نتایج جستجو برای: sulfidic mineralized zones

تعداد نتایج: 49927  

Journal: :Evolution; international journal of organic evolution 2011
Michael Tobler Maura Palacios Lauren J Chapman Igor Mitrofanov David Bierbach Martin Plath Lenin Arias-Rodriguez Francisco J García de León Mariana Mateos

We investigated replicated ecological speciation in the livebearing fish Poecilia mexicana and P. sulphuraria (Poeciliidae), which inhabit freshwater habitats and have also colonized multiple sulfidic springs in southern Mexico. These springs exhibit extreme hypoxia and high concentrations of hydrogen sulfide, which is lethal to most metazoans. We used phylogenetic analyses to test whether spri...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان - دانشکده علوم 1391

نظر به اهمیت کنودونت‎ها در تقسیمات چینه‎نگاری پالئوزوئیک و گسترش قابل توجه نهشته‎های دونین پسین و کربونیفر پیشین در منطقه کرمان سه برش چینه‎شناسی (حور، هوتک و شمس آباد) در شمال استان کرمان انتخاب و بویژه بر اساس کنودونت‎ها و بقایای ماهیان مورد مطالعه قرار گرفتند. مجموعه کنودونت‎های بدست آمده از برش حور شامل 20 گونه متعلق به دو جنس polygnathus و icriodus بوده و سنی معادل فرازنین پسین را نشان می‎...

2016
Martin Schobben Alan Stebbins Abbas Ghaderi Harald Strauss Dieter Korn Christoph Korte

In post-Cambrian time, life on Earth experienced 5 major extinction events, likely instigated by adverse environmental conditions. Biodiversity loss among marine taxa, for at least 3 of these mass extinction events (Late Devonian, end-Permian and end-Triassic), has been connected with widespread oxygen-depleted and sulfide-bearing marine water. Furthermore, geochemical and sedimentary evidence ...

اسپندیار, مهروز , رقیمی, مصطفی ,

The study of morphological and mineralogical changes within a natural acid saline seep affected landscape revealed that seasonal differences in surface mineralogy, reflecting the operation of sulfidization and oxidative sulfide weathering processes. During the wet season, the surface and near surface of the waterlogged seep and marsh areas is dominated by black sulfidic materials (pyrite) and m...

Journal: :Geochimica et Cosmochimica Acta 2021

Oxygen Minimum Zones (OMZs) are expanding in modern oceans due to anthropogenically-driven climate and environmental change. In the Eastern Mediterranean Sea (EMS), OMZs developed early Holocene as a result of decreased intermediate water ventilation, increasing temperature, increased Nile discharge primary productivity. Here, we report benthic foraminiferal numbers (BFN) species abundances, to...

2014
Brendan Headd Annette S. Engel

Terrestrial sulfidic springs support diverse microbial communities by serving as stable conduits for geochemically diverse and nutrient-rich subsurface waters. Microorganisms that colonize terrestrial springs likely originate from groundwater, but may also be sourced from the surface. As such, the biogeographic distribution of microbial communities inhabiting sulfidic springs should be controll...

2008
Andrew P. Borner Knut Kielland Marilyn D. Walker

This study was part of the International Tundra Experiment (ITEX) and examined the effects of increased winter snow depth and decreased growing season length on the phenology of four arctic plant species (Betula nana, Salix pulchra, Eriophorum vaginatum, and Vaccinium vitis-idaea) and seasonal nitrogen availability in arctic snowbed communities. Increased snow depth had a large effect on the te...

2016
Satoshi Tamazawa Kyosuke Yamamoto Kazuto Takasaki Yasuo Mitani Satoshi Hanada Yoichi Kamagata Hideyuki Tamaki

We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuo...

The classification of mineralized areas into different groups based on mineral grade and prospectivity is a practical problem in the area of optimal risk, time, and cost management of exploration projects. The purpose of this paper was to present a new approach for optimizing the grade classification model of an orebody. That is to say, through hybridizing machine learning with a metaheuristic ...

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