وقد تم تمويل هذا البحث من قبل الجيش الاميركي جائزة مكتب ابحاث W911NF-04-1-0169، مركز البحوث والتطوير الهندسي (ERDC) والمؤسسة الوطنية للعلوم منحة EAR-1029069. بالإضافة إلى ذلك، وأيد هذا البحث من قبل برامج الصيف في المرحلة الجامعية بحوث منح من مدرسة كولورادو للمناجم. الكتاب أود أن أشكر ريان Tolene وبول شولت على مساهماتهم.

<ol>
	<li>Verstraete, M. M., Schwartz, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desertification+and+global+change.">Desertification and global change.</a> Vegetatio. 91, 3-13 (1991).</li><li>Warren, A., Adams, W. M., Goudie, A. S., Orme, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desertification.">Desertification.</a> The Physical Geography of Africa. , 342-355 (1996).</li><li>Katata, G., Nagai, H., Ueda, H., Agam, N., Berliner, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+land+surface+model+including+evaporation+and+adsorption+processes+in+the+soil+for+the+land-air+exchange+in+arid+regions.">Development of a land surface model including evaporation and adsorption processes in the soil for the land-air exchange in arid regions.</a> J. Hydrometeorol. 8, 1307-1324 (2007).</li><li>Davarzani, H., Smits, K. M., Tolene, R., Illangasekare, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+of+the+effect+of+wind+speed+on+evaporation+from+soil+through+integrated+modeling+of+atmospheric+boundary+layer+and+shallow+subsurface.">Study of the effect of wind speed on evaporation from soil through integrated modeling of atmospheric boundary layer and shallow subsurface.</a> Water Resour. Res. 50, (2014).</li><li>Heitman, J. L., Horton, R., Ren, T., Nassar, I. N., Davis, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+test+of+coupled+soil+heat+and+water+transfer+prediction+under+transient+boundary+temperatures.">A test of coupled soil heat and water transfer prediction under transient boundary temperatures.</a> Soil Sci. Soc. Am. J. 72 (5), 1197-1207 (2008).</li><li>Gurr, C. G., Marshall, T. J., Hutton, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Movement+of+water+in+soil+due+to+a+temperature+gradient.">Movement of water in soil due to a temperature gradient.</a> Soil Sci. 74, 335-345 (1952).</li><li>Nassar, I. N., Horton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+transport+in+unsaturated+non-isothermal+salty+soil:+experimental+results.">Water transport in unsaturated non-isothermal salty soil: experimental results.</a> Soil Sci. Soc. Am. J. 53, 1323-1363 (1989).</li><li>Prunty, L., Horton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steady-state+Temperature+Distribution+in+Nonisothermal+unsaturated+closed+soil+cells.">Steady-state Temperature Distribution in Nonisothermal unsaturated closed soil cells.</a> Soil Sci. Soc. Am. J. 58, 1358-1363 (1994).</li><li>Bachmann, J., Horton, R., Ren, T., van der Ploeg, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+thermal+properties+of+four+wettable+and+four+water-repellent+soils.">Comparison of the thermal properties of four wettable and four water-repellent soils.</a> Soil Sci. Soc. Am. J. 65 (6), 1675-1679 (2001).</li><li>Smits, K. M., Sakaki, T., Limsuwat, A., Illangasekare, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+conductivity+of+sands+under+varying+moisture+and+porosity+in+drainage-wetting+cycles.">Thermal conductivity of sands under varying moisture and porosity in drainage-wetting cycles.</a> Vadose Zone J. 9, 1-9 (2010).</li><li>Sakaki, T., Limsuwat, A., Smits, K. M., Illangasekare, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Empirical+two-point+&#945;-mixing+Model+for+calibrating+the+ECH2O+EC-5+soil+sensor+in+sands.">Empirical two-point &#945;-mixing Model for calibrating the ECH2O EC-5 soil sensor in sands.</a> Water Resources Research. 44, W00D08 (2008).</li><li>Shokri, N., Lehmann, P., Or, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaporation+from+layered+porous+media.">Evaporation from layered porous media.</a> J. Geophys. Res. 115, B06204 (2010).</li><li>Van Brakel, J., Mujumdar, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+transfer+in+convective+drying.">Mass transfer in convective drying.</a> Advances in Drying. 1, 217-267 (1980).</li><li>Yiotis, A. G., Subos, A. G. B. o. u. d. o. u. v. i. s. A. K., Tsimpanogiannis, I. N., Yortsos, Y. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+liquid+films+on+the+drying+of+porous+media.">The effect of liquid films on the drying of porous media.</a> AIChE J. 50, 2721-2737 (2004).</li><li>Ishihara, Y., Shimojima, E., Harada, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+vapor+transfer+beneath+bare+soil+where+evaporation+is+influenced+by+a+turbulent+surface+wind.">Water vapor transfer beneath bare soil where evaporation is influenced by a turbulent surface wind.</a> J. Hydrol. 131 (1-4), 63-104 (1992).</li><li>Lehmann, P., Assouline, S., Or, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristic+lengths+affecting+evaporative+drying+of+porous+media.">Characteristic lengths affecting evaporative drying of porous media.</a> Phys. Rev. E. 77 (5 Pt 2), 056309 (2008).</li><li>Trautz, A. C., Smits, K. M., Schulte, P., Illangasekare, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensible+heat+balance+and+heat-pulse+method+applicability+to+in+situ+soil-water+evaporation.">Sensible heat balance and heat-pulse method applicability to in situ soil-water evaporation.</a> Vadose Zone J. 13, (2014).</li></ol>

تعلن الكتاب أنه ليس لديهم المصالح المالية المتنافسة.

وكان الغرض من هذا البروتوكول إلى تطوير جهاز التجريبية والإجراءات المرتبطة بها لتوليد البيانات القرار المكانية والزمانية العالية المطلوبة لدراسة التفاعلات في الغلاف الجوي الأرض مع الاحترام للحرارة وعمليات نقل جماعية. الجهاز التجريبي وصفها يتكون من خزان التربة ونف...

فهم التفاعل بين الأرض والغلاف الجوي أهمية قصوى في فهمنا لكثير من المشاكل العالمية الراهنة مثل تسرب ثاني أكسيد الكربون جيولوجيا-المعزول في التربة، وتغير المناخ والمياه والإمدادات الغذائية، وكشف دقيق للألغام الأرضية، ومعالجة المياه الجوفية والتربة. بالإضافة إلى ذلك، التبادلات الأولية للحرارة والماء التي تدفع الظروف الجوية العالمية والإقليمية تحدث على سطح الأرض. العديد من الظواهر الجوية والمناخية (مثل الأعاصير، شركة ني &amp; # 241؛ س، والجفاف، وما إلى ذلك) هي التي تحرك أساسا من العمليات المرتبطة التفاعلات سطح الغلاف الجوي البرية 1. وبما أن أكثر من نصف سطح الأرض على الأرض القاحلة أو شبه القاحلة 2-4، واصفا بدقة دورة المياه في هذه المناطق على أساس من الحرارة والماء التبادل بين الهواء في الغلاف الجوي وسطح التربة أمر بالغ الأهمية لتحسين فهمنا لل القضايا المذكورة آنفا،لا سيما في المناطق المعرضة للجفاف الممتد والتصحر. ومع ذلك، على الرغم من عقود من البحث، لا تزال هناك العديد من الثغرات المعرفية في الفهم الحالي لكيفية باطن الأرض الضحلة والغلاف الجوي تتفاعل 5. عمليات النقل التي تنطوي على الماء السائل، وبخار الماء، والحرارة في التربة الحيوية ومقترنة بقوة فيما يتعلق التفاعل مع التربة وتطبق شروط الحدود (أي، درجة الحرارة، الرطوبة النسبية، والإشعاع الحراري). نماذج انتقال الحرارة والكتلة العددية عادة الإفراط أو نغفل عددا من هذه التعقيدات ويرجع ذلك جزئيا إلى عدم وجود اختبار وصقل النظريات القائمة الناتجة عن ندرة البيانات عالية الدقة الزمنية والمكانية. قواعد البيانات المتقدمة من أجل التحقق من نموذج تفتقر في كثير من الأحيان المعلومات في الغلاف الجوي أو تحت سطح الأرض الحاسمة لاختبار النظريات بشكل صحيح، مما أدى إلى النماذج العددية التي لا تمثل بشكل صحيح للاستيرادتعتمد عمليات النمل أو على استخدام المعلمات غير مفهومة التي يتم تعديلها أو تركيبها في النموذج. ويستخدم هذا الأسلوب على نطاق واسع نظرا لبساطته وسهولة الاستخدام، ولها في بعض الطلبات التي تعرض الكثير من الجدارة. ومع ذلك، فإن هذا النهج يمكن تحسينها من خلال فهم أفضل للفيزياء وراء هذه &quot;البارامترات جمعها&quot; عن طريق إجراء التجارب تسيطر عليها بشكل جيد في ظل ظروف عابرة قادرة على اختبار الحرارة ونقل المياه نظرية 6. التجريب الدقيق في المختبر يسمح مجموعات البيانات الدقيقة لأن تتولد التي يمكن بعد ذلك أن تستخدم للتحقق من صحة النماذج العددية. البيانات المتاحة من المواقع الميدانية وغالبا ما تكون ناقصة ومكلفة للحصول على، ودرجة الرقابة اللازمة للحصول على فهم أساسي للعمليات وتوليد ويمكن اعتبار البيانات اللازمة للتحقق نموذج غير كافية في بعض الحالات. التجارب المختبرية من الظواهر الطبيعية مثل تبخر التربة يسمح ATMOSشروط pheric (أي درجة الحرارة والرطوبة النسبية وسرعة الرياح) وظروف التربة (أي نوع التربة، المسامية، والتعبئة التكوين) أن يكون للرقابة بعناية. العديد من التقنيات المخبرية المستخدمة لدراسة تبخر التربة وخصائص التربة الحرارية والهيدروليكية تستخدم أخذ العينات المدمرة 10/07. تتطلب أساليب أخذ العينات المدمرة التي يتم تفكيك عينة التربة للحصول على بيانات نقطة، ومنع قياس سلوك عابر وتعطيل الخواص الفيزيائية للتربة. هذا النهج يقدم الخطأ وعدم اليقين إلى البيانات. قياسات تدميري، مثل الطريقة المعروضة هنا، والسماح لتحديد أكثر دقة ودراسة الترابط بين خصائص التربة والعمليات 11. الهدف من هذا العمل هو تطوير جهاز دبابات التربة والبروتوكول المرتبطة لتوليد بيانات عالية الدقة المكانية والزمانية المتعلقة آثار التغيرات في الغلاف الجوي والظروف الموجودة تحت سطح الأرض علىتبخر التربة العارية. لهذا العمل، وربطه نفق الرياح الصغيرة قادرة على الحفاظ على سرعة الرياح ودرجة الحرارة ثابتة مع جهاز دبابات التربة. والمجهزة نفق الرياح وخزان التربة مع مجموعة من حالة تكنولوجيات الاستشعار الفن لجمع البيانات مستقل ومستمر. يتم قياس سرعة الرياح باستخدام الفولاذ المقاوم للصدأ نظام Pitot ثابت أنبوب تعلق على محول الضغط. ويتم رصد درجة الحرارة والرطوبة النسبية في الجو باستخدام نوعين من أجهزة الاستشعار. يتم مراقبة الرطوبة النسبية ودرجة الحرارة أيضا على سطح التربة. أجهزة الاستشعار في رطوبة التربة تحت السطحية مقياس ودرجة الحرارة. وتستخدم قياسات وزن الجهاز دبابة لتحديد التبخر من خلال توازن الكتلة المائية. للتدليل على تطبيق هذا الجهاز التجريبي والبروتوكول، ونحن تقديم مثال التبخر التربة عارية في ظل ظروف مختلفة سرعة الرياح. خزان التربة، ومعبأة بشكل متجانس مع الرمال تتميز بشكل جيد، وكان في البداية سا تماماturated وسمح لتتبخر بحرية تحت الظروف الجوية التي تسيطر عليها بعناية (أي درجة الحرارة وسرعة الرياح).

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>ECH2O EC-5 Soil Moisture Sensor (25)</td>
			<td>Decagon Devices Inc. Decagon.com</td>
			<td>40593</td>
			<td>For specifics visit: http://www.decagon.com/products/soils/volumetric-water-content-sensors/ec-5-soil-moisture-small-area-of-influence/. Sampling frequency on 10 minute intervals, accuracy is &#177;3%, and collect data using the Em50 dataloggers</td>
		</tr>
		<tr>
			<td>ECT Soil/Air Temperature Sensor (19)</td>
			<td>Decagon Devices Inc. Decagon.com</td>
			<td>40651</td>
			<td>For specifications visit http://www.decagon.com/products/canopy-atmosphere/temperature/ect-air-temperature/. Sampling frequency on 10 minute intervals, accuracy is &#177;0.5&#176;C, Measure within a temperature of 5 and 40&#176;C, and collect data using the Em50 dataloggers</td>
		</tr>
		<tr>
			<td>EHT Relative Humidity and Temperature Sensor (5)</td>
			<td>Decagon Devices Inc. Decagon.com</td>
			<td>N/A</td>
			<td>Sampling Frequency on 10 minute intervals, accuracy is &#177;3% between 5 and 100% relative humidity, and collect data using Em50 data loggers. For more information visit decagon.com</td>
		</tr>
		<tr>
			<td>Em50 Data Logger (10)</td>
			<td>Decagon Devices Inc. Decagon.com</td>
			<td>40800</td>
			<td>For specifics visit http://www.decagon.com/products/data-management/data-loggers/em50-digital-analog-data-logger/. ECH2O decagon devices, pulls data from the ECT, EC-5, and EHT sensors, and each data logger has 5 sensor connections and a com port that connects from the logger to USB to computer</td>
		</tr>
		<tr>
			<td>Sartorius Weighing Scale (1)</td>
			<td>Sartorius Corporation</td>
			<td>11209-95</td>
			<td>Sartorius Model 11209-95, Range = 65kg, Resolution = &#177;1g</td>
		</tr>
		<tr>
			<td>Infrared SalamandernCeramic Radiative Heater (1)</td>
			<td>Mor Electric Heating Assoc., Inc. http://www.morelectricheating.com/</td>
			<td>FTE 500-240</td>
			<td>5 heaters needed, adjust to ge thte right ambient/free-flow temperature</td>
		</tr>
		<tr>
			<td>2104 Temperature Control System (1)</td>
			<td>Chromalox</td>
			<td>2104</td>
			<td>Controls the heaters</td>
		</tr>
		<tr>
			<td>Infrared Temperature Sensor Regulator (1)</td>
			<td>Exergen Corporation</td>
			<td>N/A</td>
			<td>Monitors the heaters temperatures</td>
		</tr>
		<tr>
			<td>Stainless Steel Pitot-Static Tube (1)</td>
			<td>Dwyer Instruments, Inc. http://www.dwyer-inst.com/</td>
			<td>Series 160</td>
			<td>For specifics visit http://www.dwyer-inst.com/Product/%20TestEquipment/PitotTubes/Series160. Sensor sampling frequency is every 10 minutes, must be connected to differential pressure transducer and anemometer, and convert the pressure data collected into win velocities using Bernoulli&#39;s equation.</td>
		</tr>
		<tr>
			<td>1/2 inch Acrylic (1)</td>
			<td>Colorado Plastics http://www.coloradoplastics.com/</td>
			<td>N/A</td>
			<td>Specific heat of 1464 J kg^-1K^-1, thermal conductivity of 0.2 W m^-1K-1, and a density of 1150 kg m_-3</td>
		</tr>
		<tr>
			<td>Galvanized Steel Ducting Material (1)</td>
			<td>Home Depot</td>
			<td>N/A</td>
			<td>Material used to build wind- tunnel, and both round and rectangular ducting were used in construction and connected using square-to-round reducer duct</td>
		</tr>
		<tr>
			<td>Variable Speed Controller Connected to an In-Line Duct Fan (1)</td>
			<td>Suncourt, Inc. http://www.suncourt.com/</td>
			<td>VS200</td>
			<td>15.3 cm in Diameter Placed in-line with round duct</td>
		</tr>
		<tr>
			<td>Galvanized Steel Damper (1)</td>
			<td>Home Depot</td>
			<td>N/A</td>
			<td>Used to control/reduce speeds in the wind tunnel for low velocity data</td>
		</tr>
		<tr>
			<td>Accusand #30/40 (1)</td>
			<td>Unimin Corporation http://www.unimin.com/</td>
			<td>N/A</td>
			<td>This sand is silica sand and is 99.8% quartz, its grain shape is classified as rounded, the uniformity coefficient is approximately 1.2, and the grain density is 2.66 g/cm3.</td>
		</tr>
	</tbody>
</table>

exploring the effects of atmospheric forcings on evaporation: experimental integration of the atmospheric boundary layer and shallow subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages.

وكان الهدف من التجربة المقدمة هنا إلى دراسة تأثير سرعة الرياح على التبخر من التربة العارية. وتتلخص خصائص رئيسية للتربة الاختبار المستخدمة في هذه الدراسة في الجدول 2. وأجريت سلسلة من التجارب التي طبقت الشروط الحدية المختلفة على سطح التربة (أي سرعة الريا?...

Watch this Scientific Journal Video about Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface at JoVE.com

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

ويرد بروتوكول لتصميم وبناء خزان التربة ربطه إلى مناخ تسيطر نفق الرياح الصغيرة لدراسة الآثار المترتبة على التأثيرات الجوية على التبخر. والمجهزة على حد سواء خزان التربة ونفق الرياح مع تكنولوجيات الاستشعار لاستمرار قياس الموقع من الظروف البيئية في.

استكشاف تأثيرات الغلاف الجوي التأثيرات على التبخر: تجربة دمج طبقة الغلاف الجوي الحدود وتحت السطحية الضحلة

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

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8.6K Views.  Colorado School of Mines.  ويرد بروتوكول لتصميم وبناء خزان التربة ربطه إلى مناخ تسيطر نفق الرياح الصغيرة لدراسة الآثار المترتبة على التأثيرات الجوية على التبخر. والمجهزة على حد سواء خزان التربة ونفق الرياح مع تكنولوجيات الاستشعار لاستمرار قياس الموقع من الظر?...

Video: Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Surface Renewal: An Advanced Micrometeorological Method for Measuring and Processing Field-Scale Energy Flux Density Data

Advanced micrometeorological methods have become increasingly important in soil, crop, and environmental sciences. For many scientists without formal training in atmospheric science, these techniques are relatively inaccessible. Surface renewal and other flux measurement methods require an understanding of boundary layer meteorology and extensive training in instrumentation and multiple data management programs. To improve accessibility of these techniques, we describe the underlying theory of surface renewal measurements, demonstrate how to set up a field station for surface renewal with eddy covariance calibration, and utilize our open-source turnkey data logger program to perform flux data acquisition and processing. The new turnkey program returns to the user a simple data table with the corrected fluxes and quality control parameters, and eliminates the need for researchers to shuttle between multiple processing programs to obtain the final flux data. An example of data generated from these measurements demonstrates how crop water use is measured with this technique. The output information is useful to growers for making irrigation decisions in a variety of agricultural ecosystems. These stations are currently deployed in numerous field experiments by researchers in our group and the California Department of Water Resources in the following crops: rice, wine and raisin grape vineyards, alfalfa, almond, walnut, peach, lemon, avocado, and corn.

Surface renewal is a micrometeorological method that is being used increasingly to determine energy fluxes, but its technical complexity makes it inaccessible to a broad audience. We describe the steps needed to set up and calibrate a surface renewal field station, to acquire and process data, and to correctly interpret results.

Advanced micrometeorological methods have become  increasingly important in soil, crop, and environmental sciences.  For many scientists without formal ...

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.

محاكاة المختبر من الحديد (II) الغنية نظام الموجات المتقلبة عصر ما قبل الكمبري البحرية لاستكشاف نمو البكتيريا الضوئي

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

Extraction and Characterization of Surfactants from Atmospheric Aerosols

Surface-active compounds, or surfactants, present in atmospheric aerosols are expected to play important roles in the formation of liquid water clouds in the Earth&#39;s atmosphere, a central process in meteorology, hydrology, and for the climate system. But because specific extraction and characterization of these compounds have been lacking for decades, very little is known on their identity, properties, mode of action and origins, thus preventing the full understanding of cloud formation and its potential links with the Earth&#39;s ecosystems.
In this paper we present recently developed methods for 1) the targeted extraction of all the surfactants from atmospheric aerosol samples and for the determination of 2) their absolute concentrations in the aerosol phase and 3) their static surface tension curves in water, including their Critical Micelle Concentration (CMC). These methods have been validated with 9 references surfactants, including anionic, cationic and non-ionic ones. Examples of results are presented for surfactants found in fine aerosol particles (diameter &#60;1 &#956;m) collected at a coastal site in Croatia and suggestions for future improvements and other characterizations than those presented are discussed.

Methods are presented for the targeted extraction of surfactants present in atmospheric aerosols and the determination of their absolute concentrations and surface tension curves in water, including their Critical Micelle Concentration (CMC).

استخراج وتوصيف السطحي من الهباء الجوي

Surface-active compounds, or surfactants, present in atmospheric aerosols are expected to play important roles in the formation of liquid water clouds in ...

Data Processing Methods for 3D Seismic Imaging of Subsurface Volcanoes: Applications to the Tarim Flood Basalt

The morphology and structure of plumbing systems can provide key information on the eruption rate and style of basalt lava fields. The most powerful way to study subsurface geo-bodies is to use industrial 3D&#160;reflection seismological imaging. However, strategies to image subsurface volcanoes are very different from that of oil and gas reservoirs. In this study, we process seismic data cubes from the Northern Tarim Basin, China, to illustrate how to visualize sills through opacity rendering techniques and how to image the conduits by time-slicing. In the first case, we isolated probes by the seismic horizons marking the contacts between sills and encasing strata, applying opacity rendering techniques to extract sills from the seismic cube. The resulting detailed sill morphology shows that the flow direction is from the dome center to the rim. In the second seismic cube, we use time-slices to image the conduits, which corresponds to marked discontinuities within the encasing rocks. A set of time-slices obtained at different depths show that the Tarim flood basalts erupted from central volcanoes, fed by separate pipe-like conduits.

Three-dimensional (3D) reflection seismology is a powerful method for imaging subsurface volcanoes. By using industrial 3D seismological data from the Tarim Basin, we illustrate how to extract the sills and the conduits of subsurface volcanoes from seismic data cubes.

أساليب معالجة البيانات لتصوير السيزمية ثلاثية الأبعاد من البراكين تحت السطح: تطبيقات على البازلت الفيضانات تاريم

The morphology and structure of plumbing systems can provide key information on the eruption rate and style of basalt lava fields. The most powerful way ...

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using three recently developed experiments in which dust particles are exposed to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. The UV light source has a narrow bandwidth in wavelength centered at 172 nm. The beam electrons with the energy of 120 eV are created with a negatively biased hot filament. When the vacuum chamber is filled with the argon gas, a thermal plasma is created in addition to the electron beam. Insulating dust particles of a few tens of microns in diameter are used in the experiments. Dust particles are recorded to be lofted to a height up to a few centimeters with a launch speed up to 1 m/s. These experiments demonstrate that photo and/or secondary electron emission from a dusty surface changes the charging mechanism of dust particles. According to the recently developed &#34;patched charge model&#34;, the emitted electrons can be re-absorbed inside microcavities between neighboring dust particles below the surface, causing the accumulation of enhanced negative charges on the surrounding dust particles. The repulsive forces between these negatively charged particles may be large enough to mobilize and lift them off the surface. These experiments present the advanced understanding of dust charging and transport on dusty surfaces, and laid a foundation for future investigations of its role in the surface evolution of airless planetary bodies.

Dust charging and mobilization is demonstrated in three experiments with exposure to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. These experiments present the advanced understanding of electrostatic dust transport and its role in shaping the surfaces of airless planetary bodies.

طرق تجريبية من الغبار الشحن والتعبئة على الأسطح مع التعرض للأشعة فوق البنفسجية أو البلازما

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using ...

Determination of the Settling Rate of Clay/Cyanobacterial Floccules

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.

The interaction and sedimentation of the clay and bacterial cells within the marine realm, observed in natural environments, can be best investigated in a controlled lab environment. Here, we describe a detailed protocol, which outlines a novel method for measuring the sedimentation rate of clay and cyanobacterial floccules.

تحديد معدل تسوية الطين/سيانوباكتيريال فلوككوليس

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction ...

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ocean temperatures and ocean acidification, corals are increasingly under threat. To tackle these challenges, advances in cell and molecular biology have proven to be crucial for diagnosing the health of corals. Modifying some of the techniques commonly used in human medicine could greatly improve researchers&#39; ability to treat and save corals. To address this, a protocol for in situ hybridization used primarily in human medicine and evolutionary developmental biology has been adapted for use in adult corals under stress.
The purpose of this method is to visualize the spatial expression of an RNA probe in adult coral tissue that has been embedded in paraffin and sectioned onto glass slides. This method focuses on removal of the paraffin and rehydration of the sample, pretreatment of the sample to ensure permeability of the sample, pre-hybridization incubation, hybridization of the RNA probe, and visualization of the RNA probe. This is a powerful method when using non-model organisms to discover where specific genes are expressed, and the protocol can be easily adapted for other non-model organisms. However, the method is limited in that it is primarily qualitative, because expression intensity can vary depending on the amount of time used during the visualization step and the concentration of the probe. Furthermore, patience is required, as this protocol can take up to 5 days (and in many cases, longer) depending on the probe being used. Finally, non-specific background staining is common, but this limitation can be overcome.

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

The goal of this protocol is to perform in situ hybridization on adult coral samples that have been embedded in paraffin and sectioned onto glass slides. This is a qualitative method used to visualize the spatial expression of an RNA anti-sense probe in paraffin-embedded tissues.

في الموقع تقنيات التهجين لعينات المرجان الكبار جزءا لا يتجزأ من البارافين

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ...

Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only recently have microplastics in freshwater systems, such as rivers and lakes, been quantified. Microplastic sampling at the surface usually consists of deploying drift nets behind either a stationary or moving boat, which limits the sampling to environments with low levels of suspended sediments and floating or submerged debris. Previous studies that employed drift nets to collect microplastic debris typically used nets with &#8805;300 &#181;m mesh size, allowing plastic debris (particles and fibers) below this size to pass through the net and elude quantification. The protocol detailed here enables: 1) sample collection in environments with high suspended loads and floating or submerged debris and 2) the capture and quantification of microplastic particles and fibers &lt;300 &#181;m. Water samples were collected using a peristaltic pump in low-density polyethylene (PE) containers to be stored before filtering and analysis in the lab. Filtration was done with a custom-made microplastic filtration device containing detachable union joints that housed nylon mesh sieves and mixed cellulose ester membrane filters. Mesh sieves and membrane filters were examined with a stereomicroscope to quantify and separate microplastic particulates and fibers. These materials were then examined using a micro-attenuated total reflectance Fourier transform infrared spectrometer (micro ATR-FTIR) to determine microplastic polymer type. Recovery was measured by spiking samples using blue PE particulates and green nylon fibers; percent recovery was determined to be 100% for particulates and 92% for fibers. This protocol will guide similar studies on microplastics in high velocity rivers with high concentrations of sediment. With simple modifications to the peristaltic pump and filtration device, users can collect and analyze various sample volumes and particulate sizes.

Most microplastic research to date has occurred in marine systems where suspended solid levels are relatively low. Focus is now shifting to freshwater systems, which may feature high sediment loads and floating debris. This protocol addresses collecting and analyzing microplastic samples from aquatic environments that contain high suspended solid loads.

أخذ العينات، والفرز، وتميز ميكروبلاستيكس في البيئات المائية مع أحمال الرواسب المعلقة عالية وكبيرة من الحطام العائم

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only ...

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

A flow-through device for using the biodeposition method to quantify filtration and feeding behavior of bivalve mollusks was modified for shipboard use. A two-dimensional gimbal table built around the device isolates the apparatus from boat motion, thereby allowing the accurate quantification of bivalve filtration variables at offshore shellfish aquaculture sites.

تصميم واستخدام جهاز لتحديد كمية التغذية تعليق ذات الصدفتين في البحر

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves ...

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

Earth-abundant minerals play important roles in the natural hydrothermal systems. Here, we describe a reliable and cost-effective method for the experimental investigation of organic-mineral interactions under hydrothermal conditions.

وضع بروتوكول تجريبي لدراسة الآثار المعدنية على التحولات الحرارية المائية العضوية

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