Thioploca

Thioploca is a genus of filamentous sulfur bacteria which occurs along 3,000 kilometres (1,900 mi) of coast off the west of South America. A large vacuole occupies more than 80% of their cell volume and contains sulfide and nitrate which they use to make energy for their metabolism by oxidising sulfide with nitrate. The concentration of nitrate in the vacuole is extremely high (500 mM) even though the sediments in which they live are relatively very low in nitrogen (25 μM). Because they use both sulfur and nitrogen compounds they may provide an important link between the nitrogen and sulfur cycles. They secrete a sheath of mucus which they use as a tunnel to travel between the sulfide containing sediment and the nitrate containing sea water. Thioploca contains four species: