Winogradsky Columns

Acidic column (column A) and column with an alternative source of sulfur (column B)

Team; Cheiladakis Emmanouel, Grizi Olga,Varoucha Effrosyni  

Sampling

Sampling was carried out at Koronisia, Amvrakikos Bay (Greece) on 20/10/2017. Three columns were made; one as the control, one with low pH (pH=3), and the last one containing an alternative source of sulfur (rice). The nutrients used are presented below:

	Control column	Column Α	Column Β
Egg (sulfur source)	25 g	25g	-
Newspaper (Carbon source)	1 g	1 g	1 g
Mud	1/3 of the bottle	1/3 of the bottle	1/3 of the bottle
Mud with added nutrients	1/3 of the bottle	1/3 of the bottle	1/3 of the bottle
Lagoon Water (pH=8.5)	350 ml	350 ml	350 ml
Lemon Juice (pH=3)	-	100 ml	-
Rice (sulfur source)	-	-	150 g

.The rest of the bottle stayed empty, in order for aerobic bacteria to grow             

After the sampling process, the columns were placed in an accessible by light spot, at room temperature. The duration of the experiment was approximately 3 months. Through this period the columns were compared by the appearance of colour layers.

Pic.1; Typical colour zones due to bacterial growth in a Control Winogradsky column.

Hypotheses

1. In column A, pH value was stabilized at 3, where fermentation is not expected to occur in the lower layers as the fermentation bacteria (e.g Clostridium) cannot survive. As a result there is no carbon acids (which are produced by Clostridium) for sulfate-reducing bacteria to grow. This prevents or reduces the appearance of the upper layers. Also, due to the acidic environment, neither cyanobacteria will grow. In this case, no colour pattern is expected.

2. The same amount of sulfur was added in column B, using rice as a source, and if bacteria use it in the same way, we do not expect significant differences in the colour pattern between the control and the column B. 

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  Pic.2; Hypothesis A- What is expected to happen in the acidic column

Results

A.Hypothesis accepted; there was no zone observation because acidic pH prevented the growth of the expected micro-organisms.

B.Hypothesis rejected; there was also no zone observation, so it was proven that bacteria don’t use the sulfur from the rice in the same way they use it from the egg.

It needs to be clarified, though, that there is a possibility low pH or rice as a sulfur source just delayed the growth process and not completely prevents it. So in order to be absolutely sure of the result, observation for a longer period is essential.

Phases of the experiment

ü   In every photo column B is at left,control column is in the middle and column A is at right.

Pic.3; Winogradsky columns- Day 1

Pic. 4; Winogradsky columns- After 2 months

Pic.5; Winogradsky Columns- Final Phase

Yeast enriched and water bath Winogradsky Columns

Students: Bakratsas Georgios , Nikolaou Tasos  
Department of Biological Applications and Technologies, University of Ioannina

Experimental course

Sampling for the construction of the Winogradsky column took place on 20/10/2017 in the Koronissia region on the Gulf of Amvrakikos. After collecting the necessary amount of sludge (for 3 Winogradsky columns), it was enriched with the following nutrients:

• 3 g CaCO3

• 3 g CaSO4

• 3/4 of the newspaper page

• 3 eggs

• 12 g of onion-garlic mixture.

It is noted that a small amount of sludge was not enriched with nutrients to form the upper layer of the Winogradsky columns.

Our team constructed 3 columns, which were filled with 3/5 sludge, 1/5 water from the lagoon and 1/5 air. From the three columns one was the control and was placed at room temperature near a window (access to solar radiation ), the second identical to the control was placed in a water bath at a temperature of 50-55 ° C while the third was enriched with 8 g of activated yeast in the sludge layer and placed at room temperature near a window.

The second and third columns will be compared to the control.

Experimental hypotheses

1. The column placed in the water bath is expected to have less microbial variation due to the effect of temperature, which only allows the development of heat-resistant micro-organisms.

2. Larger microbial diversity is expected in the yeast column since, with the introduction of yeast, the production of alcohol which is a nutrient of the sulfur-reducing bacteria is accelerated. Therefore, the sulfur cycle is enhanced by increasing the populations of micro-organisms affected by it.

Results

At the time being, the experiment is not in a stage in which we can gather sufficient data about the bacteria in order to conclude a specific result.

Over the course of two months, we only observed a small bacterial growth in the control Winogradsky column in the upper sludge layer. In particular, the developed bacteria had a reddish color which lead us to the assumption that they belonged to the purple non-sulfur bacteria. Apart from the bacteria, there was a development of a white Fungi in the upper layer. Regarding the second and the third column, there was no observable bacterial development.

 As far as the hypotheses are concerned, both of them were rejected since neither the addition of yeast did accelerate the bacterial growth (more bacterial growth in the control) nor the amount of time for the processing of the experiment was enough for the development of heat-resistant micro-organisms (no comparison with the control is available).

Picture 1 Winogradsky columns first day

  

 Picture 2 Purple bacteria and white Fungi in Control