Abstract Organic-rich sediments of the southernmost Chilean Pacific coast and its fjord system constitute an important component of the global marine carbon budget. Sediment records from Trampa and Caribe bays and Churruca fjord in the western Magellan fjord system have been analyzed with the goal of understanding the factors controlling carbon accumulation and its regional fluctuation throughout the Holocene. The individual response in paleoproductivity at the different sites and related variations in accumulation rates document a very complex interplay among local and regional-scale environmental changes, and coastline elevation across the Holocene. Shallow sill basins close to the Pacific coast, as the ones studied here, are particularly sensitive to these processes, having responded with strong productivity changes throughout the Holocene. A Bayesian mixed model approach, using sediment archived provenance proxies, indicates that components of terrestrial plants and soils washed-out into these basins contribute with a variable proportion (20–80 wt%) of the total accumulated organic carbon. Accumulation rates of terrestrial carbon increase with the amount of precipitation in the hyper-humid mountain area, but also reflect distinct Holocene plant successions as well as long-term development of soil and vegetation cover that strongly overprint the direct precipitation impact. Over the Holocene accumulation rates of biogenic carbonate and aquatic-marine organic carbon range between 5 and 118 kg m−2 kyr−1 and 0.3–20 kg m−2 kyr−1, respectively. This variability depends on water column structure and conditions, which are regulated by the degree of marine transgression as a function of post glacial sea level rise and isostatic uplift as well as precipitation-related surface water freshening. In the Bahia Trampa record, a significant change in accumulation rates indicates a marine transgression at ca. 12.2 kyr BP, when the global sea level was 60–70 m lower than today and eustatic rise overcame isostatic rebound rates. In Caribe and Trampa records, CaCO3 accumulation rates were higher at ca. 7 kyr BP. The Churruca record shows organic carbon accumulation rates up to 36.2 kg m−2 kyr−1 during the early Holocene.

中文翻译：

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控制麦哲伦海峡西部峡湾全新世碳积累速率的环境和海岸线变化

摘要 智利太平洋最南端及其峡湾系统的富含有机质沉积物是全球海洋碳收支的重要组成部分。分析了麦哲伦峡湾系统西部 Trampa 和 Caribe 湾以及 Churruca 峡湾的沉积物记录，目的是了解控制碳积累的因素及其整个全新世的区域波动。不同地点古生产力的个体反应和积累率的相关变化记录了局部和区域尺度环境变化与全新世海岸线海拔之间非常复杂的相互作用。正如这里所研究的那样，靠近太平洋沿岸的浅基岩盆地对这些过程特别敏感，在整个全新世期间以强烈的生产力变化作为回应。贝叶斯混合模型方法，使用沉积物存档的来源代理，表明陆生植物和土壤的成分被冲刷到这些盆地中，贡献了总累积有机碳的可变比例（20-80 重量％）。在高湿山区，陆地碳的积累率随着降水量的增加而增加，但也反映了独特的全新世植物演替以及土壤和植被覆盖的长期发展，强烈叠加直接降水影响。在全新世，生物碳酸盐和水生-海洋有机碳的积累率分别在 5 到 118 kg m-2 kyr-1 和 0.3-20 kg m-2 kyr-1 之间。这种可变性取决于水柱结构和条件，受海侵程度的调节，该程度是冰川后海平面上升和均衡抬升以及与降水相关的地表水变淡的函数。在 Bahia Trampa 记录中，积累率的显着变化表明大约发生了海侵。12.2 kyr BP，当时全球海平面比今天低 60-70 m，并且海平面上升克服了均衡反弹率。在 Caribe 和 Trampa 记录中，CaCO3 积累率在大约 7 基尔 BP。Churruca 记录显示在全新世早期有机碳积累率高达 36.2 kg m-2 kyr-1。当全球海平面比今天低 60-70 m 时，海平面上升超过了均衡反弹率。在 Caribe 和 Trampa 记录中，CaCO3 积累率在约 7 基尔 BP。Churruca 记录显示在全新世早期有机碳积累率高达 36.2 kg m-2 kyr-1。当全球海平面比今天低 60-70 m 时，海平面上升超过了均衡反弹率。在 Caribe 和 Trampa 记录中，CaCO3 积累率在约 7 基尔 BP。Churruca 记录显示在全新世早期有机碳积累率高达 36.2 kg m-2 kyr-1。