Metal toxicity affects fungal and bacterial activities in soil differently
Författare
Summary, in English
Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load.
Avdelning/ar
Publiceringsår
2004
Språk
Engelska
Sidor
2966-2973
Publikation/Tidskrift/Serie
Applied and Environmental Microbiology
Volym
70
Issue
5
Fulltext
- Available as PDF - 168 kB
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Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
American Society for Microbiology
Ämne
- Biological Sciences
Status
Published
Forskningsgrupp
- Microbial Ecology
ISBN/ISSN/Övrigt
- ISSN: 0099-2240