1] Advanced Water Management Centre (AWMC), University of Queensland, St Lucia, Queensland, Australia [2] Australian Centre for Ecogenomics (ACE), School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia.
Advanced Water Management Centre (AWMC), University of Queensland, St Lucia, Queensland, Australia.
ISME J. 2014 Oct;8(10):2015-28. doi: 10.1038/ismej.2014.50. Epub 2014 Apr 17.
A replicate long-term experiment was conducted using anaerobic digestion (AD) as a model process to determine the relative role of niche and neutral theory on microbial community assembly, and to link community dynamics to system performance. AD is performed by a complex network of microorganisms and process stability relies entirely on the synergistic interactions between populations belonging to different functional guilds. In this study, three independent replicate anaerobic digesters were seeded with the same diverse inoculum, supplied with a model substrate, α-cellulose, and operated for 362 days at a 10-day hydraulic residence time under mesophilic conditions. Selective pressure imposed by the operational conditions and model substrate caused large reproducible changes in community composition including an overall decrease in richness in the first month of operation, followed by synchronised population dynamics that correlated with changes in reactor performance. This included the synchronised emergence and decline of distinct Ruminococcus phylotypes at day 148, and emergence of a Clostridium and Methanosaeta phylotype at day 178, when performance became stable in all reactors. These data suggest that many dynamic functional niches are predictably filled by phylogenetically coherent populations over long time scales. Neutral theory would predict that a complex community with a high degree of recognised functional redundancy would lead to stochastic changes in populations and community divergence over time. We conclude that deterministic processes may play a larger role in microbial community dynamics than currently appreciated, and under controlled conditions it may be possible to reliably predict community structural and functional changes over time.
采用厌氧消化（AD）作为模型过程进行了重复性长期实验，以确定生态位和中性理论对微生物群落组装的相对作用，并将群落动态与系统性能联系起来。AD 由微生物的复杂网络完成，过程稳定性完全依赖于属于不同功能类群的种群之间的协同相互作用。在这项研究中，三个独立的重复厌氧消化器用相同的多样化接种物接种，用模型底物α-纤维素供应，并在中温条件下以 10 天水力停留时间运行 362 天。操作条件和模型底物施加的选择压力导致群落组成发生了大的可重复变化，包括在运行的第一个月中丰富度的总体下降，随后是与反应器性能变化相关的同步种群动态。这包括在第 148 天同步出现和下降的独特 Ruminococcus 类群，以及在第 178 天出现的 Clostridium 和 Methanosaeta 类群，此时所有反应器的性能都稳定。这些数据表明，许多动态功能生态位可以在长时间段内由系统发育上一致的种群可预测地填充。中性理论预测，具有高度公认功能冗余的复杂群落将导致种群和群落随时间的随机变化。我们得出的结论是，确定性过程可能在微生物群落动态中发挥比目前认识到的更大的作用，并且在受控条件下，可能可以可靠地预测群落结构和功能随时间的变化。
