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Occurrence of magnetic bacteria in soil
J W Fassbinder1, H Stanjek, H Vali
1Institut für Allgemeine und Angewandte Geophysik, Ludwig-Maximilians-Universität München, FRG.
Nature
|January 11, 1990
Summary
Living magnetic bacteria were discovered in soil, suggesting they contribute to the soil
Area of Science:
- Geomicrobiology
- Soil Science
- Biomineralization
Background:
- Ferrimagnetic minerals like magnetite and maghemite are common in topsoil.
- Magnetite in soils has traditionally been attributed to inorganic processes.
- Organic processes are also known to produce magnetite.
Purpose of the Study:
- To investigate the presence and contribution of magnetic bacteria in soil environments.
- To challenge the prevailing inorganic origin theory for soil magnetite.
Main Methods:
- Detection of magnetic bacteria in soil samples using microscopy.
- Utilized an optical microscope with a rotating magnetic field.
- Employed a volumetrically calibrated depression slide for accurate cell counts.
Main Results:
- Living magnetic bacteria were identified in the A horizon of a Bavarian meadow soil profile.
- These bacteria are similar to those found in aquatic sediments.
- Accurate counts of bacterial volume density were obtained.
Conclusions:
- Living magnetic bacteria are present in terrestrial soils.
- Magnetic bacteria and their magnetofossils can significantly contribute to soil magnetic properties.
- This finding suggests a potential organic contribution to soil magnetism.