Dynamic stoichiometric response to food quality fluctuations in the heterotrophic dinoflagellate Oxyrrhis marina
Dynamic stoichiometric response to food quality fluctuations in the heterotrophic dinoflagellate Oxyrrhis marina
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DOI：
10.1007/s00227-012-2009-3
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发表时间：
2012-10-01
期刊：
影响因子：
2.4
通讯作者：
Malzahn, Arne Michael
中科院分区：
文献类型：
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作者：
Meunier, Cedric Leo;Haafke, Julia;Malzahn, Arne Michael
就营养物质而言，植物的营养比例相当不稳定，而大多数后生动物的营养比例范围则更为有限。最近有人强调，微型浮游动物的稳态能力介于这两个极端之间。然而，我们对化学计量变化的动力学知之甚少。因此，我们研究了异养甲藻尖鞭藻的化学计量如何受到影响（1）在饥饿期间和（2）在用营养丰富的藻类进行预处理后喂食营养耗尽的盐生红单胞菌时，反之亦然。我们观察到甲藻能够在饥饿 78 小时内保持其 N:P 比率恒定。我们推测，在饥饿条件下，限氮的O. marina主要使用脂肪作为能量来源，而富氮的个体也使用蛋白质作为细胞呼吸的燃料。此外，我们还发现 O. marina 对营养限制具有抵抗力，对磷限制的调节比对氮限制的调节更强。食品质量压力后微型浮游动物化学计量的这种弹性将对自上而下（营养物再矿化）和自下而上的控制（食品质量）产生重大影响。
With respect to nutrients, plants are rather non-homoeostatic while most metazoans have much more confined ranges of nutrient ratios. It was recently highlighted that the homoeostatic ability of microzooplankters lies in between these two extremes. Nevertheless, we know very little on the dynamics of stoichiometric changes. Hence, we investigated how the stoichiometry of the heterotrophic dinoflagellate Oxyrrhis marina is affected (1) during a starvation period and (2) when fed nutrient deplete Rhodomonas salina after having been pre-conditioned on nutrient replete algae and vice versa. We observed that the dinoflagellate was able to maintain its N:P ratio constant over 78 h of starvation. We inferred that under starvation, nitrogen-limited O. marina mainly used fat as energy source while nitrogen-rich individuals also used proteins as fuel in cellular respiration. Further, we showed that O. marina presents resistance to nutrient limitation, with stronger regulation against P-limitation than against N-limitation. This resilience in microzooplankton stoichiometry following food quality stress would have great implications for both top-down (nutrient remineralisation) and bottom-up controls (quality as food).