title: Optical properties of dissolved organic matter relate to different depth-specific patterns of archaeal and bacterial community structure in the North Atlantic Ocean.
abstract: Prokaryotic abundance, activity and community composition were studied in the euphotic, intermediate and deep waters off the Galician coast (NW Iberian margin) in relation to the optical characterization of dissolved organic matter (DOM). Microbial (archaeal and bacterial) community structure was vertically stratified. Among the Archaea, Euryarchaeota, especially Thermoplasmata, was dominant in the intermediate waters and decreased with depth, whereas marine Thaumarchaeota, especially Marine Group I, was the most abundant archaeal phylum in the deeper layers. The bacterial community was dominated by Proteobacteria through the whole water column. However, Cyanobacteria and Bacteroidetes occurrence was considerable in the upper layer and SAR202 was dominant in deep waters. Microbial composition and abundance were not shaped by the quantity of dissolved organic carbon, but instead they revealed a strong connection with the DOM quality. Archaeal communities were mainly related to the fluorescence of DOM (which indicates respiration of labile DOM and generation of refractory subproducts), while bacterial communities were mainly linked to the aromaticity/age of the DOM produced along the water column. Taken together, our results indicate that the microbial community composition is associated with the DOM composition of the water masses, suggesting that distinct microbial taxa have the potential to use and/or produce specific DOM compounds.
authors: IEO, Instituto Español de Oceanografía, Centro Oceanográfico de A Coruña, Apdo. 130, 15080, A Coruña, Spain.
authors: Elisa
authors: E
authors: Guerrero-Feijóo
authors: IIM-CSIC, Instituto de Investigacións Mariñas, 36208 Vigo, Spain.
authors: Mar
authors: M
authors: Nieto-Cid
authors: Department of Limnology and Bio-Oceanography, University of Vienna, A-1090, Vienna, Austria.
authors: Eva
authors: E
authors: Sintes
authors: IEO, Instituto Español de Oceanografía, Centro Oceanográfico de A Coruña, Apdo. 130, 15080, A Coruña, Spain.|Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, 36200 Vigo, Spain.
authors: Vladimir
authors: V
authors: Dobal-Amador
authors: Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36200 Vigo, Spain.
authors: Víctor
authors: V
authors: Hernando-Morales
authors: IEO, Instituto Español de Oceanografía, Centro Oceanográfico de A Coruña, Apdo. 130, 15080, A Coruña, Spain.
authors: Marta
authors: M
authors: Álvarez
authors: ICM-CSIC, Institut de Ciències del Mar, 08003, Barcelona, Spain.
authors: Vanessa
authors: V
authors: Balagué
authors: IEO, Instituto Español de Oceanografía, Centro Oceanográfico de A Coruña, Apdo. 130, 15080, A Coruña, Spain marta.varela@co.ieo.es.
authors: Marta M
authors: MM
authors: Varela
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001267:Atlantic Ocean; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D009930:Organic Chemicals / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D009930:Organic Chemicals
keywords: ARISA; Atlantic waters; CARD-FISH; DOM optical properties; T-RFLP; deep sea; diversity; marine microbes; pyrosequencing