期刊
ISME JOURNAL
卷 10, 期 11, 页码 2605-2619出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/ismej.2016.61
关键词
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资金
- Palmer LTER [ANT 08-23101]
- US National Science Foundation [ANT 08-38996, OCE 09-43278, OCE 11-29260]
- University of Georgia Graduate School (Innovative and Interdisciplinary Research Grant)
- Directorate For Geosciences
- Division Of Ocean Sciences [1237140] Funding Source: National Science Foundation
- Office of Polar Programs (OPP)
- Directorate For Geosciences [1440435] Funding Source: National Science Foundation
There are few measurements of nitrification in polar regions, yet geochemical evidence suggests that it is significant, and chemoautotrophy supported by nitrification has been suggested as an important contribution to prokaryotic production during the polar winter. This study reports seasonal ammonia oxidation (AO) rates, gene and transcript abundance in continental shelf waters west of the Antarctic Peninsula, where Thaumarchaeota strongly dominate populations of ammonia-oxidizing organisms. Higher AO rates were observed in the late winter surface mixed layer compared with the same water mass sampled during summer (mwean +/- s.e.:62 +/- 16 versus 13 +/- 2.8 nM per day, t-test P<0.0005). AO rates in the circumpolar deep water did not differ between seasons (21 +/- 5.7 versus 24 +/- 6.6 nM per day; P=0.83), despite 5- to 20-fold greater Thaumarchaeota abundance during summer. AO rates correlated with concentrations of Archaea ammonia monooxygenase (amoA) genes during summer, but not with concentrations of Archaea amoA transcripts, or with ratios of Archaea amoA transcripts per gene, or with concentrations of Betaproteobacterial amoA genes or transcripts. The AO rates we report (<0.1-220 nM per day) are similar to 10-fold greater than reported previously for Antarctic waters and suggest that inclusion of Antarctic coastal waters in global estimates of oceanic nitrification could increase global rate estimates by similar to 9%. Chemoautotrophic carbon fixation supported by AO was 3-6% of annualized phytoplankton primary production and production of Thaumarchaeota biomass supported by AO could account for similar to 9% of the bacterioplankton production measured in winter. Growth rates of thaumarchaeote populations inferred from AO rates averaged 0.3 per day and ranged from 0.01 to 2.1 per day.
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