Light, nutrients and the fatty acid composition of stream periphyton
Light, nutrients and the fatty acid composition of stream periphyton
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DOI：
10.1111/j.1365-2427.2011.02622.x
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发表时间：
2011-09-01
影响因子：
2.7
通讯作者：
Czesny, Sergiusz
中科院分区：
文献类型：
--
作者：
Hill, Walter R.;Rinchard, Jacques;Czesny, Sergiusz
1.虽然光和营养的平衡通过改变藻类的磷和氮含量来影响食草动物的食物质量，但光和营养对淡水围藻脂肪酸合成的联合影响相对未知。在这项研究中，我们在大型流过的实验溪流中操纵光和磷的浓度，以检查它们对周围植物中元素化学计量比和脂肪酸含量的影响。在两个单独的实验中，两个水平的磷(4和80微克L(-1))和三个光(17，40和110微克摩尔光子m(-2)S(-1))采用析因设计。在这两个实验中，硅藻都以附生植物群落为主，占藻类生物量的95%。溪流中的附生植物生长同时受到这两种资源的影响，即使在低供应率的情况下也是如此。附生植物的C/P和C/N比值随着光照的增加而增加，随着磷的增加而降低，这与光：营养假说(LNH)一致。在低磷浓度的溪流中，光照效应最强。围植脂肪酸反映了硅藻的优势，棕榈酸(16：1 omega7)和二十碳五烯酸(20：5 omega3)分别是主要的饱和脂肪酸(SAFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)。亚油酸(18：2 omega 6)和亚麻酸(18：3 omega 3)是绿藻和蓝藻特有的稀有酸，包括
1. While the balance of light and nutrients is known to influence the food quality of herbivores by altering algal phosphorus and nitrogen content, the combined effects of light and nutrients on fatty acid synthesis in freshwater periphyton are relatively unknown. In this study, we manipulated light and phosphorus concentration in large, flow-through experimental streams to examine their effects on both elemental stoichiometry and fatty acid content in periphyton.2. Two levels of phosphorus (4 and 80 mu g L(-1)) and three of light (17, 40, 110 mu mol photons m(-2) s(-1)) were applied in a factorial design in two separate experiments. Diatoms dominated periphyton communities in both experiments, comprising >95% of algal biovolume. Periphyton growth in the streams was simultaneously affected by both resources, even at low rates of supply.3. Periphyton C/P and C/N ratios increased with light augmentation and decreased with phosphorus enrichment, and consistent with the light : nutrient hypothesis (LNH). Light effects were strongest in streams with low phosphorus concentrations.4. Periphyton fatty acids reflected the dominance of diatoms : palmitic (16 : 0), palmitoleic (16 : 1 omega 7) and eicosapentanoic (20 : 5 omega 3) were the principal saturated (SAFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), respectively. Linoleic (18 : 2 omega 6) and linolenic (18 : 3 omega 3) acids, characteristic of chlorophytes and cyanophytes, were rare, comprising