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Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters
被引:201
作者:
Bristow, Laura A.
[1
,7
]
Dalsgaard, Tage
[2
]
Tiano, Laura
[3
]
Mills, Daniel B.
[1
]
Bertagnolli, Anthony D.
[4
,5
]
Wright, Jody J.
[6
]
Hallam, Steven J.
[6
]
Ulloa, Osvaldo
[4
,5
]
Canfield, Donald E.
[1
]
Revsbech, Niels Peter
[3
]
Thamdrup, Bo
[1
]
机构:
[1] Univ Southern Denmark, Dept Biol, Nord Ctr Earth Evolut, DK-5230 Odense M, Denmark
[2] Aarhus Univ, Arctic Res Ctr, Dept Biosci, DK-8000 Aarhus C, Denmark
[3] Aarhus Univ, Dept Biosci, Microbiol, DK-8000 Aarhus C, Denmark
[4] Univ Concepcion, Dept Oceanog, Concepcion 4070386, Chile
[5] Univ Concepcion, Inst Milenio Oceanog, Concepcion 4070386, Chile
[6] Univ British Columbia, Dept Microbiol & Immunol, Vancouver, BC V6T 1Z3, Canada
[7] Max Planck Inst Marine Microbiol, Biogeochem Dept, D-28359 Bremen, Germany
来源:
基金:
加拿大创新基金会;
加拿大自然科学与工程研究理事会;
欧洲研究理事会;
新加坡国家研究基金会;
关键词:
oxygen;
ammonium oxidation;
nitrite oxidation;
OMZ;
kinetics;
COASTAL UPWELLING ECOSYSTEM;
OXIDIZING ARCHAEA;
DEFICIENT WATERS;
AEROBIC RESPIRATION;
NITROGEN-CYCLE;
FRESH-WATER;
MARINE;
DENITRIFICATION;
BACTERIA;
NITRIFICATION;
D O I:
10.1073/pnas.1600359113
中图分类号:
O [数理科学和化学];
P [天文学、地球科学];
Q [生物科学];
N [自然科学总论];
学科分类号:
07 ;
0710 ;
09 ;
摘要:
A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O-2) sensitivity of these processes down to the O-2 concentrations present in the OMZ core (< 10 nmol.L-1) is therefore essential for understanding and modeling nitrogen loss in OMZs. We determined rates of ammonium and nitrite oxidation in the seasonal OMZ off Concepcion, Chile at manipulated O-2 levels between 5 nmol.L-1 and 20 mu mol.L-1. Rates of both processes were detectable in the low nanomolar range (5-33 nmol.L-1 O-2), but demonstrated a strong dependence on O-2 concentrations with apparent half-saturation constants (K(m)s) of 333 +/- 130 nmol.L-1 O-2 for ammonium oxidation and 778 +/- 168 nmol.L-1 O-2 for nitrite oxidation assuming one-component Michaelis-Menten kinetics. Nitrite oxidation rates, however, were better described with a two-component Michaelis-Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O-2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O-2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss.
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页码:10601 / 10606
页数:6
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