Winogradsky Column

<div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJVtowYaEQ7Ixchhk6UaBS3aVzx6lwvGuuIuAnFmFaEtCr1eToWcfVbAKLWxIHkwJIV6wXAhDQBxab0pn9cdH82ZCXsU6EumdK1s3F-cCsijFO6aw8D6KNZkV5MEuPgrR1cCDJwWodVTg2/s1600/winogradsky+coumn.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="293" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJVtowYaEQ7Ixchhk6UaBS3aVzx6lwvGuuIuAnFmFaEtCr1eToWcfVbAKLWxIHkwJIV6wXAhDQBxab0pn9cdH82ZCXsU6EumdK1s3F-cCsijFO6aw8D6KNZkV5MEuPgrR1cCDJwWodVTg2/s400/winogradsky+coumn.png" width="400" /></a></div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> Freshwater sample extracted from a pond is taken into a glass cylinder. As it is made of glass, light is able to penetrate through it. It is kept for few weeks further observations. After few weeks, a mud layer deposit at the bottom of the cylinder. As a result of microbial activities, separation of layers in the water column can be seen.<o:p></o:p></div> <div class="MsoNormal">                                                               At the beginning, aerobic respiratory organisms are taken place. They consume the large amount of organic matter present in the bottom mud layer. As they use oxygen as their terminal electron acceptor in their electro transport chains, oxygen in the mud layer is depleted. Then fermentative microorganisms become active. <i>Clostridium</i> is the one of fermentative bacteria that is active in the mud under anaerobic conditions. They use as cellulose as their substrate and produce alcohols, acids and aldehydes as their byproducts. After that anaerobic microorganisms are active. They use fermentative byproducts as their substrate in the anaerobic respirations. They use sulfate as their terminal electron acceptor in their electro transport chains. So they convert sulfate ions into hydrogen sulfide. Hydrogen sulfide reacts with iron (II) in the mud. As a result of this reaction ferrous sulfide is produced. It gives a black to the mud. Since Hydrogen sulfide is gas, it moves upward of the water column. <o:p></o:p></div> <div class="MsoNormal">                                                               Green sulfur bacteria live in the layer just above the mud. They are shown in green color due to the color of photosynthetic pigments.  The method of ATP synthase of them is photosynthesis. As the light penetrates through the water column, they are able to do photosynthesis. They use hydrogen sulfide as their electro donor to fulfill the electro deficiency in the chlorophyll. So oxidation of hydrogen sulfide give an electron the chlorophyll and convert into sulfur.  Sulfur is deposited in their cells. Reaming hydrogen sulfide moves further upward.<o:p></o:p></div> <div class="MsoNormal">                                                               Purple sulfur bacteria live in the layer just above the green sulfur bacteria. They are unable to live in bottom area where the concentration of hydrogen sulfide is high. because high concentration of hydrogen sulfide are toxic and able to kill them. They are shown in purple color due the color of their photosynthetic pigments. Their method of ATP synthase is photosynthesis and use hydrogen sulfide as their electron donor in chlorophyll. Oxidation of hydrogen sulfide fills the electron deficiency in chlorophyll and converts into sulfur. Sulfur deposit in their cells.  Reaming hydrogen sulfide reaches to the surface layer.<o:p></o:p></div> <div class="MsoNormal">                                                      In the surface layer of the water column, oxygen is highly available. Therefore Aerobic respiratory microorganisms are abundant there. So sulfur oxidizing bacteria like <i>Thiobacillus thioxidans</i> live there. They are also called as Chemolithropic organism those who use oxidation of inorganic substrate to synthesis ATP. They use hydrogen sulfide as their substrate and produce ATP.  The oxidation of hydrogen sulfide gives electrons to run an electron chain so hydrogen sulfide is converted into sulfate ions.  Sulfate ions are highly soluble in the water.  Dissolved sulfate ions come to the bottom mud layer. Again   Sulfate is used as terminal electron acceptor by anaerobic respiratory microorganisms and release hydrogen sulfide.<o:p></o:p></div> <br /> <div class="MsoNormal">                                                      Therefore all the activities taken place in the water column are interrelated.  Product or byproducts of a reaction become substrate of electron donor or terminal electron acceptor of other reactions. <o:p></o:p></div> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-65880709-1', 'auto'); ga('send', 'pageview'); </script>

Winogradsky Column

Freshwater sample extracted from a pond is taken into a glass cylinder. As it is made of glass, light is able to penetrate through it...

Read more »