Effects of N and P enrichment on competition between phytoplankton and benthic algae in shallow lakes: a mesocosm study
Effects of N and P enrichment on competition between phytoplankton and benthic algae in shallow lakes: a mesocosm study
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DOI：
10.1007/s11356-014-3680-3
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发表时间：
2015-03
影响因子：
5.8
通讯作者：
Xiufeng Zhang;Xue-ying Mei;R. D. Gulati;Zhengwen Liu
中科院分区：
文献类型：
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作者：
Xiufeng Zhang;Xue-ying Mei;R. D. Gulati;Zhengwen Liu
共生浮游植物与底栖藻类对资源的竞争，深刻影响着浅湖富营养化过程中的动态变化，但它们在湖泊生态系统功能中的作用和生境不同。通过一项实验验证了这样一种假设，即与氮(N)和磷(P)联合富集对浮游植物的益处大于底栖藻类。采用叶绿素a （Chla）测定了12种添加氮、磷或两者同时添加的浅水中生态系统中浮游植物和底栖藻类的生长情况。我们发现富氮对底栖藻类的生长有促进作用，而对浮游植物没有促进作用。富磷对底栖藻类的生长有负面影响，对浮游植物的生长没有影响。N+P富集对底栖藻类有负面影响，但对浮游植物的生长有促进作用，从而降低了底栖藻类对这两类初级生产者总生物量的贡献比例。因此，在与底栖藻类的竞争中，N+P联合富集比单独富集或单独富集更有利于浮游植物。我们的研究表明，N+P的联合富集促进了浮游植物对底栖藻类的优势，并对浅湖生态系统的营养动力学产生了影响。
Competition for resources between coexisting phytoplankton and benthic algae, but with different habitats and roles in functioning of lake ecosystems, profoundly affects dynamics of shallow lakes in the process of eutrophication. An experiment was conducted to test the hypothesis that combined enrichment with nitrogen (N) and phosphorus (P) would be a greater benefit to phytoplankton than benthic algae. The growth of phytoplankton and benthic algae was measured as chlorophyll a (Chla) in 12 shallow aquatic mesocosms supplemented with N, P, or both. We found that enrichment with N enhanced growth of benthic algae, but not phytoplankton. P enrichment had a negative effect on benthic algal growth, and no effect on the growth of phytoplankton. N+P enrichment had a negative effect on benthic algae, but enhanced the growth of phytoplankton, thus reducing the proportion of benthic algae contributing to the combined biomass of these two groups of primary producers. Thus, combined N+P enrichment is more favorable to phytoplankton in competition with benthic algae than enrichment with either N or P alone. Our study indicates that combined enrichment with N+P promotes the dominance of phytoplankton over benthic algae, with consequences for the trophic dynamics of shallow lake ecosystems.