological stress in terrestrial vegetation. Indeed, elevated sedimentary Hg concentrations coincide with the extinction interval at multiple sites across Europe. Here we show, palynological and geochemical records that gives insight in the dynamics between the Hg cycle and terrestrial vegetation, indicating repeated phytotoxicity in Early Jurassic deposits.</p><p>The abundance of mutagenic spores and the concentration of Hg are quantified in shallow marine sediments in the Schandelah-1 core (northern Germany) across the T/J boundary and the Early Jurassic (Hettangian). The results show increased mutagenic spore abundances with accompanying Hg/TOC anomalies across the end-Triassic extinction and within the lowermost Hettangian. This is consistent with studies from Sweden and Denmark and therefore confirming synchronous mutagenesis in and around coastal European margins. In addition, the Hettangian of Schandelah contains a record of long-term vegetational disturbance in the form of recurrent fern spikes and elevated mutagenic spore intervals, accompanied by Hg/TOC anomalies of similar magnitude. This suggests an overall link between volcanogenic pollution and vegetational disturbance. Based on qualitative analyses of organic matter (OM), which show an overall positive correlation between Hg concentration and terrestrial indicators, alternative sources for sedimentary Hg-enrichment such as vegetation reservoirs should be considered. This characterization of OM indicates an intermediate step in the Hg cycle, likely mediated by vegetation and/or climate feedbacks.</p><p>Atmospheric Hg-loading via volcanism can explain the synchronous enrichments of Hg concentrations at the TJ boundary interval in multiple sites across the globe. In contrast, the Hettangian anomalies of Schandelah-1, appear to be mainly driven by environmental/ecological perturbations corresponding to intensifying warm/humid conditions. Extreme seasonality alternating between high rainfall and droughts, perhaps due to eccentricity maxima, leading to increased soil erosion, wildfires and transport/degradation of terrestrial OM could potentially recycle and redistribute Hg long after initial deposition. These implications suggest a more dominant role of climate-induced Hg-remobilization, rather than direct volcanic emissions, to the mutagenesis in terrestrial vegetation. This could, in addition, lead to asynchronous and local impacts mainly in the proximity of landmasses.</p>

Natural emissions of mercury to the atmosphere in Canada

2003 ◽  
Vol 11 (1) ◽  
pp. 17-36 ◽  
Author(s):  
G M Richardson ◽  
I A Mitchell ◽  
M Mah-Paulson ◽  
T Hackbarth ◽  
R G Garrett
Keyword(s):  
Salt Spray ◽  
Probabilistic Methods ◽  
Natural Source ◽  
Confidence Limits ◽  
Terrestrial Vegetation ◽  
Volcanic Emissions ◽  
Natural Sources ◽  
Relative Contribution ◽  
Natural Emissions ◽  
Global Inventory

The only Canadian inventory of natural source emissions of mercury (Hg) was prepared in 1981, but is now considered unreliable. As a result, the primary reference relied upon by Canadian regulators concerning the relative contribution of natural sources to environmental Hg contamination is a global inventory that was published in 1989. The relevance to Canada of a global inventory that included volcanic emissions is questionable. Therefore, a new inventory of natural Hg emissions in Canada was undertaken. Consistent with earlier inventories, natural Hg emission sources included wind erosion of soil, sea salt spray, forest and brush fires, biogenic Hg vapour emissions from terrestrial vegetation, and evasion of vapour from soil, ocean surfaces (within territorial limits) and lakes and rivers. Meteoritic dust was also considered. Recognizing the variability and uncertainty in available data, probabilistic methods were employed to derive mean estimates with 90% confidence limits. Estimated total annual natural source emissions of Hg in Canada averaged 1.1 × 106 kg with lower and upper 90% confidence limits of 0.54 × 106 and 2.3 × 106 kg. Evasion of Hg vapour from terrestrial vegetation and evasion from soil predominated as natural sources of Hg in Canada; other sources were minor or insignificant. The estimated mean annual emission was approximately one third of that estimated in 1981. It was impossible with currently-available data to quantitatively differentiate natural emissions of Hg from those that are re-emitted following previous anthropogenic release and deposition. Therefore, the estimates provided herein include an unquantifiable contribution by re-emitted anthropogenic Hg.Key words: natural, mercury, emissions, atmosphere, Canada.

scholarly journals A quantitative approach for identifying plant ecogroups in the Romanian Early Jurassic terrestrial vegetation

2016 ◽  
Vol 446 ◽  
pp. 44-54 ◽  
Author(s):  
Maria Barbacka ◽  
Mihai Emilian Popa ◽  
Józef Mitka ◽  
Emese Bodor ◽  
Zoltán Püspöki ◽  
...  
Keyword(s):  
Early Jurassic ◽  
Quantitative Approach ◽  
Terrestrial Vegetation

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Formation of high temperature phase in flash-evaporated SnSe films

1990 ◽  
Vol 48 (4) ◽  
pp. 698-699
Author(s):  
J.P.S. Hanjra
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Energy Gap ◽  
Dominant Role ◽  
Fine Powder ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Water Mixture ◽  
Flash Evaporation ◽  
Photovoltaic Applications

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.

Chronic Pain: Fundamental Scientific Considerations, Specifically for Legal Claims

2013 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Robert J. Barth
Keyword(s):  
Health Outcomes ◽  
Pain Perception ◽  
Driving Forces ◽  
Psychological Treatment ◽  
Dominant Role ◽  
Meta Analysis ◽  
General Medicine ◽  
Pain Syndrome ◽  
Problematic Relationship

Abstract Scientific findings have indicated that psychological and social factors are the driving forces behind most chronic benign pain presentations, especially in a claim context, and are relevant to at least three of the AMA Guides publications: AMA Guides to Evaluation of Disease and Injury Causation, AMA Guides to Work Ability and Return to Work, and AMA Guides to the Evaluation of Permanent Impairment. The author reviews and summarizes studies that have identified the dominant role of financial, psychological, and other non–general medicine factors in patients who report low back pain. For example, one meta-analysis found that compensation results in an increase in pain perception and a reduction in the ability to benefit from medical and psychological treatment. Other studies have found a correlation between the level of compensation and health outcomes (greater compensation is associated with worse outcomes), and legal systems that discourage compensation for pain produce better health outcomes. One study found that, among persons with carpal tunnel syndrome, claimants had worse outcomes than nonclaimants despite receiving more treatment; another examined the problematic relationship between complex regional pain syndrome (CRPS) and compensation and found that cases of CRPS are dominated by legal claims, a disparity that highlights the dominant role of compensation. Workers’ compensation claimants are almost never evaluated for personality disorders or mental illness. The article concludes with recommendations that evaluators can consider in individual cases.

(World Wide) Work 2.0

2016 ◽  
Vol 11 (1) ◽  
pp. 91-103
Author(s):  
Carole Cusack ◽  
David Pecotic
Keyword(s):  
Open Source ◽  
World Wide ◽  
First Generation ◽  
Dominant Role ◽  
The Internet ◽  
Digital Ethnography ◽  
Beliefs And Practices ◽  
Web Presence ◽  
Theoretical Approaches ◽  
Online Engagement

The occult and the internet intersect in four ways: as a static medium for information; as a space where contested information or ideological conflict may occur; as a facilitator of communication; and as a medium for esoteric practice. The last type of activity is rare, but it is intriguing, in that technology can shape and inform beliefs and practices in unanticipated ways. Online engagement with the ‘Work’, the movement produced by the Greek Armenian spiritual teacher and esotericist G. I. Gurdjieff (c. 1866-1949) and his immediate followers, is an under-researched instance of online esoteric practice. This article addresses this scholarly desideratum, bringing the theoretical approaches of online religion and digital ethnography to bear on the Gurdjieff Internet Guide (GIG) website, founded by Reijo Oksanen (b. 1942) and later maintained by Kristina Turner, who created an accompanying Facebook page. The GIG manifests a shift away from the sectarian secrecy of the ‘Foundation’ groups, founded by Jeanne de Salzmann (1889-1990) after Gurdjieff’s death to formalise and protect the content of the Work, and the limited web presence that the Foundation permits. The GIG moves towards an ecumenical ‘open source’ approach to the dissemination of Gurdjieff’s teachings rooted in independent groups founded by other first generation followers of Gurdjieff who remained outside of the Foundation. It is argued that the deregulation of the religious and spiritual marketplace of the contemporary West, coupled with the dominant role played by the Internet in disseminating information, has radically transformed the Gurdjieff tradition, collapsing hierarchies and esoteric strategies, democratizing access for seekers, and creating new ritual and teaching modes.

PERSPECTIVE DEVELOPMENT OF WORLD PRODUCTION OF FEEDS FOR AQUACULTURE: ALTERNATIVE SOURCES OF RAW MATERIALS

2017 ◽  
pp. 67-78
Author(s):  
Lina Yurievna Lagutkina
Keyword(s):  
Raw Materials ◽  
Limiting Factors ◽  
Current Status ◽  
Feed Production ◽  
The World ◽  
Market Trends ◽  
Alternative Sources ◽  
World Industry ◽  
First Time ◽  
A Current

The author of the article discloses the prospects of development of the world feed production for aquaculture based on the analysis of key innovative technological and market trends. The author specifies that shortage, high cost, low ecological compatibility of traditional raw materials - fish flour - are among major limiting factors in the development of production of feeds for aquaculture. This fact, in turn, limits sustainable development of aquaculture both in Russia, and in the world in general. The article presents the overview of a current status of the world industry of feed production in aquaculture, where the regional situation is studied, as well. For the first time, there is given the outlook of innovative technologies in feed production based on the alternative sources of protein (on the example of projects of leading aquabiotechnological companies) which will determine industry’s objectives for the mid-term perspective.

POEZJA OKSYMORONU. O METAFORYCE W WIERSZACH KRASIŃSKIEGO / THE POETRY OF THE OXYMORON: ZYGMUNT KRASIŃSKI’S VERSE

2013 ◽  
Vol 54 (3) ◽  
pp. 17-27
Author(s):  
Łukasz Niewczas
Keyword(s):  
Dominant Role

Summary This re-reading of Zygmunt Krasiński’s lyrical verse rejects (at least to some extent) the generally held view of his poetry as some kind of literary fossils. To demonstrate its genuine complexity the author of this article focuses on Krasiński’s use of the oxymoron, an aspect of his poetic art that has been neglected by the critics. The oxymoron, which seems to be his favourite metaphoric device, is analysed here on the level of poetic ontology, poetic semantics, and metaphoric imagery. In each of those spheres oxymorons play a dominant role: Krasiński uses them to construct his poetic world, to complicate and problematize his meanings, and to create a highly dramatic imagery. Finally, it is argued that the shift in Krasiński’s use of the oxymoron from a sign of cleavage to that of a balanced whole corresponds to a similar evolution in his ontological views.

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