Mixotrophic versus photoautotrophic specialist algae as food for zooplankton: The light: nutrient hypothesis might not hold for mixotrophs
Mixotrophic versus photoautotrophic specialist algae as food for zooplankton: The light: nutrient hypothesis might not hold for mixotrophs
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DOI：
10.4319/lo.2005.50.4.1290
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发表时间：
2005-07-01
影响因子：
4.5
通讯作者：
Stibor, H
中科院分区：
文献类型：
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作者：
Katechakis, A;Haseneder, T;Stibor, H
我们饲养了混合营养型（Ochromonas tuberculata和Cryptomonas sp.）和光合自养专业藻类（Scenedesmus）在不同的光：磷供应，并比较了它们作为浮游动物（大型蚤）的食物的效果。根据灯光：营养假说（LNH），生物量和营养化学计量的光养专家强烈依赖于光：磷供应。如果这是真的，食草动物的生长和繁殖力应限制食物数量在低光照强度和化学计量的食物质量在高光照强度。反过来，磷肥应导致从食物质量的限制过渡到食物数量的限制。在相反的LNH，生物量和营养物质的化学计量的mixotrophs几乎不受影响的光和溶解的营养物质的供应的改变。细菌计数表明，混合营养体补偿光或磷缺乏的异养营养。与光养专家相比，隐单胞菌的饮食因此在大多数光下能够实现类似或更高且更稳定的次级生产：营养供应。O.然而，tuberculata似乎有毒。我们的研究结果表明，混合营养体可能有一个平衡的影响，在传输效率的变化所造成的扰动，光和营养供应。
We reared mixotrophic (Ochromonas tuberculata and Cryptomonas sp.) and photoautotrophic specialist algae (Scenedesmus obliquus) at different light: phosphorus supplies and compared their effects as food for zooplankton (Daphnia magna). According to the light: nutrient hypothesis (LNH), biomass and nutrient stoichiometry of phototrophic specialists depend strongly on light: phosphorus supplies. If this is true, herbivore growth and fecundity should be limited by food quantity at low light intensities and by stoichiometric food quality at high light intensities. In turn, phosphorus fertilization should cause a transition from limitation by food quality to limitation by food quantity. In contrast to the LNH, biomass and nutrient stoichiometry of mixotrophs were almost unaffected by alterations in the supply of light and dissolved nutrients. Bacterial counts indicate that mixotrophs compensated for light or phosphorus deficiency by heterotrophic nutrition. Compared to phototrophic specialists, a diet of Cryptomonas sp. therefore enabled a similar or higher and more stable secondary production at most light: nutrient supplies. O. tuberculata, however, appeared to be toxic. Our results indicate that mixotrophs might have a balancing effect on variations in transfer efficiency caused by perturbations to light and nutrient supplies.