Introduction
Prokaryotes (Bacteria and Archea) collectively encompass a taxonomic and a metabolic diversity that far exceeds that of plants and animals (the so-called ‘higher animals’). This week we will set up a model microbial ecosystem (a microcosm) called a Winogradsky column that will simply and elegantly demonstrate a cross section of that diversity.
Sergei Winogradsky (1856-1953) who, along with Martinus Willem Beijerinck developed the technique, was a pioneering Russian microbiologist who worked in the late 1800’s and early 1900’s, when microbiology was still a fledgling science. At a time when microbiological methods barely existed and most microbiologists focused on the ‘germ-theory’ of disease, the isolation of individual microbes and the characterization of ‘domesticated’ laboratory strains, Winogradsky focused on environmental microbiology and developed techniques for cultivating and studying complex microbial communities (such as the Winogradsky column). In so doing, he made great advances in our understanding of environmental microbiology, microbial diversity, microbial physiology, microbial autotrophy (the ability to obtain energy from non-organic substances) and environmental nutrient cycling (particularly sulfur and nitrogen cycling). He is considered one of the founding fathers of microbial ecology.
The Winogradsky column is a miniature, self-contained ecosystem that in many ways models ecological conditions found in a typical Michigan lake in late summer. Spring thaw results in a mixing of lake water so that the water is more or less uniform at different depths. As summer progresses gradients begin to form in the water column (light gradient, temperature gradient, nutrient, O2 and H2S concentration gradients). These gradients result in a complex interaction of microbes with their environment and with one another resulting in a series of community successions and, ultimately, stratification of microbial populations in the water column.
Similarly, the Winogradsky column begins as a uniform slurry of soil, mud or lake sediment and water (preferably from some outdoor source) supplemented with nutrients (carbon and sulfur). The ingredients are mixed into a uniform slurry, poured into a tall, transparant vessicle such as a test tube, graduated cylinder or soda bottle and exposed to sunlight to provide energy for the system and to enrich for both aerobic and anoxic photosynthetic bacteria. The sediment, soil and water serve as inocula of diverse microbial populations with diverse metabolic processes.
A series of gradients (e.g. oxygen, H2S) soon develop in the column as a result of bacterial metabolic processes. For example, aerobic photosynthetic organisms and exposure to the air will produce O2 near the top of the column which can then be used by other microbes for aereobic respiration. Similarly, sulfate reducers in the anoxic region near the bottom of the column will produce H2S, which can be used by H2S utilizers and anoxic phototrophs. Different organisms soon gain a competitive advantage in different regions of the column causing a stratification and continual regional succession of organisms. Because this culture system more closely resembles a natural environment than do traditional culture methods, a wider variety of physiological types can be observed than by the more standard culture methods. Also, different microbes will be concentrated (enriched) in specific regions of the column where local conditions are optimal for their particular growth (e.g areobes at the top in the oxic zone and anaerobes at the bottom, anoxic zone). Winogradsky columns demonstrate the interdependence of diverse microorganisms in complex communities for survival and growth. As such, variations in Winogradsky column ingredients and manipulations are as infinite as your imagination will allow. Virtually any microbial process could be studied with the correct design and initial inocula.
Materials and Methodology
Field Collected Sediment
Paper Towels (Carbon Source)
Chemical Sources: FeSO4, CaCO3, Nitrogen rich Fertilizer
Test Tubes, Salt Water
Procedure * Bolded steps have already been completed
Your lab table will make 4 different Winogradsky Columns which vary in type of additional materials to add in. 1) Control; 2) FeSO4; 3) CaCO3; and 4) Nitrogen Fertilizer
Maintaining the columns
Once constructed, the Winogradsky columns can be kept for months to years. The microbial communities can slowly change over time and making them interesting to continually observe. To maintain the columns and prevent them from drying out, periodically add water so there is a layer of water on top of the sediment mixture. During weekly observations and Thursday lectures ensure that a layer of water remains on your colums.
Safety
Soil samples used to build Winogradsky columns should generally only contain non-pathogenic microbes. However, it is always best to practice safe science. As such, students and teachers should be careful to not directly touch, consume, or inhale contents of the Winogradsky columns. When handling the Winogradsky columns, make sure lids are tightened and secure. However (and this is of equal importance), make certain not to store the columns with lids tightened. Columns must be stored with the lids loose. Gases produced by microorganisms can build up quickly and must be allowed to escape to avoid a build-up of pressure that may lead to column explosion.
Are you busy and do not have time to handle your assignment? Are you scared that your paper will not make the grade? Do you have responsibilities that may hinder you from turning in your assignment on time? Are you tired and can barely handle your assignment? Are your grades inconsistent?
Whichever your reason is, it is valid! You can get professional academic help from our service at affordable rates. We have a team of professional academic writers who can handle all your assignments.
Students barely have time to read. We got you! Have your literature essay or book review written without having the hassle of reading the book. You can get your literature paper custom-written for you by our literature specialists.
Do you struggle with finance? No need to torture yourself if finance is not your cup of tea. You can order your finance paper from our academic writing service and get 100% original work from competent finance experts.
Computer science is a tough subject. Fortunately, our computer science experts are up to the match. No need to stress and have sleepless nights. Our academic writers will tackle all your computer science assignments and deliver them on time. Let us handle all your python, java, ruby, JavaScript, php , C+ assignments!
While psychology may be an interesting subject, you may lack sufficient time to handle your assignments. Don’t despair; by using our academic writing service, you can be assured of perfect grades. Moreover, your grades will be consistent.
Engineering is quite a demanding subject. Students face a lot of pressure and barely have enough time to do what they love to do. Our academic writing service got you covered! Our engineering specialists follow the paper instructions and ensure timely delivery of the paper.
In the nursing course, you may have difficulties with literature reviews, annotated bibliographies, critical essays, and other assignments. Our nursing assignment writers will offer you professional nursing paper help at low prices.
Truth be told, sociology papers can be quite exhausting. Our academic writing service relieves you of fatigue, pressure, and stress. You can relax and have peace of mind as our academic writers handle your sociology assignment.
We take pride in having some of the best business writers in the industry. Our business writers have a lot of experience in the field. They are reliable, and you can be assured of a high-grade paper. They are able to handle business papers of any subject, length, deadline, and difficulty!
We boast of having some of the most experienced statistics experts in the industry. Our statistics experts have diverse skills, expertise, and knowledge to handle any kind of assignment. They have access to all kinds of software to get your assignment done.
Writing a law essay may prove to be an insurmountable obstacle, especially when you need to know the peculiarities of the legislative framework. Take advantage of our top-notch law specialists and get superb grades and 100% satisfaction.
We have highlighted some of the most popular subjects we handle above. Those are just a tip of the iceberg. We deal in all academic disciplines since our writers are as diverse. They have been drawn from across all disciplines, and orders are assigned to those writers believed to be the best in the field. In a nutshell, there is no task we cannot handle; all you need to do is place your order with us. As long as your instructions are clear, just trust we shall deliver irrespective of the discipline.
Our essay writers are graduates with bachelor's, masters, Ph.D., and doctorate degrees in various subjects. The minimum requirement to be an essay writer with our essay writing service is to have a college degree. All our academic writers have a minimum of two years of academic writing. We have a stringent recruitment process to ensure that we get only the most competent essay writers in the industry. We also ensure that the writers are handsomely compensated for their value. The majority of our writers are native English speakers. As such, the fluency of language and grammar is impeccable.
There is a very low likelihood that you won’t like the paper.
Not at all. All papers are written from scratch. There is no way your tutor or instructor will realize that you did not write the paper yourself. In fact, we recommend using our assignment help services for consistent results.
We check all papers for plagiarism before we submit them. We use powerful plagiarism checking software such as SafeAssign, LopesWrite, and Turnitin. We also upload the plagiarism report so that you can review it. We understand that plagiarism is academic suicide. We would not take the risk of submitting plagiarized work and jeopardize your academic journey. Furthermore, we do not sell or use prewritten papers, and each paper is written from scratch.
You determine when you get the paper by setting the deadline when placing the order. All papers are delivered within the deadline. We are well aware that we operate in a time-sensitive industry. As such, we have laid out strategies to ensure that the client receives the paper on time and they never miss the deadline. We understand that papers that are submitted late have some points deducted. We do not want you to miss any points due to late submission. We work on beating deadlines by huge margins in order to ensure that you have ample time to review the paper before you submit it.
We have a privacy and confidentiality policy that guides our work. We NEVER share any customer information with third parties. Noone will ever know that you used our assignment help services. It’s only between you and us. We are bound by our policies to protect the customer’s identity and information. All your information, such as your names, phone number, email, order information, and so on, are protected. We have robust security systems that ensure that your data is protected. Hacking our systems is close to impossible, and it has never happened.
You fill all the paper instructions in the order form. Make sure you include all the helpful materials so that our academic writers can deliver the perfect paper. It will also help to eliminate unnecessary revisions.
Proceed to pay for the paper so that it can be assigned to one of our expert academic writers. The paper subject is matched with the writer’s area of specialization.
You communicate with the writer and know about the progress of the paper. The client can ask the writer for drafts of the paper. The client can upload extra material and include additional instructions from the lecturer. Receive a paper.
The paper is sent to your email and uploaded to your personal account. You also get a plagiarism report attached to your paper.
GET A PERFECT SCORE!!! 
Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.
You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.
Read moreEach paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.
Read moreThanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.
Read moreYour email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.
Read moreBy sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.
Read more