| DOI: | 10.1002/2016GB005503
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| Scopus记录号: | 2-s2.0-85018577375
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| 论文题名: | Modest net autotrophy in the oligotrophic ocean |
| 作者: | Letscher R; T; , Moore J; K
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| 刊名: | Global Biogeochemical Cycles
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| ISSN: | 8866236
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| 出版年: | 2017
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| 卷: | 31, 期:4 | | 起始页码: | 699
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| 结束页码: | 708
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| 语种: | 英语
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| 英文关键词: | autotrophic
; heterotrophic
; metabolic state
; net community production
; oligotrophic gyres
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| Scopus关键词: | autotrophy
; carbon fixation
; euphotic zone
; gyre
; in situ measurement
; marine environment
; metabolism
; net primary production
; oceanic general circulation model
; oligotrophic environment
; open ocean
; organic carbon
; respiration
; seasonal variation
; Atlantic Ocean
; Atlantic Ocean (North)
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| 英文摘要: | The metabolic state of the oligotrophic subtropical ocean has long been debated. Net community production (NCP) represents the balance of autotrophic carbon fixation with heterotrophic respiration. Many in vitro NCP estimates based on oxygen incubation methods and the corresponding scaling relationships used to predict the ecosystem metabolic balance have suggested the ocean gyres to be net heterotrophic; however, all in situ NCP methods find net autotrophy. Reconciling net heterotrophy requires significant allochthonous inputs of organic carbon to the oligotrophic gyres to sustain a preponderance of respiration over in situ production. Here we use the first global ecosystem-ocean circulation model that contains representation of the three allochthonous carbon sources to the open ocean, to show that the five oligotrophic gyres exhibit modest net autotrophy throughout the seasonal cycle. Annually integrated rates of NCP vary in the range ~1.5–2.2 mol O2 m−2 yr−1 across the five gyre systems; however, seasonal NCP rates are as low as ~1 ± 0.5 mmol O2 m−2 d−1 for the North Atlantic. Volumetric NCP rates are heterotrophic below the 10% light level; however, they become net autotrophic when integrated over the euphotic zone. Observational uncertainties when measuring these modest autotrophic NCP rates as well as the metabolic diversity encountered across space and time complicate the scaling up of in vitro measurements to the ecosystem scale and may partially explain the previous reports of net heterotrophy. The oligotrophic ocean is autotrophic at present; however, it could shift toward seasonal heterotrophy in the future as rising temperatures stimulate respiration. ©2017. American Geophysical Union. All Rights Reserved. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/77749
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| Appears in Collections: | 气候变化事实与影响
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作者单位: | Earth System Science, University of California, Irvine, CA, United States
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| Recommended Citation: | |
Letscher R,T,, Moore J,et al. Modest net autotrophy in the oligotrophic ocean[J]. Global Biogeochemical Cycles,2017-01-01,31(4)
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