Ringraziamo il gruppo H.O.G presso la Arizona State University per lo sviluppo della metodologia iniziale di questi esperimenti idrotermali, e in particolare, ringraziamo I. Gould, Shock E., L. Williams, C. Gordana, H. Hartnett, K. Fecteau, K. Robinson e C. Bockisch, per loro orientamento e assistenza disponibile. Yang Z. e X. Fu erano finanziate da fondi di avvio da Oakland University a z Yang.

1. preparare il campione per esperimento idrotermale
<ol><li>Scegliere le dimensioni dei tubi di vetro quarzo o silice, per esempio, 2 mm diametro interno (ID) x 6 mm di diametro esterno (OD) o 6 mm ID x 12 mm OD anche e determinare la quantità di composti organici e minerali da utilizzare. In questo lavoro, gli importi di nitrobenzene e magnetite (Fe3O4) per caricare nel tubo di silice (ad es., 2 mm ID x 6 mm OD) sono 3,0 µ l e 13,9 mg, rispettivamente. Nota: I tubi di grande diametro consentono più facile caricamento dei materiali ma richiedono maggiori sforzi di tenuta del tubo.</li>
	<li>Tagliare il tubo di vetro pulito silice in piccoli pezzi con ~ 30 cm di lunghezza utilizzando un tagliatubi. Tenuta un'estremità del tubo chiuso utilizzando una torcia ossidrogeno con una testa di fiamma appropriato. Attenzione: Seguire le procedure di sicurezza per l'utilizzo della torcia ossidrogeno.</li>
	<li>Pesare la quantità predeterminata di partenza composto organico su un 0.1 mg-scala dell'equilibrio (se è solido) e trasferirlo nel tubo di vetro di silice utilizzando una carta di pesatura. Se il composto è liquido (ad es., nitrobenzene in questo caso), utilizzare una siringa di microlitro (ad es. 10 µ l) per trasferirlo nel tubo di silice. Aggiungere i minerali pesati nel tubo di silice mediante una pipetta Pasteur e quindi aggiungere acqua deionizzata e deossigenato (ad es., 0,3 mL). MΩ·cm uso 18,2 acqua deionizzata e si deoxygenate di sonicazione.</li>
	<li>Collegare il tubo di silice per una linea del vuoto (ID ~ 1 cm) con una valvola chiusa. Immergere il tubo in un pallone Dewar riempito con azoto liquido per ~ 3 min fino a quando le sostanze organiche e l'acqua sono completamente congelati. Attenzione: Seguire le procedure di sicurezza per il trasferimento e l'utilizzo di azoto liquido.</li>
	<li>Quando il tubo rimane immerso in azoto liquido, aprire la valvola del vuoto e rimuovere l'aria dallo spazio di testa del tubo. Nota: Questo processo dovrebbe durare fino a quando la pressione scende sotto 100 mtorr sul manometro della pompa del vuoto.</li>
	<li>Spegnere la valvola, rimuovere la provetta dall'azoto liquido e lasciare che il tubo caldo fino a temperatura ambiente. Picchiettare delicatamente il fondo della provetta per rilasciare le bolle d'aria rimanente dalla soluzione per spazio di testa.</li>
	<li>Ripetere il ciclo Disgelo-pompa sopra per altre due volte e tenere il tubo in azoto liquido prima di sigillare l'altra estremità del tubo. Chiudere la linea del vuoto e utilizzare la fiamma ossidrica per rendere l'intero tubo chiuso. Nota: Quando il tubo viene sottoposto a esperimenti idrotermali, diminuirà il volume dello spazio di testa del tubo a causa dell'espansione di acqua liquida. Ad esempio, la densità dell'acqua riduce circa il 30% da temperatura ambiente a 300 ° C. Calcolare e lasciare abbastanza volume di spazio di testa quando il tubo di tenuta.</li>
</ol>2. impostare l'esperimento idrotermale
<ol><li>Dopo i passaggi di sigillamento, mettere il tubo di silice in un piccolo tubo d'acciaio (~ 30 cm di lunghezza e 1,5 cm di diametro) con tappi a vite allentate, al fine di evitare danni da qualsiasi pressione edificio o guasto del tubo all'interno del tubo.</li>
	<li>Collocare il tubo in un forno o forno ben controllato di temperatura e calore fino alla temperatura desiderata (ad es., 150 ° C in questo lavoro). Utilizzare una termocoppia all'interno del forno per monitorare la temperatura attraverso la reazione idrotermale.</li>
	<li>Appena il tempo di reazione è raggiunta (ad es., 2 h in questo lavoro), placare il tubo di silice mettendo rapidamente il tubo in acqua e ghiaccio. Nota: Il processo di spegnimento dura meno di 1 min raffreddare a temperatura ambiente, che evita potenziali reazioni retrograde.</li>
</ol>3. analizzare il campione dopo l'esperimento
<ol><li>Aprire il tubo di silice utilizzando una taglierina per tubi e trasferire rapidamente tutti i prodotti (ad es., ~0.3 mL in tubo di silice) in un flaconcino di vetro da 10 mL utilizzando una pipetta Pasteur.</li>
	<li>Estrarre i prodotti biologici con 3 mL di diclorometano (DCM) soluzione contenente dodecano 8,8 mM come standard interno per gas cromatografia (GC). Tappo il flacone e agitare per passa per 2 min e vortice per 1 min. Nota: Ciò contribuisce a facilitare l'estrazione dei prodotti biologici nella fase organica. Inoltre, sciacquare le pareti conferente dispensare e all'interno del tubo di silice con DCM per garantire il recupero di prodotti. Per campioni con alto contenuto minerale, Sonicare li nella soluzione DCM per migliore estrazione.</li>
	<li>Consentire le particelle minerali di stabilirsi nella soluzione di estrazione (cioè, DCM con dodecano) per 5 min, uso una pipetta di Pasteur attentamente trasferire ~ 1 mL del campione dallo strato DCM (cioè, lo strato inferiore) in un flaconcino di GC.</li>
	<li>Analizzare la distribuzione di prodotti biologici mediante GC con una colonna di poli-capillare (per esempio, 5% diphenyl/95% dimetilsiloxano) e un rivelatore a ionizzazione di fiamma. Impostare il forno GC con un programma per iniziare a 50 ° C e tenere premuto per 8 min, aumentare a 10 ° C/min fino a 220 ° C e tenere premuto per 10 min, aumentare a 20 ° C/min a 300 ° C e tenere premuto per 5 min, impostare la temperatura iniettore a 300 ° C. Nota: Il programma di GC dovuto essere cambiate in base al tipo di composti organici analizzato.</li>
	<li>Costruire le curve di taratura GC tracciando il rapporto tra area del picco dell'analita per lo standard interno contro la concentrazione dell'analita.</li>
	<li>Calcolare la conversione di reazione basata sulle concentrazioni di materiale organico di partenza prima e dopo la reazione, cioè, conversione % = ([iniziale] – [finale]) ⁄ [iniziale] × 100%. Utilizzare le conversioni per determinare se il minerale facilita o rallenta le trasformazioni organiche idrotermale.</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>

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In questo studio, abbiamo utilizzato il nitrobenzene con minerale magnetite come esempio per dimostrare come valutare minerali effetti sulle reazioni organiche idrotermale. Anche se gli esperimenti vengono eseguiti in tubi di vetro di silice, risultati altamente riproducibili sono osservati negli esperimenti magnetite, vale a dire, 30.3 ± 1,4% nella conversione di nitrobenzene, che suggerisce l'efficacia e l'affidabilità di questo protocollo di idrotermale. Negli esperimenti no-minerale, la conversione di nitr...

Ambienti idrotermali (cioè, mezzi acquosi ad elevate temperature e pressioni) sono onnipresenti sulla terra. La chimica idrotermale di composti organici gioca un ruolo essenziale in una vasta gamma di impostazioni geochimiche, come organici bacini sedimentari, serbatoi di petrolio e la biosfera profonda1,2,3. Le trasformazioni di carbonio organico in sistemi idrotermali si verificano non solo in puro mezzo acquoso ma anche con materiali inorganici disciolti o solidi, quali minerali abbondanti a terra. Minerali sono stati trovati per drammaticamente e selettivamente influenza la reattività idrotermale di vari composti organici,1,4,5 ma come identificare gli effetti minerali in complessi sistemi idrotermali rimane ancora una sfida. L'obiettivo di questo studio è quello di fornire un protocollo sperimentale relativamente semplice per studiare minerali effetti sulle reazioni organiche idrotermale.
Gli studi di laboratorio delle reazioni idrotermali utilizzano tradizionalmente robusti reattori che sono fatti di oro, titanio o in acciaio inox6,7,8,9. Ad esempio, sacchi d'oro o le capsule sono stati favorevolmente utilizzati, perché l'oro è flessibile, e permette la pressione del campione deve essere comandato da pressurizzazione dell'acqua esternamente, che evita la generazione di una fase di vapore all'interno del campione. Tuttavia, questi reattori sono costosi e potrebbero essere associati con potenziali effetti catalitici metallo10. Quindi, è assolutamente necessario trovare un metodo alternativo con basso costo ma di alta affidabilità per questi esperimenti idrotermali.
Negli ultimi anni, provette di vetro al quarzo o silice fusa sono state applicate più frequentemente al idrotermale esperimenti11,12,13. Rispetto al prezioso oro o titanio, vetro di quarzo o silice è notevolmente più economico, ma anche il materiale forte. Ancora più importante, tubi al quarzo hanno indicato gli effetti catalitici poco e può essere come inerte come l'oro per le reazioni idrotermali11,14. In questo protocollo, descriviamo un metodo generale per lo svolgimento di esperimenti organico-minerale idrotermali su piccola scala in tubi di silice con pareti spesse. Vi presentiamo un esperimento di esempio utilizzando un composto di modello (cioè, nitrobenzene) in presenza/assenza di un minerale di ossido di ferro (cioè, magnetite) in una soluzione idrotermale di 150 ° C, al fine di mostrare l'effetto minerale, anche per dimostrare la efficacia di questo metodo.

<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

Organico-minerale interazioni ampiamente si verificano in ambienti idrotermali, quali sorgenti termali, geyser sulla terra e le sorgenti idrotermali nell'oceano profondo. Ruoli dei minerali sono fondamentali in molti processi geochimici organici idrotermali. Tradizionale metodologia idrotermale, che include l'utilizzo di reattori in acciaio inox, titanio, platino o oro, è associata solitamente con il costo elevato o effetti catalitici metallici indesiderati. Recentemente, c'è una crescente tendenza per utilizzando i tubi di quarzo o silice fusa vetro convenienti e inerti negli esperimenti idrotermali. Qui, forniamo un protocollo per compiere esperimenti idrotermali in organico-minerale in tubi di silice, e descriviamo i passi essenziali nella preparazione dei campioni, messa a punto sperimentale, separazione di prodotti e analisi quantitativa. Inoltre dimostriamo un esperimento utilizzando un composto organico di modello, nitrobenzene, per mostrare l'effetto di un minerale contenente ferro, magnetite, sulla sua degradazione sotto una determinata condizione idrotermale. Questa tecnica può essere applicata per studiare complessi organo-minerali idrotermali interazioni in un sistema di laboratorio relativamente semplici.

Per illustrare come utilizzare questo approccio per studiare le interazioni organico-minerale idrotermale, un semplice esperimento utilizzando un composto di modello, nitrobenzene, è stata condotta con minerale magnetite (Fe3O4) in una condizione idrotermale di 150 ° C e 5 bar per 2 h. Per visualizzare l'effetto minerale, un esperimento di nitrobenzene senza minerale inoltre è stato effettuato nella stessa circostanza idrotermale. Come mostrato in <strong class="x...

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-abbondanti minerali svolgono i ruoli importanti nei sistemi idrotermali naturali. Qui, descriviamo un metodo affidabile e conveniente per l'indagine sperimentale delle interazioni organico-minerale in condizioni idrotermali.

Un protocollo sperimentale per lo studio di minerali effetti sulle trasformazioni organiche idrotermale

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 Views.  Oakland University. Terra-abbondanti minerali svolgono i ruoli importanti nei sistemi idrotermali naturali. Qui, descriviamo un metodo affidabile e conveniente per l'indagine sperimentale delle interazioni organico-minerale in condizioni idrotermali.

Video: 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.

Protocollo sperimentale per eterogeneità del terreno manipolazione Plant-indotta

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.

Simulazione Laboratorio di ferro (II) ricchi di Precambriano Marine Upwelling sistema per esplorare la crescita di batteri fotosintetici

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.

Terreno lisimetro scavo per accoppiate idrologici, geochimiche e microbiologiche Investigations

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.

Giardini chimici come flusso attraverso Reattori simulando naturali idrotermali Sistemi

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

Chimica

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.

Installazione colonna sperimentale per lo studio anaerobici biogeochimici interazioni tra batteri, oligoelementi e idrossidi di ferro (ossi)

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.

Simulazione di camini idrotermali della Terra primordiale in un ambiente a gradiente termico

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.

Bioprospezione dei microrganismi estremofili per affrontare l'inquinamento ambientale

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.

Trasformazione degli avanzi organici delle famiglie in un sostituto della torba

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.

Utilizzo di celle di reazione oro-titanio flessibili per simulare l'attività microbica dipendente dalla pressione nel contesto del biomining del sottosuolo

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

Ingegneria

Sintesi e scoperta di MOF a base di fosfonati: un approccio solvotermico

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).

Autore in primo piano: Accelerare le scoperte nella chimica dei materiali microporosi 

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.

Scoperta e ottimizzazione della sintesi di composti isoreticolari a base di al(III) fosfonato metallo-organico mediante metodi ad alta produttività

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