State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu Province, China.
Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Lower Saxony, Germany.
PeerJ. 2023 Aug 3;11:e15720. doi: 10.7717/peerj.15720. eCollection 2023.
Human activities are increasing the input of atmospheric particulate pollutants to forests. The components of particulate pollutants include inorganic anions, base cations and hydrocarbons. Continuous input of particulate pollutants may affect soil functioning in forests, but their effects may be modified by soil fauna. However, studies investigating how soil fauna affects the effects of particulate pollutants on soil functioning are lacking. Here, we investigated how earthworms and the particulate components interact in affecting soil enzymatic functions in a deciduous () and a coniferous () forest in southeast China. We manipulated the addition of nitrogen (N, ammonium nitrate), sodium (Na, sodium chloride) and polycyclic aromatic hydrocarbons (PAHs, five mixed PAHs) in field mesocosms with and without , an earthworm species colonizing forests in eastern China. After one year, N and Na addition increased, whereas PAHs decreased soil enzymatic functions, based on average Z scores of extracellular enzyme activities. Earthworms generally stabilized soil enzymatic functions via neutralizing the effects of N, Na and PAHs addition in the deciduous but not in the coniferous forest. Specifically, earthworms neutralized the effects of N and Na addition on soil pH and the effects of the addition of PAHs on soil microbial biomass. Further, both particulate components and earthworms changed the correlations among soil enzymatic and other ecosystem functions in the deciduous forest, but the effects depended on the type of particulate components. Generally, the effects of particulate components and earthworms on soil enzymatic functions were weaker in the coniferous than the deciduous forest. Overall, the results indicate that earthworms stabilize soil enzymatic functions in the deciduous but not the coniferous forest irrespective of the type of particulate components. This suggests that earthworms may neutralize the influence of atmospheric particulate pollutants on ecosystem functions, but the neutralization may be restricted to deciduous forests.
人类活动正在增加大气颗粒物污染物向森林的输入。颗粒物污染物的成分包括无机阴离子、碱基阳离子和碳氢化合物。颗粒物污染物的持续输入可能会影响森林土壤的功能，但土壤动物可能会改变它们的影响。然而，目前缺乏研究调查土壤动物如何影响颗粒物污染物对土壤功能的影响。在这里，我们研究了在中国东南部的落叶林（）和针叶林（）中，蚯蚓和颗粒物成分如何相互作用影响土壤酶功能。我们在野外中尺度模拟实验中操纵了氮（N，硝酸铵）、钠（Na，氯化钠）和多环芳烃（PAHs，五种混合 PAHs）的添加，同时添加和不添加一种在中国东部森林中广泛分布的蚯蚓物种。一年后，N 和 Na 的添加增加了，而 PAHs 的添加降低了土壤酶的功能，这是基于细胞外酶活性的平均 Z 分数。蚯蚓通常通过中和落叶林中 N、Na 和 PAHs 添加的影响来稳定土壤酶的功能，但在针叶林中则不然。具体来说，蚯蚓中和了 N 和 Na 添加对土壤 pH 的影响，以及 PAHs 添加对土壤微生物生物量的影响。此外，颗粒物成分和蚯蚓都改变了落叶林中土壤酶和其他生态系统功能之间的相关性，但这种影响取决于颗粒物成分的类型。一般来说，在针叶林中，颗粒物成分和蚯蚓对土壤酶功能的影响比在落叶林中弱。总的来说，这些结果表明，蚯蚓稳定了落叶林中的土壤酶功能，但在针叶林中则不然，而与颗粒物成分的类型无关。这表明蚯蚓可能会中和大气颗粒物污染物对生态系统功能的影响，但这种中和作用可能仅限于落叶林。
