Modelling terrigenous DOC across the north west European Shelf: Fate of riverine input and impact on air-sea CO2 fluxes
Modelling terrigenous DOC across the north west European Shelf: Fate of riverine input and impact on air-sea CO2 fluxes
复制标题
对欧洲西北部大陆架的陆源 DOC 进行建模：河流输入的命运及其对海气 CO2 通量的影响
DOI：
10.1016/j.scitotenv.2023.168938
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发表时间：
2024
影响因子：
9.8
通讯作者：
Powley H
中科院分区：
文献类型：
--
作者：
Powley H
水生系统中的陆源碳越来越被认为是全球碳循环的重要组成部分。尽管如此，人们对海岸和海洋系统中陆源溶解有机碳（tDOC）的命运和分布知之甚少。我们在西北欧大陆架的三维水动力-生物地球化学模型中实现了tDOC从陆地到海洋连续体退化的理论框架。该模型的一个关键特征是光化学和细菌tDOC降解率都与年龄有关，这是我们描述海洋环境中碳循环能力的一个进步。在1986-2015年期间，182±17 Gmol / yr的河流tDOC输入到陆架。结果表明，细菌降解是去除陆架上tDOC的最主要过程，占总去除通量的73±6%(132±11 Gmol yr - 1)，而河流tDOC的21±3%（39±6 Gmol yr - 1）被平流排出陆架，光化学降解去除河流通量的5±0.5%。在模式中明确地包括tDOC使海气二氧化碳（CO2）通量减少了112±8 Gmol yr - 1(4±0.4%)，大约相当于英国化学工业在2020年释放的二氧化碳量。这一减少量相当于流入货架的河流tDOC的62%，而流入食物网的河流tDOC约为17%。这项工作可以改进地球系统模型对tDOC命运的假设，并表明在模型中纳入tDOC可以影响生态系统动力学和改变预测的全球海洋碳收支。
Terrigenous carbon in aquatic systems is increasingly recognised as an important part of the global carbon cycle. Despite this, the fate and distribution of terrigenous dissolved organic carbon (tDOC) in coastal and oceanic systems is poorly understood. We have implemented a theoretical framework for the degradation of tDOC across the land to ocean continuum in a 3D hydrodynamical-biogeochemical model on the North West European Shelf. A key feature of this model is that both photochemical and bacterial tDOC degradation rates are age dependant constituting an advance in our ability to describe carbon cycling in the marine environment. Over the time period 1986-2015, 182±17 Gmol yr−1of riverine tDOC is input to the shelf. Results indicate that bacterial degradation is by far the most important process in removing tDOC on the shelf, contributing to 73±6 % (132±11 Gmol yr−1) of the total removal flux, while 21±3 % (39±6 Gmol yr−1) of riverine tDOC was advected away from the shelf and photochemical degradation removing 5±0.5 % of the riverine flux. Explicitly including tDOC in the model decreased the air-sea carbon dioxide (CO2) flux by 112±8 Gmol yr−1(4±0.4 %), an amount approximately equivalent to the CO2released by the UK chemical industry in 2020. The reduction is equivalent to 62 % of the riverine tDOC input to the shelf while approximately 17 % of riverine input is incorporated into the foodweb. This work can improve the assumptions of the fate of tDOC by Earth System Models and demonstrates that the inclusion of tDOC in models can impact ecosystem dynamics and change predicted global carbon budgets for the ocean.