Applying the light: nutrient hypothesis to stream periphyton
Applying the light: nutrient hypothesis to stream periphyton
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DOI：
10.1111/j.1365-2427.2009.02309.x
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发表时间：
2010-05-01
影响因子：
2.7
通讯作者：
Roberts, Brian J.
中科院分区：
文献类型：
--
作者：
Fanta, Shari E.;Hill, Walter R.;Roberts, Brian J.
1. 光：营养假说（LNH）认为藻类的营养含量是由藻类生长过程中可获得的光和溶解营养的平衡决定的。实验室和自然溪流中的光和磷梯度被用来检验LNH与溪流周生的相关性。可控光梯度(12-426 lmol光子m（-2) s(-1)）和溶解活性磷（DRP, 3-344 μ g -1）被实验应用于大流量的实验室溪流中，在自然溪流中，冠层覆盖度的自然变化和废水处理设施的排放产生了光梯度（0.4-35 mol光子m（-2）天（-1））和DRP （10-1766 μ g -1）。周围植物磷含量受光照和DRP梯度的强烈影响，在实验室溪流中为1.8 ~ 10.7 μ g mg AFDM(-1)，在自然溪流中为2.3 ~ 36.9 μ g mg AFDM（-1）。磷含量随光照的增加而降低，随水柱磷的增加而增加。光和磷的同时作用与LNH一致，即光和养分的平衡决定了藻类的养分含量。在实验室溪流的实验中，随DRP的增加，周围植物磷呈双曲线增加。然后摄入量开始稳定在50 μ g L-1.4左右。在实验室和自然溪流中，周围植物磷与光磷比的关系都是高度非线性的，磷含量随着光磷比的增加而急剧下降，然后在更高的光磷比时趋于平稳。虽然光和DRP都影响了周围植物的磷含量，但在实验室和自然溪流中，DRP的影响都比光强得多。DRP比光照更能解释周围植物磷的总体变异，光照效应仅在较低的磷浓度下才明显(
1. The light : nutrient hypothesis (LNH) states that algal nutrient content is determined by the balance of light and dissolved nutrients available to algae during growth. Light and phosphorus gradients in both laboratory and natural streams were used to examine the relevance of the LNH to stream periphyton. Controlled gradients of light (12-426 lmol photons m(-2) s(-1)) and dissolved reactive phosphorus (DRP, 3-344 mu g L-1) were applied experimentally to large flow-through laboratory streams, and natural variability in canopy cover and discharge from a wastewater treatment facility created gradients of light (0.4-35 mol photons m(-2) day(-1)) and DRP (10-1766 mu g L-1) in a natural stream.2. Periphyton phosphorus content was strongly influenced by the light and DRP gradients, ranging from 1.8 to 10.7 mu g mg AFDM(-1) in the laboratory streams and from 2.3 to 36.9 mu g mg AFDM(-1) in the natural stream. Phosphorus content decreased with increasing light and increased with increasing water column phosphorus. The simultaneous effects of light and phosphorus were consistent with the LNH that the balance between light and nutrients determines algal nutrient content.3. In experiments in the laboratory streams, periphyton phosphorus increased hyperbolically with increasing DRP. Uptake then began levelling off around 50 mu g L-1.4. The relationship between periphyton phosphorus and the light : phosphorus ratio was highly nonlinear in both the laboratory and natural streams, with phosphorus content declining sharply with initial increases in the light : phosphorus ratio, then leveling off at higher values of the ratio.5. Although light and DRP both affected periphyton phosphorus content, the effects of DRP were much stronger than those of light in both the laboratory and natural streams. DRP explained substantially more of the overall variability in periphyton phosphorus than did light, and light effects were evident only at lower phosphorus concentrations (