Abstract. Quantification and mapping of surficial seabed sediment organic carbon have wide-scale relevance for marine ecology, geology and environmental resource management, with carbon densities and accumulation rates being a major indicator of geological history, ecological function and ecosystem service provisioning, including the potential to contribute to nature-based climate change mitigation. While global analyses can appear to provide a definitive understanding of the spatial distribution of sediment carbon, regional maps may be constructed at finer resolutions and can utilise targeted data syntheses and refined spatial data products and therefore have the potential to improve these estimates. Here, we report a national systematic review of data on organic carbon content in seabed sediments across Canada and combine this with a synthesis and unification of the best available data on sediment composition, seafloor morphology, hydrology, chemistry and geographic settings within a machine learning mapping framework. Predictive quantitative maps of mud content, dry bulk density, organic carbon content and organic carbon density were produced along with cell-specific estimates of their uncertainty at 200 m resolution across 4 489 235 km2 of the Canadian continental margin (92.6 % of the seafloor area above 2500 m) (https://doi.org/10.5683/SP3/ICHVVA, Epstein et al., 2024). Fine-scale variation in carbon stocks was identified across the Canadian continental margin, particularly in the Pacific Ocean and Atlantic Ocean regions. Overall, we estimate the standing stock of organic carbon in the top 30 cm of surficial seabed sediments across the Canadian shelf and slope to be 10.9 Gt (7.0–16.0 Gt). Increased empirical sediment data collection and higher precision in spatial environmental data layers could significantly reduce uncertainty and increase accuracy in these products over time.

中文翻译：

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加拿大大陆边缘表层沉积物中有机碳储量的预测绘图

摘要。表层海底沉积物有机碳的量化和绘图与海洋生态、地质和环境资源管理具有广泛的相关性，碳密度和积累率是地质历史、生态功能和生态系统服务提供的主要指标，包括贡献潜力以自然为基础的气候变化减缓。虽然全球分析似乎可以提供对沉积物碳的空间分布的明确了解，但区域地图可以以更精细的分辨率构建，并且可以利用有针对性的数据合成和精细的空间数据产品，因此有可能改进这些估计。在这里，我们报告了对加拿大海底沉积物有机碳含量数据的全国系统审查，并将其与机器学习绘图中有关沉积物成分、海底形态、水文学、化学和地理环境的最佳可用数据的综合和统一相结合框架。绘制了加拿大大陆边缘 4 489 235 km2（占海底面积的 92.6%）泥浆含量、干容重、有机碳含量和有机碳密度的预测定量图，以及 200 m 分辨率下的不确定性的单元特定估计值。 2500 m 以上）（https://doi.org/10.5683/SP3/ICHVVA，Epstein 等人，2024）。整个加拿大大陆边缘，特别是太平洋和大西洋地区，都发现了碳储量的细微变化。总体而言，我们估计加拿大陆架和斜坡表层海底沉积物顶部 30 厘米的有机碳储量为 10.9 Gt (7.0–16.0 Gt)。随着时间的推移，增加经验沉积物数据收集和提高空间环境数据层的精度可以显着减少不确定性并提高这些产品的准确性。