Agradecemos o Grupo H.O.G. na Arizona State University para desenvolver a metodologia inicial desses experimentos hidrotermais, e em particular, agradecemos I. Gould, E. choque, L. Williams, C. Gleiner, H. Hartnett, K. Fecteau, K. Robinson e C. Bockisch, por sua orientação e assistência útil. Z. Yang e X. Fu foram financiados por fundos de inicialização da Universidade de Oakland para z. Yang.

1. preparar a amostra para experimento hidrotermal
<ol><li>Escolher o tamanho dos tubos de vidro de quartzo ou sílica, por exemplo, 2 mm diâmetro interno (ID) x 6 mm de diâmetro externo (OD) ou 6 mm ID x 12 milímetros OD e determinar as quantidades de compostos orgânicos e minerais para usar. Neste trabalho, os montantes de nitrobenzeno e magnetita (Fe3O4) para carregar dentro do tubo de silicone (por exemplo, 2 mm ID x 6 milímetros OD) são 3,0 µ l e 13,9 mg, respectivamente. Nota: Os tubos de grande diâmetro permitam mais fácil carregamento dos materiais, mas exigem mais esforços da selagem do tubo.</li>
	<li>Corte os tubos de vidro de sílica limpa em pedaços pequenos com ~ 30 cm de comprimento, usando um cortador de tubo. Feche uma das extremidades do tubo fechado usando um maçarico oxyhydrogen com uma cabeça chama apropriado. Cuidado: Siga os procedimentos de segurança para a utilização da tocha oxyhydrogen.</li>
	<li>Pese a quantidade predeterminada do composto orgânico inicial em um 0.1 mg-escala equilibrar (se for sólido) e transferi-lo para o tubo de vidro de sílica usando um papel de pesagem. Se o composto é líquido (por exemplo, nitrobenzeno, neste caso), use uma seringa de microlitro (por exemplo, 10 µ l) para transferi-lo para o tubo de sílica pequeno. Adicione os minerais pesados para o tubo de sílica através de uma pipeta Pasteur e em seguida, adicione água deionizada e pobre em oxigênio (por exemplo, 0,3 mL). MΩ·cm de uso 18.2 água desionizada e deoxygenate-lo pelo sonication.</li>
	<li>Conecte o tubo de sílica para uma linha de vácuo (ID ~ 1 cm) com uma válvula fechada. Mergulhe o tubo em um frasco de Dewar preenchido com nitrogênio líquido para ~ 3 min, até que a água e produtos orgânicos são completamente congelados. Cuidado: Siga os procedimentos de segurança para a transferência e usando nitrogênio líquido.</li>
	<li>Quando o tubo permanece imerso em nitrogênio líquido, abra a válvula de vácuo e retire o headspace do tubo de ar. Nota: Este processo deve durar até que a pressão cai abaixo de 100 mtorr no manômetro da bomba de vácuo.</li>
	<li>Desligue a válvula, retire o tubo do nitrogênio líquido e deixe aquecer a temperatura do tubo. Bata levemente a parte inferior do tubo para libertar as bolhas de ar restante da solução para headspace.</li>
	<li>Repita o ciclo de congelamento-descongelamento-bomba acima por mais duas vezes e mantenha o tubo em nitrogênio líquido antes de selar a outra extremidade do tubo. Fechar a linha de vácuo e usar a flama oxyhydrogen tornar o tubo inteiro fechado. Nota: Quando o tubo passa por experimentos hidrotermais, o volume de headspace do tubo irá diminuir devido a expansão de água líquida. Por exemplo, a densidade da água reduz cerca de 30% da temperatura de 300 ° C. Calcular e deixar volume suficiente espaço livre quando da selagem do tubo.</li>
</ol>2. montar o experimento hidrotermal
<ol><li>Após as etapas da selagem, coloque o tubo de sílica em um pequeno tubo de aço (~ 30 cm de comprimento e 1,5 cm de diâmetro) com tampas de rosca frouxas, a fim de evitar danos de qualquer edifício de pressão ou falha do tubo no interior do tubo.</li>
	<li>Coloque o tubo em um forno de temperatura bem controlada ou forno e aquecê-lo até a temperatura desejada (por exemplo, 150 ° C neste trabalho). Use um termopar no interior do forno para monitorar a temperatura através da reação hidrotermal.</li>
	<li>Assim que o tempo de reação é atingido (por exemplo, 2h neste trabalho), saciar o tubo de sílica, rapidamente, colocando o tubo em um banho de água gelada. Nota: O processo de têmpera leva menos de 1 min para arrefecer a temperatura, o que evita possíveis reações retrógradas.</li>
</ol>3. analisar a amostra após a experiência
<ol><li>Abrir o tubo de sílica, usando um cortador de tubo e rapidamente transferir todos os produtos (por exemplo, ~0.3 mL em tubo de sílica pequeno) dentro de um frasco de vidro de 10 mL com uma pipeta Pasteur.</li>
	<li>Extrair os produtos orgânicos com 3 mL de solução de diclorometano (DCM) que contém dodecane de 8.8 mM como padrão interno para cromatografia gasosa (GC). Tampa o frasco e agitar que isso por mãos por 2 min e vórtice por 1 min. Nota: Isso ajuda a facilitar a extracção de produtos orgânicos na fase orgânica. Além disso, enxágue transferidora paredes pipeta e no interior do tubo de sílica com DCM para garantir a recuperação de produtos. Para amostras com alto conteúdo mineral, proceda à sonicação-los na solução DCM para melhor extração.</li>
	<li>Permitir que as partículas minerais de assentar na solução de extração (ou seja, DCM com dodecane) 5 min. Use uma pipeta Pasteur transferir com cuidado ~ 1 mL da amostra da camada de DCM (ou seja, a camada inferior) para um frasco de GC.</li>
	<li>Analise a distribuição de produtos orgânicos utilizando GC com uma coluna de poli-capilar (por exemplo, 5% diphenyl/95% dimetilssiloxano) e um detector de ionização de chama. Configurar o forno de GC com um programa para iniciar a 50 ° C e segure por 8 min, aumentar em 10 ° C/min até 220 ° C e aguarde 10 min, aumentar em 20 ° C/min até 300 ° C e mantenha premido durante 5 min. do conjunto, a temperatura do injetor para 300 ° C. Nota: O programa de GC que precisava ser mudado baseado no tipo de compostos orgânicos sendo analisado.</li>
	<li>Construa as curvas de calibração de GC, traçando a relação de área do pico do analito para o padrão interno versus a concentração do analito.</li>
	<li>Calcular a reação de conversão baseada sobre as concentrações de matéria-prima orgânica antes e após a reação, ou seja, % de conversão = ([inicial]-[final]) ⁄ [inicial] × 100%. Use as conversões para determinar se o mineral facilita ou retarda as transformações orgânicas hidrotermais.</li>
</ol>

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	<li>Yang, Z., Gould, I. R., Williams, L. B., Hartnett, H. E., Shock, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+iron-containing+minerals+on+hydrothermal+reactions+of+ketones.">Effects of iron-containing minerals on hydrothermal reactions of ketones.</a> Geochimica et Cosmochimica Acta. 223, 107-126 (2018).</li><li>Seewald, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organic-inorganic+interactions+in+petroleum-producing+sedimentary+basins.">Organic-inorganic interactions in petroleum-producing sedimentary basins.</a> Nature. 426 (6964), 327-333 (2003).</li><li>Sogin, M. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+diversity+in+the+deep+sea+and+the+underexplored+"rare+biosphere".">Microbial diversity in the deep sea and the underexplored "rare biosphere".</a> Proceedings of the National Academy of Sciences. 103 (32), 12115 (2006).</li><li>McCollom, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+Simulations+of+Abiotic+Hydrocarbon+Formation+in+Earth's+Deep+Subsurface.">Laboratory Simulations of Abiotic Hydrocarbon Formation in Earth's Deep Subsurface.</a> Reviews in Mineralogy and Geochemistry. 75 (1), 467-494 (2013).</li><li>Foustoukos, D. I., Seyfried, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrocarbons+in+Hydrothermal+Vent+Fluids:+The+Role+of+Chromium-Bearing+Catalysts.">Hydrocarbons in Hydrothermal Vent Fluids: The Role of Chromium-Bearing Catalysts.</a> Science. 304 (5673), 1002 (2004).</li><li>Bell, J. L. S., Palmer, D. A., Pittman, E. D., Lewan, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=10.1007/978-3-642-78356-2_9.">10.1007/978-3-642-78356-2_9.</a> Organic Acids in Geological Processes. , 226-269 (1994).</li><li>Palmer, D. A., Drummond, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+decarboxylation+of+acetate.+Part+I.+The+kinetics+and+mechanism+of+reaction+in+aqueous+solution.">Thermal decarboxylation of acetate. Part I. The kinetics and mechanism of reaction in aqueous solution.</a> Geochimica et Cosmochimica Acta. 50 (5), 813-823 (1986).</li><li>Yang, Z., Gould, I. R., Williams, L. B., Hartnett, H. E., Shock, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+central+role+of+ketones+in+reversible+and+irreversible+hydrothermal+organic+functional+group+transformations.">The central role of ketones in reversible and irreversible hydrothermal organic functional group transformations.</a> Geochimica et Cosmochimica Acta. 98, 48-65 (2012).</li><li>McCollom, T. M., Ritter, G., Simoneit, B. R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+Synthesis+Under+Hydrothermal+Conditions+by+Fischer-+Tropsch-Type+Reactions.">Lipid Synthesis Under Hydrothermal Conditions by Fischer- Tropsch-Type Reactions.</a> Origins of life and evolution of the biosphere. 29 (2), 153-166 (1999).</li><li>Bell, J. L. S., Palmer, D. A., Barnes, H. L., Drummond, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+decomposition+of+acetate:+III.+Catalysis+by+mineral+surfaces.">Thermal decomposition of acetate: III. Catalysis by mineral surfaces.</a> Geochimica et Cosmochimica Acta. 58 (19), 4155-4177 (1994).</li><li>Yang, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrothermal+Photochemistry+as+a+Mechanistic+Tool+in+Organic+Geochemistry:+The+Chemistry+of+Dibenzyl+Ketone.">Hydrothermal Photochemistry as a Mechanistic Tool in Organic Geochemistry: The Chemistry of Dibenzyl Ketone.</a> The Journal of Organic Chemistry. 79 (17), 7861-7871 (2014).</li><li>Yang, Z., Hartnett, H. E., Shock, E. L., Gould, I. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organic+Oxidations+Using+Geomimicry.">Organic Oxidations Using Geomimicry.</a> The Journal of Organic Chemistry. 80 (24), 12159-12165 (2015).</li><li>Venturi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mineral-assisted+production+of+benzene+under+hydrothermal+conditions:+Insights+from+experimental+studies+on+C6+cyclic+hydrocarbons.">Mineral-assisted production of benzene under hydrothermal conditions: Insights from experimental studies on C6 cyclic hydrocarbons.</a> Journal of Volcanology and Geothermal Research. 346, 21-27 (2017).</li><li>Lemke, K. H., Rosenbauer, R. J., Bird, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peptide+Synthesis+in+Early+Earth+Hydrothermal+Systems.">Peptide Synthesis in Early Earth Hydrothermal Systems.</a> Astrobiology. 9 (2), 141-146 (2009).</li><li>Byrappa, K., Yoshimura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Hydrothermal Technology. , (2001).</li><li>Johnson, J. W., Oelkers, E. H., Helgeson, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SUPCRT92:+A+software+package+for+calculating+the+standard+molal+thermodynamic+properties+of+minerals,+gases,+aqueous+species,+and+reactions+from+1+to+5000+bar+and+0+to+1000&#176;C.">SUPCRT92: A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000&#176;C.</a> Computers &amp; Geosciences. 18 (7), 899-947 (1992).</li></ol>

Os autores não têm nada para divulgar.

Neste estudo, nós costumávamos nitrobenzeno com mineral magnetita como exemplo para demonstrar como avaliar efeitos minerais hidrotermais reações orgânicas. Embora os experimentos são realizados em tubos de vidro de sílica pequeno, altamente reprodutíveis resultados são observados nas experiências de magnetita, ou seja, 30,3 ± 1,4% na conversão de nitrobenzeno, que sugere a eficácia e a confiabilidade do presente protocolo hidrotermal. Nos experimentos não-mineral, a conversão de nitrobenzeno é 5...

Ambientes hidrotermais (ou seja, meios aquosos em elevadas temperaturas e pressões) são onipresentes na terra. A química hidrotermal de compostos orgânicos desempenha um papel essencial em uma ampla gama de configurações geoquímicas, tais como bacias sedimentares orgânicas, reservatórios de petróleo e a biosfera profunda1,2,3. Transformações do carbono orgânico em sistemas hidrotérmicos não só ocorrem em meio aquoso puro, mas também com materiais inorgânicos dissolvidos ou sólidos, tais como terra-abundantes minerais. Foram encontrados minerais drasticamente e seletivamente influenciar a reatividade hidrotermal de vários compostos orgânicos,1,4,5 , mas como identificar os efeitos de minerais em complexos sistemas hidrotérmicos ainda permanece como um desafio. O objetivo deste estudo é fornecer um protocolo experimental relativamente simples para estudar efeitos minerais hidrotermais reações orgânicas.
Os estudos de laboratório de reações hidrotermais tradicionalmente usam reatores robustos que são feitas de ouro, titânio ou aço inoxidável6,7,8,9. Por exemplo, sacos de ouro ou cápsulas têm sido favoravelmente utilizadas, porque o ouro é flexível e permite que a pressão da amostra a ser controlado pelo pressurizar a água externamente, que evita a geração de uma fase de vapor dentro da amostra. No entanto, estes reatores são caros e podem ser associados com potenciais efeitos catalíticos metal10. Portanto, é imperativo encontrar um método alternativo com baixo custo, mas alta confiabilidade para estas experiências hidrotermais.
Nos últimos anos, os tubos de reação de vidro de quartzo ou sílica fundida foram mais frequentemente aplicados ao experimentos hidrotermal11,12,13. Em relação ao precioso ouro ou titânio, vidro de quartzo ou sílica é consideravelmente mais barato, mas também o material forte. Mais importante, tubos de quartzo têm demonstrado efeitos catalíticos pequeno e pode ser tão inertes como o ouro para as reações hidrotermal11,14. Neste protocolo, descrevemos um método geral para a realização de pequenos experimentos de orgânico-mineral hidrotermais em tubos de paredes grossas de sílica. Apresentamos um experimento de exemplo usando um modelo composto (ou seja, nitrobenzeno) na presença/ausência de um mineral de óxido de ferro (ou seja, magnetita) em uma solução hidrotermal de 150 ° C, a fim de mostrar o efeito do mineral, bem como para demonstrar a eficácia deste método.

<table><tbody><tr><td>&lt;strong&gt;Chemicals:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Dichloromethane</td><td>VWR</td><td>BDH23373.400</td><td></td></tr><tr><td>Dodecane</td><td>Sigma-Aldrich</td><td>297879</td><td></td></tr><tr><td>Nitrobenzene</td><td>Sigma-Aldrich</td><td>252379</td><td></td></tr><tr><td>Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>310050</td><td></td></tr><tr><td>Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>637106</td><td></td></tr><tr><td>&lt;strong&gt;Supplies:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Silica tube</td><td></td><td></td><td></td></tr><tr><td>Vacuum pump</td><td>WELCH</td><td>2546B-01</td><td></td></tr><tr><td>Vacuum line</td><td></td><td></td><td></td></tr><tr><td>Oven</td><td>Hewlett Packard</td><td>5890</td><td></td></tr><tr><td>Thermocouple</td><td>BENETECH</td><td>GM1312</td><td></td></tr><tr><td>Gas chromatography</td><td>Agilent</td><td>7820A</td><td></td></tr></tbody></table>

an experimental protocol for studying mineral effects on organic hydrothermal transformations

Orgânica-mineral interações ocorrem amplamente em ambientes hidrotermais, como fontes termais, gêiseres em terra e as fontes hidrotermais no oceano profundo. Funções dos minerais são essenciais em muitos processos hidrotermais de geoquímicos orgânicos. Metodologia hidrotérmico tradicional, que inclui o uso de reatores, feitos de ouro, platina, titânio ou aço inoxidável, é geralmente associada com o alto custo ou indesejáveis efeitos catalíticos metais. Recentemente, há uma tendência crescente para usando os cost-effective e inertes de quartzo ou sílica fundida tubos de vidro em experimentos hidrotermais. Aqui, nós fornecemos um protocolo para realização de experiências hidrotermais de minerais orgânicos em tubos de sílica, e descrevemos as etapas essenciais na preparação da amostra, configuração experimental, separação de produtos e análise quantitativa. Também demonstramos um experimento usando um composto orgânico de modelo, nitrobenzeno, para mostrar o efeito de um mineral que contenham ferro, magnetita, em sua degradação sob uma condição específica hidrotermal. Esta técnica pode ser aplicada para estudar o complexas orgânico-mineral hidrotermais interações em um sistema de laboratório relativamente simples.

Para demonstrar como usar esta abordagem para estudar interações hidrotermais de minerais e orgânicos, um experimento simples usando um modelo composto, nitrobenzeno, foi conduzido com o mineral magnetita (Fe3O4) em uma condição hidrotermal de 150 ° C e 5 barras para 2h. Para mostrar o efeito do mineral, um experimento de nitrobenzeno sem mineral também foi realizado sob a mesma condição hidrotermal. Como mostrado na Figura 1a, ...

Watch this Scientific Journal Video about An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations at JoVE.com

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Terra-abundantes minerais desempenham papéis importantes em sistemas hidrotérmicos naturais. Aqui, descrevemos um método confiável e econômico para a investigação experimental das interações minerais orgânicos sob condições hidrotermais.

Um protocolo Experimental para estudar efeitos Mineral sobre transformações hidrotermais orgânicos

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the ...

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5.6K visualizações.  Oakland University. Terra-abundantes minerais desempenham papéis importantes em sistemas hidrotérmicos naturais. Aqui, descrevemos um método confiável e econômico para a investigação experimental das interações minerais orgânicos sob condições hidrotermais.

Vídeo: An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity

Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as plant-soil feedbacks (PSF) have large effects on plant performance, and create environmental heterogeneity that depends on the community composition. Understanding the importance of PSF for plant community assembly necessitates understanding of the role of heterogeneity in PSF, in addition to mean PSF effects. Here, we describe a protocol for manipulating plant-induced soil heterogeneity. Two example experiments are presented: (1) a field experiment with a 6-patch grid of soils to measure plant population responses and (2) a greenhouse experiment with 2-patch soils to measure individual plant responses. Soils can be collected from the zone of root influence (soils from the rhizosphere and directly adjacent to the rhizosphere) of plants in the field from conspecific and heterospecific plant species. Replicate collections are used to avoid pseudoreplicating soil samples. These soils are then placed into separate patches for heterogeneous treatments or mixed for a homogenized treatment. Care should be taken to ensure that heterogeneous and homogenized treatments experience the same degree of soil disturbance. Plants can then be placed in these soil treatments to determine the effect of plant-induced soil heterogeneity on plant performance. We demonstrate that plant-induced heterogeneity results in different outcomes than predicted by traditional coexistence models, perhaps because of the dynamic nature of these feedbacks. Theory that incorporates environmental heterogeneity influenced by the assembling community and additional empirical work is needed to determine when heterogeneity intrinsic to the assembling community will result in different assembly outcomes compared with heterogeneity extrinsic to the community composition.

Understanding the role of environmental heterogeneity in species coexistence has typically focused on types of heterogeneity that are extrinsic to the community&#8217;s species composition. We provide novel detailed methods for creating soil heterogeneity treatments using soils subject to plant-soil feedback conditioning, or heterogeneity intrinsic to the community composition.

Protocolo experimental para indução-Plant Manipulando heterogeneidade do solo

Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as ...

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Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

Laboratório de Simulação de um ferro (II) rico em Precambrian Marinha Ressurgência do sistema para explorar o crescimento de bactérias fotossintéticas

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

This study presents an excavation method for investigating subsurface hydrological, geochemical, and microbiological heterogeneity of a soil lysimeter. The lysimeter simulates an artificial hillslope which was initially under homogeneous condition and had been subjected to approximately 5,000 mm of water over eight cycles of irrigation in an 18-month period.

Monólito escavação para Coupled Hidrológicos, geoquímicos e microbiológicos Investigações

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled ...

Chemical Gardens as Flow-through Reactors Simulating Natural Hydrothermal Systems

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment allows for testing of various proposed ocean / hydrothermal fluid chemistries that could have driven reactions toward the origin of life in environments on the early Earth, early Mars, or even other worlds such as the icy moons of the outer planets. We show experiments that include growth of chemical garden structures under anoxic conditions simulating the early Earth, inclusion of trace components of phosphates / organics in the injection solution to incorporate them into the structure, a switch of the injection solution to introduce a secondary precipitating anion, and the measurement of membrane potentials generated by chemical gardens. Using this method, self-assembling chemical garden structures were formed that mimic the natural chimneys precipitated at submarine hydrothermal springs, and these precipitates can be used successfully as flow-through reactors by feeding through multiple successive &#8220;hydrothermal&#8221; injections.

We describe chemical garden formation via injection experiments that allow for laboratory simulations of natural chemical garden systems that form at submarine hydrothermal vents.

Jardins químicos como Fluxo através Reatores simulando Naturais sistemas hidrotérmicos

Here we report experimental simulations of hydrothermal chimney growth using injection chemical garden methods. The versatility of this type of experiment ...

Química

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as redox potential (Eh) and pH, but also to microbial activities that can play a direct or indirect role on speciation and/or mobility. Indeed, some bacteria can directly oxidize As(III) to As(V) or reduce As(V) to As(III). Likewise, bacteria are strongly involved in Hg cycling, either through its methylation, forming the neurotoxin monomethyl mercury, or through its reduction to elemental Hg&#176;. The fates of both As and Hg are also strongly linked to soil or aquifer composition; indeed, As and Hg can bind to organic compounds or (oxy)hydroxides, which will influence their mobility. In turn, bacterial activities such as iron (oxy)hydroxide reduction or organic matter mineralization can indirectly influence As and Hg sequestration. The presence of sulfate/sulfide can also strongly impact these particular elements through the formation of complexes such as thio-arsenates with As or metacinnabar with Hg.
Consequently, many important questions have been raised on the fate and speciation of As and Hg in the environment and how to limit their toxicity. However, due to their reactivity towards aquifer components, it is difficult to clearly dissociate the biogeochemical processes that occur and their different impacts on the fate of these TE.
To do so, we developed an original, experimental, column setup that mimics an aquifer with As- or Hg-iron-oxide rich areas versus iron depleted areas, enabling a better understanding of TE biogeochemistry in anoxic conditions. The following protocol gives step by step instructions for the column set-up either for As or Hg, as well as an example with As under iron and sulfate reducing conditions.

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

Fate and speciation of arsenic and mercury in aquifers are closely related to physio-chemical conditions and microbial activity. Here, we present an original experimental column setup that mimics an aquifer and enables a better understanding of trace element biogeochemistry in anoxic conditions. Two examples are presented, combining geochemical and microbiological approaches.

Instalação de coluna experimental para estudar anaeróbicas biogeoquímicas interações entre bactérias, oligoelementos e hidróxidos de ferro (oxi)

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as ...

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 &#176;C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperature&#160;gradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.

The goal of this protocol is to form simulated hydrothermal chimneys via chemical garden injection experiments and introduce a thermal gradient across the inorganic precipitate membrane, using a 3D printable condenser that can be reproduced for educational purposes.

Simulação das primeiras chaminés hidrotérmicas da Terra em um ambiente de gradiente térmico

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the ...

Bioprospecting of Extremophilic Microorganisms to Address Environmental Pollution

Geothermal springs are rich in various metal ions due to the interaction between rock and water that takes place in the deep aquifer. Moreover, due to seasonality variation in pH and temperature, fluctuation in element composition is periodically observed within these extreme environments, influencing the environmental microbial communities. Extremophilic microorganisms that thrive in volcanic thermal vents have developed resistance mechanisms to handle several metal ions present in the environment, thus taking part to complex metal biogeochemical cycles. Moreover, extremophiles and their products have found an extensive foothold in the market, and this holds true especially for their enzymes. In this context, their characterization is functional to the development of biosystems and bioprocesses for environmental monitoring and bioremediation. To date, the isolation and cultivation under laboratory conditions of extremophilic microorganisms still represent a bottleneck for fully exploiting their biotechnological potential. This work describes a streamlined protocol for the isolation of thermophilic microorganisms from hot springs as well as their genotypical and phenotypical identification through the following steps: (1) Sampling of microorganisms from geothermal sites ("Pisciarelli", a volcanic area of Campi Flegrei in Naples, Italy); (2) Isolation of heavy metal resistant microorganisms; (3) Identification of microbial isolates; (4) Phenotypical characterization of the isolates. The methodologies described in this work might be generally applied also for the isolation of microorganisms from other extreme environments.

The isolation of heavy metal-resistant microbes from geothermal springs is a hot topic for the development of bioremediation and environmental monitoring biosystems. This study provides a methodological approach for isolating and identifying heavy metal tolerant bacteria from hot springs.

Bioprospecção de microrganismos extreílicos para enfrentar a poluição ambiental

Geothermal springs are rich in various metal ions due to the interaction between rock and water that takes place in the deep aquifer. Moreover, due to ...

Transformation of Organic Household Leftovers into a Peat Substitute

A two-step procedure is described for the synthesis of a carbon material with a similar composition and properties as peat. The produced hydrochar is made suitable for agricultural applications by removing plant growing inhibitory substances. Wet household waste such as fruit peel, coffee grounds, inedible vegetable parts, or wet lignocellulosic material in general, are treated in presence of water at 215 &#x00B0;C and 21 bar in an autoclave, i.e., by hydrothermal carbonization. All these leftovers have a considerable water content of up to 90 weight % (wt%). Adding water extends the procedure to drier materials such as nutshells or even garden prunings and compostable polymers, i.e., the plastic bag for collection of the leftovers.
Usually, the resulting carbon material, called hydrochar, produces a negative effect on plant growth when added to soil. It is supposed that this effect is caused by adsorbed phytotoxic compounds. A simple post-treatment under inert atmosphere (absence of oxygen) at 275 &#x00B0;C removes these substances. Therefore, the raw hydrochar is placed on a glass frit of a vertical tubular quartz reactor. A nitrogen gas flow is applied in down-flow direction. The tube is heated to the desired temperature by means of a heating mantle for up to one hour.
The success of the thermal treatment is easily quantified by thermogravimetry (TG), carried out in air. A weight loss is determined when the temperature of 275 &#x00B0;C is reached, since volatile content is desorbed. Its amount is reduced in the final material, in comparison to the untreated hydrochar.
The two-step treatment converts household leftovers, including compostable bags employed for their collection, into a carbon material that may serve as plant growth promoter and, at the same time, as a carbon sink for climate change mitigation.

A protocol for hydrothermal carbonization of vegetable food waste in an autoclave is presented, with subsequent dry thermal treatment at 275 &#x00B0;C in a continuous flow reactor desorbing volatile organic substances. The aim is to produce a carbon material suitable as soil amendment product or substrate component.

Transformação das sobras orgânicas do agregado familiar em um substituto da turfa

A two-step procedure is described for the synthesis of a carbon material with a similar composition and properties as peat. The produced hydrochar is made ...

Using Flexible Gold-Titanium Reaction Cells to Simulate Pressure-Dependent Microbial Activity in the Context of Subsurface Biomining

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging obstacles, including the special environmental conditions that need to be replicated, e.g., high pressure and in some cases acidic solutions. The former requires an experimental setup suitable for pressurization up to 100 bar, while the latter demands a fluid container with high chemical resistance against corrosion and unwanted chemical reactions with the container wall. To meet these conditions for an application in the field of in situ biomining, a special flexible gold-titanium reaction cell inside a rocking high-pressure reactor was used in this study. The described system allowed simulation of in situ biomining through sulfur-driven microbial iron reduction in an anoxic, pressure-controlled, highly chemically inert experimental environment. The flexible gold-titanium reaction cell can accommodate up to 100 mL of sample solution, which can be sampled at any given time point while the system maintains the desired pressure. Experiments can be performed on timescales ranging from hours to months. Assembling the high-pressure reactor system is fairly time consuming. Nevertheless, when complex and challenging (microbiological) processes occurring in the earth&#39;s deep subsurface in chemically aggressive fluids have to be investigated in the laboratory, the advantages of this system outweigh the disadvantages. The results found that even at high pressure the microbial consortium is active, but at significantly lower metabolic rates.

This protocol describes microbial experiments under elevated pressures to study in situ biomining processes. The experimental approach employs a rocking high-pressure reactor equipped with a gold-titanium reaction cell containing a microbial culture in an acidic, iron-rich medium.

Usando células de reação de ouro-titânio flexíveis para simular atividade microbiana dependente de pressão no contexto da Biomineração subsuperficial

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging ...

Engenharia

Síntese e descoberta de MOFs à base de fosfonatos: uma abordagem solvotérmica

Discovery and Synthesis Optimization of Isoreticular Al(III) Phosphonate-Based Metal-Organic Framework Compounds Using High-Throughput Methods

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This manuscript describes the synthesis of metal-organic frameworks (MOFs) from solution using an HT reactor system, resulting in the discovery of various phosphonate-based MOFs of the composition [Al2H12-x(PMP)3]Clx&#8729;6H2O (H4PMP = N,N &#39;-piperazine bis(methylenephosphonic acid)) for x = 4, 6, denoted as Al-CAU-60-xHCl, containing trivalent aluminum ions. This was accomplished under solvothermal reaction conditions by systematically screening the impact of the molar ratio of the linker to the metal and the pH of the reaction mixture on the product formation. The protocol for the HT investigation includes six steps: a) synthesis planning (DOE = design of&#160;experiment) within the HT methodology, b) dosing and working with in-house developed HT reactors, c) solvothermal synthesis, d) synthesis workup using in-house developed filtration blocks, e) characterization by HT powder X-ray diffraction, and f) evaluation of the data. The HT methodology was first used to study the influence of acidity on the product formation, leading to the discovery of Al-CAU-60&#8729;xHCl (x = 4 or 6).

Autor em destaque: Acelerando a descoberta na química de materiais microporosos 

The targeted synthesis of new metal-organic frameworks (MOFs) is difficult, and their discovery depends on the knowledge and creativity of the chemist. High-throughput methods allow complex synthetic parameter fields to be explored quickly and efficiently, accelerating the process of finding crystalline compounds and identifying synthetic and structural trends.

Descoberta e Otimização da Síntese de Compostos Metal-Orgânicos Isoreticulares à Base de Al(III) Fosfonato Usando Métodos de Alto Rendimento

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This ...