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首页> 外文期刊>Biogeosciences >Box-modelling of the impacts of atmospheric nitrogen deposition and benthic remineralisation on the nitrogen cycle of the eastern tropical South Pacific
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Box-modelling of the impacts of atmospheric nitrogen deposition and benthic remineralisation on the nitrogen cycle of the eastern tropical South Pacific

机译:大气氮沉积和底栖再矿化对东方热带南太平洋氮循环影响的箱型建模

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Both atmospheric deposition and benthic remineralisation influence the marine nitrogen cycle, and hence ultimately also marine primary production. The biological and biogeochemical relations in the eastern tropical South Pacific (ETSP) among nitrogen deposition, benthic denitrification and phosphorus regeneration are analysed in a?prognostic box model of the oxygen, nitrogen and phosphorus cycles in the ETSP. Atmospheric nitrogen deposition (?≈?1.5 Tg N yrsup?1/sup for the years 2000–2009) is offset by half in the model by reduced Nsub2/sub fixation, with the other half transported out of the model domain. Model- and data-based benthic denitrification in our model domain are responsible for losses of 0.19 and 1.0?Tg Tg N yrsup?1/sup, respectively, and both trigger nitrogen fixation, partly compensating for the NOsub3/subsup?/sup loss. Model- and data-based estimates of enhanced phosphate release via sedimentary phosphorus regeneration under suboxic conditions are 0.062 and 0.11 Tg N yrsup?1/sup, respectively. Since phosphate is the ultimate limiting nutrient in the model, even very small additional phosphate inputs stimulate primary production and subsequent export production and NOsub3/subsup?/sup loss in the oxygen minimum zone (OMZ). A?sensitivity analysis of the local response to both atmospheric deposition and benthic remineralisation indicates dominant stabilising feedbacks in the ETSP, which tend to keep a?balanced nitrogen inventory; i.e. nitrogen input by atmospheric deposition is counteracted by decreasing nitrogen fixation; NOsub3/subsup?/sup loss via benthic denitrification is partly compensated for by increased nitrogen fixation; enhanced nitrogen fixation stimulated by phosphate regeneration is partly counteracted by stronger water-column denitrification. Even though the water column in our model domain acts as a?NOsub3/subsup?/sup source, the ETSP including benthic denitrification might be a?NOsub3/subsup?/sup sink.
机译:既有大气沉积和底栖再矿化都会影响海洋氮循环,因此最终也是海洋初级生产。在ETSP中氧气,氮和磷循环的氧气,氮和磷循环的预后盒模型中,在氮沉积中的生物和生物地球化学关系(ETSP)中的氮沉积,底栖抵抗和磷再生。大气氮沉积(?≈1.5  Tg  n  n  yr 1 为2000-2009岁)通过减少的n 2 固定来偏移模型中的一半,另一半从模型域输出。我们模型领域的模型和基于数据的底栖抵消负责0.19和1.0?TG&Thinsp; Tg&Thinsp; N&Thinsp; Yr 1 ,以及触发氮固定,部分补偿了否 3 丢失。通过在中解毒条件下通过沉积磷再生通过沉积磷再生的基于模型和基于数据的估计为0.062和0.11&Thinsp; Tg  n  yr ?1 。由于磷酸盐是模型中的最终限制营养素,即使是非常小的磷酸盐输入甚至刺激初级生产和随后的出口生产,并且没有 3 氧气最小区中的损失(OMZ )。 a?对局部沉积局部反应的敏感性分析和底乳酸的响应表明ETSP中的主要稳定反馈,这往往会保持α平衡的氮素库存;即通过减少氮固定来抵消大气沉积的氮气输入; NO 3 β通过弯曲反硝化的损耗通过增加的氮固定部分补偿;通过较强的水柱反硝化,通过磷酸盐再生刺激的增强的氮固定部分地抵消。即使我们的模型域中的水列用作?No 3 源,包括底栖拒绝的ETSP可能是a?no 3 水槽。

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