Microbial growth and nutrition

thumb|300px|Overview of cycle between autotrophs and heterotrophs. [[Photosynthesis is the main means by which plants, algae and many bacteria produce organic compounds and oxygen from carbon dioxide and water (green arrow).]]

right|thumb|300px|The bright colors of Grand Prismatic Spring in [[Yellowstone National Park are produced by thermophiles, a type of extremophile.]]

right|thumb|Terrestrial and aquatic phototrophs: plants grow on a fallen log floating in algae-rich water

GFAJ-1 is a strain of rod-shaped bacteria in the family Halomonadaceae. It is an extremophile that was isolated from the hypersaline and alkaline Mono Lake in eastern California by geobiologist Felisa Wolfe-Simon, a NASA research fellow in residence at the US Geological Survey. In a 2010 Science journal publication, the authors claimed that the microbe, when starved of phosphorus, is capable of substituting arsenic for a small percentage of its phosphorus to sustain its growth. Immediately after publication, other microbiologists and biochemists expressed doubt about this claim, which was robu

thumb|Earthworms are soil-dwelling detritivores. Detritivores (also known as detrivores, detritophages, detritus feeders or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, vertebrates, and plants that eat detritus or carry out coprophagy. By doing so, all these detritivores contribute to decomposition and the nutrient cycles. Detritivores should be distinguished from other decomposers, such as many species of bacteria, fungi and protists, which are unable to ingest discr

A chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic (chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which use photons. Chemotrophs can be either autotrophic or heterotrophic. Chemotrophs can be found in areas where electron donors are present in high concentration, for instance around hydrothermal vents.

thumb|The lichen [[Xanthoria elegans can continue to photosynthesize at .]]

A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37 °C (about 99 °F). The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eukarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Oxygen requirements for mesophiles can be aerobi

thumb|Transmission electron microscope image of a cross section through a soybean (Glycine max) [[root nodule. The nitrogen fixing bacteria, and fungi Bradyrhizobium japonicum, infects the roots and establishes a symbiosis. This high magnification image shows part of a cell with single bacteroid (bacterium-like cell or modified bacterial cell) within their symbiosomes. In this image, you can also see endoplasmic reticulum, Golgi apparatus and cell wall.]]

300px|thumb|right|Anaerobic bacteria can be identified by growing them in test tubes of [[thioglycollate broth: 1: Obligate aerobes need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest. 2: Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest. 3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more

microorganisms which "breathe" sulfates

right|thumb|Blue-green Algae|Blue-green algae cultured in specific media. Blue-green algae can be helpful in agriculture as they have the capability to fix atmospheric nitrogen to soil. This nitrogen is helpful to the crops. Blue-green algae is used as a biofertilizer.

group of compounds

Osmotrophy is a form of heterotrophic nutrition and a cellular feeding mechanism involving the direct absorption of dissolved organic compounds by osmosis. Organisms that use osmotrophy are called osmotrophs. Osmotrophy is used by diverse groups of organisms. Organisms that use osmotrophy include microorganisms like bacteria, many species of protists and most fungi. Invertebrate animal groups like molluscs, sponges, corals, brachiopods and echinoderms may use osmotrophic feeding as a supplemental food source. A common subset of osmotrophy is lysotrophy, in which organisms secrete enzymes into

Photoheterotrophs (Gk: photo = light, hetero = (an)other, troph = nourishment) are heterotrophic phototrophs—that is, they are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source. Consequently, they use organic compounds from the environment to satisfy their carbon requirements; these compounds include carbohydrates, fatty acids, and alcohols. Examples of photoheterotrophic organisms include purple non-sulfur bacteria, green non-sulfur bacteria, and heliobacteria. These microorganisms are ubiquitous in aquatic habitats, occupy unique niche-spaces, and

Halotolerance is the ability of organisms to live in salt concentrations beyond which is necessary for their growth. Halotolerant species are found in saline waters and soils. Halotolerant microorganisms include bacteria, archaea, and fungi. Halophilic microorganisms require salt to grow; halotolerant organisms may be classified as some degree halophilic, but are often contrasted from halophiles because halotolerant organisms do not require a high-salinity environment. Halotolerant microorganisms are of considerable biotechnological interest as their roles in saline ecosystems remains unknown.

A lithoautotroph is an organism that derives energy from reactions of reduced compounds of mineral (inorganic) origin. Two types of lithoautotrophs are distinguished by their energy source; photolithoautotrophs derive their energy from light, while chemolithoautotrophs (chemolithotrophs or chemoautotrophs) derive their energy from chemical reactions. Chemolithoautotrophs are exclusively microbes. Photolithoautotrophs include macroflora such as plants; these do not possess the ability to use mineral sources of reduced compounds for energy. Most chemolithoautotrophs belong to the domain Bacteria

Organism with complex nutritional requirement(need specific nutrients to grow)