Chemosynthetic Autotrophs

Essay by PaperNerd ContributorCollege, Undergraduate August 2001

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Twenty-six hundred meters below our world of light, through the murky depths, resides a world completely alien to our own. It was not until 1977, when the first manned submarine was able to enter such depths and explore this oasis of life that resides around the earth's nourishing thermal vents. Here, a vast community of organisms thrive under very harsh circumstances, and most importantly, in the absence of life-giving light. How is this possible? Chemoautotrophic microbes.

Chemoautotrophic bacteria are the primary producers on the ocean floor, where light cannot reach. Unlike most organisms, these bacteria do not need carbohydrates, vitamins, protein, and sugar to create energy, and ultimately to survive. Instead, these bacteria utilize an alternate source for synthesizing energy. This method is commonly known as chemosynthesis. Chemosynthesis is the process of making energy by oxidizing simple inorganic compounds. These compounds include reduced gases such as ammonia, sulfur, and methane.

With the help of enzymes, energy can be made by breaking down these compounds and absorbing the valence electrons as shown in Diagram 1. (General 357) For chemosynthesis to occur, the perfect combination of inorganic compounds, oxygen, nitrogen-containing salts, and carbon must exist.

Currently, three different categories of chemoautotrophs, or "gas eaters" have been identified. The first are those that oxidize nitrogen compounds. These bacteria are predominantly found in lakes and swamps, where the soil is porous enough to allow ammonia, and other nitrous gases to escape. These chemoautotrophs are directly involved in the nitrogen cycle, because they use the organic nitrogen given off in the waste products of plants and animals to create energy. In turn, they give off a usable form of ammonia for the plants and animals to use. There is much diversity within these nitrogen bacteria that allow it to function more efficiently in its specific...