Identificador persistente para citar o vincular este elemento: http://hdl.handle.net/10553/134590
Título: Dark Diazotrophy during the Late Summer in Surface Waters of Chile Bay, West Antarctic Peninsula
Autores/as: Alcamán-Arias, María E.
Cifuentes-Anticevic, Jerónimo
Castillo-Inaipil, Wilson
Farías, Laura
Sanhueza, Cynthia
Morales Gómez, Beatriz
Verdugo, Josefa
Abarzua, Leslie
Ridley, Christina
Tamayo-Leiva, Javier
Díez, Beatriz
Clasificación UNESCO: 2510 Oceanografía
Palabras clave: Diazotrophy
Heterotrophic diazotrophy
Nitrogen fixation
WAP/new production
Fecha de publicación: 2022
Publicación seriada: Microorganisms 
Resumen: Although crucial for the addition of new nitrogen in marine ecosystems, dinitrogen (N2) fixation remains an understudied process, especially under dark conditions and in polar coastal areas, such as the West Antarctic Peninsula (WAP). New measurements of light and dark N2 fixation rates in parallel with carbon (C) fixation rates, as well as analysis of the genetic marker nifH for diazotrophic organisms, were conducted during the late summer in the coastal waters of Chile Bay, South Shetland Islands, WAP. During six late summers (February 2013 to 2019), Chile Bay was characterized by high NO3- concentrations (~20 µM) and an NH4+ content that remained stable near 0.5 µM. The N:P ratio was approximately 14.1, thus close to that of the Redfield ratio (16:1). The presence of Cluster I and Cluster III nifH gene sequences closely related to Alpha-, Delta-and, to a lesser extent, Gammaproteobacteria, suggests that chemosynthetic and heterotrophic bacteria are primarily responsible for N2 fixation in the bay. Photosynthetic carbon assimilation ranged from 51.18 to 1471 nmol C L−1 d−1, while dark chemosynthesis ranged from 9.24 to 805 nmol C L−1 d−1. N2 fixation rates were higher under dark conditions (up to 45.40 nmol N L−1 d−1) than under light conditions (up to 7.70 nmol N L−1 d−1), possibly contributing more than 37% to new nitrogen-based production (≥2.5 g N m−2 y−1). Of all the environmental factors measured, only PO43- exhibited a significant correlation with C and N2 rates, being negatively correlated (p < 0.05) with dark chemosynthesis and N2 fixation under the light condition, revealing the importance of the N:P ratio for these processes in Chile Bay. This significant contribution of N2 fixation expands the ubiquity and biological potential of these marine chemosynthetic diazotrophs. As such, this process should be considered along with the entire N cycle when further reviewing highly productive Antarctic coastal waters and the diazotrophic potential of the global marine ecosystem.
URI: http://hdl.handle.net/10553/134590
ISSN: 2076-2607
DOI: 10.3390/microorganisms10061140
Fuente: Microorganisms [ISSN 2076-2607], v. 10 (6) 1140, (Mayo 2022)
Colección:Artículos
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