The crucial influence of trophic status on the relative requirement of nitrogen to phosphorus for phytoplankton growth
The crucial influence of trophic status on the relative requirement of nitrogen to phosphorus for phytoplankton growth
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DOI：
10.1016/j.watres.2022.118868
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发表时间：
2022-07-20
期刊：
影响因子：
12.8
通讯作者：
Nakano，Shin-ichi
中科院分区：
文献类型：
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作者：
Jiang，Mengqi;Nakano，Shin-ichi
弄清浮游植物生长对氮磷的相对需求模式，对于缓解富营养化和水系管理具有重要意义。浮游植物生长的相对N-P需求被认为是决定生态系统中物种优势和解释浮游植物对养分供应的反应的一个基本特征。这些要求随着环境营养状况的不同而不同，尽管这种变化尚不清楚。在这里，我们使用8种浮游植物(其中3种由我们研究，5种由以前的研究推断)的实验数据，评估了不同绝对营养水平下的相对N-P需求。结果表明，浮游植物生长对N-P的相对需要量随着绝对营养水平的增加而降低。因此，在低营养条件下，N可能是促进浮游植物生长的关键，而在营养充足的条件下，P可能是浮游植物生长的主要限制因素。这一结果不仅适用于单一物种，也适用于物种组合，它们与沿水体N：P梯度发生的物种迁移无关。在我们的大营养状态梯度中观察到的反应可能有助于阐明N和P减少在缓解富营养化对生态系统的影响方面的相对重要性。
Clarifying the pattern of relative nitrogen (N)-to-phosphorus (P) requirements for phytoplankton growth is of great significance for eutrophication mitigation and aquatic system management. The relative N-to-P requirement for phytoplankton growth is considered an essential trait determining species dominance within ecosystems and explaining phytoplankton response to nutrient availability. These requirements vary with environmental trophic status, though this variation remains unclear. Here, we evaluated the relative N-to-P requirements under different absolute nutrient levels using previous and current experimental data on eight phytoplankton species (three studied by us and five extrapolated from previous studies). Results showed that relative N-to-P requirements for phytoplankton growth decreased as absolute nutrient levels increased. Thus, N may be crucial for enhancing phytoplankton growth under low nutrient conditions, whereas P may be the primary limiting factor of phytoplankton growth under sufficient nutrient conditions. This result applies to single species as well as species assemblages, which are independent of species shifts occurring along water N:P gradients. The response observed in our large trophic status gradient may help elucidate the relative importance of N and P reductions in mitigating the impact of eutrophication on ecosystems.