title: Variability of nitrifying communities in surface coastal waters of the Eastern South Pacific (∼36° S).
abstract: We report the seasonal and single-diurnal variability of potentially active members of the prokaryote community in coastal surface waters off central Chile and the relationship between nitrifiers and solar radiation by combining 16S cDNA-based pyrosequencing, RT-qPCR of specific gene markers for nitrifiers (amoA, for general AOA, AOA-A, AOA-B, Nitrosopumilus maritimus and beta-AOB; and 16S rRNA gene for Nitrospina-like NOB), and solar irradiance measurements. We also evaluated the effects of artificial UVA-PAR and PAR spectra on nitrifiers by RT-qPCR. All nitrifiers (except AOA-B ecotype) were detected via RT-qPCR but AOA was the only group detected by pyrosequencing. Results showed high variability in their transcriptional levels during the day which could be associated to sunlight intensity thresholds in winter although AOA and Nitrospina-like NOB transcript number were also potentially related with environmental substrate availability. Only N. maritimus amoA transcripts showed a significant negative correlation with solar irradiances in both periods. During spring-summer, Nitrospina transcripts decreased at higher sunlight intensities, whereas the opposite was found during winter under natural (in situ) and artificial light experiments. In summary, a nitrifying community with variable tolerance to solar radiation is responsible for daily nitrification, and was particularly diverse during winter in the study area.
authors.affiliation: Programa de Postgrados en Oceanografía, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.|Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Chile, Valparaíso.|Interdisciplinary Center for Aquaculture Research (INCAR), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.
authors.forename: Héctor A
authors.initials: HA
authors.lastname: Levipan
authors.affiliation: Programa de Biodiversidad and Departamento de Biología. Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Avda. Leopoldo Carvallo 270, Playa Ancha, Valparaíso, Chile.
authors.forename: Verónica
authors.initials: V
authors.lastname: Molina
authors.affiliation: Centro de Investigación Marina Quintay (CIMARQ), Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Chile, Valparaíso.
authors.forename: Cristóbal
authors.initials: C
authors.lastname: Anguita
authors.affiliation: Programa de Postgrados en Oceanografía, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.|Interdisciplinary Center for Aquaculture Research (INCAR), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.
authors.forename: Angel
authors.initials: A
authors.lastname: Rain-Franco
authors.affiliation: Laboratorio de Ecología Microbiana y Toxicología Ambiental, Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Lucy
authors.initials: L
authors.lastname: Belmar
authors.affiliation: Interdisciplinary Center for Aquaculture Research (INCAR), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.|COPAS SUR-AUSTRAL, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160C, Concepción, Chile.|Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique, Banyuls/Mer, F-66650, France.
authors.forename: Camila
authors.initials: C
authors.lastname: Fernandez