Spatial response of coastal marshes to increased atmospheric CO2
Spatial response of coastal marshes to increased atmospheric CO2
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DOI：
10.1073/pnas.1516286112
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发表时间：
2015-12-22
影响因子：
11.1
通讯作者：
Marani, Marco
中科院分区：
文献类型：
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作者：
Ratliff, Katherine M.;Braswell, Anna E.;Marani, Marco
沿海沼泽的海拔和范围取决于相对海平面上升速率（RRSLR）、无机沉积物沉积引起的表面加积和植物产生的有机土壤之间的相互作用。这些增生过程的变化，在当地和全球的强迫，如沉积物输送到海岸，营养物质浓度和大气中的二氧化碳，但其相对重要性沼泽恢复力增加RRSLR仍不清楚。特别是，沼泽吸收大气中的CO2在高速率，从而在全球碳循环中发挥了重要作用，但大气中的CO2浓度增加，气候变化的一个迫在眉睫的方面，尚未被隔离和量化的形态表达。利用现有的观测文献和空间上明确的生态形态动力学模型，我们探讨沼泽增加大气CO2的反应，相对于无机沉积物的可用性和氮水平升高的变化。我们发现，沼泽植被对大气CO2浓度升高的反应是相似的幅度不同的无机泥沙浓度引起的反应，它增加了阈值RRSLR启动沼泽淹没高达60%的强迫范围内探索。此外，我们发现，沼泽的反应是内在的空间依赖性，并不能充分捕获通过0维表示沼泽动态。我们的研究结果意味着，沿海沼泽地，以及它们所代表的主要碳汇，对可预见的气候变化的适应力比以前认为的要大得多。
The elevation and extent of coastal marshes are dictated by the interplay between the rate of relative sea-level rise (RRSLR), surface accretion by inorganic sediment deposition, and organic soil production by plants. These accretion processes respond to changes in local and global forcings, such as sediment delivery to the coast, nutrient concentrations, and atmospheric CO2, but their relative importance for marsh resilience to increasing RRSLR remains unclear. In particular, marshes up-take atmospheric CO2 at high rates, thereby playing a major role in the global carbon cycle, but the morphologic expression of increasing atmospheric CO2 concentration, an imminent aspect of climate change, has not yet been isolated and quantified. Using the available observational literature and a spatially explicit ecomorphodynamic model, we explore marsh responses to increased atmospheric CO2, relative to changes in inorganic sediment availability and elevated nitrogen levels. We find that marsh vegetation response to foreseen elevated atmospheric CO2 is similar in magnitude to the response induced by a varying inorganic sediment concentration, and that it increases the threshold RRSLR initiating marsh submergence by up to 60% in the range of forcings explored. Furthermore, we find that marsh responses are inherently spatially dependent, and cannot be adequately captured through 0-dimensional representations of marsh dynamics. Our results imply that coastal marshes, and the major carbon sink they represent, are significantly more resilient to foreseen climatic changes than previously thought.