Estimates of atmospheric dry deposition and associated input of nutrients to Gulf of Aqaba seawater
Estimates of atmospheric dry deposition and associated input of nutrients to Gulf of Aqaba seawater
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DOI：
10.1029/2006jd007858
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发表时间：
2007-02-27
影响因子：
4.4
通讯作者：
Paytan, Adina
中科院分区：
文献类型：
--
作者：
Chen, Ying;Mills, Sally;Paytan, Adina
[1]2003年8月至2005年9月，计算了以色列埃拉特亚喀巴湾北岸的干沉降速率和可溶性无机氮（N）、磷（P）和铁（Fe）的相关输入。在气溶胶颗粒物的水溶性部分中的主要无机氮化合物是硝酸盐（60%）和铵（38%），平均浓度分别为35和22 nmol m（-3）的空气。可溶性磷酸盐在0.09和2 nmol m（-3）空气之间，平均值为0.4 nmol m（-3）空气。可溶性无机氮和可溶性磷酸盐分别约占可溶性总氮和可溶性总磷的86%和69%;差异归因于有机氮和磷化合物。可溶性气溶胶Fe的平均浓度为0.3 nmol m（-3）空气。我们的测量结果的可溶性营养盐浓度与以前报道的东地中海地区的数据相媲美。干沉降通量的营养素估计每个采样日期使用的尺寸依赖的沉积模型。估算的通量在采样期间变化很大，海水可溶性无机氮、磷和铁的平均通量分别为38、0.2和0.02 mmol m（-2）d（-1）。可溶性磷通量呈季节性变化，冬季（9 ~ 12月）输入量较大。无机N/P的摩尔比在海水中的可溶性部分的干沉积物（范围从32到541）远高于雷德菲尔德比（N/P = 16），这表明大气输入的营养物质增加的可能性，在海湾的P限制。大气沉降可以贡献相当大的比例（35%）的溶解无机氮的真光层期间的分层（4 ~ 10月），该源的氮通量可维持10%以上的表层初级生产力，并可能维持夏季所有的新生产力;然而，由于与沉降通量计算有关的误差和尘埃通量的时间变化，这些估计具有较大的不确定性。大气输入的海水中溶解的铁是在很大的过量相比，所需的浮游植物生长驱动的N沉降。
[1] Dry deposition rates and associated inputs of soluble inorganic nitrogen (N) phosphorus (P) and iron (Fe) were calculated for the north coast of the Gulf of Aqaba in Eilat, Israel, between August 2003 and September 2005. The main inorganic N compounds in the water soluble fraction of aerosol particles were nitrate (60%) and ammonium (38%), with mean concentrations of 35 and 22 nmol m(-3) of air, respectively. Soluble phosphate ranged between 0.09 and 2 nmol m(-3) of air with a mean value of 0.4 nmol m(-3) of air. The soluble inorganic nitrogen and soluble phosphate account for approximately 86% and 69% of total soluble nitrogen and total soluble phosphorus, respectively; the difference is assigned to organic N and P compounds. The mean concentration of soluble aerosol Fe was 0.3 nmol m(-3) of air. Our measurements of the soluble nutrient concentrations are comparable to data previously reported for the eastern Mediterranean area. Dry deposition fluxes of nutrients were estimated for each sampling date using a size-dependent deposition model. The estimated fluxes were highly variable over the sampling period with the mean fluxes of 38, 0.2 and 0.02 mmol m(-2) d(-1) for seawater soluble inorganic N, P and Fe, respectively. The soluble phosphate flux shows a seasonal pattern with higher input during the winter (September to December) than in other seasons. The inorganic N/P molar ratios in the seawater-soluble fraction of the dry deposition (ranging from 32 to 541) were well above the Redfield ratio (N/P = 16), suggesting that atmospheric inputs of nutrients increase the likelihood for P limitation in the Gulf. Atmospheric deposition could contribute a substantial fraction (35%) of dissolved inorganic N to the euphotic zone during the stratification period (April to October), and the N flux from this source could support over 10% of surface primary production and possibly all of the new production during the summer; however, these estimates have a relatively large uncertainty due to error associated with deposition flux calculation and the temporal variability in dust flux. Atmospheric input of seawater-soluble Fe is in large excess compared to that required for the phytoplankton growth driven by the N deposition.