Algae-bacteria interactions and their effects on aggregation and organic matter flux in the sea
Algae-bacteria interactions and their effects on aggregation and organic matter flux in the sea
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DOI：
10.1111/j.1462-2920.2006.00999.x
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发表时间：
2006-06-01
影响因子：
5.1
通讯作者：
Simon, Meinhard
中科院分区：
文献类型：
--
作者：
Grossart, Hans-Peter;Czub, Gertje;Simon, Meinhard
藻类（主要是硅藻）的聚集是海洋水层系统的一个重要过程，常常终止浮游植物大量繁殖，并导致微粒有机物以海洋雪的形式下沉。这一过程已被广泛研究，但异养细菌的具体作用在很大程度上被忽视，主要是因为现场研究和大多数实验工作是在非纯条件下进行的。我们测试的假设，藻类-细菌的相互作用是有用的聚合动力学和有机物通量。一系列的聚集实验已经进行了滚动罐中的两个典型的温带地区的海洋硅藻（中肋骨条藻和海链藻圆）在无菌处理和一个接种海洋细菌。指数增长的S。中肋骨条藻和圆胸藻表现出明显不同的聚集行为。这反映在它们的溶解有机物（DOM）、透明外聚合物颗粒（TEP）和含蛋白质颗粒（CSP）的显著不同的释放，以及它们的细菌生物降解性和可降解性。S.中肋骨条仅少量聚集，并且它们的细菌定殖保持低水平。溶解有机物，TEP和CSP释放的这一微生物主要消耗自由生活的细菌。而圆形圆酵母则迅速聚集，释放出的DOM、TEP和CSP能抵抗细菌的消耗。然而，在静止生长期用圆藻培养物进行的实验显示出快速的细菌定植和藻类细胞的分解。我们的研究强调了异养细菌对控制海洋系统中浮游植物的发展和聚集的重要性。
Aggregation of algae, mainly of diatoms, is an important process in marine pelagic systems, often terminating phytoplankton blooms and leading to the sinking of particulate organic matter in the form of marine snow. This process has been studied extensively, but the specific role of heterotrophic bacteria has largely been neglected, mainly because field studies and most experimental work were performed under non-axenic conditions. We tested the hypothesis that algae-bacteria interactions are instrumental in aggregate dynamics and organic matter flux. A series of aggregation experiments has been carried out in rolling tanks with two marine diatoms typical of temperate regions (Skeletonema costatum and Thalassiosira rotula) in an axenic treatment and one inoculated with marine bacteria. Exponentially growing S. costatum and T rotula exhibited distinctly different aggregation behavior. This was reflected by their strikingly different release of dissolved organic matter (DOM), transparent exopolymer particles (TEP) and protein-containing particles (CSP), as well as their bacterial biodegradability and recalcitrance. Cells of S. costatum aggregated only little and their bacterial colonization remained low. Dissolved organic matter, TEP and CSP released by this alga were largely consumed by free-living bacteria. In contrast, T rotula aggregated rapidly and DOM, TEP and CSP released resisted bacterial consumption. Experiments conducted with T rotula cultures in the stationary growth phase, however, showed rapid bacterial colonization and decomposition of algal cells. Our study highlights the importance of heterotrophic bacteria to control the development and aggregation of phytoplankton in marine systems.