Editing Thiomargarita namibiensis (section)

== Occurrence ==
''Thiomargarita namibiensis'' was found in the continental shelf off the coast of [[Namibia]], an area with high plankton productivity and low oxygen concentrations between 0-3 μM, and nitrate concentrations of 5-28 μM.<ref name="Schulz Brinkhoff Ferdelman et al 19994">{{cite journal |last1=Schulz |first1=H. N. |last2=Brinkhoff |first2=T. |last3=Ferdelman |first3=T. G. |last4=Mariné |first4=M. Hernández |last5=Teske |first5=A. |last6=Jørgensen |first6=B. B. |date=16 April 1999 |title=Dense Populations of a Giant Sulfur Bacterium in Namibian Shelf Sediments |journal=Science |volume=284 |issue=5413 |pages=493–495 |bibcode=1999Sci...284..493S |doi=10.1126/science.284.5413.493 |pmid=10205058}}</ref> ''Thiomargarita namibiensis'' is most prevalent in the Walvis Bay area at 300 feet deep,<ref name="WHOI 1999 Giant Sulfur Bacteria Discovered32">{{cite press release |title=Giant Sulfur Bacteria Discovered off African Coast |date=16 April 1999 |publisher=Woods Hole Oceanographic Institution |url=https://www.whoi.edu/press-room/news-release/giant-sulfur-bacteria-discovered-off-african-coast/}}</ref> but they are distributed along the coast of Namibia from Palgrave Point to Lüderitzbucht.<ref>{{cite web |date=29 October 2007 |title=Distribution of Thiomargarita namibiensis along the namibian coast |url=https://commons.wikimedia.org/wiki/File:DistributionThiomargaritaNamibiensisNamibia.jpg}}{{self-published inline|date=April 2024}}</ref> ''T. namibiensis'' is not found across the entire shelf, it is only found within a specific sediment type, diatomaceous mud, which is composed mainly of dead diatoms. Diatomaceous mud has high sulfate reduction rates and high levels of organic material.<ref name="Schulz 2006 The Genus Thiomargarita2">{{cite book |last1=Schulz |first1=Heide N. |title=The Prokaryotes |date=2006 |isbn=978-0-387-25496-8 |pages=1156–1163 |chapter=The Genus Thiomargarita |doi=10.1007/0-387-30746-X_47}}</ref> The most bacteria were obtained from the upper 3cm of sediment in the sample, with concentrations decreasing exponentially past this point.<ref name="Schulz Schulz 20052">{{cite journal |last1=Schulz |first1=Heide N. |last2=Schulz |first2=Horst D. |date=21 January 2005 |title=Large Sulfur Bacteria and the Formation of Phosphorite |journal=Science |volume=307 |issue=5708 |pages=416–418 |bibcode=2005Sci...307..416S |doi=10.1126/science.1103096 |pmid=15662012}}</ref> Here, ''Thiomargarita namibiensis'' is easily suspended in moving ocean currents due to the sheath around the cells, which makes it easy for the bacteria to passively float.<ref name=":32">{{cite press release |title=Biggest Bacteria Ever Found -- May Play Underrated Role In The Environment |date=16 April 1999 |publisher=American Association For The Advancement Of Science |url=https://www.sciencedaily.com/releases/1999/04/990416081113.htm |work=ScienceDaily}}</ref> In this section of sediment, there were sulfide concentrations of 100-800 μM.<ref name="Schulz Brinkhoff Ferdelman et al 19994" />

Although previously undiscovered, ''T. namibiensis'' is not uncommon in its environment. It is by far the most common [[benthos]] bacterium of the Namibian shelf, comprising almost 0.8% of the sediment volume.<ref>{{cite journal |last=Schulz |first=Heide |date=March 2002 |title=Thiomargarita namibiensis: Giant microbe holding its breath |url=https://www.researchgate.net/publication/256398005 |journal=ASM News |volume=68 |issue=3 |pages=122–127}}</ref> About 8% of the shelf with diatomaceous mud has free gases are present in shallow depths.<ref name="Schulz 2006 The Genus Thiomargarita2" /> When the gas is released from the sediment, sulfide is released into the water column. ''T. namibiensis'' is more prevalent in areas with free gas, suggesting that the presence of suspended sulfide is beneficial to the bacteria. ''T. namibiensis'' will oxidize the hydrogen sulfide (H2S) from the sediment into sulfur and sulfide, thus allowing less sulfide into the water column and detoxifying the water.<ref name="Winkel Salman-Carvalho Woyke et al 20162">{{cite journal |last1=Winkel |first1=Matthias |last2=Salman-Carvalho |first2=Verena |last3=Woyke |first3=Tanja |last4=Richter |first4=Michael |last5=Schulz-Vogt |first5=Heide N. |last6=Flood |first6=Beverly E. |last7=Bailey |first7=Jake V. |last8=Mußmann |first8=Marc |date=21 June 2016 |title=Single-cell Sequencing of Thiomargarita Reveals Genomic Flexibility for Adaptation to Dynamic Redox Conditions |journal=Frontiers in Microbiology |volume=7 |page=964 |doi=10.3389/fmicb.2016.00964 |pmc=4914600 |pmid=27446006 |doi-access=free}}</ref><ref name=":8" /> However, the supply of sulfide produced by the underlying sediment can be too much for the cell to oxidize all of it, and sulfide still enters the water column. The Namibian coastal environmental experiences strong upwelling, resulting in low oxygen levels with large amounts of plankton. The lower waters lack oxygen due to the multitude of microorganisms releasing carbon dioxide while they perform heterotrophic respiration to generate energy.<ref name="Schulz Brinkhoff Ferdelman et al 19994" />

Since the ''Thiomargarita namibiensis'' are immobile, they are unable to seek a more ideal environment when sulfide and nitrate levels are low in this environment.<ref name="Girnth Grünke Lichtschlag et al 2011" /> They simply remain in position and wait for levels to increase once again so that they can undergo respiration and other processes.<ref name="WHOI 1999 Giant Sulfur Bacteria Discovered" /> This is possible because ''T. namibiensis'' have the ability to store large supplies of sulfur and nitrate.<ref name="Max Planck 1999 The largest Bacterium" /> The organism also has a direct impact on its environment. [[Apatite]], a mineral high in [[phosphorite]], is correlated with the abundance of ''T. namibiensis'' through phosphogenesis.<ref name=":8">{{cite journal |last1=Auer |first1=Gerald |last2=Hauzenberger |first2=Christoph A. |last3=Reuter |first3=Markus |last4=Piller |first4=Werner E. |title=Orbitally paced phosphogenesis in M editerranean shallow marine carbonates during the middle M iocene M onterey event |journal=Geochemistry, Geophysics, Geosystems |date=April 2016 |volume=17 |issue=4 |pages=1492–1510 |doi=10.1002/2016GC006299 |pmid=27570497 |pmc=4984836 |bibcode=2016GGG....17.1492A }}</ref> Internal polyphosphate and nitrate are used as external electron acceptors in the presence of acetate, releasing enough phosphate to cause precipitation. While the amount directly created by ''T. namibiensis'' cannot be calculated, it is a significant contribution to the large amounts of hydroxyapatite in solid-phase shelf sediment.<ref name="Schulz Schulz 2005">{{cite journal |last1=Schulz |first1=Heide N. |last2=Schulz |first2=Horst D. |date=21 January 2005 |title=Large Sulfur Bacteria and the Formation of Phosphorite |journal=Science |volume=307 |issue=5708 |pages=416–418 |bibcode=2005Sci...307..416S |doi=10.1126/science.1103096 |pmid=15662012}}</ref> The Mexican strain was primarily found in the top centimeter of sediment sampled from cold seeps in the Gulf of Mexico. The top 3cm of sediment from the Gulf of Mexico locations contained sulfide concentrations of 200-1900 μM.<ref name="Kalanetra_2005" />[[File:ThiomargaritaFeeding.jpg|thumb|250px|''Thiomargarita namibiensis'', collecting nitrate and oxygen in water above the bottom in case of being resuspended and collecting sulfide in the sediments]]