Distribution of the marine cyanobacteria Trichodesmium and their association with iron-rich particles in the South Atlantic Ocean
Distribution of the marine cyanobacteria Trichodesmium and their association with iron-rich particles in the South Atlantic Ocean
复制标题
DOI：
10.3354/ame01810
复制
发表时间：
2016-01-01
影响因子：
1.4
通讯作者：
Yunes, Joao Sarkis
中科院分区：
文献类型：
--
作者：
Bif, Mariana Bernardi;Yunes, Joao Sarkis
由于毛藻属的成员具有固定大气氮 (N-2) 的能力，因此常见于营养有限的热带和亚热带海洋盆地。然而，N-2 固定需要补充铁和磷，这可能成为毛藻生长的限制营养物质。为了了解南大西洋一个研究较少的地区毛藻的生态和分布，我们从密集的种群中收集了物理、化学和生物数据。尽管磷酸盐浓度相对较低（157 000 个毛状体 l(-1)）。使用光学显微镜，发现生物颗粒和石质颗粒的混合物附着在菌落上；成分分析显示含有高浓度的铁（平均颗粒成分的 12-29%）、磷（1-3%）和锌（1-5%）。来自最南端站的颗粒具有独特的钛成分（5-6%），这被认为是拉普拉塔河羽流沉积物区域输入的示踪剂。细菌与一些 Trichodesmium 菌落相关，表明颗粒溶解和再矿化是增加营养物质可用性的机制，从而促进 N-2 固定。这项研究提供了有关南大西洋毛藻的分布及其与颗粒和细菌的关系的新信息，以适应额外的营养获取。
Members of the genus Trichodesmium are commonly found in nutrient-limited tropical and subtropical ocean basins due to their capacity to fix atmospheric nitrogen (N-2). However, N-2 fixation requires supplementary iron and phosphorus, which can potentially become limiting nutrients for the growth of Trichodesmium. In order to understand the ecology and distribution of Trichodesmium in a poorly studied region of the South Atlantic Ocean, we collected physical, chemical, and biological data from dense populations. Despite relatively low concentrations of phosphate (157 000 trichomes l(-1)). Using light microscopy, mixtures of biogenic and lithogenic particles were found attached to the colonies; composition analysis revealed high concentrations of iron (12-29% of the average particle composition), phosphorus (1-3%), and zinc (1-5%). Particles from the southernmost stations were unique in their titanium composition (5-6%), which was considered a tracer for the regional input of sediments by the La Plata River plume. Bacteria were associated with some Trichodesmium colonies, suggesting particle dissolution and remineralization as a mechanism for increasing the availability of nutrients, thus facilitating N-2 fixation. This study provides new information about the distribution of Trichodesmium in the South Atlantic Ocean and its association with particles and bacteria as an adaptation for extra nutrient acquisition.