Soil microbial respiration and PICT responses to an industrial and historic lead pollution: a field study

Abstract

We performed a field investigation to study the long-term impacts of Pb soil contamination on soil microbial communities and their catabolic structure in the context of an industrial site consisting of a plot of land surrounding a secondary lead smelter. Microbial biomass, catabolic profiles, and ecotoxicological responses (PICT) were monitored on soils sampled at selected locations along 110-m transects established on the site. We confirmed the high toxicity of Pb on respirations and microbial and fungal biomasses by measuring positive correlations with distance from the wall factory and negative correlation with total Pb concentrations. Pb contamination also induced changes in microbial and fungal catabolic structure (from carbohydrates to amino acids through carboxylic malic acid). Moreover, PICT measurement allowed to establish causal linkages between lead and its effect on biological communities taking into account the contamination history of the ecosystem at community level. The positive correlation between qCO2 (based on respiration and substrate use) and PICT suggested that the Pb stress-induced acquisition of tolerance came at a greater energy cost for microbial communities in order to cope with the toxicity of the metal. In this industrial context of long-term polymetallic contamination dominated by Pb in a field experiment, we confirmed impacts of this metal on soil functioning through microbial communities, as previously observed for earthworm communities.

Soil Properties and Multi-Pollution Affect Taxonomic and Functional Bacterial Diversity in a Range of French Soils Displaying an Anthropisation Gradient

“…The differences of substrate-induced respiration observed among soils were less pronounced using the MicroResp than the Biolog method, and were essentially linked to the soil basal respiration rates as previously observed [63]. Contrarily to many studies [63,64,65], basal respiration rates and substrate-induced respiration were mostly not affected by pollution (metals and PAH) level. Additionally to the bacterial activity, MicroResp can also integrate fungal respiration.…”

Sheltering Role of Well-Decayed Conifer Logs for Forest Floor Fungi in Long-Term Polluted Boreal Forests

“…The fungal diversity in forest litter decreased in the gradient of pollution, which corroborates the results of soil fungi research in the vicinity of this and other similar enterprises (Liao and Xie, 2007;Wang et al, 2007;Blagodatskaya et al, 2008;Hui et al, 2012;Bérard et al, 2014Bérard et al, , 2016Chen et al, 2014;Mikryukov andDulya, 2017, 2018). In addition to heavy metal toxicity, the nearly complete elimination of herbaceous vegetation (Trubina, 2009(Trubina, , 2020 likely played an essential role in the impoverishment of fungal communities, which was exemplified by the substantial loss of biotrophic and saprotrophic species associated with herbaceous plants and their litter.…”

“…They are characterized by altered soil pH and extremely high concentrations of metals in the soil (Dudka and Adriano, 1997;Kozlov et al, 2009). Due to the toxic effect of metals aggravated by high soil acidity, soil fungi and bacteria decline in abundance and diversity close to the sources of pollution (Chen et al, 2014;Mikryukov et al, 2015;Bérard et al, 2016;Mikryukov and Dulya, 2017), while earthworms, enchytraeids, mollusks, and millipedes are almost absent (Bengtsson et al, 1983;Spurgeon and Hopkin, 1996;Vorobeichik, 1998;. It is reasonable to consider any potential "safety island" mitigating pollution load on biota, maintaining its diversity and functioning, and facilitating its restoration after the load cessation.…”

Bacterial community tolerance to Cu in soils with geochemical baseline concentrations (GBCs) of heavy metals: Importance for pollution induced community tolerance (PICT) determinations using the leucine incorporation method

“…Since 3 H Leucine incorporation requires a laboratory dedicated to radioactive elements, it may be limited for risk assessment studies and for routine and numerous measurements. The use of other end-points in the detection phase of PICT than Leu incorporation has been described: Community Level Physiological Profiling (CLPP) using Biolog plates (Scmitt et al, 2004), MicroResp™ (Wakelin et al, 2014;Bérard et al, 2016), or dehydrogenase enzymatic activity (Aliasgharzad et al, 2011). However, 3 H leucine incorporation method is generally fast, simple and sensitive.…”

“…The determination of Pollution Induced Community Tolerance (PICT) could be used as a direct indicator of the toxicity of Cu on soil microorganisms (Blanck, 2002). PICT is a sensitive technique and a promising tool to detect metal impacts in contaminated soil both in the field and under laboratory conditions using the microbial communities as indicators (Brandt et al, 2010;Berg et al, 2012;Wakelin et al, 2014;Bérard et al, 2016;Liu et al, 2017). PICT is based in the following premise: if there is a toxic effect of a pollutant on the soil microorganisms, more tolerant species or strains will be favored compared to more sensitive ones, and hence the whole microbial community will become more Cu tolerant.…”