Metabarcoding of zooplankton communities is becoming more common, but molecular results must be interpreted carefully and validated with morphology-based analyses, where possible. To evaluate our metabarcoding approach within the California Current Ecosystem, we tested whether physical subsampling and PCR replication affects observed community composition; whether community composition resolved by metabarcoding is comparable to morphological analyses by digital imaging; and whether pH neutralization of ethanol with ammonium hydroxide affects molecular diversity. We found that (1) PCR replication was important to accurately resolve alpha diversity and that physical subsampling can decrease sensitivity to rare taxa; (2) there were significant correlations between relative read abundance and proportions of carbon biomass for most taxonomic groups analyzed, but such relationships showed better agreement for the more dominant taxonomic groups; and (3) ammonium hydroxide in ethanol had no effect on molecular diversity. Together, these results indicate that with appropriate replication, paired metabarcoding and morphological analyses can characterize zooplankton community structure and biomass, and that metabarcoding methods are to some extent indicative of relative community composition when absolute measures of abundance or biomass are not available.

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关于解释浮游动物元条形码和将分子方法与形态分析相结合的建议

浮游动物群落的元条形码变得越来越普遍，但必须仔细解释分子结果，并在可能的情况下通过基于形态学的分析进行验证。为了评估我们在加州当前生态系统中的元条形码方法，我们测试了物理二次抽样和 PCR 复制是否会影响观察到的群落组成；通过元条形码解析的群落组成是否与通过数字成像进行的形态分析具有可比性；以及用氢氧化铵中和乙醇的 pH 值是否会影响分子多样性。我们发现 (1) PCR 复制对于准确解析 alpha 多样性很重要，并且物理二次采样可以降低对稀有分类群的敏感性；(2) 对于所分析的大多数分类群，相对读数丰度和碳生物量比例之间存在显着相关性，但这种关系对更占优势的分类群表现出更好的一致性；(3) 乙醇中的氢氧化铵对分子多样性没有影响。总之，这些结果表明，通过适当的复制，成对的元条形码和形态分析可以表征浮游动物群落结构和生物量，并且元条形码方法在一定程度上指示了当没有绝对的丰度或生物量测量值时的相对群落组成。