Quantifying Marine Sedimentary Carbon: A New Spatial Analysis Approach Using Seafloor Acoustics, Imagery, and Ground-Truthing Data in Scotland
Quantifying Marine Sedimentary Carbon: A New Spatial Analysis Approach Using Seafloor Acoustics, Imagery, and Ground-Truthing Data in Scotland
复制标题
量化海洋沉积碳：苏格兰海底声学、成像和地面实况数据的新空间分析方法
DOI：
10.3389/fmars.2020.00588
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发表时间：
2020-07-28
影响因子：
3.7
通讯作者：
Austin, William E. N.
中科院分区：
文献类型：
--
作者：
Hunt, Corallie;Demsar, Urska;Austin, William E. N.
海洋沉积物是重要的有机质储存库，有效地将有机碳(OC)埋藏在地质时间尺度上，从而提供气候调节服务。然而，该海相沉积有机碳储集库的空间分布没有得到很好的约束。在这项研究中，我们利用高分辨率多波束回声探测仪(MBES)在苏格兰西海岸的Fjordic模型站点Loch Creran进行测量，以开发一种新的方法来预测表层沉积物中有机碳的分布。采用综合方法，我们使用MBES调查、视频图像和地面真实数据来生成高分辨率(2x2m)的表面碳地图，并计算出10厘米的储量。我们发现，反向散射测量可靠地揭示了一个不均匀的海底，OC与MBES反向散射信号作为沉积物成分的函数具有很强的相关性。我们估计，在MBEs调查区域(7.96公里(2)；总面积的60%)的混合沉积物中，大约有12,346+/-2,677吨有机碳存在，而克里兰湖(13.27公里(2))的有机碳含量则增加到20,577+/-4,462吨(13.27公里(2))。按面积归一化，我们发现含有少量砂和砾石的细粒沉积物比均匀的细粒沉积物含有更多的有机碳。这项初步工作提出了一种新的方法学方法，利用高分辨率的MBES调查来改进沉积碳(C)的空间制图和确定C热点，从而能够在沉积碳核算、海底管理和气候缓解战略中考虑这一资源。
Marine sediments are important repositories of organic matter, effectively burying organic carbon (OC) over geological timescales thus providing a climate regulation service. However, the spatial distribution of this marine sedimentary OC store is not well constrained. In this study we leverage a high resolution multibeam echosounder (MBES) survey taken at Loch Creran, a model fjordic site on the west coast of Scotland, to develop a new methodology for predicting the distribution of OC in surface sediments. Using an integrated approach, we use MBES survey, video imagery and ground-truthing data to produce a high-resolution (2 x 2 m) map of surficial carbon and calculate a 10 cm stock. We find that the backscatter survey reliably uncovers a heterogeneous seabed and that OC correlates strongly with the MBES backscatter signal as a function of sediment composition. We estimate that there are approximately 12,346 +/- 2,677 t of OC held within the top 10 cm of mixed sediments across the MBES survey area (7.96 km(2); 60% of the total area), upscaled to 20,577 +/- 4,462 t of OC across Loch Creran (13.27 km(2)). Normalised by area, we find that fine sediments with small fractions of sand and gravel hold more OC than homogenous fine sediments. This initial work proposes a novel methodological approach to using high resolution MBES surveys to improve the spatial mapping of sedimentary carbon (C) and identification of C hotspots, enabling consideration of this resource in sedimentary carbon accounting, seabed management and climate mitigation strategies.