University of Michigan, Ann Arbor, Department of Ecology & Evolutionary Biology, Ann Arbor, MI USA.
The University of Texas at Austin, Department of Integrative Biology, Austin, TX USA.
FEMS Microbiol Ecol. 2020 Apr 1;96(4). doi: 10.1093/femsec/fiaa029.
Eukaryotic communities commonly display a positive relationship between biodiversity and ecosystem function (BEF) but the results have been mixed when assessed in bacterial communities. Habitat heterogeneity, a factor in eukaryotic BEFs, may explain these variable observations but it has not been thoroughly evaluated in bacterial communities. Here, we examined the impact of habitat on the relationship between diversity assessed based on the (phylogenetic) Hill diversity metrics and heterotrophic productivity. We sampled co-occurring free-living (more homogenous) and particle-associated (more heterogeneous) bacterial habitats in a freshwater, estuarine lake over three seasons: spring, summer and fall. There was a strong, positive, linear relationship between particle-associated bacterial richness and heterotrophic productivity that strengthened when considering dominant taxa. There were no observable BEF trends in free-living bacterial communities for any diversity metric. Biodiversity, richness and Inverse Simpson's index, were the best predictors of particle-associated production whereas pH was the best predictor of free-living production. Our findings show that heterotrophic productivity is positively correlated with the effective number of taxa and that BEF relationships are associated with microhabitats. These results add to the understanding of the highly distinct contributions to diversity and functioning contributed by bacteria in free-living and particle-associated habitats.
真核生物群落通常表现出生物多样性与生态系统功能（BEF）之间的正相关关系，但在评估细菌群落时，结果却存在差异。生境异质性是真核生物 BEF 的一个因素，它可以解释这些可变的观察结果，但在细菌群落中尚未得到彻底评估。在这里，我们研究了生境对基于（系统发育）Hill 多样性指标评估的多样性与异养生产力之间关系的影响。我们在三个季节（春季、夏季和秋季）中对淡水河口湖中自由生活（更均匀）和颗粒相关（更多样化）的细菌生境进行了共现采样：自由生活和颗粒相关。颗粒相关细菌丰富度与异养生产力之间存在强烈的正线性关系，当考虑主要类群时，这种关系会增强。对于任何多样性指标，自由生活细菌群落中都没有观察到 BEF 趋势。多样性、丰富度和倒数 Simpson 指数是颗粒相关生产的最佳预测因子，而 pH 是自由生活生产的最佳预测因子。我们的研究结果表明，异养生产力与有效分类单元数呈正相关，而 BEF 关系与微生境相关。这些结果增加了对自由生活和颗粒相关生境中细菌对多样性和功能贡献的高度不同的理解。
