Ammonia-Oxidizing -Proteobacteria from the Oxygen Minimum Zone off Northern Chile䌤 Vero ´nica Molina,1* Osvaldo Ulloa,1 Laura Farı´as,1 Homero Urrutia,2 Salvador Ramı´rez,1 Pilar Junier,3 and Karl-Paul Witzel3 Laboratorio de Procesos Oceanogra ´ficos y Clima, Departamento de Oceanografı´a & Centro de Investigacio ´n Oceanogra ´fica en el Pacı´fico Sudoriental, Universidad de Concepcio ´n, Concepcio ´n, Chile1; Departamento de Microbiologı´a, Universidad de Concepcio ´n, Concepcio ´n, Chile2; and Max-Planck-Institut fu ¨r Limnologie, Plo ¨n, Germany3 Received 26 September 2006/Accepted 28 March 2007
The composition of ammonia-oxidizing bacteria from the -Proteobacteria subclass (AOB) was studied in the surface and upper-oxycline oxic waters (2- to 50-m depth, ⬃200 to 44 M O2) and within the oxygen minimum zone (OMZ) suboxic waters (50- to 400-m depth,
