Oxygen transfer at the sediment/water interface for sediment bed with rough surface
Oxygen transfer at the sediment/water interface for sediment bed with rough surface
复制标题
粗糙表面沉积物床沉积物/水界面的氧传递
DOI：
10.1029/2018jg004602
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Higashino,M.
中科院分区：
文献类型：
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作者：
S. Ishikawa;S. Kure;R. Yagi;B. PRIYAMBODHO;石川彰真，呉修一;Higashino,M. and Stefan,H.G.;八木隆聖，呉修一;Higashino,M.
建立了粗糙面泥沙床的泥沙需氧量模型。选择水力学中常用的当量泥沙粗糙度来表示粗糙度元素的大小，并将SOD表示为剪切速度所描述的近床湍流强度、微生物耗氧速率(即最大氧化速率)和粗糙度高度的函数。模拟结果表明，床面粗糙度增强了氧气从水柱到底泥表面的传递。床面粗糙度对超氧化物歧化的影响取决于剪切速度和微生物耗氧速率。在微生物摄氧率较低的情况下，随着剪切速度的增加，超氧化物歧化酶迅速趋于恒定值。无论剪切速度如何，床面粗糙度对超氧化物歧化的影响都不大，因为超氧化物歧化可以很大程度上限制侧限。在微生物摄氧率较高的情况下，表面粗糙度对测定超氧化物歧化酶起着重要作用，因为超氧化物歧化酶受水体到底泥表面的氧转移控制，即转移限制。粗糙度越大，水流向底泥表面的氧传递速率越快，剪切速度越大，导致超氧化物歧化能力增强。该模型能较好地再现粗糙床上的实验超氧化物歧化现象。
A model of sediment oxygen demand (SOD) for a sediment bed with a rough surface was presented. The equivalent sand roughness commonly used in hydraulics was chosen to express the size of roughness elements, and SOD was expressed as a function of the intensity of near‐bed turbulence described by the shear velocity; microbial oxygen uptake rate, that is, the maximum oxidation rate; and roughness height. The modeling results show that bed roughness enhances oxygen transfer from the water column to the sediment surface. The effects of bed roughness on SOD depend on both the shear velocity and microbial oxygen uptake rate. At low microbial oxygen uptake rate, SOD approaches a constant value rapidly as the shear velocity increases. Bed roughness barely influences SOD regardless of the shear velocity because SOD can substantially besediment side limiting. The roughness height plays an important role in determining SOD at high microbial oxygen uptake rate, because SOD can be controlled by oxygen transfer from the water column to the sediment surface, that is,transfer limiting. Increasing roughness height makes the oxygen transfer rate from flowing water to the sediment surface faster as well as increasing shear velocity, resulting in raised SOD. The proposed mode can substantially reproduce the experimental SOD for rough bed.