Intraspecific variation and energy channel coupling within a Chilean kelp forest
Intraspecific variation and energy channel coupling within a Chilean kelp forest
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智利海带森林内的种内变异和能量通道耦合
DOI：
10.1002/ecy.3198
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发表时间：
2020
期刊：
影响因子：
4.8
通讯作者：
Newsome, S.
中科院分区：
文献类型：
--
作者：
Elliott Smith, E;Harrod, C;Docmac, F;Newsome, S.
各种类型的初级生产或能源渠道对消费者群体的广泛重要性已变得越来越明显。然而，这种“多渠道”摄食背后的机制仍然知之甚少，特别是对于水生生态系统来说，由于潜在能量渠道的多样性，这些生态系统构成了独特的后勤限制。在这里，我们使用整体组织同位素分析和单个氨基酸的碳同位素(δ13C)分析来表征远洋和底栖能源对智利北部海带森林消费者群落的相对贡献。我们测量了散装组织的δ13C和δ15N，其中我们分析了来自9个初级生产组(n=41)和11个近岸消费类群(n=1.56)的6种必需氨基酸的δ13C值。利用EAAδ13C数据，我们使用线性判别分析来评估本地浮游植物(浮游植物/颗粒有机物)和底栖生物(海藻、红藻和绿藻)末端成员之间EAAδ13C值的差异。有了这个模型，我们能够正确地将近90%的生产商样品归类到它们的原始分组，这比传统的大宗同位素分析有了很大的改进。有了这个EAA同位素文库，我们然后使用自举重新采样的LDA方法为每个消费者和物种生成了最重要的生产源的概率分布。我们在物种水平上发现了群落内多渠道取食的证据。无脊椎动物倾向于集中于远洋或底栖生物的能量，13-67%的EAA来自远洋来源。相比之下，营养水平较高的流动(鱼类)分类群在每个渠道使用的比例更相等，从19%到47%之间的骨盆来源的能量。在一个分类群中，多渠道饲养是个体之间能量渠道使用专业化的结果，据估计，56个个体消费者中有37个人的EAA>；80%来自单一渠道。我们的研究揭示了尖端的同位素技术如何表征沿海食物网中的能量流动动态，这是一个历史上很难解决的话题。更广泛地说，我们的工作提供了一种机制，说明多渠道摄食如何在近岸社区发生，我们建议在其他生态系统中研究这种模式。
The widespread importance of variable types of primary production, or energy channels, to consumer communities has become increasingly apparent. However, the mechanisms underlying this “multichannel” feeding remain poorly understood, especially for aquatic ecosystems that pose unique logistical constraints given the diversity of potential energy channels. Here, we use bulk tissue isotopic analysis along with carbon isotope (δ13C) analysis of individual amino acids to characterize the relative contribution of pelagic and benthic energy sources to a kelp forest consumer community in northern Chile. We measured bulk tissue δ13C and δ15N for >120 samples; of these we analyzed δ13C values of six essential amino acids (EAA) from nine primary producer groups (n= 41) and 11 representative nearshore consumer taxa (n= 56). Using EAA δ13C data, we employed linear discriminant analysis (LDA) to assess how distinct EAA δ13C values were between local pelagic (phytoplankton/particulate organic matter), and benthic (kelps, red algae, and green algae) endmembers. With this model, we were able to correctly classify nearly 90% of producer samples to their original groupings, a significant improvement on traditional bulk isotopic analysis. With this EAA isotopic library, we then generated probability distributions for the most important sources of production for each individual consumer and species using a bootstrap‐resampling LDA approach. We found evidence for multichannel feeding within the community at the species level. Invertebrates tended to focus oneitherpelagic or benthic energy, deriving 13–67% of their EAA from pelagic sources. In contrast, mobile (fish) taxa at higher trophic levels used more equal proportions of each channel, ranging from 19% to 47% pelagically derived energy. Within a taxon, multichannel feeding was a result of specialization among individuals in energy channel usage, with 37 of 56 individual consumers estimated to derive >80% of their EAA from a single channel. Our study reveals how a cutting‐edge isotopic technique can characterize the dynamics of energy flow in coastal food webs, a topic that has historically been difficult to address. More broadly, our work provides a mechanism as to how multichannel feeding may occur in nearshore communities, and we suggest this pattern be investigated in additional ecosystems.