Department of Biology, Aarhus University, Ole Worms Allé 1, 8000 Aarhus, Denmark; School of Ecological and Environmental Sciences, East China Normal University, 200241 Shanghai, China.
Department of Geography and Spatial Information Techniques, Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, 315211 Ningbo, China.
Sci Total Environ. 2021 Dec 1;798:149169. doi: 10.1016/j.scitotenv.2021.149169. Epub 2021 Jul 20.
Stream biofilms are complex aggregates of diverse organism groups that play a vital role in global carbon and nitrogen cycles. Most of the current studies on stream biofilm focus on a limited number of organism groups (e.g., bacteria and algae), and few have included both prokaryote and eukaryote communities simultaneously. In this study, we incubated artificial substrates in five Danish lowland streams exhibiting different hydrological and physico-chemical conditions and explored the dynamics of community composition and diversity of the benthic biofilm, including both prokaryotes and eukaryotes. We found that few phyla in the prokaryote (Gammaproteobacteria and Bacteroidetes) and eukaryote (Cercozoa) communities accounted for over two-thirds of the total abundance at most of the sites. Both prokaryotic and eukaryotic diversity displayed the same temporal patterns, i.e., diversity peaked in July and January. We also found that hydrological and physico-chemical variables significantly explained the variation in the community composition at phylum level for both prokaryotes and eukaryotes. However, a large proportion of variation remained unexplained, which can be ascribed to important but unmeasured variables like light intensity and biological factors such as trophic and non-trophic interactions as revealed by network analysis. Therefore, we suggest that use of a multitrophic level perspective is needed to study biofilm i.e., the "microbial jungles", where high occurrences of trophic and non-trophic interactions are expected.
溪流生物膜是由多种生物群体组成的复杂聚集体，在全球碳氮循环中起着至关重要的作用。目前大多数关于溪流生物膜的研究都集中在有限数量的生物群体（例如细菌和藻类）上，很少同时包括原核生物和真核生物群落。在这项研究中，我们在五个具有不同水文和物理化学条件的丹麦低地溪流中培养人工基质，并探索了包括原核生物和真核生物在内的底栖生物膜群落组成和多样性的动态。我们发现，大多数地点的原核生物（γ变形菌纲和拟杆菌门）和真核生物（原生动物门）群落中，很少有门的丰度超过三分之二。原核生物和真核生物的多样性都表现出相同的时间模式，即多样性在 7 月和 1 月达到峰值。我们还发现，水文和物理化学变量显著解释了原核生物和真核生物在门水平上群落组成的变化。然而，很大一部分变异仍然无法解释，这可以归因于重要但未测量的变量，如光照强度以及网络分析显示的营养和非营养相互作用等生物因素。因此，我们建议需要采用多营养层次的视角来研究生物膜，即“微生物丛林”，预计这里会有大量的营养和非营养相互作用。
