Journal
ISME JOURNAL
Volume 7, Issue 11, Pages 2192-2205Publisher
NATURE PUBLISHING GROUP
DOI: 10.1038/ismej.2013.96
Keywords
nitrification; nitrite oxidation; nitrospina; oxygen minimum zone; pyrosequencing
Categories
Funding
- National Science Foundation Oceanography Award [10-34943]
- Directorate For Geosciences
- Division Of Ocean Sciences [1132155] Funding Source: National Science Foundation
- Directorate For Geosciences
- Division Of Ocean Sciences [1129260] Funding Source: National Science Foundation
Ask authors/readers for more resources
Nitrogen (N) is an essential nutrient in the sea and its distribution is controlled by microorganisms. Within the N cycle, nitrite (NO2-) has a central role because its intermediate redox state allows both oxidation and reduction, and so it may be used by several coupled and/or competing microbial processes. In the upper water column and oxygen minimum zone (OMZ) of the eastern tropical North Pacific Ocean (ETNP), we investigated aerobic NO2- oxidation, and its relationship to ammonia (NH3) oxidation, using rate measurements, quantification of NO2--oxidizing bacteria via quantitative PCR (QPCR), and pyrosequencing. (NO2-)-N-15 oxidation rates typically exhibited two subsurface maxima at six stations sampled: one located below the euphotic zone and beneath NH3 oxidation rate maxima, and another within the OMZ. (NO2-)-N-15 oxidation rates were highest where dissolved oxygen concentrations were <5 mu M, where NO2- accumulated, and when nitrate (NO3-) reductase genes were expressed; they are likely sustained by NO3- reduction at these depths. QPCR and pyrosequencing data were strongly correlated (r(2) = 0.79), and indicated that Nitrospina bacteria numbered up to 9.25% of bacterial communities. Different Nitrospina groups were distributed across different depth ranges, suggesting significant ecological diversity within Nitrospina as a whole. Across the data set, (NO2-)-N-15 oxidation rates were decoupled from (NH4+)-N-15 oxidation rates, but correlated with Nitrospina (r(2) = 0.246, P<0.05) and NO2- concentrations (r(2) = 0.276, P<0.05). Our findings suggest that Nitrospina have a quantitatively important role in NO2- oxidation and N cycling in the ETNP, and provide new insight into their ecology and interactions with other N-cycling processes in this biogeochemically important region of the ocean.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available