Data for: "Phytoplankton diversity affects biomass and energy production differently during community development" in Functional Ecology (2021)

Biodiversity determines the productivity and stability of ecosystems but some aspects of biodiversity-ecosystem functioning relationships remain poorly resolved. One key uncertainty is the inter-relationship between biodiversity, energy and biomass production as communities develop over time. Energy production drives biomass accumulation but the ratio of the two processes can change during community development. How biodiversity affects these temporal patterns remains unknown. We empirically assessed how species diversity mediates the rates of increase and maximum values of biomass and net energy production in experimental phytoplankton communities over ten days in the laboratory. We used five phytoplankton species to assemble three levels of diversity (monocultures, bicultures and communities) to quantify changes in biomass production and energy fluxes (energy produced by photosynthesis, consumed by metabolism, and net energy production as their difference) as the cultures move from a low density, low competition system to a high density, high competition system.We find that species diversity affects both biomass and energy fluxes but in different ways. Diverse communities produce net energy and biomass at faster rates, reaching greater maximum biomass but with no difference in maximum net energy production. Bounds on net energy production are stronger than those on biomass because competition limits energy fluxes as biomass accumulates over time. In summary, diversity initially enhances productivity by diffusing competitive interactions but metabolic density-dependence reduces these positive effects as biomass accumulates in older communities. By showing how biodiversity affects both biomass and energy production during community development, our results demonstrate the mechanism that underlies positive biodiversity effects and offer a framework for predicting the consequences of disturbance on ecosystem functioning.

生物多样性决定生态系统的生产力和稳定性，然而，生物多样性与生态系统功能关系的一些方面仍然没有得到充分解析。其中一个关键的不确定性在于生物多样性、能量和生物量生产之间的相互关系，随着群落随时间发展而变化。能量生产推动生物量的积累，但这两个过程的比例在群落发展过程中可能会发生变化。生物多样性如何影响这些时间模式尚不清楚。我们通过实验评估了物种多样性如何调节实验性浮游生物群落十天内生物量和净能量生产率的增加速率及最大值。我们使用了五种浮游生物物种构建三个层次的多样性水平（单种培养、双种培养和群落），以量化生物量生产率和能量通量（光合作用产生的能量、代谢消耗的能量以及净能量生产率作为其差值）的变化，随着培养系统从低密度、低竞争系统向高密度、高竞争系统的转变。我们发现物种多样性影响生物量和能量通量，但影响方式不同。多样化的群落以更快的速度产生净能量和生物量，达到更大的生物量最大值，但最大净能量生产率没有差异。净能量生产率的界限比生物量更强，因为随着生物量的积累，竞争限制了能量通量。总之，多样性最初通过扩散竞争相互作用来增强生产力，但随着生物量在较老群落中积累，代谢密度依赖性降低了这些积极效应。通过展示生物多样性如何影响群落发展过程中的生物量和能量生产，我们的研究结果揭示了正生物多样性效应背后的机制，并为预测干扰对生态系统功能的影响提供了一个框架。