Iron-Stimulated Phytoplankton Blooms in the Southern Ocean: a Brief Review
Iron-Stimulated Phytoplankton Blooms in the Southern Ocean: a Brief Review
复制标题
DOI：
10.1007/s41976-019-00012-y
复制
发表时间：
2019-03
期刊：
影响因子：
--
通讯作者：
S. C. Tripathy;Babula Jena
中科院分区：
文献类型：
--
作者：
S. C. Tripathy;Babula Jena
迄今为止，在南大洋进行了9次铁施肥实验，包括7次人工施肥和2次自然富集事件。1999年2月在极锋以南进行了第一次人工添加铁SOIREE，随后在SO的不同部门进行了六次实验（EisenEx，SOFeX-N，SOFeX-S，EIFEX，SOLAS-SAGE和LOHAFEX），涉及多国和跨学科的努力。此外，在SO群岛下游进行了两项自然施肥研究（KEOPS和CROZEX）。本文总结了在SO中进行的所有铁富集实验的重要发现，并解释了卫星数据观察到的浮游植物水华动力学，并概括了铁夹带到水柱的可能来源。早期人工海洋施肥实验的结果显示，铁对浮游植物生物量，群落组成和输出生产的SO的强烈影响。利用卫星获取的叶绿素a浓度（2002-2016年）来表征SO中浮游植物水华的每月演变。结果表明，在7月（南冬）和1月（南夏），水华的面积范围分别为110万至1810万km 2。水华在有利的环境中是明显的，具有最佳的光照条件，铁的沉积来源于浅水深区域（< 1公里），大陆尘埃平流，以及通过海冰融化从边缘冰区提供铁。在12月和1月（南半球夏季），SO贡献了全球海洋浮游植物水华的60%，水华发生的主导区域位于SO的大西洋部门，这可能归因于从巴塔哥尼亚和区域物理过程的富铁粉尘输入。
Nine iron fertilization experiments have been carried out in the Southern Ocean (SO) so far comprising of seven artificial fertilization and two naturally enriched events. The first artificial iron addition, SOIREE, was conducted south of the polar front in February 1999 followed by six more experiments (EisenEx, SOFeX-N, SOFeX-S, EIFEX, SOLAS-SAGE, and LOHAFEX) took place in different sectors of the SO involving multinational and trans-disciplinary efforts. Besides, two naturally fertilized studies (KEOPS and CROZEX) were carried out in the downstream of the SO islands. This article summarizes the significant findings of all the iron-enrichment experiments carried out in the SO and explains the phytoplankton bloom dynamics as observed by satellite data and recapitulates the possible sources of iron entrainment to the water column. Findings from the earlier artificial ocean fertilization experiments revealed strong influence of iron on phytoplankton biomass, community composition, and export production in the SO. Satellite-derived chlorophyll-a concentrations (2002–2016) are utilized to characterize the monthly evolution of phytoplankton blooms in the SO. Results suggest that the areal extent of the bloom varied from 1.1 to 18.1 million km2during July (austral winter) and January (austral summer), respectively. The blooms are pronounced in a conducive environment with the optimal light condition, sedimentary source of iron from shallow bathymetric region (< 1 km), continental dust advection, and supply of iron from the marginal ice zone through sea-ice melting. In toto, the SO contributes up to 60% of global ocean phytoplankton blooms during December and January (austral summer), and the dominant region of bloom occurrence is located in the Atlantic sector of the SO, which could be ascribed to iron-rich dust input from Patagonia and regional physical processes.