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  • What are the three steps of the nitrogen cycle?

Sulfur cycle

Sulfur is an essential element for the macromolecules of living organisms. As part of the amino acids cysteine and methionine, it is involved in the formation of proteins. It is also found in several vitamins necessary for the synthesis of important biological molecules like coenzyme A . Several groups of microbes are responsible for carrying out processes involved in the sulfur cycle ( [link] ). Anoxygenic photosynthetic bacteria as well as chemoautotrophic archaea and bacteria use hydrogen sulfide as an electron donor , oxidizing it first to elemental sulfur (S 0 ), then to sulfate ( SO 4 2 ) . This leads to stratification of hydrogen sulfide in soil, with levels increasing at deeper, more anaerobic depths.

Many bacteria and plants can use sulfate as a sulfur source. Decomposition dead organisms by fungi and bacteria remove sulfur groups from amino acids, producing hydrogen sulfide, returning inorganic sulfur to the environment.

Sulfur cycle. Atmospheric sulfur (SO2 gas) is taken in by plants. Plant residues and animal manures and biosolids produce organic sulfur. Mineralization produces sulfate (SO42-). Immobilization reverts sulfate back to organic sulfur. Sulfate is converted to H2S via anaerobic respiration. Decomposition also produces H2S. Sulfate can be absorbed or converted to mineral sulfur. Bacterial reduction converts sulfate to reduced sulfur (H2S, HS). Oxidation converts reduced sulfur and elemental sulfur (SO0) to sulfate.
This figure summarizes the sulfur cycle. Note that specific groups of prokaryotes each may participate in every step in the cycle. (credit: modification of work by NOAA)
  • Which groups of microbes carry out the sulfur cycle?

Other biogeochemical cycles

Beyond their involvement in the carbon, nitrogen, and sulfur cycles, prokaryotes are involved in other biogeochemical cycles as well. Like the carbon, nitrogen, and sulfur cycles, several of these additional biogeochemical cycles, such as the iron (Fe), manganese (Mn), and chromium (Cr) cycles, also involve redox chemistry, with prokaryotes playing roles in both oxidation and reduction. Several other elements undergo chemical cycles that do not involve redox chemistry. Examples of these are phosphorus (P), calcium (Ca), and silica (Si) cycles. The cycling of these elements is particularly important in oceans because large quantities of these elements are incorporated into the exoskeletons of marine organisms. These biogeochemical cycle s do not involve redox chemistry but instead involve fluctuations in the solubility of compounds containing calcium, phosphorous, and silica. The overgrowth of naturally occurring microbial communities is typically limited by the availability of nitrogen (as previously mentioned), phosphorus, and iron. Human activities introducing excessive amounts of iron, nitrogen, or phosphorus (typically from detergents) may lead to eutrophication .

Bioremediation

Microbial bioremediation leverages microbial metabolism to remove xenobiotic s or other pollutants. Xenobiotics are compounds synthesized by humans and introduced into the environment in much higher concentrations than would naturally occur. Such environmental contamination may involve adhesives, dyes, flame retardants, lubricants, oil and petroleum products, organic solvents, pesticides, and products of the combustion of gasoline and oil. Many xenobiotics resist breakdown, and some accumulate in the food chain after being consumed or absorbed by fish and wildlife, which, in turn, may be eaten by humans. Of particular concern are contaminants like polycyclic aromatic hydrocarbon (PAH) , a carcinogenic xenobiotic found in crude oil, and trichloroethylene (TCE) , a common groundwater contaminant.

Questions & Answers

the product obtained by simplest conventional microbial process is
shridhan Reply
the product obtained by simplest conventional microbial fermentation process is
shridhan
curd
Mounika
beer cheese
Khushi
what is macrobiology
Esther Reply
study in microorganisms
Siva
what is lactose
adekanbi Reply
codomint marker such as RELP are useful for
Nandan Reply
how this process start
Radhika Reply
deffination of staining
Bhavanimangali Reply
It's using dies to differentiate microorganism
shalon
Staining can be defined as a process of using stains or dye to differentiate microorganisms in an environment or habitat.
adeolu
with the aid of a well labeled diagram describe the conducting system
Maridad Reply
what is cellular immunity
namugenyi Reply
Cellular Immunity. -Lymphocytes act against target cell. -Acts directly by killing infected cells.
abdinor
What are NK cells
Peter
Natural killer cells
Rahaba
what are Antigen determinant
mary
cellular immunity is the state where the lymphocytes destroy the infected or targeted cell
cynthia
any examples of oedema
cynthia
introduction of microbial diversity-1
Bhavanimangali Reply
List the type of micro organism arround us and how they can be seen and with what kind of instrument
clinton Reply
how is the arrangements of bacteria in bacilli
Vaidah Reply
Provide some examples of bacterial structures that might be used as antibiotic targets and explain why.
Vaidah
Coccobacilli, Club-Shaped bacilli, Bacilli with rounded ends, Fuilform bacilli, Bacilli with ends square.
Enoch
three main antibiotic targets in bacteria: The cell wall or membranes that surrounds the bacterial cell. The machineries that make the nucleic acids DNA and RNA. The machinery that produce proteins
Rushikesh
The bacterial cell wall. Protein production. and DNA synthesis. Why, this is because most drugs (antibiotics) affects the cell wall of the bacteria, which makes the bacteria weak or susceptible in human body.
Enoch
UV rays affecting the..
Mali Reply
what is microbiology
Baba Reply
Microbiology is the study of microorganisms, which are prokaryotic and eukaryotic cell which includes bacteria, fungi, viruses and pathogenic protozoa.
Enoch
Microbiology is the branch of Life science which deals with scientific study of many Microorganisms.
Rushikesh
what is types of microbiology
Alsheikh
Immunology, Bacteriology, Virology, Mycology, Algology etc
Enoch
Virology, Immunology, Bacteriology, Algology, Mycology, Protoozology etc
Enoch
and what is mycology
Alsheikh
Immunology, Serology, Virology, Microbial Genetics, Parasitology, Bacteriology, Mycology, Molecular, Cell Biology, Agricultural, Water,Soil, Food Industrial ,Pharmaceutical, Applied, Environmental, Clinical, Medical,Marine Microbiology, Microbial Systematics, Etc, are & many types of Microbiology.
Rushikesh
study of fungi is called mycology
Munna
Mycology is the branch of Microbiology which deals with scientific study of Fungi.
Rushikesh
Study of microorganisms,which we can't see with our naked eye is called microbiology
Munna
Mycology is the scientific study of Fungi.
Enoch
virology is the study of viruses
Oppah
what is microbiology? microbiology is the study of small microorganisms that we can not with our naked eyes.
Leticia
what is taxonomical classification of microbiology
Bami
The algae, protozoa, slime moulds, fungi, bacteria, archaea and viruses ,are taxonomic classification of Microorganisms
Rushikesh
We have Bacteria, Archaea, Protozoa, Algae, Fungi, Viruses.
Enoch
microbiology is the study of microbes too small to be seen by naked eyes
Maridad
microbiology is a branch of biology which deals with study of smallest living microrganisms such as bacteria protozoa fungi and viruses
Chaitra
microbiology is the study of microorganisms which can't be seen by our naked eyes
Nakaweesi
Micro - Minute Bio - Life Logus - Study
Roshan
what is the meaning of antimicrobial susceptibility testing
Devshree Reply
seven gram positive bacteria
Okocha Reply
seven examples of gram negative bacteria
Okocha
seven examples of gram negative bacteria
Okocha

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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