Subseafloor sedimentary life in the South Pacific Gyre
Subseafloor sedimentary life in the South Pacific Gyre
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DOI：
10.1073/pnas.0811793106
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发表时间：
2009-07-14
影响因子：
11.1
通讯作者：
Stancin, Andrea M.
中科院分区：
文献类型：
--
作者：
D'Hondt, Steven;Spivack, Arthur J.;Stancin, Andrea M.
低生产力的南太平洋环流（SPG）是地球上最大的海洋省。它的沉积物积累非常缓慢（每百万年0.1-1米）。这种沉积物含有一个生物群落，其特征是生物量非常低，代谢活性非常低。在取心SPG沉积物的每个深度，平均细胞丰度比以前勘探的所有海底群落的相同深度低3到4个数量级。每个SPG站点的海底沉积群落的净呼吸速率比以前勘探的站点的速率低1至3个数量级。由于低呼吸速率和沉积物的稀薄，在这个地区的大部分沉积物柱中，间隙水都是含氧的。因此，SPG的沉积群落主要是有氧的，不像以前探索的海底群落。水的放射性分解产生的H(2)是该群落重要的电子供体来源。这个群落的每细胞呼吸速率（以氧化/还原当量计算）比以前探索过的厌氧海底群落高约2个数量级。在世界上几乎一半的海洋中，海底沉积物中的呼吸速率和细胞浓度可能接近SPG沉积物中的呼吸速率和细胞浓度。
The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1-1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H(2) by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment.