Nutrient regimes control phytoplankton ecophysiology in the South Atlantic
Nutrient regimes control phytoplankton ecophysiology in the South Atlantic
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DOI：
10.5194/bg-11-463-2014
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发表时间：
2014-01-01
期刊：
影响因子：
4.9
通讯作者：
Henderson, G. M.
中科院分区：
文献类型：
--
作者：
Browning, T. J.;Bouman, H. A.;Henderson, G. M.
快速重复率荧光测定法（FRRf）测量浮游植物physiology从跨流域南大西洋巡航（作为GEOTRACES计划的一部分）的特点是两个占主导地位的生态生理制度的基础上解释的营养限制。在东大西洋海盆南极绕极流（ACC）北方亚南极区的南亚热带辐合带（SSTC）以南，沃茨的特征是叶绿素浓度升高，大型浮游植物细胞占主导地位，表观光化学效率（F-v/F-m）较低。船上24小时铁（Fe）添加孵育实验证实，Fe应力是主要负责低F-v/F-m，与Fe除了这些沃茨，无论是在人工瓶添加或天然发生的下游富集从戈夫岛，显着增加F-v/F-m值。在南大西洋环流南部边界的SSTC以北，浮游植物的特点是高值的F-v/F-m，再加上低的常量营养素浓度和增加的存在的picocyanobacteria，被解释为条件的Fe充满，平衡的常量营养素有限的增长。F-v/F-m和Fe：硝酸盐比值之间的空间相关性被发现，支持这两种营养盐的相对供应比可以控制模式的限制，从而在亚热带环流和ACC制度的浮游植物的生理生态。
Fast Repetition Rate fluorometry (FRRf) measurements of phytoplankton photophysiology from an across-basin South Atlantic cruise (as part of the GEOTRACES programme) characterised two dominant ecophysiological regimes which were interpreted on the basis of nutrient limitation. South of the South Subtropical Convergence (SSTC) in the northern sub-Antarctic sector of the Antarctic Circumpolar Current (ACC) in the Eastern Atlantic Basin, waters are characterised by elevated chlorophyll concentrations, a dominance by larger phytoplankton cells, and low apparent photochemical efficiency (F-v/F-m). Shipboard 24 h iron (Fe) addition incubation experiments confirmed that Fe stress was primarily responsible for the low F-v/F-m, with Fe addition to these waters, either within the artificial bottle additions or naturally occurring downstream enrichment from Gough Island, significantly increasing F-v/F-m values. To the north of the SSTC at the southern boundary of the South Atlantic Gyre, phytoplankton are characterised by high values of F-v/F-m which, coupled with the low macronutrient concentrations and increased presence of picocyanobacteria, are interpreted as conditions of Fe replete, balanced macronutrient-limited growth. Spatial correlation was found between F-v/F-m and Fe: nitrate ratios, supporting the suggestion that the relative supply ratios of these two nutrients can control patterns of limitation and consequently the ecophysiology of phytoplankton in subtropical gyre and ACC regimes.