This paper assesses the size, shape and spatial organisation of organic, carbon-rich debris (peat blocks) in an upland fluvial peatland ecosystem. Peat block inventories collected in 2002 and 2012 at an alluvial reach of Trout Beck (North Pennines; United Kingdom) provide independent surveys for investigating the physical characteristics and spatial organisation of the organic debris. Peat blocks deposited along the 450 m reach represent a substantial volume of fluvially derived in-channel sediment and carbon flux at the macroscale (total peat volume 11 m3 (2002) and 17 m3 (2012)). Results show that inferred peat block transport distances depend on their size and shape. Smaller and more spherical equant shaped peat blocks are transported 1.62 and 1.72 times the distance of prolate and elongate shaped peat blocks. Downstream fining relationships provide a first-order approximation of peat block degradation rates. These degradation rates are high (up to 2 mm/m for the a-axis) and indicate considerable fine sediment release during transport. Hypsometric relations show that 73% of peat blocks are distributed within 1 channel width of the thalweg, indicating lateral organisation and a pattern of preferential deposition at the active channel margin. The local effects of obstructions from topography, roughness and slope promote peat block deposition, but given the low density of the blocks and close proximity to the flow the potential for re-entrainment is high.

中文翻译：

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高地河流泥炭地生态系统中大型泥炭块的空间组织和物理特征

本文评估了高地河流泥炭地生态系统中有机富碳碎片（泥炭块）的大小、形状和空间组织。2002 年和 2012 年在 Trout Beck（北奔宁山脉；英国）冲积区收集的泥炭块清单为调查有机碎片的物理特征和空间组织提供了独立调查。沿 450 米河段沉积的泥炭块代表了大量河流衍生的河道内沉积物和宏观尺度上的碳通量（泥炭总量为 11 立方米（2002 年）和 17 立方米（2012 年））。结果表明，推断的泥炭块运输距离取决于它们的大小和形状。更小和更多球形等长形泥炭块的运输距离是长形和细长形泥炭块的 1.62 和 1.72 倍。下游细化关系提供了泥炭块降解率的一阶近似值。这些降解率很高（a 轴高达 2 毫米/米），表明在运输过程中释放了相当多的细粒沉积物。Hypsometric 关系表明 73% 的泥炭块分布在 thalweg 的 1 个通道宽度内，表明横向组织和活动通道边缘的优先沉积模式。来自地形、粗糙度和坡度的障碍物的局部影响促进了泥炭块的沉积，但鉴于块的密度低且靠近水流，再夹带的可能性很高。Hypsometric 关系表明 73% 的泥炭块分布在 thalweg 的 1 个通道宽度内，表明横向组织和活动通道边缘的优先沉积模式。来自地形、粗糙度和坡度的障碍物的局部影响促进了泥炭块的沉积，但鉴于块的密度低且靠近水流，再夹带的可能性很高。Hypsometric 关系表明 73% 的泥炭块分布在 thalweg 的 1 个通道宽度内，表明横向组织和活动通道边缘的优先沉积模式。来自地形、粗糙度和坡度的障碍物的局部影响促进了泥炭块的沉积，但鉴于块的密度低且靠近水流，再夹带的可能性很高。