User:Sere.fed/sandbox

Introduction
The Iron is a widespread element that is used by living organism for the formation of proteins involved in biochemical reactions, for example, Iron is involved in the production of Iron–sulfur protein s, Hemoglobin and Coordination complex.

As Liebig's law of the minimum says, the element present in the smallest amount (called Limiting factor), is the one that determines the growth rate of a population of organisms. The Iron is one of those limiting compound that has a key role in the structuration of phytoplancton communities and determines its abundance, it's particullary important in the HNLC       (High-nutrient, low-chlorophyll regions), where the percentage and the presence of Micronutrient s is mandatory for the total amount of primary production. Iron-oxidizing bacteria are chemotrophic bacteria that derive the energy they need to live and multiply by oxidizing dissolved Ferrous ion to Ferric iron. Those bacteria are known to grow and proliferate in waters containing iron concentrations as low as 0.1 mg/L. However, at least 0.3 ppm of dissolved oxygen is needed to carry out oxidation.

Species and Biosignature
Known species of bacteria with microbial metabolisms based on iron oxidation include Thiobacillus ferrooxidans and Leptospirillum ferrooxidans.

Some of the FeOB, like Gallionella ferruginea and Mariprofundis ferrooxydans are able to produce some particular extracellular stalk-ribbon structures rich in iron, those are known as a typical Biosignature of Iron-oxidizing bacteria. Finding in a sample of water those stalks indicates the presence FeOB in that area, that occured in the present or in the past.