Significance of macroscale peat flux for carbon export in upland fluvial systems

泥炭地含有高达全球陆地碳的30%。然而，这些敏感环境中的许多都受到气候变化和人类造成的退化的严重威胁。在英国，高地泥炭地构成了这种资源的重要组成部分，科学家们已经开发出了描述这些系统的碳收支模型。虽然这类模型正变得越来越复杂，但出口大型(约100-1000毫米长)泥炭块和碎片从未包括在内。然而，泥炭块迁移是高地河流系统有机沉积物总通量的一个重要组成部分，必须包括在碳收支估计中。了解这一独特过程的性质和这种通量的潜在大小是至关重要的，因为河流成分是旱地碳收支中第二重要的组成部分，而旱地管理者现在正在利用碳收支研究来实施碳管理战略。我们的目标是首次确定大型泥炭块运输(&gt；100毫米)在高地集水区碳收支中的重要性。我们将检验三个主要假设：1.泥炭块体输送的启动(通过浮选)是块体尺寸和流动河流的局部水力的函数。这样的过程从未被完全记录下来。2.泥炭块总通量是河流碳通量的重要组成部分，在某些高流量事件中可能会超过颗粒有机通量。目前还没有量化数据来检验这一点。3.在河道内泥炭块运移活跃的地方，由于泥炭块的快速磨损和破裂，下游河流的颗粒有机碳值将会升高。这三个假设将在一系列尺度上进行检验：微观尺度(单个泥炭块尺度)；中观尺度(以河坝尺度储存的泥炭块)；宏观尺度(泥炭块河段沉积物收支)和集水区尺度。这些实验将在北宾宁的摩尔屋和上蒂斯代尔国家级自然保护区进行。监测嵌套在这四个尺度上，涉及一个新颖的集成系统，包括数据记录器、环境传感器和三个远程数码相机。

Peatlands contain up to 30% of global terrestrial carbon. However, many of these sensitive environments are seriously threatened by changing climate and human-induced degradation. Upland peatlands form a significant part of this resource in the UK and scientists have developed carbon budget models to describe these systems. Although such models are becoming increasingly sophisticated, the export of large (c.100-1000 mm length scale) peat blocks and debris has never been included. However, peat block transport is an important component of the total organic sediment flux in upland fluvial systems and must be included in carbon budget estimates. Understanding the nature of this unique process and the potential magnitude of this flux is essential because fluvial components are the second most important component in the upland terrestrial carbon budget and carbon budget studies are now being used by upland managers to implement strategies on carbon stewardship. Our aim is to determine, for the first time, the significance of large peat block transport (> 100 mm) in the carbon budget of an upland catchment. We will test three main hypotheses: 1. The initiation of peat block transport (by flotation) is a function of block dimensions and the local hydraulics of the flowing river. Such a process has NEVER been fully documented. 2. The total peat block flux is a significant component of the total fluvial carbon flux and, in some high flow events may exceed the particulate organic flux. There is currently NO quantitative data to test this. 3. Where active in-channel peat block transport occurs, the river reaches downstream will show elevated values of particulate organic carbon due to rapid abrasion and breakdown of peat blocks. These three hypotheses will be tested at a range of scales: micro (individual peat block scale); meso (peat blocks store at the river bar scale), macro (peat block river reach sediment budget) and catchment scale. These experiments will be carried out at the Moor House and Upper Teesdale National Nature Reserve in the North Pennines. Monitoring is nested at these four scales and involves a novel, integrated system of data loggers, environmental sensors and three remote digital cameras.