Winoblog: SECOND POST. FIRST CHANGES ON COLUMNS

Winogradsky column lab page!

Welcome to the Winogradsky column lab page! Students from the Departments of Biological Applications and Technology, University of Ioannina and Icthyology and Aquatic Environment, University of Thessaly, Greece and the Microbiology course, Faculty of Sciences, University of Cádiz, Spain, discuss their findings on Winogradsky columns they constructed!

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Καλωσορίσατε στη σελίδα των Winobloggers! Διαδικτυακός τόπος συνάντησης φοιτητών, φοιτητριών και διδασκόντων δύο Τμημάτων από την Ελλάδα: Tμήμα Βιολογικών Εφαρμογών και Τεχνολογιών, Παν/μιο Ιωαννίνων και Τμήμα Γεωπονίας, Ιχθυολογίας και Υδάτινου Περιβάλλοντος, Παν/μιο Θεσσαλίας και ενός από την Ισπανία: Σχολή Θετικών Επιστημών, Πανεπιστήμιο του Cadiz. Παρακολουθούμε, σχολιάζουμε, ρωτάμε, απαντάμε σχετικά με τα πειράματά μας, τις στήλες Winogradsky!

Bienvenidos a la pagina web de los Winobloggers! Aquí los estudiantes y profesores de dos departamentos griegos, el Departamento de Aplicaciones y Tecnologías Biológicas de la Universidad de Ioannina y el Departmento de Agricultura, Ictiología y Sistemas Acuáticos de la Universidad de Thessalia, junto con los estudiantes de Microbiología de la Facultad de Ciencias en la Universidad de Cádiz, se reúnen para observar, comentar, preguntar y responder a preguntas relacionadas con nuestro experimento, la columna Winogradsky.

Monday 5 June 2017

SECOND POST. FIRST CHANGES ON COLUMNS

MICROORGANIMS ACTIVITY AND FIRST CHANGES ON WINOGRADSKY COLUMNS

23/03/2017

After 12 days we returned to the laboratory to see how the columns had progressed. We have to clarify that, by an error, the column that was planned to darkness conditions was put down to sunlight and vice versa. Based on the following potos, we are going to comment visual change that each column has experienced due to the different processes that have occurred.

At first glance, we can see a gradation of the colors depending on the preferences of each microorganism for a particular substrate, as well as, depending on the oxygen availability conditions. At greater depth less amount of oxygen.

If we focus on the bottom part we can see a difference between a lighter gray layer and a darker layer. The presence of this clear grayish layer shows the presence of fermenting microorganisms. In this layer we find microorganisms which are considered chymotrophs, that is to say, thet are able to use reduced inorganic compounds as substrates in order to obtain energy and usying it in the respiratory metabolism. In fact, this kind of microorganism were discovered by Winogradsky.

On the other hand, we can already see how the first methane bubbles appear throughout the column, as a result of cellular respiration or metabolism of microorganisms. We can also observe black spots due to iron sulfide (FeS), product of the following chemical reaction:

SO₄^-2+ Organic Matter ------> H₂S + CO₂

H₂S + Fe^{+2 ------>} FeS

A yellowish green color begins to appear on the Surface of the column that we brought to sunlight. This is due to the presence of aerobic sulfo-oxidizers, photosynthetic bacterias or Cianobacterias, and seeweeds which need sunlight to carry out Oxygen Photosynthesis.

As far as darkness column, can see that the surface has formed a thin layer of sediment. In a few weeks we will return to lab to check how columns have definitely changed.