High-salinity Winogradsky column, 2017

Students: Niki Chondrelli, Steven Moschos 

Department of Biological Applications and Technologies, University of Ioannina

Experiment

We constructed two Winogradsky columns with mud and water from the lagoon in Koronisia, in 20th October 2017. We used newspaper as a carbon source and egg as a source of sulfur and carbonate ions. In one column we also added 50gr of salt to check how it would affect the growth of microorganisms. 

 

Hypothesis

We expect a delay in the bacterial growth in the salt-enriched column but similar colour patterns.

Our hypothesis is based on the fact that in every broad taxonomic group there are halophilic species, therefore no significant difference will be observed in the colour patterns. Possibly the diversity of the high-salinity column will be more limited, but this can not be deduced with simple observation, unless a group is completely absent. Also, due to the increased salinity, the number of microorganisms that survive and consequently grow in this column will be lower compared to the standard and therefore the formation of colonies will be delayed.

Results

Our hypothesis was rejected, since we observed the same rates of bacterial growth in both columns. This could be due to the fact that the mud we collected exhibited high salinity (about 80‰) so halophilic species were already abundant in it, and the addition of salt didn't significantly change their growth conditions.

As it can be seen in the pictures that follow, the colour patterns are similar in both columns throughout the experiment but the colour of the water differs (reddish in the standard column and muddy in the salt-enriched one).

Standard, 26/11/17

Salt, 26/11/17

Standard, 23/11/17

Salt, 23/11/17

Standard, 14/12/17

Salt, 14/12/17

Winogradsy column - Light efect Hipothesis

Four Winogradsy columns were constructed. (pictures from the columns can be found here:( https://drive.google.com/drive/folders/1PRv055DWphKSB6fsl9J6ypOXioezNHev?usp=sharing )

Researchers : George Kazantzidis , Giota Kontogeorgiou, Dimitris Papanikos. 

Department of Biological Applications and Technologies

Hypothesis: Using different color filters for each winogradsky column we expect different microorganisms growth depending on the color allowed in each column.

Materials and methods

Place of experiment

Mud was selected from Amvrakikos Lagoon western Greece (39° 0'25.69"Β, 20°55'7.19"Α) at 20/10/2017.

The weather was sunny and the place from which we gathered the mud was wet but not mumbled. The place is known for high eutrophic levels. Also Amvrakikos lagoon is polluted cause many rivers from Western Greece end to it, carrying a lot of fertilizers from crops.

Materials

Mud and water were taken from the lagoon. In the mud was added 2gr of cellulose (crushed paper) and calcium carbonate (one egg, whole).  The mud was mixed in order to homogenize. In each column (plastic bottle 1,5L) was filled 2/3 with mud (1L) and 1/3 with water(0,5L). one column was used as standard and the others for the Hypothesis. Each from the 3 columns was wrapped with plastic color filter membrane. The three membranes used were blue (450nm), red (680nm) and green (520nm). All four columns were placed in sunny place at marine biology lab (University of ioannina).

Results

Our first hypothesis was that in the standard column we will find all kinds of bacterial communities. By contrast, in the green column we expected to find only purple sulfur and non-sulfur bacteria in the middle of the column because they are the only ones that can use the green light for energy production. In the red column we expected to find green photosynthetic bacteria and not purple  bacteria (because purple bacteria does not absorb red light). In the blue column we expected to find all types of bacteria but in less abundance than in the standard column (blue light is absorbed by all kinds of photosynthetic bacteria). We do not expected changes in the non-photosynthetic bacteria communities. 

Two months after the construction of the column we do not observe any difference in our columns. We assume that is too early to have bacterial growth because the membrane filters reflect a large amount of light outside of the column.

One interesting result is at the water bacterial communities which are grown at all columns but with different microorganisms (observed with eyes) as they form different shapes of communities.