Direct evidence for nitrogen isotope discrimination during sedimentation and early diagenesis in Lake Kasumigaura, Japan
Direct evidence for nitrogen isotope discrimination during sedimentation and early diagenesis in Lake Kasumigaura, Japan
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DOI：
10.1016/j.orggeochem.2010.10.010
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发表时间：
2011-02-01
影响因子：
3
通讯作者：
Sato, Takayuki
中科院分区：
文献类型：
--
作者：
Kohzu, Ayato;Imai, Akio;Sato, Takayuki
从1979年到2007年，以1个月到5年的时间间隔，从日本霞浦湖中心采集了沉积物岩心样品。我们评价了沉积和成岩作用中氮同位素组成的变化程度。我们估计成岩作用过程中的同位素歧视的程度，通过比较历史变化的N同位素组成的表面沉积物（顶部2厘米）对沉积物芯样（15厘米深）的同位素组成的垂直剖面。沉积过程中的（15）N富集程度似乎是显着的优先N分解，发生在悬浮颗粒有机质的低C/N比值值的时期。我们记录了（15）N亏损沉积物深约3厘米在成岩作用。沉积和成岩过程中氮同位素区别的对比方向表明，同位素迁移跨越氧化还原边界的变化机制。(C)2010爱思唯尔有限公司保留所有权利。
Sediment core samples from the center of Lake Kasumigaura, Japan, were collected from 1979 to 2007 at intervals of 1 month to 5 yr. We evaluated the degree of modification in N isotope composition during sedimentation and diagenesis. We estimated the degree of isotope discrimination during diagenesis by comparing historical changes in N isotope composition of the surface sediment (top 2 cm) against the vertical profile of the isotope composition of sediment core samples (15 cm depth). The degree of (15)N enrichment during sedimentation appeared to be significant under the preferential N decomposition that occurred in the periods with low C/N ratio values of suspended particulate organic matter. We documented (15)N depletion in sediment deeper than approximately 3 cm during diagenesis. The contrasting directions of N isotope discrimination during sedimentation and diagenesis suggest changing mechanisms of isotopic shift across an oxidation-reduction boundary. (C) 2010 Elsevier Ltd. All rights reserved.