Nutrient limitation of periphyton in Idaho streams: results from nutrient diffusing substrate experiments
Nutrient limitation of periphyton in Idaho streams: results from nutrient diffusing substrate experiments
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爱达荷州溪流附生植物的养分限制：养分扩散基质实验的结果
DOI：
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发表时间：
2009
影响因子：
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通讯作者：
Adam B. Goodwin
中科院分区：
文献类型：
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作者：
B. Sanderson;H. J. Coe;C. Tran;K. Macneale;Deborah L. Harstad;Adam B. Goodwin
摘要美国太平洋西北部的许多溪流和河流天生营养贫乏，这些生态系统中的初级生产力被认为是营养有限的。在许多这样的溪流中，产卵的鲑鱼提供的海生营养物数量的减少可能会加剧营养不良的程度。为了测试初级生产者是否受到营养物质的限制，利用营养物质扩散底物(NDS)实验，在美国爱达荷州中部的13条萨蒙河流域溪流中测量了藻类对N、P以及N和P(N+P)组合的响应。在2003至2006年间，进行了38项实验，以确定营养限制是否在不同溪流之间和个别溪流内随着时间的推移而变化。大多数河流的初级生产者表现出某种形式的营养限制。39%的试验建议N、P限制，18%建议N限制，11%建议一级N和次要P限制，32%不建议N或P限制。单个溪流的营养限制类型随时间变化，13条溪流中有7条N或P的相对重要性随季节或年度变化。控制基质和处理基质上的藻类累积率受水温、光照以及环境N和P浓度的影响最强。在所有实验中，在环境N浓度较低和环境P浓度较高的溪流中，N基质上的藻类累积率较高。我们的结果表明，氮和磷的组合通常限制了这些溪流中的初级生产者。我们努力确定这些溪流目前的营养限制，这对管理者来说将是有价值的，他们考虑将营养添加作为提高溪流生产力的工具，以造福于受威胁和濒危的鲑鱼。
Abstract Many streams and rivers in the Pacific Northwest of the US are inherently oligotrophic, and primary production in these ecosystems is assumed to be nutrient-limited. In many of these streams, reductions in the amount of marine-derived nutrients delivered by spawning salmonids could be exacerbating the degree of oligotrophication. To test whether primary producers are nutrient-limited, nutrient diffusing substrate (NDS) experiments were used to measure algal responses to amendments of N, P, and a combination of N and P (N+P) in 13 Salmon River basin streams in central Idaho, USA. Thirty-eight experiments were conducted between 2003 and 2006 to determine whether nutrient limitation varied among streams and over time within individual streams. Primary producers in most streams showed some form of nutrient limitation. Thirty-nine percent of our experiments suggested N and P colimitation, 18% suggested N limitation, 11% suggested primary N and secondary P limitation, and 32% did not indicate limitation by either N or P. The type of nutrient limitation within individual streams varied with time, and the relative importance of N or P changed seasonally or annually in 7 of the 13 streams. Algal accrual rates on control and treatment substrates were most strongly predicted by water temperature, light, and ambient concentrations of N and P. Among all of the experiments, algal accrual rates were greater on N substrates in streams with lower ambient N concentrations and greater ambient P concentrations. Our results suggest that a combination of N and P typically limits primary producers in these streams. Our efforts to characterize current nutrient limitation in these streams will be of value to managers considering nutrient additions as a tool to improve stream productivity to benefit threatened and endangered salmonids.