Micropara-Winogradsky Column Peregrino PDF

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Student HandoutHands-on ActivityWinogradsky Columns: MicrobialEcology in the ClassroomBioInteractive PublishedPage 12013 of 8Name: Peregrino, Joyce Ann P. Prof: Chastine CardenasSection: CON-1A Date: May 22, 2021WINOGRADSKYCOLUMNNewEraUniversityNo. 9 Central Avenue, New Era, Quezon City 1107, Philip...

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Hands-on Activity Winogradsky Columns: Microbial Ecology in the Classroom

Student Handout

New Er Eraa Unive University rsity No. 9 Central Avenue, New Era, Quezon City 1107, Philippines

College of Nursing CONMP-18-Microbiology and Parasitology 2nd Semester | S.Y. 2020-2021

Name: Peregrino, Joyce Ann P.

Prof: Chastine Cardenas

Section: CON-1A

Date: May 22, 2021

WINOGRADSKY COLUMN

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Published 2013 Page 1 of 8

Weekly Observations Observations During the Week Of: Week 0 Actual Date: 03/21/2021

Week 1 Actual Date: 03/29/2021

Week 2 Actual Date: 04/05/2021

Week 3 Actual Date: 04/12/2021

Control Column

Carbon Column

Sulfur Column

Carbon and Sulfur Column

Week 4 Actual Date: 04/19/2021

Week 5 Actual Date: 04/26/2021

Week 6 Actual Date: 05/03/2021

Week 7 Actual Date: 05/10/2021

Week 8 Actual Date: 05/17/2021

Hands-on Activity Winogradsky Columns: Microbial Ecology in the Classroom

Student Handout

QUESTIONS During the course of the experiment, spend some time considering the following questions. Some of these questions may require extra research. Feel free to consult a microbiology textbook (e.g., to learn about the sulfur cycle). 1. How do your columns differ? How are they the same? Explain the differences you see. 

As time goes on, each column makes a difference, as does its color change. Base on my observation, The control column did not change color, the carbon column turned pale blue green, as did the sulfur column, and the carbon+sulfur column turned darker blue green. They are the same in the way they undergo change over the day.

2. Did you observe changes in the control column? If so, explain why they occurred. 

Yes, Since the sediment contains natural forms of carbon, sulfur, and other nutrients, gradients can form in the control column. The same microbial processes will take place, but to a lesser degree (depending on the sediment source).

3. Winogradsky columns form oxygen concentration gradients. Predict the distribution of oxygen throughout the column. (Consider the entire column: the sediment, the water, and the air.) 

The oxygen gradient in the column grows over time, from high at the top to fully anoxic (no oxygen) at the bottom. The oxygen concentration is highest in the overlying air, and it decreases as you descend through the water and sediment to the bottom of the column. The oxygen is uniformly distributed in the column when it is prepared. Respiration consumes it in the column, but only the photosynthetic layer at the top produces it. Any oxygen from the topmost layer that diffuses down into the sediment interacts with chemical compounds in the anoxic layer.

4. Winogradsky columns form sulfide concentration gradients as well. In the columns that contain egg yolk, predict how sulfide will be distributed throughout the column. (Consider the entire column: the sediment, the water, and the air.) 

Sulfide concentrations would be greatest at the bottom (anoxic) of the column and decrease upward, with no sulfide present at the top of the sediment or in the surrounding water. Sulfur will be distributed throughout the column by mixing once it has been prepared. Anaerobic respiration converts sulfur to sulfide, which occurs only at the bottom of the column. Any sulfide that diffuses upward will react with oxygen (either abiotically or through microbial metabolism).

5. Sulfur reduction is a form of anaerobic respiration. Desulfovibrio are an example of bacteria that reduce sulfur as a way of respiring in the absence of oxygen and release sulfide. Where in the columns would you expect to find them? 

Desulfovibrio can be located near the bottom of the columns, where oxygen is scarce.

6. Purple sulfur bacteria and green sulfur bacteria are two types of bacteria that use sulfide to support photosynthesis. In general, green sulfur bacteria tolerate higher levels of sulfide than purple sulfur bacteria do. Predict where the green and purple sulfur bacteria would be in relation to each other. Also predict where in the column the purple sulfur bacteria would be in relation to the Desulfovibrio bacteria. 

Since there is less sulfide in the layer above the green sulfur bacteria, purple sulfur bacteria would be concentrated there. The green and purple sulfur bacteria will also be coated on top of the Desulfovibrio bacteria. Desulfovibrio can reduce sulfur, so they create sulfide, which helps green and purple sulfur bacteria to work. Desulfovibrio, on the other hand, do not need light and will be located lower in the column.

Hands-on Activity Winogradsky Columns: Microbial Ecology in the Classroom

Student Handout

7. If samples were extracted from the various layers of all the columns, where would you find photosynthetic organisms such as cyanobacteria and algae? Explain why. 

Since photosynthetic cyanobacteria and algae need only water, carbon dioxide, and light, which is most extreme at the top of the column, they would most likely be sampled from the water at the top of each column.

8. Explain how Winogradsky columns illustrate the diversity of microorganisms found on Earth today in terms of the diversity of niches they occupy. 

Depending on the availability of oxygen and other nutrients, different layers form in the column. Each of these layers is occupied by different groups of species, but they all came from the same original sample. This demonstrates that even in very common habitats, such as your backyard stream, there is a rich variety of species. In addition, the gradients are the product of microbial metabolism. This shows that microbes don’t only adapt to their surroundings; their metabolisms actually build chemical niches in them.

9. Explain what the Winogradsky columns illustrate about life on early Earth. 

Despite the fact that much of the strata in the columns are anoxic, life abounds. Similarly, the early atmosphere of earth lacked oxygen, but microfossils and geochemical evidence indicate that life existed everywere. A wide range of bacteria have evolved to survive in the absence of oxygen. Winogradsky columns are ecosystems in which the waste products of one group of organisms help another grow (e.g., Desulfovibrio produce sulfide,which supports the growth of green and purple sulfur bacteria). Microbes form the ecosystem in this way to provide ecological niches for other. Cyanobacteria are the species responsible for the oxygenation of Earth on a global scale. Larger and more complex life forms could only evolve after oxygen was accumulated (via photosynthesis).

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