מארק נורדהוף סייע בתכנון ויישום של חיבורי צינורות. אלן שטרובה עזרה כדי לבחור ולרכוש ציוד המשמש.

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המחברים אין לחשוף.

קהילות מיקרוביאלי באוקיינוס ​​Precambrian הוסדרו על ידי, או שונות כתוצאה, פעילותם ואת התנאים גיאוכימיים רווחים. בפרשו את מקורותיה של BIF, חוקרים בדרך כלל להסיק את קיומו או אי פעילות של מיקרואורגניזמים על בסיס סדימנטולוגיה או גיאוכימיה של BIF, למשל, סמית et al. 23...

Precambrian (4.6 כדי 0,541 Gy לפני) האווירה חוו הצטברות הדרגתית של חמצן photosynthetically מיוצר (O 2), אולי מלווה שינויים צעד לעבר &quot;אירוע חמצון הגדול&quot; כביכול (Goe) בכ 2.4 Gy לפני, ו שוב נאופרוטרוזואיקון (לפני 1 כדי 0,541 Gy) כמו O אטמוספרי 2 ניגש 1 רמות מודרניות. כחוליות הם השרידים האבולוציונית של אורגניזמים הראשון המסוגל חמצנית הפוטוסינתזה 2. מחקרים ראיות ודגימת גיאוכימיות לתמוך תפקיד בסביבות החוף רדוד מחסה קהילות פעילות של כחוליות או אורגניזמים המסוגלים פוטוסינתזה חמצנית או phototrophs חמצנית, יצירת נאות מדבר חמצן המקומית באוקיינוס ​​השטח מתחת אווירה anoxic בעיקר 3-5. בתצהיר של תצורות ברזל טריטון (BIFs) ממי ים ברחבי נקודות Precambrian לברזל (II) (Fe (II)) כמו ג גיאוכימיים גדולonstituent של מי ים, ולו ברמה מקומית, במהלך בתצהיר שלהם. חלק BIFs הגדול הם פיקדונות מים עמוקים, ויצר ממדף המדרון קונטיננטלית. כמות Fe שהופקדה אינה עולה בקנה אחד מבחינת מאזן מסה עם קונטיננטלית בעיקר (כלומר, בליה) מקור. לכן, חלק גדול מן Fe בוודאי שסופקו שינוי הידרותרמיות של קרקעית הים mafic או ultramafic קרום 6. אומדני השיעור של Fe שהופקדו סירה של בסביבות החוף עולה בקנה אחד עם Fe (II) שסופק אוקיינוס ​​השטח באמצעות גאות 7. על מנת Fe להיות מועברת בזרמי גאות, חייבים להיות נוכח הצורה המצומצמת, ניידת - כמו Fe (II). מדינת החמצון הממוצעת של Fe נשמרה BIF היא 2.4 8 וזה מקובל לחשוב BIF לשמר Fe שהופקד החל Fe (III), נוצר כאשר גאות Fe (II) היה מחומצן, ככל הנראה על ידי חמצן. לכן, היכרות עם פוטנציאל Fe (II) מנגנוני חמצון לאורך המדרון environments חשוב להבין איך BIF נוצר. יתר על כן, אפיון גיאוכימיים מעודן של משקעים ימיים זיהה כי תנאי ferruginous, שבו Fe (II) נכח עמודת מי anoxic תפסו חלק מתמשך של האוקיינוסים ברחבי Precambrian, וייתכן שלא היה מוגבלים רק על הזמן והמקום שם BIF הופקד 9. לכן, לפחות שני מיליארדים שנים של ההיסטוריה של כדור הארץ, ממשקי חיזור בין Fe (II) ו- O 2 באוקיינוסים הרדודים היו דבר שבשגרה סבירה. מחקרים רבים לנצל אתרים מודרניים שהנם אנלוגים כימיים ו / או ביולוגיים של תכונות שונות של אוקיינוס ​​Precambrian. דוגמא טובה לכך הן אגמי ferruginous שבו Fe (II) הוא יציב ובהווה במי משטח שטוף שמש תוך פעילות פוטוסינתזה (לרבות על ידי כחוליות) זוהה 10-13. תוצאות מחקרים אלה מספקים תובנה מאפיינים גיאוכימיים מיקרוביאלי של oxic כדי anoxic / ferchemocline ruginous. עם זאת באתרים אלה הנם מרובדת בדרך כלל פיסיים עם אנכים קצת ערבוב 14, ולא הממשקים הכימיים המתרחשים במערכת גאות, והם חשבו לתמוך בייצור החמצן ביותר Precambrian זמן 4. אנלוג טבעי כדי לחקור את הפיתוח של נווה מדבר חמצן ימי מתחת אווירת anoxic, ותמורת Fe (II) מערכת גאות -rich בטור מים עיליים שטוף שמש אינו זמינה על כדור הארץ המודרנית. לכן, מערכת במעבדה שיכול לדמות אזור הגאות ferruginous וגם לתמוך בצמיחה של כחוליות ו photoferrotrophs נדרשת. ההבנה וההזדהות של תהליכים מיקרוביאליים האינטראקציה שלהם עם בתווך מימי גאות המייצג ים Precambrian מקדם את ההבנה יכול להשלים את המידע שנצבר מהרשומה רוק כדי להבין את התהליכים biogeochemical ייחודי מלא על פני כדור הארץ הקדום. </p&gt; לצורך מטרה זו, טור מעבדה בקנה מידה נועד שבו Fe (II) -rich בינוני הים (pH הניטראלי) נשאב לתוך החלק התחתון של הטור, ו נשאב החוצה מהחלק העליון. תאורה סופק בראש כדי ליצור &quot;אזור photic&quot; 4 ס&quot;מ רוחב שתמכו בצמיחת של כחוליות ב -3 ס&quot;מ העליון. סביבות טבעיות הן מרובדת והתייצב בדרך כלל על ידי מילויים physicochemical, כמו מליחות או טמפרטורה. על מנת לייצב את עמוד מים על בקנה מידת מעבדה, צילינדר הטור ארוז עם מטריקס חרוז זכוכית נקבובי שעזר לשמור על הקמת תבניות גיאוכימיים שהתפתחו במהלך הניסוי. זרם גז רציף N 2 / CO 2 יושם כדי לשטוף האמיץ של הטור על מנת לשמור על אווירת anoxic רעיונית של אוקיינוס ​​לפני Goe 15. לאחר זרימה מתמדת של Fe (II) הוקמה, כחוליות היו מחוסנות לאורך הטור, ו growt שלהםח היה פיקוח על ידי ספירת תאים על דגימות הוסרו דרך נמלי דגימה. חמצן היה פיקוח באתרו על ידי הצבת רדידי optode רגיש חמצן על הקיר הפנימי של הטור גליל המדידות נעשו עם סיב אופטי מבחוץ הטור. התפצלות המימייה Fe הייתה לכמת ידי דגימות הסרה מנמלי דגימה אופקיות נפתר עומק ונותחה עם שיטת Ferrozine. הניסויים השליטים אביוטי והתוצאות להפגין הוכחה של קונספט - כי אנלוגי בקנה מידה מעבדתי של עמודת מים העתיקה, שמרו בבידוד מהאטמוספרה, הוא בר השגה. כחוליות גדלות ויוצר חמצן, והתגובות בין Fe (II) והחמצן היו פתירות. בזאת, מתודולוגיה עיצוב, הכנה, הרכבה, ביצוע, ודגימה של טור כזה מוצגת, יחד עם תוצאות ריצת 84 שעות של הטור בעוד מחוסן עם sp Synechococcus cyanobacterium הימי. PCC 7002.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Widdel flask (5 L)</td>
			<td>Ochs</td>
			<td>110015</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Glass bottles (5 L)</td>
			<td>Rotilabo</td>
			<td>Y682.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Glass pipettes (5 mL)</td>
			<td></td>
			<td>51714</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>0.22 &#181;m Steritop filter unit (0.22&#160;&#181;m Polyethersulfone membrane)</td>
			<td>Millipore</td>
			<td>X337.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Aluminum foil</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile Luer Lock glass syringe, filled with cotton</td>
			<td></td>
			<td>C681.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock stainless steel needles (150 mm, 1.0 mm ID)</td>
			<td></td>
			<td>201015</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma</td>
			<td>433209</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Sigma</td>
			<td>208094</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma</td>
			<td>C4901</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>NH4Cl</td>
			<td>Sigma</td>
			<td>A9434</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>P5655</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>KBr</td>
			<td>Sigma</td>
			<td>P3691</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>P9541</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Glass cylinder</td>
			<td></td>
			<td>Y310.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Glass wool</td>
			<td></td>
			<td>7377.2</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Glass beads (&#248; 0.55 - 0.7&#160;mm)</td>
			<td></td>
			<td>11079105</td>
			<td>biospec.com</td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (&#248; 1.2 cm)</td>
			<td></td>
			<td>271024</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Petri Dish, glass (&#248; 8.0 cm)</td>
			<td></td>
			<td>T939.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Polymers glue</td>
			<td></td>
			<td>OTTOSEAL S68</td>
			<td>adchem.de</td>
		</tr>
		<tr>
			<td>Optical oxygen sensor foil (for oxygen analysis, see below)</td>
			<td></td>
			<td>&#8211; on request &#8211;</td>
			<td>presens.de</td>
		</tr>
		<tr>
			<td>Rubber tubing (35 mm, 7 mm ID)</td>
			<td></td>
			<td>770350</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (3.0 mm, luer lock male = LLM)</td>
			<td></td>
			<td>P343.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (3.0 mm, luer lock female = LLF)</td>
			<td></td>
			<td>P335.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Rubber tubing (25 mm, 0.72 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Rubber tubing (50 mm, 7 mm ID)</td>
			<td></td>
			<td>770350</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Luer Lock stainless steel needle (150 mm, 1.0 mm ID)</td>
			<td></td>
			<td>201015</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Luer Lock glass syringe (10 mL)</td>
			<td></td>
			<td>C680.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Loose cotton&#160;</td>
			<td></td>
			<td>&#8211;</td>
			<td></td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (&#248; 1.75 cm)</td>
			<td></td>
			<td>271050</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Stainless steel needle (40 mm, 1.0 mm ID)</td>
			<td>Sterican</td>
			<td>4665120</td>
			<td>bbraun.de</td>
		</tr>
		<tr>
			<td>Luer Lock stainless steel needle (150 mm, 1.5 mm ID)</td>
			<td></td>
			<td>201520</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>position: Luer Lock female connector part at C.7</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Polymers glue</td>
			<td></td>
			<td>OTTOSEAL S68</td>
			<td>adchem.de</td>
		</tr>
		<tr>
			<td>Stainless steel needle (120 mm, 0.7 mm ID)</td>
			<td>Sterican</td>
			<td>4665643</td>
			<td>bbraun.de</td>
		</tr>
		<tr>
			<td>Rubber tubing (40 mm, 0.74 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Heat shrink tubing (35 mm, 3 mm ID shrunk)</td>
			<td></td>
			<td>541458 - 62</td>
			<td>conrad.de</td>
		</tr>
		<tr>
			<td>Tube clamp</td>
			<td></td>
			<td>STHC-C-500-4</td>
			<td>tekproducts.com</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (1.0 mm, LLF)</td>
			<td></td>
			<td>P334.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock plastic cap (LLM)</td>
			<td></td>
			<td>CT69.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Glass bottle (5 L)</td>
			<td>Rotilabo</td>
			<td>Y682.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (for GL45)</td>
			<td></td>
			<td>444704</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Stainless steel capillary (300 mm, 0.74 mm ID)</td>
			<td></td>
			<td>56736</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Stainless steel capillary (50 mm, 0.74 mm ID)</td>
			<td></td>
			<td>56737</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Shrink tubing (35 mm, 3 mm ID shrunk)</td>
			<td></td>
			<td>541458 - 62</td>
			<td>conrad.de</td>
		</tr>
		<tr>
			<td>Rubber tubing (100 mm, 0.74 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (1.0 mm, LLF)</td>
			<td></td>
			<td>P334.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock glass syringe (10 mL)</td>
			<td></td>
			<td>C680.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Loose cotton&#160;</td>
			<td></td>
			<td>&#8211;</td>
			<td></td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (&#248; 1.75 cm)</td>
			<td></td>
			<td>271050</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Stainless Steel needle (40 mm, 0.8 mm ID)</td>
			<td>Sterican</td>
			<td>4657519</td>
			<td>bbraun.de</td>
		</tr>
		<tr>
			<td>Luer Lock glass syringe (5 mL)</td>
			<td></td>
			<td>C679.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (&#248; 1.75 mm)</td>
			<td></td>
			<td>271050</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Stainless steel needle (40 mm, 0.8 mm ID)</td>
			<td>Sterican</td>
			<td>4657519</td>
			<td>bbraun.de</td>
		</tr>
		<tr>
			<td>Rubber tubing (40 mm, 0.74 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Glass bottle (2 L)</td>
			<td>Rotilabo</td>
			<td>X716.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Butyl rubber stopper (for GL45)</td>
			<td></td>
			<td>444704</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Stainless steel capillary (50 mm, 0.74 mm ID)</td>
			<td></td>
			<td>56736</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Rubber tubing (30 mm x 0.74 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Rubber tubing (100 mm x 0.74 mm ID)</td>
			<td></td>
			<td>2600185</td>
			<td>newageindustries.com</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (1.0 mm, LLF)</td>
			<td></td>
			<td>P334.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock 3-way connector (LLF, 2x LLM)</td>
			<td></td>
			<td>6134</td>
			<td>cadenceinc.com</td>
		</tr>
		<tr>
			<td>Light source</td>
			<td>Samsung</td>
			<td>SI-P8V151DB1US</td>
			<td>samsung.com</td>
		</tr>
		<tr>
			<td>Peristalic pump</td>
			<td>Ismatec</td>
			<td>EW-78017-35</td>
			<td>coleparmer.com</td>
		</tr>
		<tr>
			<td>Pumping tubing (0.89 mm ID)</td>
			<td></td>
			<td>EW-97628-26</td>
			<td>coleparmer.com</td>
		</tr>
		<tr>
			<td>Stainless steel capillary (200 mm, 0.74 mm ID)</td>
			<td></td>
			<td>56736</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Stainless steel capillary (400 mm, 0.74 mm ID)</td>
			<td></td>
			<td>56737</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Supel-Inert Foil (Tedlar - PFC) gas pack (10 L)</td>
			<td></td>
			<td>30240-U</td>
			<td>sigmaaldrich.com</td>
		</tr>
		<tr>
			<td>Rubber tube (30 mm, 6 mm ID)</td>
			<td></td>
			<td>770300</td>
			<td>labor-ochs.de</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (3.0 mm, LLM)</td>
			<td></td>
			<td>P343.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Luer Lock tube connector (3.0 mm, LLF)</td>
			<td></td>
			<td>P335.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Gas-tight syringe (20 mL)</td>
			<td></td>
			<td>C681.1</td>
			<td>carlroth.com</td>
		</tr>
		<tr>
			<td>Bunsen burner</td>
			<td></td>
			<td>&#8211;</td>
			<td></td>
		</tr>
		<tr>
			<td>Fiber optic oxygen meter for oxygen quantification</td>
			<td>Presens</td>
			<td>TR-FB-10-01</td>
			<td>presens.de</td>
		</tr>
		<tr>
			<td>Vacuum pump</td>
			<td></td>
			<td>&#8211;</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone glue for oxygen optodes</td>
			<td>Presens</td>
			<td>PS1</td>
			<td>presens.de</td>
		</tr>
	</tbody>
</table>

laboratory simulation of an iron(ii)-rich precambrian marine upwelling system to explore the growth of photosynthetic bacteria

רעיון קונבנציונלי להפקדה של כמה תצורות ברזל Banded Precambrian (BIF) ממשיך בהנחת ברזל שחור [Fe (II)] גא ממקורות הידרותרמיות באוקיינוס ​​Precambrian היה חמצון על ידי חמצן מולקולרי [O 2] המיוצר על ידי כחוליות. BIFs הבכור, שהופקדו לפני האירוע חמצון הגדול (Goe) בסביבות 2.4 מיליארד שנים (Gy) לפני, יכלו להיווצר על ידי חמצון ישירה של Fe (II) על ידי anoxygenic photoferrotrophs בתנאים anoxic. כשיטה לבדיקת דפוסי גיאוכימיים מינרלוגיות המתפתחים בתרחישים ביולוגיים שונים, עצבנו טור זרימה דרך אנכי ארוך 40 סנטימטר כדי לדמות Fe anoxic (II) -rich נציג מערכת גאות הימית של אוקיינוס ​​קדום בסולם מעבדה . הגליל היה ארוז עם מטריקס חרוז זכוכית נקבובי כדי לייצב את הדרגתיים גיאוכימיים, דגימות נוזל כימות ברזל יכול להילקח ברחבי עמודת המים. החמצן המומס היההלא פולשני לאתר באמצעות optodes מבחוץ. תוצאות מניסויים ביוטיים כי מעורב ונתיבים גאים של Fe (II) מלמטה, שיפוע אור ברור מלמעלה, ובהווה כחוליות בעמודת המים, עדות ברורה תכנית להקמת Fe (III) משקע מינרליים ופיתוח של chemocline בין Fe (II) ו- O 2. עמודה זו מאפשרת לנו לבחון את השערות להיווצרות של BIFs ידי culturing כחוליות (ובסופו של photoferrotrophs בעתיד) בתנאי Precambrian ימיים מדומים. יתר על כן אנו משערים כי מושג הטור שלנו מאפשר הסימולציה של סביבות כימיות ופיסיקליות שונות - כולל משקעים ימיים או אֲגַמִי רדודים.

ניסוי בקרה ניסויי שליטת אביוטי (10 ימים) הפגינו ריכוזי חמצן נמוכים בעקביות (O 2 &lt;0.15 מ&quot;ג / L) ללא תנודות משמעותיות Fe (II) -profile ברחבי עמודת המים הגאים. ההיווצרות של משקעים (כנרא...

Watch this Scientific Journal Video about Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria at JoVE.com

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

אנחנו מדומים מערכת גאות הימית ferruginous Precambrian בטור זרימה דרך אנכי בקנה מידה במעבדה. המטרה היתה להבין כיצד פרופילים גיאוכימיים של O 2 ו- Fe (II) להתפתח כפי כחוליות תוצרת O 2. התוצאות מראות על הקמת chemocline בשל Fe (II) חמצון ידי מיוצר photosynthetically O 2.

סימולצית מעבדה של הברזל (II) -rich Precambrian ימי גאות מערכת לחקור את הצמיחה של חיידקים פוטוסינתטיים

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

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

11.7K Views.  University of Tuebingen.  אנחנו מדומים מערכת גאות הימית ferruginous Precambrian בטור זרימה דרך אנכי בקנה מידה במעבדה. המטרה היתה להבין כיצד פרופילים גיאוכימיים של O 2 ו- Fe (II) להתפתח כפי כחוליות תוצרת O 2. התוצאות מראות על הקמת chemocline בשל Fe (II) חמצון ידי מיוצר photosynthetically O ...

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

A Fish-feeding Laboratory Bioassay to Assess the Antipredatory Activity of Secondary Metabolites from the Tissues of Marine Organisms

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with the goal of examining the ecological functions of secondary metabolites from the tissues of marine organisms. The result has been a progression of protocols that have increasingly refined the ecological relevance of the experimental approach. Here we present the most up-to-date version of a fish-feeding laboratory bioassay that enables investigators to assess the antipredatory activity of secondary metabolites from the tissues of marine organisms. Organic metabolites of all polarities are exhaustively extracted from the tissue of the target organism and reconstituted at natural concentrations in a nutritionally appropriate food matrix. Experimental food pellets are presented to a generalist predator in laboratory feeding assays to assess the antipredatory activity of the extract. The procedure described herein uses the bluehead, Thalassoma bifasciatum, to test the palatability of Caribbean marine invertebrates; however, the design may be readily adapted to other systems. Results obtained using this laboratory assay are an important prelude to field experiments that rely on the feeding responses of a full complement of potential predators. Additionally, this bioassay can be used to direct the isolation of feeding-deterrent metabolites through bioassay-guided fractionation. This feeding bioassay has advanced our understanding of the factors that control the distribution and abundance of marine invertebrates on Caribbean coral reefs and may inform investigations in diverse fields of inquiry, including pharmacology, biotechnology, and evolutionary ecology.

This bioassay employs a model predatory fish to assess the presence of feeding-deterrent metabolites from organic extracts of the tissues of marine organisms at natural concentrations using a nutritionally comparable food matrix.

מעבדה מבדק-האכלת דגים לבחינת פעילות Antipredatory של משני מטבוליטים מהרקמות של אורגניזמים ימיים

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with ...

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. 
This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Microbial sulfate reduction is a process of great importance in environmental biotechnology. The success of the sulfidogenic reactors depends among other factors on the microbial composition of the sludge. Here, we present a protocol to develop sulfidogenic sludge from hydrothermal vents sediments in a UASB reactor for reductive dechlorination purposes.

פיתוח של Sulfidogenic בוצה מים משקעים וטריכלוריטן הפחתה בכור שמיכת Upflow אנאירובית בוצה

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate ...

Spotting Cheetahs: Identifying Individuals by Their Footprints

The cheetah (Acinonyx jubatus) is Africa's most endangered large felid and listed as Vulnerable with a declining population trend by the IUCN1. It ranges widely over sub-Saharan Africa and in parts of the Middle East. Cheetah conservationists face two major challenges, conflict with landowners over the killing of domestic livestock, and concern over range contraction. Understanding of the latter remains particularly poor2. Namibia is believed to support the largest number of cheetahs of any range country, around 30%, but estimates range from 2,9053 to 13,5204. The disparity is likely a result of the different techniques used in monitoring.
Current techniques, including invasive tagging with VHF or satellite/GPS collars, can be costly and unreliable. The footprint identification technique5 is a new tool accessible to both field scientists and also citizens with smartphones, who could potentially augment data collection. The footprint identification technique analyzes digital images of footprints captured according to a standardized protocol. Images are optimized and measured in data visualization software. Measurements of distances, angles, and areas of the footprint images are analyzed using a robust cross-validated pairwise discriminant analysis based on a customized model. The final output is in the form of a Ward's cluster dendrogram. A user-friendly graphic user interface (GUI) allows the user immediate access and clear interpretation of classification results.
The footprint identification technique algorithms are species specific because each species has a unique anatomy. The technique runs in a data visualization software, using its own scripting language (jsl) that can be customized for the footprint anatomy of any species. An initial classification algorithm is built from a training database of footprints from that species, collected from individuals of known identity. An algorithm derived from a cheetah of known identity is then able to classify free-ranging cheetahs of unknown identity. The footprint identification technique predicts individual cheetah identity with an accuracy of &gt;90%.

The cheetah (Acinonyx jubatus) is an iconic, endangered species, but conservation efforts are challenged by habitat shrinkage and conflict with commercial farmers. The footprint identification technique, a robust, accurate and cost-effective image classification system, is a new approach to monitoring cheetahs.

בחינת ברדלסים: אנשי זיהוי על ידי עקביהם

The cheetah (Acinonyx jubatus) is Africa's most endangered large felid and listed as Vulnerable with a declining population trend by the IUCN1. It ranges ...

VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders

Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and detritus, and excreting particulate and dissolved compounds, they serve as important agents for benthic-pelagic coupling. Accurately measuring the compounds removed and excreted by suspension feeders (such as sponges, ascidians, polychaetes, bivalves) is crucial for the study of their physiology, metabolism, and feeding ecology, and is fundamental to determine the ecological relevance of the nutrient fluxes mediated by these organisms. However, the assessment of the rate by which suspension feeders process particulate and dissolved compounds in nature is restricted by the limitations of the currently available methodologies. Our goal was to develop a simple, reliable, and non-intrusive method that would allow clean and controlled water sampling from a specific point, such as the excurrent aperture of benthic suspension feeders, in situ. Our method allows simultaneous sampling of inhaled and exhaled water of the studied organism by using minute tubes installed on a custom-built manipulator device and carefully positioned inside the exhalant orifice of the sampled organism. Piercing a septum on the collecting vessel with a syringe needle attached to the distal end of each tube allows the external pressure to slowly force the sampled water into the vessel through the sampling tube. The slow and controlled sampling rate allows integrating the inherent patchiness in the water while ensuring contamination free sampling. We provide recommendations for the most suitable filtering devices, collection vessel, and storing procedures for the analyses of different particulate and dissolved compounds. The VacuSIP system offers a reliable method for the quantification of undisturbed suspension feeder metabolism in natural conditions that is cheap and easy to learn and apply to assess the physiology and functional role of filter feeders in different ecosystems.

VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders

We introduce the VacuSIP, a simple, non-intrusive, and reliable method for clean and accurate point sampling of water. The system was developed and evaluated for the simultaneous collection of the water inhaled and exhaled by benthic suspension feeders in situ, to cleanly measure removal and excretion of particulate and dissolved compounds.

VacuSIP, שיטת INEX משופרת<em&gt; באתרו</em&gt; מדידה של חלקיקים מומס תרכובות מעובד על ידי האכלת השעית Active

Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and ...

Ecotoxicological Method with Marine Bacteria Vibrio anguillarum to Evaluate the Acute Toxicity of Environmental Contaminants

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food webs. Toxicity testing based on microorganisms are widely used because they are relatively quick, reproducible, cheap, and are not associated with ethical issues. Here, we describe an ecotoxicological method to evaluate the biological response of the marine bacterium Vibrio anguillarum. This method assesses the acute toxicity of chemical compounds, including new contaminants such as nanoparticles, as well as environmental samples. The endpoint is the reduction of bacterial culturability (i.e., the capability to replicate and form colonies) due to exposure to a toxicant. This reduction can be generally referred to as mortality. The test allows for the determination of the LC50, the concentration that causes a 50% decrease of bacteria actively replicating and forming colonies, after a 6 h exposure. The culturable bacteria are counted in terms of colony forming units (CFU), and the &#34;mortality&#34; is evaluated and compared to the control. In this work, the toxicity of copper sulphate (CuSO4) was evaluated. A clear dose-response relationship was observed, with a mean LC50 of 1.13 mg/L, after three independent tests. This protocol, compared to existing methods with microorganisms, is applicable in a wider range of salinity and has no limitations for colored/turbid samples. It uses saline solution as the exposure medium, avoiding any possible interferences of growth medium with the investigated contaminants. The LC50 calculation facilitates comparisons with other bioassays commonly applied to ecotoxicological assessments of the marine environment.

Ecotoxicological Method with Marine Bacteria Vibrio anguillarum to Evaluate the Acute Toxicity of Environmental Contaminants

This work describes a new protocol to assess the ecotoxicity of pollutants, including emerging contaminants such as nanomaterials, using the marine bacterium Vibrio anguillarum. This method allows for the determination of the LC50, or mortality, the concentration that causes a 50% decrease in bacteria culturability, after a 6 h exposure.

שיטה אקוטוקסיקולוגית עם חיידקים ימיים<em&gt; תזונת ויבריו</em&gt; כדי להעריך את רעילות חריפה של מזהמים סביבתיים

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food ...

Comparison of Scale in a Photosynthetic Reactor System for Algal Remediation of Wastewater

An experimental methodology is presented to compare the performance of two different sized reactors designed for wastewater treatment. In this study, ammonia removal, nitrogen removal and algal growth are compared over an 8-week period in paired sets of small (100 L) and large (1,000 L) reactors designed for algal remediation of landfill wastewater. Contents of the small and large scale reactors were mixed before the beginning of each weekly testing interval to maintain equivalent initial conditions across the two scales. System characteristics, including surface area to volume ratio, retention time, biomass density, and wastewater feed concentrations, can be adjusted to better equalize conditions occurring at both scales. During the short 8-week representative time period, starting ammonia and total nitrogen concentrations ranged from 3.1-14 mg NH3-N/L, and 8.1-20.1 mg N/L, respectively. The performance of the treatment system was evaluated based on its ability to remove ammonia and total nitrogen and to produce algal biomass. Mean &#177; standard deviation of ammonia removal, total nitrogen removal and biomass growth rates were 0.95&#177;0.3 mg NH3-N/L/day, 0.89&#177;0.3 mg N/L/day, and 0.02&#177;0.03 g biomass/L/day, respectively. All vessels showed a positive relationship between the initial ammonia concentration and ammonia removal rate (R2=0.76). Comparison of process efficiencies and production values measured in reactors of different scale may be useful in determining if lab-scale experimental data is appropriate for prediction of commercial-scale production values.

An experimental methodology is presented to compare the performance of small (100 L) and large (1,000 L) scale reactors designed for algae remediation of landfill wastewater. System characteristics, including surface area to volume ratio, retention time, biomass density, and wastewater feed concentrations, can be adjusted based on application.

השוואת סולם ב כור מערכת פוטוסינתזה משיקום אצות של שפכים

An experimental methodology is presented to compare the performance of two different sized reactors designed for wastewater treatment. In this study, ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

הפקת חומרי הדברה אורגנוכלורינים מפלסטיק וגלגול סוג פלסטיק

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell counts. Plant materials used include roots, sprouts, leaves, and cut fruits. The methods described are inexpensive, easy, and suitable for small sample sizes. Binding is measured in the laboratory and a variety of incubation media and conditions can be used. The effect of inhibitors can be determined. Situations that promote and inhibit binding can also be assessed. In some cases it is possible to distinguish whether various conditions alter binding primarily due to their effects on the plant or on the bacteria.

An easy method for measuring and characterizing bacterial adhesion to plants, particularly roots and sprouts, is described in this article.

דבקותה של חיידקים לשתול משטחים הנמדדים במעבדה

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Development of New Methods for Quantifying Fish Density Using Underwater Stereo-video Tools

The use of video camera systems in ecological studies of fish continues to gain traction as a viable, non-extractive method of measuring fish lengths and estimating fish abundance. We developed and implemented a rotating stereo-video camera tool that covers a full 360 degrees of sampling, which maximizes sampling effort compared to stationary camera tools. A variety of studies have detailed the ability of static, stereo-camera systems to obtain highly accurate and precise measurements of fish; the focus here was on the development of methodological approaches to quantify fish density using rotating camera systems. The first approach was to develop a modification of the metric MaxN, which typically is a conservative count of the minimum number of fish observed on a given camera survey. We redefine MaxN to be the maximum number of fish observed in any given rotation of the camera system. When precautions are taken to avoid double counting, this method for MaxN may more accurately reflect true abundance than that obtained from a fixed camera. Secondly, because stereo-video allows fish to be mapped in three-dimensional space, precise estimates of the distance-from-camera can be obtained for each fish. By using the 95% percentile of the observed distance from camera to establish species-specific areas surveyed, we account for differences in detectability among species while avoiding diluting density estimates by using the maximum distance a species was observed. Accounting for this range of detectability is critical to accurately estimate fish abundances. This methodology will facilitate the integration of rotating stereo-video tools in both applied science and management contexts.

We describe a new method for counting fishes, and estimating relative abundance (MaxN) and fish density using rotating stereo-video camera systems. We also demonstrate how to use distance from camera (Z distance) to estimate species-specific detectability.

פיתוח שיטות חדשות לכימות תנועת הדגים בצפיפות בכלים סטריאו-וידאו תת-מימי

The use of video camera systems in ecological studies of fish continues to gain traction as a viable, non-extractive method of measuring fish lengths and ...

The Barnacle Balanus improvisus as a Marine Model - Culturing and Gene Expression

Barnacles are marine crustaceans with a sessile adult and free-swimming, planktonic larvae. The barnacle Balanus (Amphibalanus) improvisus is particularly relevant as a model for the studies of osmoregulatory mechanisms because of its extreme tolerance to low salinity. It is also widely used as a model of settling biology, in particular in relation to antifouling research. However, natural seasonal spawning yields an unpredictable supply of cyprid larvae for studies. A protocol for the all-year-round culturing of B. improvisus has been developed and a detailed description of all steps in the production line is outlined (i.e., the establishment of adult cultures on panels, the collection and rearing of barnacle larvae, and the administration of feed for adults and larvae). The description also provides guidance on troubleshooting and discusses critical parameters (e.g., the removal of contamination, the production of high-quality feed, the manpower needed, and the importance of high-quality seawater). Each batch from the culturing system maximally yields roughly 12,000 nauplii and can deliver four batches in a week, so up to almost 50,000 larvae per week can be produced. The method used to culture B. improvisus is, probably, to a large extent also applicable to other marine invertebrates with free-swimminglarvae. Protocols are presented for the dissection of various tissues from adults as well as the production of high-quality RNA for studies on gene expression. It is also described how cultured adults and reared cyprids can be utilized in a wide array of experimental designs for examining gene expression in relation to external factors. The use of cultured barnacles in gene expression is illustrated with studies of possible osmoregulatory roles of Na+/K+ ATPase and aquaporins.

The Barnacle Balanus improvisus as a Marine Model - Culturing and Gene Expression

The barnacle Balanus (Amphibalanus) improvisus is a model for studying osmoregulation and antifouling. However, natural seasonal spawning yields an unpredictable supply of cyprid larvae. Here, a protocol for the all-year-round culturing of B. improvisus is described, including the production of larvae. The use of cultured barnacles in gene expression studies is illustrated.

זיפרגליים Balanus improvisus כמודל ימית - Culturing, ביטוי גנים

Barnacles are marine crustaceans with a sessile adult and free-swimming, planktonic larvae. The barnacle Balanus (Amphibalanus) improvisus is particularly ...