The role of the microbial loop in benthic communities - combining food web theory and ecological stoichiometry

围生植物群落通常被认为是主要的自养群落，受营养和光照供应以及食草动物的存在控制。最近的证据表明，包括细菌、鞭毛虫、纤毛虫和小型动物在内的围植生物的异养成分具有关键但尚未被探索的作用。在这里，我们从实验上阐述了原生生物对营养物质再生的重要性，从而产生了底栖微藻。我们特别强调生态化学计量学，分析了原生动物消费者营养成分(C：N：P比率)的灵活性及其对初级生产者的供应率和比率的影响。实验将根据不同的光照、营养和溶解有机质供应条件，对不同复杂性的围生植物群落进行交叉分类。

Periphyton communities are often envisioned as primarily autotrophic communities controlled by nutrient and light supply as well as grazer presence. Recent evidence suggests a pivotal, yet underexplored role of the heterotrophic components of periphyton, which comprise bacteria, flagellates, ciliates and meiofauna. Here, we experimentally address the importance of protists for the regeneration of nutrients and thus the production of benthic microalgae. We put a special emphasis on ecological stoichiometry, analysing the flexibility of nutrient content (C:N:P ratio) of protozoan consumers as well as their consequences for the supply rates and ratios to the primary producers. The experiments will cross-classify periphyton communities of different complexity with different conditions of light, nutrient and dissolved organic matter supply. The results will allow 1) describing the functioning of periphyton communities, which represent the most important primary producers in many shallow aquatic habitats, 2) addressing the importance of a microbial loop in the benthos, and 3) extending the concept of ecological stoichiometry to a heterotrophic assemblage.