Does the transport of dissolved organic nutrients affect export production in the Atlantic Ocean?
Does the transport of dissolved organic nutrients affect export production in the Atlantic Ocean?
复制标题
溶解有机养分的运输是否会影响大西洋的出口生产？
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
G. Wolff
中科院分区：
文献类型：
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作者：
V. Roussenov;Richard G. Williams;C. Mahaffey;G. Wolff
在最近沿子午样带测量的基础上，对大西洋应用了无机营养物和溶解有机氮（DON）和磷（DOP）的简化循环和运输模型。DON和DOP分为半溶池和难溶池，前者的寿命为6个月，后者保存在内部，但在光化学反应区分解，其寿命为6 - 12年。半可溶池通常只占表面DON的10%，但占DOP的95%。在透光区，DON和DOP优先在上升流区产生。DON和DOP的地表浓度升高通常发生在混合层较薄的热带地区，但在混合层较厚的高纬度地区则被稀释。作为Ekman风驱动环流和翻转环流的一部分，DON和DOP从热带向北输送到副热带北部环流。同时，硝酸盐和磷酸盐的深度整合向南输送导致北大西洋副热带地区硝酸盐和磷酸盐的损失，这部分由DON和DOP的供应补偿。与背景模式粒子输出0.2 mol N m−2 yr−1相比，DON输入增强了副热带环流的粒子输出，典型的增强幅度为0.05 mol N m−2 yr−1。DOP的输入似乎更为显著（由于其耐火含量较小），通常在副热带环流中增加12 mmol P m−2 yr−1的颗粒输出，这足以满足颗粒输出所需磷的一半。
A simplified cycling and transport model for inorganic nutrients and dissolved organic nitrogen (DON) and phosphorus (DOP) is applied to the Atlantic, on the basis of recent measurements along a meridional transect. The DON and DOP are separated into semilabile pools with a lifetime of 6 months and a refractory pool which is conserved in the interior, but photochemically breaks down in the euphotic zone with a lifetime of 6–12 years. The semilabile pool typically only makes up 10% of the surface DON, but up to 95% of DOP. DON and DOP are preferentially produced over upwelling zones in the euphotic zone. Elevated surface concentrations of DON and DOP generally occur over the tropics where the mixed layer is thin, but become diluted at higher latitudes where the mixed layer is thick. There is a northward transport of DON and DOP from the tropics into the northern subtropical gyre, as part of the Ekman wind‐driven circulation and overturning circulation. At the same time, there is a depth‐integrated southward transport of nitrate and phosphate leading to a loss of nitrate and phosphate over the subtropics of the North Atlantic, which is partly compensated by the supply of DON and DOP. Inputs of DON enhance the particle export over the subtropical gyres by typically 0.05 mol N m−2 yr−1, compared with a background model particle export of typically 0.2 mol N m−2 yr−1. Inputs of DOP appear to be more significant (owing to their smaller refractory content) in increasing particle export by typically 12 mmol P m−2 yr−1 over the subtropical gyre, which is sufficiently large to supply half of the phosphorus requirements for particle export.