Patterns and controls of lotic algal stable carbon isotope ratios
Patterns and controls of lotic algal stable carbon isotope ratios
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DOI：
10.4319/lo.2004.49.3.0850
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发表时间：
2004-05-01
影响因子：
4.5
通讯作者：
Finlay, JC
中科院分区：
文献类型：
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作者：
Finlay, JC
稳定碳同位素比的空间和时间变化（即，δ（13）C）是水生食物网同位素特征的常见但知之甚少的特征。我调查的因素，控制三角洲（13）C的藻类（浓度和三角洲（13）C的无机碳，藻类分馏，和生长速率）在浅滩栖息地跨越梯度流大小和生产力在北方加州。绿色刚毛藻、微藻影响的石表生物膜及其食草动物的δ（13）C具有显著的季节和空间变化。藻类和草食动物三角洲（13）C在C-13中的小型非生产性支流（-44ppm至-30ppm）中耗尽，而下游更具生产性的站点（-31ppm至-23ppm）。刚毛藻和石生生物膜的藻类δ（13）C的大部分变化由溶解CO2（CO2 aq）通过对CO2 aq的δ（13）C和光合分馏的影响来确定。与此相反，其他两个分类群（蓝细菌Nostoc pruniforme和红色Nostoc Lemanea sp.）由于其不同的无机碳获取模式，δ（13）C或分馏对不同的无机碳可用性的响应几乎没有变化。虽然在某些情况下，藻类三角洲（13）C的变化可能会使三角洲（13）C的使用复杂化，以解决消费者的饮食来源，更好地了解这种变化应改善三角洲（13）C技术在水生食物网研究中的使用。
Spatial and temporal variations in stable carbon isotope ratios (i.e., delta(13)C) of primary producers are common but poorly understood features of isotopic characterizations of aquatic food webs. I investigated factors that control delta(13)C of algae (concentration and delta(13)C of inorganic carbon, algal fractionation, and growth rates) in riffle habitats across a gradient in stream size and productivity in northern California. There was considerable seasonal and spatial variation in delta(13)C of the green alga Cladophora glomerata, microalgal-influenced epilithic biofilms, and their herbivores. Algal and herbivore delta(13)C were depleted in C-13 in small, unproductive tributary streams (-44parts per thousand to -30parts per thousand) compared with more productive sites downstream (-31parts per thousand to -23parts per thousand). The majority of variation in algal delta(13)C of Cladophora and epilithic biofilms was determined by dissolved CO2 (CO2aq) via effects on delta(13)C of CO2aq and photosynthetic fractionation. In contrast, two other taxa (the cyanobacterium Nostoc pruniforme and the red alga Lemanea sp.) showed little variation in delta(13)C or fractionation in response to varied inorganic carbon availability because of their distinct modes of inorganic carbon acquisition. Although variation in algal delta(13)C might complicate use of delta(13)C to resolve consumer diet sources under some circumstances, better understanding of such variation should improve the use of delta(13)C techniques in aquatic food web studies.