Hicks N, Ubbara G R, Silburn B, Smith H E K, Kröger S, Parker E R, Sivyer D, Kitidis V, Hatton A, Mayor D J, Stahl H
Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, PA37 1QA UK.
6Present Address: Department of Chemistry, University of Glasgow, University Avenue, Joseph Black Building, Glasgow, G12 8QQ UK.
Biogeochemistry. 2017;135(1):35-47. doi: 10.1007/s10533-017-0326-9. Epub 2017 Mar 29.
Shelf sediments play a vital role in global biogeochemical cycling and are particularly important areas of oxygen consumption and carbon mineralisation. Total benthic oxygen uptake, the sum of diffusive and faunal mediated uptake, is a robust proxy to quantify carbon mineralisation. However, oxygen uptake rates are dynamic, due to the diagenetic processes within the sediment, and can be spatially and temporally variable. Four benthic sites in the Celtic Sea, encompassing gradients of cohesive to permeable sediments, were sampled over four cruises to capture seasonal and spatial changes in oxygen dynamics. Total oxygen uptake (TOU) rates were measured through a suite of incubation experiments and oxygen microelectrode profiles were taken across all four benthic sites to provide the oxygen penetration depth and diffusive oxygen uptake (DOU) rates. The difference between TOU and DOU allowed for quantification of the fauna mediated oxygen uptake and diffusive uptake. High resolution measurements showed clear seasonal and spatial trends, with higher oxygen uptake rates measured in cohesive sediments compared to the permeable sediment. The significant differences in oxygen dynamics between the sediment types were consistent between seasons, with increasing oxygen consumption during and after the phytoplankton bloom. Carbon mineralisation in shelf sediments is strongly influenced by sediment type and seasonality.
陆架沉积物在全球生物地球化学循环中发挥着至关重要的作用，是耗氧和碳矿化的特别重要区域。总底栖生物摄氧量，即扩散介导和动物介导摄氧量之和，是量化碳矿化的可靠指标。然而，由于沉积物中的成岩过程，摄氧率是动态的，并且在空间和时间上可能会有所变化。在凯尔特海的四个底栖地点，涵盖了从粘性沉积物到渗透性沉积物的梯度，在四次巡航中进行了采样，以捕捉氧气动态的季节性和空间变化。通过一系列培养实验测量了总摄氧量（TOU）速率，并在所有四个底栖地点获取了氧微电极剖面，以提供氧渗透深度和扩散性氧摄取（DOU）速率。TOU和DOU之间的差异使得能够量化动物介导的氧摄取和扩散摄取。高分辨率测量显示出明显的季节性和空间趋势，与渗透性沉积物相比，粘性沉积物中的氧摄取率更高。沉积物类型之间氧动态的显著差异在不同季节之间是一致的，在浮游植物大量繁殖期间和之后耗氧量增加。陆架沉积物中的碳矿化受到沉积物类型和季节性的强烈影响。
