Do nutrients limit algal periphyton in small blackwater coastal plain streams?
Do nutrients limit algal periphyton in small blackwater coastal plain streams?
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DOI：
10.1111/j.1752-1688.2007.00103.x
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发表时间：
2007-10-01
影响因子：
2.4
通讯作者：
Pringle, Catherine M.
中科院分区：
文献类型：
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作者：
Carey, Richard O.;Vellidis, George;Pringle, Catherine M.
我们研究潜在的营养限制藻类附着生物量的黑水河排水的格鲁吉亚沿海平原。以前的研究已经调查了大型黑水河中浮游藻类的营养限制，但实际上没有关于藻类附着生物如何在较小，低流量的溪流中在不同光照条件下对营养物做出反应的科学信息。我们使用了修改后的马特洛克periphytometer（营养扩散基质），以确定藻类生长是否是营养有限和/或光限制在九个站点跨越一系列的人类影响，从相对不受干扰的森林流域高度干扰的农业用地。在每个试验点的遮荫和阳光条件下，我们采用了四种处理：（1）对照，（2）N（NO3-N），（3）P（PO 4-P），（4）N + P（NO3-N+ PO 4-P）。叶绿素a响应测量10个重复的基板每个处理，15天后，在原位曝光。叶绿素a值没有接近被定义为滋扰水平的水平（即，100-200 mg/m2），即使在阳光充足的条件下也能对养分富集作出反应。对于格鲁吉亚沿海平原溪流，藻类附着生物的生长似乎主要受到光限制，并且在光隙和/或接受阳光的开阔区域中可能受到次要营养限制（最常见的是P或N + P组合）。
We examine the potential for nutrient limitation of algal periphyton biomass in blackwater streams draining the Georgia coastal plain. Previous studies have investigated nutrient limitation of planktonic algae in large blackwater rivers, but virtually no scientific information exists regarding how algal periphyton respond to nutrients under different light conditions in smaller, low- flow streams. We used a modification of the Matlock periphytometer ( nutrient- diffusing substrata) to determine if algal growth was nutrient limited and / or light limited at nine sites spanning a range of human impacts from relatively undisturbed forested basins to highly disturbed agricultural sites. We employed four treatments in both shaded and sunny conditions at each site: ( 1) control, (2) N (NO3-N), (3) P (PO4-P), and (4) N + P (NO3-N+PO4-P). Chlorophyll a response was measured on 10 replicate substrates per treatment, after 15 days of in situ exposure. Chlorophyll a values did not approach what have been defined as nuisance levels (i.e., 100-200 mg/m(2)), even in response to nutrient enrichment in sunny conditions. For Georgia coastal plain streams, algal periphyton growth appears to be primarily light limited and can be secondarily nutrient limited ( most commonly by P or N + P combined) in light gaps and / or open areas receiving sunlight.