Long-term impacts of heavy metals on soil microbial diversity numbers and function

土壤不仅支持植物的生长，而且对养分的循环也至关重要。土壤微生物在这些过程中扮演着绝对重要的角色。它们的种群数量庞大且多样化，但一些细菌和真菌群体以及一些特定的过程对环境变化非常敏感，例如有毒金属的积累。这些金属是一个可能强烈影响土壤未来可持续利用的因素的一个例子。然而，目前欧盟对土壤中有毒金属的风险评估完全依赖短期实验室测试，这可能不能反映金属在环境中的长期影响。此外，许多关于有毒金属对环境影响的调查使用了污染严重的地点，这些地点的植物生长因急性金属毒性而严重减少，而不是考虑有毒金属的长期积累，这些有毒金属通常积累缓慢并造成长期污染。土壤微生物群落中的生物多样性在维持土壤功能方面的作用尚未被很好地理解，尽管人们假设一个称为土壤弹性(在存在胁迫，例如金属污染的情况下继续执行功能的能力)的因素依赖于土壤微生物种群中不同个体的存在。如果有毒金属的积累导致微生物多样性减少，这种对压力(来自化学、物理或生物因素)的恢复能力可能会受到损害。该提案旨在评估锌(污水污泥和镀锌(镀锌)金属中存在的土壤常见污染物)和铜(也存在于污泥和动物粪便中)对微生物群落的耐受性、关键微生物过程以及负责土壤功能的关键群体的遗传多样性的影响。六年前在英国不同类型的土壤上进行的长期污水-污泥实验所得的土壤，以及距离镀锌结构越来越远的锌浓度不断下降的土壤，将提供独特的实验材料来解决这些问题。将使用生理和分子生物学方法测量一系列微生物参数。结果将与土壤化学测量有关，以确定对土壤微生物产生毒性的确切化学条件。立法者可以利用这些信息来应用于其他情况，并通过防止未来积累关键的土地来帮助增加土地的可持续利用。

Soil not only supports plant growth, but also is crucial for the cycling of nutrients. Soil microorganisms play an absolutely essential role in these processes. Their populations are large and diverse but some groups of bacteria and fungi, as well as some specific processes are sensitive to environmental changes such as the build up of toxic metals. These metals are an example of a factor that could strongly affect the sustainable future use of soils. However, the current EU risk assessments of toxic metals in soils rely exclusively on short-term laboratory tests, which may not reflect the long-term effects of metals in the environment. Also many investigations on the impact of toxic metals in the environment use heavily polluted sites where plant growth is severely decreased due to acute metal toxicity, rather than considering the long-term accumulation of toxic metals that normally build up slowly and cause chronic pollution. The role of biodiversity within soil microbial groups plays in maintaining soil functions is not well understood, although it is assumed that a factor known as soil resilience (the ability to continue to perform functions in the presence of stress, e.g. metal pollution) relies on the presence of diverse individuals within the soil microbial population. This resilience to stress (from chemical, physical or biological factors) may be compromised if microbial diversity is reduced as a result of toxic metal accumulation. The proposal aims to evaluate the effects of zinc, a common pollutant of soil present in sewage sludge and galvanised (zinc coated) metal, and copper which is also present in sludge and animal manures, on the tolerance of microbial communities, key microbial processes, and the genetic diversity of key groups responsible for soil functions. Soils from long-term sewage-sludge experiments set up six years ago on different soil types in the UK, and soil with decreasing concentrations of zinc at increasing distances away from galvanised structures, will provide unique experimental materials to tackle these issues. A range of microbial parameters will be measured using both physiological and molecular biological assays. The results will be related to soil chemical measurements to establish the exact chemical conditions that induce toxicity to soil microbes. This information can be used by legislators to apply to other situations and help to increase the sustainable use of land by preventing critical accumulations from building up in the future.