Ptacnik Robert, Solimini Angelo G, Andersen Tom, Tamminen Timo, Brettum Pål, Lepistö Liisa, Willén Eva, Rekolainen Seppo
Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway.
Proc Natl Acad Sci U S A. 2008 Apr 1;105(13):5134-8. doi: 10.1073/pnas.0708328105. Epub 2008 Mar 28.
The relationship between species diversity and ecosystem functioning has been debated for decades, especially in relation to the "macroscopic" realm (higher plants and metazoans). Although there is emerging consensus that diversity enhances productivity and stability in communities of higher organisms; however, we still do not know whether these relationships apply also for communities of unicellular organisms, such as phytoplankton, which contribute approximately 50% to the global primary production. We show here that phytoplankton resource use, and thus carbon fixation, is directly linked to the diversity of phytoplankton communities. Datasets from freshwater and brackish habitats show that diversity is the best predictor for resource use efficiency of phytoplankton communities across considerable environmental gradients. Furthermore, we show that the diversity requirement for stable ecosystem functioning scales with the nutrient level (total phosphorus), as evidenced by the opposing effects of diversity (negative) and resource level (positive) on the variability of both resource use and community composition. Our analyses of large-scale observational data are consistent with experimental and model studies demonstrating causal effects of microbial diversity on functional properties at the system level. Our findings point at potential linkages between eutrophication and pollution-mediated loss of phytoplankton diversity. Factors reducing phytoplankton diversity may have direct detrimental effects on the amount and predictability of aquatic primary production.
物种多样性与生态系统功能之间的关系已争论了数十年，尤其是在“宏观”领域（高等植物和后生动物）。尽管越来越多的人达成共识，即多样性可提高高等生物群落的生产力和稳定性；然而，我们仍然不知道这些关系是否也适用于单细胞生物群落，例如浮游植物，它们对全球初级生产的贡献约为50%。我们在此表明，浮游植物的资源利用以及由此产生的碳固定与浮游植物群落的多样性直接相关。来自淡水和咸淡水栖息地的数据集表明，在相当大的环境梯度范围内，多样性是浮游植物群落资源利用效率的最佳预测指标。此外，我们表明，稳定生态系统功能所需的多样性随着营养水平（总磷）而变化，多样性（负）和资源水平（正）对资源利用和群落组成变异性的相反影响证明了这一点。我们对大规模观测数据的分析与实验和模型研究一致，这些研究表明微生物多样性在系统层面上对功能特性具有因果效应。我们的研究结果指出了富营养化与污染介导的浮游植物多样性丧失之间的潜在联系。降低浮游植物多样性的因素可能会对水生初级生产的数量和可预测性产生直接的有害影响。
