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Only a minority of bacteria grow after wetting in both natural and post-mining biocrusts in a hyperarid, phosphate mine
Soil ( IF 6.8 ) Pub Date : 2023-01-09 , DOI: 10.5194/egusphere-2022-1510
Talia Gabay, Eva Petrova, Osnat Gillor, Yaron Ziv, Roey Angel

Abstract. Biological soil crusts (biocrusts) are key contributors to desert ecosystem functions; therefore, biocrust restoration following mechanical disturbance is imperative. In the Negev Desert hyperarid regions, phosphate mining has been practiced for over 60 years, destroying soil habitats, and fragmenting the landscape. To understand the effects of mining activity on soil health, we previously characterized the biocrust communities in four phosphate mining sites over spatial (post-mining and natural plots) and temporal (2–10 years since restoration) scales. We showed that bacterial abundance, richness, and diversity in natural plots were significantly higher than in post-mining plots, regardless of temporal scale. In this study, we selected one mining site and used DNA stable isotope probing (DNA-SIP) to identify which bacteria grow in post-mining and natural biocrusts. Since biocrust communities activate only after wetting, we incubated the biocrusts with H218O for 96 hours under ambient conditions. We then evaluated the physicochemical soil properties, chlorophyll a concentrations, activation, and functional potential of the biocrusts. The DNA-SIP assay revealed low bacterial activity in both plot types and no significant differences in the proliferated communities’ composition when comparing post-mining and natural biocrusts. We further found no significant differences in the microbial functional potential, photosynthetic rates, or soil properties. Our results suggest that growth of hyperarid biocrust bacteria after wetting is minimal. We hypothesize that due to the harsh climatic conditions, during wetting bacteria devote their meager resources to prepare for the coming drought, by focusing on damage repair, and organic compound synthesis and storage rather than on growth. These low growth rates contribute to the sluggish recovery of desert biocrusts following major disturbances such as mining. Therefore, our findings highlight the need for implementing active restoration practices following mining.

中文翻译:

在高度干旱的磷酸盐矿中,在天然和开采后的生物结壳中润湿后,只有少数细菌生长

摘要。生物土壤结皮(生物结皮)是沙漠生态系统功能的关键贡献者;因此,机械干扰后的生物结皮恢复势在必行。在内盖夫沙漠极度干旱地区,磷酸盐开采已经进行了 60 多年,破坏了土壤栖息地,破坏了景观。为了解采矿活动对土壤健康的影响,我们之前在空间(采矿后和自然地块)和时间(恢复后 2-10 年)尺度上对四个磷酸盐矿区的生物结壳群落进行了表征。我们表明,无论时间尺度如何,自然地块中的细菌丰度、丰富度和多样性都明显高于采矿后地块。在这项研究中,我们选择了一个采矿地点,并使用 DNA 稳定同位素探测 (DNA-SIP) 来确定哪些细菌在采矿后和天然生物结壳中生长。由于生物结壳群落仅在润湿后激活,我们将生物结壳与 H2 18O 在环境条件下保持 96 小时。然后,我们评估了生物结皮的物理化学土壤特性、叶绿素 a 浓度、活化和功能潜力。DNA-SIP 分析显示两种地块类型的细菌活性较低,并且在比较采矿后和天然生物结壳时,增殖群落的组成没有显着差异。我们进一步发现微生物功能潜力、光合速率或土壤特性没有显着差异。我们的结果表明,润湿后极度干旱生物结壳细菌的生长极小。我们假设,由于恶劣的气候条件,在潮湿期间,细菌通过专注于损伤修复、有机化合物合成和储存而不是生长,将其微薄的资源用于为即将到来的干旱做准备。这些低增长率导致沙漠生物结壳在采矿等重大干扰后恢复缓慢。因此,我们的研究结果强调了在采矿后实施积极恢复实践的必要性。
更新日期:2023-01-09
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