High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth
High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth
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DOI：
10.1038/ngeo1773
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发表时间：
2013-04-01
影响因子：
18.3
通讯作者：
Kitazato, Hiroshi
中科院分区：
文献类型：
--
作者：
Glud, Ronnie N.;Wenzhoefer, Frank;Kitazato, Hiroshi
微生物控制着海洋沉积物中有机物的分解。分解，反过来，有助于海洋养分再生和影响有机碳的保存（1）。一般来说，海底分解率随着水深的增加而下降，尽管鉴于深海深渊的广阔范围，深海沉积物在数量上对全球碳循环很重要（2、3）。然而，海洋最深的区域几乎还没有被探索过（4）。在这里，我们在中西部太平洋马里亚纳海沟的挑战者深渊（Challenger Deep）沉积物中观察到微生物活动，该海沟近11，000米深，是地球上最深的海洋遗址。我们使用了一个自主的微剖面系统来评估底栖动物的耗氧率。我们表明，虽然大型底栖动物的存在是有限的挑战者深，氧气的生物消耗率很高，超过率在附近的6,000米深的网站的两倍。同样，从这两个地点收集的沉积物分析显示，在挑战者深渊的微生物细胞浓度较高。此外，对沉积物Pb-210剖面的分析表明，海沟中沉积物相对较多。我们的结论是，在挑战者深渊的有机物沉积升高保持在极端压力下，这种环境的特点强化微生物的活动。
Microbes control the decomposition of organic matter in marine sediments. Decomposition, in turn, contributes to oceanic nutrient regeneration and influences the preservation of organic carbon(1). Generally, rates of benthic decomposition decline with increasing water depth, although given the vast extent of the abyss, deep-sea sediments are quantitatively important for the global carbon cycle(2,3). However, the deepest regions of the ocean have remained virtually unexplored(4). Here, we present observations of microbial activity in sediments at Challenger Deep in the Mariana Trench in the central west Pacific, which at almost 11,000 m depth represents the deepest oceanic site on Earth. We used an autonomous micro-profiling system to assess benthic oxygen consumption rates. We show that although the presence of macrofauna is restricted at Challenger Deep, rates of biological consumption of oxygen are high, exceeding rates at a nearby 6,000-m-deep site by a factor of two. Consistently, analyses of sediments collected from the two sites reveal higher concentrations of microbial cells at Challenger Deep. Furthermore, analyses of sediment Pb-210 profiles reveal relatively high sediment deposition in the trench. We conclude that the elevated deposition of organic matter at Challenger Deep maintains intensified microbial activity at the extreme pressures that characterize this environment.