Rapid formation of large aggregates during the spring bloom of Kerguelen Island: observations and model comparisons
Rapid formation of large aggregates during the spring bloom of Kerguelen Island: observations and model comparisons
复制标题
凯尔盖朗岛春季开花期间大聚集体的快速形成：观测和模型比较
DOI：
10.5194/bg-11-4393-2014
复制
发表时间：
2014
期刊：
影响因子：
4.9
通讯作者：
S. Blain
中科院分区：
文献类型：
--
作者：
M.;G. Jackson;F. Carlotti;M. Picheral;L. Stemmann;S. Blain
虽然聚集体的产生及其随后的下沉是有机物从透光层向下运动的一种途径，但以前从未报道过从非聚集颗粒到聚集颗粒的快速转变。在Kerguelen海洋和高原比较研究巡航2（KEOPS2，2011年10月至11月）期间，我们使用水下视觉剖面仪在开花前阶段制作了一个颗粒尺寸分布（PSD;尺寸范围为0.052至几毫米当量球直径）的垂直剖面，并在开花早期阶段的48小时内制作了7个垂直剖面。在这些自然铁肥沃茨东南Kerguelen岛（南大洋），总粒子数量丰度增加了四倍以上，在此期间。在48小时的调查中观察到与粒径分布变化相关的大量总体积增加，表明大颗粒的快速形成及其在混合层底部的积累。一维粒子动力学模型的结果支持凝聚的机制负责快速聚集体的形成和发展的VT次表面最大值。水华初期和水华前期的VT剖面比较表明，水华发生后，200 m以下的颗粒输出量增加。这些结果突出了凝聚在形成大颗粒和触发碳出口的早期阶段的自然铁肥开花的作用，而浮游动物放牧可能占主导地位的季节晚些时候。观察到的快速变化说明迫切需要测量碳输出通量与高采样时间分辨率。我们的研究结果是第一次发表在现场观测的快速积累的海洋聚集体和他们的出口，这一快速的事件与浮游植物生长和凝结的模型的一般协议。
While production of aggregates and their subsequent sinking is known to be one pathway for the downward movement of organic matter from the euphotic zone, the rapid transition from non-aggregated to aggregated particles has not been reported previously. We made one vertical profile of particle size distributions (PSD; sizes ranging from 0.052 to several millimeters in equivalent spherical diameter) at pre-bloom stage and seven vertical profiles 3 weeks later over a 48 h period at early bloom stage using the Underwater Vision Profiler during the Kerguelen Ocean and Plateau Compared Study cruise 2 (KEOPS2, October– November 2011). In these naturally iron-fertilized waters southeast of Kerguelen Island (Southern Ocean), the total particle numerical abundance increased by more than four-fold within this time period. A massive total volume increase associated with particle size distribution changes was observed over the 48 h survey, showing the rapid formation of large particles and their accumulation at the base of the mixed layer. The results of a one-dimensional particle dynamics model support coagulation as the mechanism responsible for the rapid aggregate formation and the development of the V T subsurface maxima. The comparison of V T profiles between early bloom stage and pre-bloom stage indicates an increase of particulate export below 200 m when bloom has developed. These results highlight the role of coagulation in forming large particles and triggering carbon export at the early stage of a naturally iron-fertilized bloom, while zoo-plankton grazing may dominate later in the season. The rapid changes observed illustrate the critical need to measure carbon export flux with high sampling temporal resolution. Our results are the first published in situ observations of the rapid accumulation of marine aggregates and their export and the general agreement of this rapid event with a model of phyto-plankton growth and coagulation.
影响因子：
4.5
作者：
H. Ploug;M. Iversen;G. Fischer
通讯作者：
H. Ploug;M. Iversen;G. Fischer