Biological activity in metal-contaminated calcareous agricultural soils: the role of the organic matter composition and the particle size distribution.
Organic matter (OM) plays a key role in microbial response to soil metal contamination, yet little is known about how the composition of the OM affects this response in Mediterranean calcareous agricultural soils. A set of Mediterranean soils, with different contents and compositions of OM and carbonate and fine mineral fractions, was spiked with a mixture of Cd, Cu, Pb, and Zn and incubated for 12 months for aging. Microbial (Biolog Ecoplates) and enzyme activities (dehydrogenase, DHA; β-galactosidase, BGAL; phosphatase, PHOS; and urease, URE) were assessed and related to metal availability and soil physicochemical parameters. All enzyme activities decreased significantly with metal contamination: 36-68 % (DHA), 24-85 % (BGAL), 22-72 % (PHOS), and 14-84 % (URE) inhibitions. Similarly, catabolic activity was negatively affected, especially phenol catabolism (∼86 % compared to 25-55 % inhibition for the rest of the substrates). Catabolic and DHA activities were negatively correlated with ethylenediaminetetraacetic acid (EDTA)-extractable Cd and Pb, but positively with CaCl2, NaNO3, and DTPA-extractable Cu and Zn. Soluble OM (water- and hot-water-soluble organic C) was positively related to enzyme and catabolic activities. Recalcitrant OM and fine mineral fractions were positively related to BGAL and PHOS. Conversely, catabolic activity was negatively related to clay and positively to silt and labile OM. Results indicate that the microbial response to metal contamination is highly affected by texture and OM composition.
Departamento de Biología Vegetal I, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, C/ Jose Antonio Nováis, 12, Ciudad Universitaria, 28040, Madrid, Spain.
Luisa
L
Martin Calvarro
Ana
A
de Santiago-Martín
Javier
J
Quirós Gómez
Concepción
C
González-Huecas
Jose R
JR
Quintana
Antonio
A
Vázquez
Antonio L
AL
Lafuente
Teresa M
TM
Rodríguez Fernández
Rosalía
R
Ramírez Vera
D000383:Agriculture; D002119:Calcium Carbonate / Q000737:chemistry; D004492:Edetic Acid; D004787:Environmental Pollution / Q000706:statistics & numerical data; D008670:Metals / Q000032:analysis / Q000633:toxicity*; D010316:Particle Size; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D001616:beta-Galactosidase / Q000378:metabolism
D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D004492:Edetic Acid; D001616:beta-Galactosidase; D002119:Calcium Carbonate