Benthic solute exchange and carbon mineralization in two shallow subtidal sandy sediments:: Effect of advective pore-water exchange
Benthic solute exchange and carbon mineralization in two shallow subtidal sandy sediments:: Effect of advective pore-water exchange
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DOI：
10.4319/lo.2007.52.5.1943
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发表时间：
2007-09-01
影响因子：
4.5
通讯作者：
Huettel, Markus
中科院分区：
文献类型：
--
作者：
Cook, Perran L. M.;Wenzhofer, Frank;Huettel, Markus
我们进行了四个实地活动，以评估底栖动物的O-2消耗和平流孔隙水流在近岸渗透性沉积物在北海和波罗的海的影响。对流孔隙水输送对底栖箱孵化中的O-2和TCO 2底栖交换有显著影响，与仅扩散交换的设置相比，当施加100-300 L m（-2）d（-1）的冲洗速率时，交换率增加高达2.5倍。估计原位交换率使用氧气渗透和体积O-2消耗和TCO 2生产率的范围内测量的腔室。平流溶质交换的贡献是高度可变的，并依赖于沉积物地形。平流过程也有显着的影响，在原位分布的O-2内的沉积物，与特征的二维模式的O-2分布在整个涟漪，也深地下O-2池，被观察到。当底栖生物矿化率低，平流孔隙水流量高，由于沉积物地形发育良好，矿化途径主要是有氧的。相比之下，矿化主要是通过硫酸盐还原时，底栖生物矿化率高，平流孔隙水流量低，由于地形不发达。以前的研究底栖矿化浅桑迪沉积物一般忽略了这些动态，因此，忽略了渗透性沉积物在沿海生态系统中的功能的关键方面。
We conducted four field campaigns to evaluate benthic O-2 consumption and the effect of advective pore-water flow in nearshore permeable sediments in the North Sea and Baltic Sea. Advective pore-water transport had a marked effect on the benthic exchange of O-2 and TCO2 in benthic chamber incubations, with the rates of exchange increasing by a factor of up to 2.5 when imposing flushing rates of 100-300 L m(-2) d(-1), compared to settings with diffusive exchange only. Estimates of in situ exchange rates using oxygen penetration and volumetric O-2 consumption and TCO2 production rates were within the range measured in the chambers. The contribution of advection to solute exchange was highly variable and dependent on sediment topography. Advective processes also had a pronounced influence on the in situ distribution of O-2 within the sediment, with characteristic two-dimensional patterns of O-2 distribution across ripples, and also deep subsurface O-2 pools, being observed. Mineralization pathways were predominantly aerobic when benthic mineralization rates were low and advective pore-water flow high as a result of well-developed sediment topography. By contrast, mineralization proceeded predominantly through sulfate reduction when benthic mineralization rates were high and advective pore-water flow low as a result of poorly developed topography. Previous studies of benthic mineralization in shallow sandy sediments have generally ignored these dynamics and, hence, have overlooked crucial aspects of permeable sediment function in coastal ecosystems.