Wir danken der H.O.G-Gruppe an der Arizona State University für die Entwicklung der ersten Methodik dieser hydrothermalen Experimente, und vor allem danken wir I. Gould, E. Schock, L. Williams, C. Glein, H. Hartnett, K. Fecteau, K. Robinson und C. Bockisch, für ihre Anleitungen und hilfreiche Unterstützung. Start-Fonds von der Oakland University, Z. Yang wurden Z. Yang und X. Fu finanziert.

1. bereiten Sie das Beispiel für hydrothermale Experiment
<ol><li>Wählen Sie die Größe der Quarz oder Kieselsäure Glasröhren, z. B. 2 mm Innendurchmesser (ID) x 6 mm Außendurchmesser (OD) oder 6 mm ID X 12 mm OD, und bestimmen Sie die Mengen an organischen Verbindungen und Mineralien zu verwenden. In diesem Werk sind die Beträge der Nitrobenzene und Magnetit (Fe3O4) zum Laden in die Kieselsäure-Röhre (z.B. 2 mm ID X 6 mm OD) 3,0 µL und 13,9 mg. Hinweis: Die großen Durchmesser Rohre erlauben leichter Beladung der Materialien aber erfordern mehr Anstrengungen der Rohr-Versiegelung.</li>
	<li>Schneiden Sie die Glasröhren sauber Kieselsäure in kleine Stücke mit ~ 30 cm in der Länge mit einem Rohrschneider. Versiegeln Sie ein Ende des Rohres mit einer Knallgas-Taschenlampe mit einem entsprechenden Flamme Kopf geschlossen. Achtung: Befolgen Sie die Sicherheitsvorschriften für die Verwendung von Knallgas Fackel.</li>
	<li>Wiegen Sie die vorgegebene Menge der organischen Verbindung ab auf eine 0,1 mg-Skala auszugleichen (wenn sie fest ist) und in der Kieselsäure Glasrohr mit einem Gewicht von Papier zu übertragen. Wenn die Verbindung ist Flüssigkeit (z.B. Nitrobenzene in diesem Fall), eine Mikroliter Spritze (z. B. 10 µL) verwenden, um es in das kleine Kieselsäure-Rohr übertragen. Fügen Sie die gewogenen Mineralien in die Kieselsäure-Röhre durch eine Pasteurpipette hinzu, und fügen Sie deionisiertes und sauerstoffarmes Wasser (z.B. 0,3 mL). 18.2 MΩ·cm deionisiertes Wasser verwenden und durch Ultraschallbehandlung ebenso.</li>
	<li>Schließen Sie die Kieselsäure-Schlauch an einer Vakuumleitung (~ 1 cm ID) mit geschlossenem Ventil. Tauchen Sie das Rohr in ein Dewar-Fläschchen gefüllt mit flüssigem Stickstoff für ~ 3 min. bis das organische und das Wasser komplett gefroren sind. Achtung: Befolgen Sie die Sicherheitsvorkehrungen für die Übertragung und Verwendung von flüssigem Stickstoff.</li>
	<li>Wenn das Rohr eingetaucht in flüssigem Stickstoff bleibt, öffnen Sie das Vakuumventil und entfernen Sie die Luft aus den Kopfraum des Rohres. Hinweis: Dieser Prozess sollte dauern, bis der Druck unter 100 Mtorr auf dem Manometer der Vakuumpumpe fällt.</li>
	<li>Schalten Sie das Ventil, entfernen Sie das Rohr aus dem flüssigen Stickstoff zu und lassen Sie das Rohr auf Raumtemperatur Aufwärmen. Klopfen Sie leicht den Boden des Röhrchens, die verbleibenden Luftblasen aus Lösung Headspace freizugeben.</li>
	<li>Wiederholen Sie den oben genannten Gefrier-Pumpe-tau-Zyklus für zwei weitere Male und halten Sie das Rohr in flüssigem Stickstoff vor dem Versiegeln des andere Ende des Schlauches. Schließen Sie die Vakuumleitung und verwenden Sie Knallgas Flamme, um das gesamte Rohr geschlossen zu machen. Hinweis: Wenn das Rohr hydrothermale Experimenten unterzogen wird, sinkt die Headspace-Lautstärke des Rohres durch flüssiges Wasser Expansion. Zum Beispiel reduziert die Dichte von Wasser etwa 30 % von Raumtemperatur bis 300 ° C. Berechnen Sie und verlassen Sie genügend Kopfraum Volumen zu, wenn das Rohr abdichten.</li>
</ol>2. richten Sie die hydrothermalen Experiment
<ol><li>Nach der Versiegelungen Schritten habe das Kieselsäure Rohr in ein kleines Stahlrohr (~ 30 cm Länge und 1,5 cm Durchmesser) mit losen Schraubverschlüsse, um Schäden von jedem Druck Gebäude oder Rohr Fehler innerhalb des Rohres zu vermeiden.</li>
	<li>Platzieren Sie das Rohr in einem gut temperierten Ofen oder Herd und Erhitzen Sie es auf die gewünschte Temperatur (z. B. 150 ° C in dieser Arbeit). Verwenden Sie ein Thermoelement im Inneren des Ofens, zur Überwachung der Temperatur durch die hydrothermalen Reaktion.</li>
	<li>Sobald die Reaktionszeit (z. B. 2 h in dieser Arbeit) erreicht ist, Stillen Sie Kieselsäure Rohr indem Sie das Rohr schnell in ein Eis-Wasserbad setzen. Hinweis: Der abschreckprozess dauert weniger als 1 min Abkühlen auf Raumtemperatur, wodurch mögliche retrograde Reaktionen vermieden werden.</li>
</ol>3. analysieren Sie die Probe nach dem Experiment
<ol><li>Die Kieselsäure-Röhre mit einem Rohrschneider öffnen und schnell alle Produkte (z.B. ~0.3 mL in kleinen Kieselsäure Röhre) in ein 10 mL-Glas-Fläschchen mit einer Pasteurpipette übertragen.</li>
	<li>Extrahieren Sie die Bio-Produkte mit 3 mL Dichlormethan (DCM) Lösung, die 8,8 mM Dodecane als interner Standard für die Gaschromatographie (GC) enthält. Verschließen Sie die Flasche und schütteln Sie es durch für 2 min und Vortex es für 1 min Hände. Hinweis: Dadurch wird um die Gewinnung von Bio-Produkten in die organische Phase zu erleichtern. Auch, spülen Sie die Übertragung von pipettieren und im inneren Wände der Kieselsäure-Röhre mit DCM um Produkte Erholung zu gewährleisten. Beschallen sie für Proben mit hohem mineralischen Gehalt in DCM-Lösung für bessere Extraktion.</li>
	<li>Ermöglichen Sie die mineralische Partikel sich in der Extraktionslösung (d. h.DCM mit Dodecane) niederzulassen 5 min. Einsatz einer Pasteurpipette vorsichtig ~ 1 mL der Probe in ein GC-Fläschchen aus dem DCM-Layer (d. h. die Unterschicht) übertragen.</li>
	<li>Analysieren Sie die Bio-Produkt-Vertrieb mit GC mit einer Poly-Kapillare Spalte (z. B. 5 % diphenyl/95% Dimethylsiloxane) und einem Flammenwächter Ionisation. Richten Sie den GC-Ofen mit einem Programm starten bei 50 ° C und halten Sie für 8 min., bei 10 ° C/min auf 220 ° C erhöhen und halten Sie für 10 min, bei 20 ° C/min bis 300 ° C zu erhöhen und halten Sie für 5 min. Set die Injektor-Temperatur bis 300 ° C. Hinweis: Die GC-Programm geändert werden basierend auf dem Typ von organischen Verbindungen, die analysiert wird.</li>
	<li>Bauen Sie die GC Kalibrierkurven durch das Flächenverhältnis der Höhepunkt des Analyten an den internen Standard gegen die Konzentration des Analyten zu plotten.</li>
	<li>Berechnen Sie die Reaktion Konvertierung anhand der Konzentrationen von organischen Ausgangsmaterial vor und nach der Reaktion, d.h., Konvertierung % = ([ersten]-[final]) ⁄ [ersten] × 100 %. Verwenden Sie die Konvertierungen um zu bestimmen, ob das Mineral erleichtert oder die hydrothermalen organische Veränderungen verlangsamt.</li>
</ol>

<ol>
	<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>

Die Autoren haben nichts preisgeben.

In dieser Studie verwendeten wir Nitrobenzene mit Mineral Magnetit als Beispiel um zu demonstrieren, wie man mineralische Effekte auf hydrothermale organische Reaktionen zu bewerten. Obwohl die Experimente im kleinen Kieselsäure Glasröhren durchgeführt werden, sind hoch reproduzierbare Ergebnisse in Magnetit Experimente, d. h. 30,3 ± 1,4 % bei Nitrobenzene Umwandlung, beobachtet, die die Wirksamkeit und die Zuverlässigkeit dieser schlägt hydrothermale Protokoll. In den keine-Mineral-Experimenten ist die Um...

Hydrothermale Umgebungen (d.h., wässrigen Medien bei erhöhten Temperaturen und Druck) sind überall auf der Erde. Die hydrothermale Chemie organischer Verbindungen spielt eine wesentliche Rolle in einer Vielzahl von geochemischen Einstellungen, z. B. organische Sedimentbecken, Erdöl-Lagerstätten und der tiefen Biosphäre1,2,3. Organischen Kohlenstoffs Transformationen in hydrothermalen Systemen auftreten, nicht nur in rein wässrigen Medium sondern auch mit gelösten oder feste anorganische Materialien, wie Erde reichlich Mineralien. Mineralien gefunden wurden, dramatisch und selektiv beeinflussen die hydrothermale Reaktivität von verschiedenen organischen Verbindungen,1,4,5 , aber wie die mineralische Effekte in komplexen hydrothermalen Systemen zu identifizieren Dennoch ist nach wie vor eine Herausforderung. Das Ziel dieser Studie ist es, ein relativ einfaches experimentelle Protokoll bieten für mineralische Effekte auf hydrothermale organische Reaktionen zu studieren.
Die Laborstudien hydrothermale Reaktionen verwenden traditionell robuste Reaktoren, die aus Gold, Titan oder Edelstahl6,7,8,9bestehen. Zum Beispiel wurden gold Taschen oder Kapseln günstig eingesetzt, da Gold flexibel ist und den Probe Druck ermöglicht durch Druckbeaufschlagung Wasser extern gesteuert werden, der vermeidet erzeugen eine Dampfphase innerhalb der Probe. Aber diese Reaktoren sind teuer und potenzielle Metall katalytische Effekte10zugeordnet werden könnten. Daher ist es zwingend notwendig, um eine alternative Methode mit niedrigen Kosten, aber hohe Zuverlässigkeit für diese hydrothermalen Experimente zu finden.
In den letzten Jahren wurden Reaktion Rohre aus Quarz oder Fused-Silica Glas häufiger auf hydrothermale Experimente11,12,13angewendet. Im Vergleich zu edlem Gold oder Titan, ist Quarz oder Silica Glas deutlich billiger, aber auch das starke Material. Noch wichtiger ist, quarzröhren wenig katalytische Wirkung gezeigt haben und kann so träge wie Gold für die hydrothermale Reaktionen11,14. In diesem Protokoll beschreiben wir eine allgemeine Methode für kleine hydrothermale organisch-mineralische Experimente in Kieselsäure dickwandigen Rohren. Wir präsentieren ein Beispiel-Experiment mit einer Modell-Verbindung (d. h. Nitrobenzene) in die Anwesenheit/Abwesenheit von einem Eisenoxid Mineral (z.B. Magnetit) in einer hydrothermalen Lösung von 150 ° C um die mineralischen Wirkung sowie zeigen, zeigen die Wirksamkeit dieser Methode.

<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

Organisch-mineralische Interaktionen sind weit verbreitet in hydrothermalen Umgebungen wie heiße Quellen, Geysire auf dem Land und der hydrothermalen Quellen in der Tiefsee auftritt. Rollen von Mineralien sind in vielen hydrothermalen bio-geochemischen Prozesse entscheidend. Traditionellen hydrothermalen Methodik, die beinhaltet die Verwendung von Reaktoren aus Gold, Titan, Platin oder Edelstahl hergestellt, ist in der Regel verbunden mit hohen Kosten oder unerwünschte Metall katalytische Effekte. Vor kurzem, gibt es eine wachsende Tendenz für die kostengünstige und inerten Quarz oder Fused-Silica-Glasröhren in hydrothermalen Experimente verwenden. Hier bieten wir ein Protokoll für Bio-Mineral hydrothermalen Experimente in Kieselsäure Röhren, und wir beschreiben die wesentlichen Schritte in der Probenvorbereitung, Versuchsaufbau Produkte Trennung und Quantitative Analyse. Wir zeigen auch ein Experiment mit einem Modell organische Verbindung, Nitrobenzene, um zu zeigen, die Wirkung einer eisenhaltigen Minerals Magnetit, auf deren Abbau unter einer bestimmten Bedingung der hydrothermalen. Diese Technik kann angewendet werden, um komplexe organische Mineral hydrothermalen Interaktionen in einem relativ einfachen Laborsystem zu untersuchen.

Zur Demonstration, wie dieser Ansatz verwenden, um hydrothermale organisch-mineralische Interaktionen, ein einfaches Experiment mit Hilfe eines zusammengesetzten Modells zu untersuchen, wurde Nitrobenzene, mit Mineral Magnetit (Fe3O4) bei 150 ° C und 5 hydrothermale Zustand durchgeführt Bars für 2 h. Um die mineralischen Wirkung zeigen, war ein Experiment von Nitrobenzene ohne Mineral auch unter den gleichen Bedingungen, hydrothermale durchgeführt. Wie in <strong...

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

Erde-reichlich Mineralien spielen eine wichtige Rolle in der natürlichen hydrothermalen Systemen. Hier beschreiben wir eine zuverlässige und kostengünstige Methode für die experimentelle Untersuchung von organisch-mineralische Interaktionen unter hydrothermalen Bedingungen.

Ein experimentelles Protokoll für die Untersuchung von mineralischen Auswirkungen auf organische hydrothermalen Transformationen

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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Universidad de Cartagena UDEC

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5.6K Aufrufe.  Oakland University. Erde-reichlich Mineralien spielen eine wichtige Rolle in der natürlichen hydrothermalen Systemen. Hier beschreiben wir eine zuverlässige und kostengünstige Methode für die experimentelle Untersuchung von organisch-mineralische Interaktionen unter hydrothermalen Bedingungen.

Serie: 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.

Versuchsprotokoll für die Manipulation von Plant-induzierte Bodenheterogenität

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

Forschung

Umwelt

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.

Labor Simulation eines Eisen (II) -reichen Präkambrium Meeres Upwelling-System das Wachstum von Bakterien zu erkunden Photosynthetic

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.

Boden Lysimeter Ausgrabung Gekoppelte hydrologische, geochemische und mikrobiologische Untersuchungen

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.

Chemische Gardens als Durchflussreaktoren Simulation natürlicher Hydrothermale Systeme

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

Chemie

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.

Experimentelle Spalte Setup für das Studium der anaerober biogeochemischer Interaktionen zwischen Eisen (Oxy) Hydroxide, Spurenelemente und Bakterien

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.

Simulation von hydrothermalen Schornsteinen der frühen Erde in einer Umgebung mit thermischem Gradienten

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.

Bioprospektion extremophiler Mikroorganismen zur Bekämpfung der Umweltverschmutzung

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.

Umwandlung von Bio-Haushaltsresten in einen Torfersatz

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.

Verwendung flexibler Gold-Titan-Reaktionszellen zur Simulation druckabhängiger mikrobieller Aktivität im Kontext des Subsurface Biominings

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

Ingenieurwesen

Synthese und Entdeckung von Phosphonat-basierten MOFs: Ein solvothermer Ansatz

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 im Rampenlicht: Beschleunigung der Entdeckung in der mikroporösen Materialchemie 

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.

Entdeckung und Syntheseoptimierung von isoretikulären al(III)-phosphonat-basierten metallorganischen Gerüstverbindungen mit Hochdurchsatzmethoden

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