1. The Mystery of Microbes! Isha Lamba 7D Science

2. Introduction Microbesare tiny creatures that cannot be seen by the naked eye. They are microscopic. And they exist in huge numbers and are widely spread almost everywhere. Just a single gram of soil may contain more than 1 billion microbes. Viruses, Bacteria, Fungi and Protists form the main types of microbes, but there is a huge further variety in form of different species in each of these types. Just 1 gram of soil may have microbes belonging to more than 10,000 species. All microbes require water to live.

3. Microbes are omnipresent Microbes inhabit almost every niche, from 20 miles beneath to 20 miles above the Earth's surface. They can survive at temperatures as cold as -20 degrees Celsius to hotter than the boiling temperature of water. Microbes can thrive on a huge range of foods including oil and toxic wastes. Microbes exist all over the earth’s surface. Most of Earth's biomass lives in the oceans, and most of this biomass is microbes. Microbes are found in abundance in many aquatic environments, such as streams, puddles, ponds, lakes, rivers, swamps, oceans and seas. Plenty of microbes are present even within our clean homes right from the cutting boards in our kitchen to the shower curtain in our bathrooms, or our beds, couch or carpet in our living rooms. All plants and animals depend on microbes for their survival and interact with them in important ways. Many foods, including cheese, chocolate, tea, bread, root beer, and many others are processed by microbes.

4. Importance of Microbes Microbes play a useful role in agriculture and the growth of our crops by helping the plants in form of making the soil fertile and by killing the unwanted pests such as insects. Microbes degrade the complex organic wastes into useful simpler substances that can be used by plants. They decay and breakdown grass, leaves, other types of plant and animal wastes and even the kitchen waste and convert these into humus. Some microbes which live near the roots of the plants (in the rhizosphere) help the plants through their symbiotic associations with the roots of plants. Some microbes which are able to thrive in chemical environments can degrade and remove toxins like oil and pesticides. The right type of microbes on our skin and inside our guts keep us healthy.

5. Importance of Microbes Ruminant animals such as goats, deer, and giraffes, digest their food with the help of billions of microbes inside their guts that live in the rumens (stomachs). The green microbes having chlorophyll, help convert the solar energy into chemical energy in form of food by photosynthesis. This then forms the source of energy for many other organisms in the food chain. Yeast (a type of microbe) ferments the sugars enabling us to make wine and beers. It is also ued to make the bread rise. Lactobacillus acidophillus (another type of microbe) helps us make yoghurt from milk and sour-dough bread from flour-dough.

6. Presence of Microbes in Water Where there is water, there are microbes Ponds contain a rich diversity of microbes that include:- Photosynthesizerslike Algae (Spirogyra, Diatoms), Blue green photosynthetic bacteria are called cyanobacteria. HeterotrophslikeActinopod, Amoeba Microbial Animals like Rotifer, Hydra Sulfate Reducers like Desulfovibrio, and Desulfomonileteidjii Methane producers called Methanogens

7. Presence of Microbes on Land There is very rich Biodiversity of microbes over land with a variety of microbial habitats. These include :- Soil, compost, on and around plants Everywhere in our homes including beds, couches and bathrooms. Stone buildings and on statues Habitats with extreme temperature like hot springs and snow Toxic waste dumps

8. Presence of Microbes in and on Animals Most animals are intimately associated with microbes. Microbes live in their guts, in their mouths, and on their skin. Streptococcus grows in our mouth and causes dental cavities, and gum disease. Helicobacter pylori inside our stomach Bacteroides, E. coli, Klebsiella, Bifidobacterium and Methanobacteriumsmithii in our large intestines Propionibacterium acne, and Staphylococcus epidermidis on our skin Rumen symbionts, cellulose degraders, and methane producers in the stomachs of cows and other cattle

9. Advantages of Microbes Some Microbes are good for agriculture and growth of plants. An important nutrient – Nitrogen – is fixed from the atmosphere by some microbes (Rhizobium and Azotobacter). Phosphorus is also supplied by microbes like Mycorrhizal fungi. Some microbes are extremely important for breaking down waste products, which then act as a fertilizer for the soil, and thus helping in plant growth. Another benefit of microbes is that farmers don’t need to use too many chemicals for controlling pests since now microbes can be used to kill unwanted insects and plants. This is known as bio-control. Microbes are useful in production of food stuff such as Beer, Wine, Bread, Chocolate, Natto, and Yoghurt.

10. Disadvantages of Microbes Microbes can be harmful as they can cause diseases both in plants and animals. Microbes causing plant disease include fungi, viruses, and bacteria. Plant diseases include the rotting, wilting, spots, losing leaves, paling of color, stunting, growing of tumors, overgrowth and death of plants. Some of the microbes that cause plant diseases are: Rust Fungi, Rhizoctonia, Tobacco Mosaic Virus, Agrobacterium tumefaciens, Burkholderia cepacia, etc. Microbes can cause dental cavities, gum diseases, stomach ulcers, and a variety of infectious diseases.