Mediation of macronutrients and carbon by post-disturbance shelf sea sediment communities
Mediation of macronutrients and carbon by post-disturbance shelf sea sediment communities
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DOI：
10.1007/s10533-017-0350-9
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发表时间：
2017-09-01
期刊：
影响因子：
4
通讯作者：
Solan, Martin
中科院分区：
文献类型：
--
作者：
Hale, Rachel;Godbold, Jasmin A.;Solan, Martin
底栖生物群落在有机物矿化和陆架海生物地球化学许多方面的调节中发挥着重要作用。很少有研究考虑到群落结构的变化与不同程度的物理干扰影响沉积物的常量营养素和碳的干扰停止后。在这里，我们调查的动物活动（沉积物颗粒改造和生物灌溉）的社区已经存活对比水平的底鱼捕捞影响沉积物有机碳含量和常量营养素浓度（[NH 4-N]，[NO2-N]，[NO3-N]，[PO 4-P]，[SiO 4-Si]）。我们发现，有机碳含量和[NO3-N]下降的粘性沉积物群落，经历了捕捞频率的增加，而[NH 4-N]，[NO2-N]，[PO 4-P]和[SiO 4-Si]不受影响。[NH 4-N]在非粘性沉积物中增加，经历了更高的捕鱼频率。进一步的分析表明，群落的结构调整的方式是不同的沉积物类型和捕捞频率之间的物理干扰，但群落结构的变化并没有影响生物扰动和相关的有机碳和营养物浓度的水平。我们的研究结果表明，在物理干扰的存在下，无论沉积物类型，大量营养元素和碳循环的调解越来越多地反映了生物体-沉积物关系的脱钩。事实上，对于维持生物地球化学功能最重要的是，在扰动后不成比例地表现出来的，是居住在沉积物-水界面或占据沉积物剖面较深部分的物种的特征。
Benthic communities play a major role in organic matter remineralisation and the mediation of many aspects of shelf sea biogeochemistry. Few studies have considered how changes in community structure associated with different levels of physical disturbance affect sediment macronutrients and carbon following the cessation of disturbance. Here, we investigate how faunal activity (sediment particle reworking and bioirrigation) in communities that have survived contrasting levels of bottom fishing affect sediment organic carbon content and macronutrient concentrations ([NH4-N], [NO2-N], [NO3-N], [PO4-P], [SiO4-Si]). We find that organic carbon content and [NO3-N] decline in cohesive sediment communities that have experienced an increased frequency of fishing, whilst [NH4-N], [NO2-N], [PO4-P] and [SiO4-Si] are not affected. [NH4-N] increases in non-cohesive sediments that have experienced a higher frequency of fishing. Further analyses reveal that the way communities are restructured by physical disturbance differs between sediment type and with fishing frequency, but that changes in community structure do little to affect bioturbation and associated levels of organic carbon and nutrient concentrations. Our results suggest that in the presence of physical disturbance, irrespective of sediment type, the mediation of macronutrient and carbon cycling increasingly reflects the decoupling of organism-sediment relations. Indeed, it is the traits of the species that reside at the sediment-water interface, or that occupy deeper parts of the sediment profile, that are disproportionately expressed post-disturbance, that are most important for sustaining biogeochemical functioning.