The Effects of Roundup™ on Benthic Microbial Assemblages

Given the wide usage of Roundup, a common herbicide, the impacts of its presence in ecological communities are of great interest. Many studies have investigated the effects of glyphosate, the active ingredient in Roundup, on different factions of an ecosystem including on animals, plants, microorganisms, and nutrients. The current study expanded upon these works using Roundup instead of glyphosate to provide a realistic application in which to observe the development of microbial assemblages and nutrient composition in two different habitats. Winogradsky columns were prepared using benthic material from a ditch and a pond. Varying concentrations of Roundup were introduced to the columns at the beginning of the study and microbial growth and nutrient compositions from each column were measured weekly. The results indicate that the presence of Roundup has varying effects on microorganisms and nutrients. While photosynthetic microbes were negatively impacted, a shift in the microbial composition to heterotrophic microbes indicates that these microorganisms were able to utilize some ingredients in Roundup as a nutrient source. Additionally, the temporal analysis of nutrient compositions indicated that microbes metabolize glyphosate starting with the phosphate moiety even when the other compounds in Roundup are present. While these trends were observed in both benthic habitats, the composition of the ecological community can affect its ability to utilize the ingredients in Roundup as a nutrient source.

Methods
Please see the published Methods for complete data collection processes

鉴于常用除草剂农达（Roundup）的广泛使用，其在生态群落中的存留所产生的影响备受学界关注。诸多研究已针对农达的有效成分草甘膦（glyphosate）对生态系统各组分（包括动物、植物、微生物及营养物质）的影响展开了探究。本研究在既往研究基础上进行拓展，采用农达而非草甘膦开展实验，以搭建更贴近实际的应用场景，从而观测两种不同生境中微生物群落（microbial assemblages）与营养物质组成的动态变化。本实验以沟渠与池塘的底栖沉积物为原料制备维诺格拉斯基柱（Winogradsky columns）。实验初始阶段，向各组柱体施加不同浓度的农达，并每周测定各柱体中的微生物生长情况与营养物质组成。研究结果显示，农达的存留对微生物与营养物质存在差异化影响。尽管光合微生物（photosynthetic microbes）受到了负面影响，但微生物群落结构向异养微生物（heterotrophic microbes）的转变表明，此类微生物能够利用农达中的部分成分作为营养源。此外，对营养物质组成的时序分析显示，即便农达中存在其他化合物，微生物仍会优先从磷酸基团（phosphate moiety）开始代谢草甘膦。尽管上述趋势在两种底栖生境中均有体现，但生态群落的组成会影响其将农达成分作为营养源加以利用的能力。
方法 请参阅已发表的方法学部分以获取完整的数据采集流程