Soil Testate Amoebae and Diatoms as Bioindicators of an Old Heavy Metal Contaminated Floodplain in Japan

• Published in: Microbial ecology Vol. 79; no. 1; pp. 123 - 133
• Main Authors: Wanner, Manfred, Birkhofer, Klaus, Fischer, Thomas, Shimizu, Miki, Shimano, Satoshi, Puppe, Daniel
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01.01.2020; Springer US; Springer Nature B.V
• Subjects: Amoeba; Amoeba - growth & development; Amoeba - metabolism; Bacillariophyceae; Biogeochemical cycles; Biogeochemistry; Bioindicators; Biomedical and Life Sciences; Biomonitoring; Calcium chloride; Cobalt; Copper; Copper - analysis; Copper - metabolism; Correlation; Density; Detention basins; Diatoms; Diatoms - growth & development; Diatoms - metabolism; Ecological monitoring; Ecology; Ecotoxicology; Environmental Biomarkers; Environmental Monitoring; Floodplains; Floods; Fluxes; Geoecology/Natural Processes; Heavy metals; Indicator organisms; Indicator species; Japan; Lead; Lead - analysis; Lead - metabolism; Life Sciences; Metal concentrations; Metals, Heavy - analysis; Metals, Heavy - metabolism; Microbial Ecology; Microbiology; Nature Conservation; Plankton; Pollution; Protists; Silicon; Soil; Soil - chemistry; Soil - parasitology; Soil contamination; Soil investigations; SOIL MICROBIOLOGY; Soil Pollutants - analysis; Soil Pollutants - metabolism; Soil pollution; Soil testing; Soils; Taxa; Water Quality/Water Pollution; Zinc; Zinc - analysis; Zinc - metabolism; Japan; Soil protists; Silicon; Heavy metals; Aged soils; Floodplain
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-019-01383-x

Soil protists are rarely included in ecotoxicological investigations, despite their fundamental role in ecological processes. Moreover, testate amoebae and diatoms contribute considerably to silicon fluxes in soils. We investigated the effects of heavy metals on testate amoebae (species and individual densities) and diatoms (individual densities) in aged soils of a floodplain (Watarase retarding basin, Japan) taking soil samples from two unpolluted reference sites and two polluted sites. The total concentrations of Cu, Pb, and Zn in soil were higher at the polluted sites as compared with the reference sites. The available concentrations of Co, Cu, and Zn in CaCl₂ extracts were higher at the polluted sites but available Pb was not detectable. Testate amoeba taxonomic richness was higher in the reference sites (45/38 taxa) than in the polluted sites (36/27 taxa). The reference sites had higher diatom and amoeba densities than the polluted sites. There was a significant negative correlation between total testate amoeba density and heavy metal concentration (available Co), while significant negative correlations were found between diatom density and Co, Cu, and Zn (available and total concentration). Densities of Cyclopyxis kahli cyclostoma, Centropyxis spp., and Trinema complanatum were negatively correlated to concentrations of available heavy metals. The observed decrease in individual numbers due to heavy metal pollution resulted in a considerable decline in protozoic (testate amoebae) and protophytic (pennate diatoms) silicon pools. Our data suggest that heavy metal pollution affects biogeochemical cycling in this system.