Sources, degradation, and transport of organic matter in the New Britain Shelf-Trench Continuum, Papua New Guinea
Sources, degradation, and transport of organic matter in the New Britain Shelf-Trench Continuum, Papua New Guinea
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巴布亚新几内亚新不列颠陆架海沟连续体有机物的来源、降解和迁移
DOI：
10.1029/2018jg004691
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Chen Duofu
中科院分区：
文献类型：
--
作者：
Luo Min;Gieskes Joris;Chen Linying;Scholten Jan;Pan Binbin;Lin Gang;Chen Duofu
深海海沟被认为是有机质的沉积中心和微生物成岩活动的热点。在这里，我们探索的来源，降解和运输的有机物在陆架-海沟连续使用7个短沉积物岩心收集沿着两个断面之间的水深1,553和8,901米，在新不列颠海沟地区，巴布亚新几内亚。沉积有机质的碳同位素组成（δ 13 C）和放射性碳含量（Δ 14 C）以及总有机碳/总氮比值（TOC/TN）表明，沉积前期土壤有机质主要来自海藻和陆源C3维管植物的混合。此外，海沟轴部位的特点是陆源有机物质的堆积升高。用沉积物-水界面溶解无机碳通量估算的有机物矿化速率表明，海沟轴部位的矿化速率比深海部位高出约三倍。（高达50%）反映了最近可能由地震引起的质量消耗事件的发生，这是造成前老化，陆源有机物沉积到海沟底部。这种构造触发的沉积事件，这也被证明是发生在日本海沟，汤加海沟，并可能在许多其他的海沟，可能有效地运输陆源有机质的超深海沟，从而支持陆源有机质埋藏在超深海沟的海洋有机碳预算的重要性。此外，我们假设，超深渊沟可能有一个独特的微生物群落，能够喂养的老，难降解的陆源有机物。
Hadal trenches are considered as depocenters for organic matter and hotspots for microbial diagenetic activity. Here, we explore the sources, degradation, and transport of organic matter in the shelf‐trench continuum using seven short sediment cores collected along two transects with water depths ranging between 1,553 and 8,901 m in the New Britain Trench area, Papua New Guinea. Carbon isotopic compositions (δ13C) and radiocarbon contents (Δ14C) of sedimentary organic matter accompanied by total organic carbon/total nitrogen ratios suggest an important contribution from the preaged soil organic matter mixed by the marine algae and terrigenous C3vascular plants. In addition, the trench axis sites are characterized by elevated accumulation of terrigenous organic materials. Rates of organic matter mineralization approximated by dissolved inorganic carbon fluxes at the sediment‐water interface reveal an approximately threefold higher rate at the trench axis sites than the abyssal sites.210Pbxsprofiles and burial of carbonate (up to 50%) at both trench axis sites reflect recent occurrence of mass‐wasting events possibly induced by earthquakes, which is responsible for the transport of preaged, terrigenous organic matter to the trench bottom. This tectonically triggered deposition event, which was also shown to occur in the Japan Trench, the Tonga Trench, and probably in many other trenches, is likely to efficiently transport terrigenous organic matter to hadal trenches, thereby underpinning the importance of terrigenous organic matter burial in hadal trenches for the ocean organic carbon budget. Furthermore, we hypothesize that hadal trenches may host a distinct microbial community that is capable of feeding on old, refractory terrigenous organic matter.