The response of soil microbiota to hydrocarbon contamination has been studied normally several months after the event. However, as those studies represent a “long-term” context for microbial processes, since protozoa succession can be achieved after 28 days, we wonder how fast does trophic structure of ciliates and flagellates recover from a strong pulse of petroleum contamination under the influence of Medicago sativa. We hypothesized that the root effect of M. sativa would promote faster recovery of the protozoan trophic structure, in comparison with the level reached in unplanted microcosms. The abundances of individuals, species, and trophic groups of ciliates and flagellates were determined at 1, 7, 14, and 30 days after a single pulse of 50,000 ppm of light petroleum on soil microcosms unplanted and planted with M. sativa, and their respective controls. Protozoan diversity and trophic groups were strongly reduced immediately after the pulse of contamination. Ciliates and flagellate trophic diversity increased steadily in all microcosms after 7 days. However, unplanted contaminated and planted contaminated microcosms remained the poorest communities and reached full recovery of trophic groups after 30 days. Also, the protozoan communities were segregated into 2 groups: the first from petroleum and the second formed by non-polluted microcosms. These results suggest that petroleum is a strong selection factor leading to an alternative protozoan community composition and the root effect of M. sativa promotes faster recovery of ciliate and flagellate communities after a devastation produced by a strong pulse of petroleum contamination.

中文翻译：

---

M促进的土壤原生动物群落结构恢复。强烈的碳氢化合物污染脉冲后的苜蓿

事件发生几个月后，通常已经研究了土壤微生物对碳氢化合物污染的响应。但是，由于这些研究代表了微生物过程的“长期”情况，由于原生动物的演替可以在28天后实现，因此我们想知道，在以下情况的影响下，纤毛和鞭毛的营养结构能从石油污染的强脉冲中恢复多快？紫花苜蓿。我们假设M的根效应。苜蓿与未植入的微观世界相比，将促进原生动物营养结构的更快恢复。在单脉冲50,000 ppm轻质石油对未种植和种植M的土壤微观世界进行一次脉冲后的1、7、14和30天，确定了纤毛虫和鞭毛的个体，物种和营养组的丰度。苜蓿，以及它们各自的控件。污染脉冲后，原生动物的多样性和营养族迅速减少。7天后，纤毛和鞭毛的营养多样性在所有微观世界中稳定增加。但是，未种植的受污染和种植的受污染的缩影仍然是最贫穷的社区，并在30天后完全恢复了营养族。此外，原生动物群落分为两类：第一类来自石油，第二类由无污染的微观世界组成。这些结果表明，石油是导致替代原生动物群落组成和M根效应的强选择因子。苜蓿 在强烈的石油污染造成的破坏之后，促进纤毛虫和鞭毛虫群落的更快恢复。