Simultaneous analysis of δ13C, δ15N and δ34S ratios uncovers food web relationships and the trophic importance of epiphytes in an eelgrass, Zostera marina community
Simultaneous analysis of δ13C, δ15N and δ34S ratios uncovers food web relationships and the trophic importance of epiphytes in an eelgrass, Zostera marina community
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DOI：
10.3354/meps10569
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发表时间：
2014-02
影响因子：
2.5
通讯作者：
Agnes Mittermayr;T. F. Hansen;U. Sommer
中科院分区：
文献类型：
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作者：
Agnes Mittermayr;T. F. Hansen;U. Sommer
这项试点研究采用了碳、氮和硫稳定同位素比的同步分析来检查波罗的海西部大叶藻系统的食物网。 2011 年 3 月至 9 月期间，在 Z. marina 的生长季节采集了三种潜在食物来源：鳗草、附生藻类和海藻以及 69 个消费物种的样本。附生植物的 δ13C 测量值（-14.1‰±1.8 SD）与鳗草的 δ13C 值（-11.6‰±1.8 SD）接近，难以明确区分这些食物来源。两种碳源，而seston δ13C 值（-20.9‰ ± 3.5 SD）明显不同。通过额外使用 δ34S 解决了这个经常遇到的问题，从而可以轻松区分沉积物和海水中的硫的值。初级生产者 δ34S 值的范围从 Z. marina 叶的 5.6 ‰ (± 2.3 SD) 到附生植物的 14.2 ‰ (± 1.6 SD) 和 seston 的 11.9 ‰ (± 3.3 SD)。 δ34S 和 δ13C 值的组合使碳源的分离成为可能，并能够向消费者分配潜在的食物来源并描述其营养关系。该鳗草群落的稳定同位素比分析数据强烈表明了基于附生植物和水生植物生产的食物网。 δ15N 值显示了一个由大量通才组成的食物网，并且在所分析的消费者物种中杂食性很高。这意味着占据每一个可能的营养位置，这是由 δ15N 值的连续分布支持的。之前描述的鳗草食物网可能需要重新评估以包括硫，以便提供关于主要碳源的清晰图片。
Simultaneous analysis of carbon, nitrogen and sulphur stable isotope ratios was applied in this pilot study to examine the food web of a Zostera marina L. system in the western Baltic Sea. Samples of three potential food sources: eelgrass, epiphytic algae and seston, as well as 69 consumer species were collected during the growing season of Z. marina from March to September 2011. The measured δ13C values of epiphytes (-14.1‰ ± 1.8 SD) were close to δ13C values of eelgrass (-11.6‰ ± 1.8 SD), impeding a clear distinction of those two carbon sources, whereas seston δ13C values (-20.9‰ ± 3.5 SD) were clearly different. This frequently encountered problem was solved by the additional use of δ34S, which resulted in easily distinguishable values for sediment and seawater derived sulphur. Values of primary producer δ34S ranged from 5.6‰ (± 2.3 SD) for Z. marina leaves to 14.2‰ (± 1.6 SD) for epiphytes and 11.9‰ (± 3.3 SD) for seston. The combination of δ34S and δ13C values made a separation of carbon sources possible and enabled the allocation of potential food sources to consumers and a description of their trophic relationships. The data of stable isotope ratio analysis of this eelgrass community strongly indicate a food web based on epiphyte and seston production. δ15N values show a food web consisting of large numbers of generalists and a high degree of omnivory amongst the consumer species analysed. This implies an occupation of every trophic position possible, which is supported by a continuous distribution of δ15N values. Previously described eelgrass food webs may have to be re-evaluated to include sulfur in order to provide a clear picture on primary carbon sources.