کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4677938 | 1634822 | 2011 | 5 صفحه PDF | دانلود رایگان |
An important characteristic of magnetotactic bacteria (MTB) is the anisotropy of one-dimensionally aligned magnetite particles. This paper introduces the use of ferromagnetic resonance spectroscopy (FMR) at two different frequencies to compare the anisotropic properties of magnetite chains of cultured intact MTB with those of lake sediments of Holocene age in order to detect magnetofossils and to characterize their preservation in a geological system. Magnetite chains of intact MTB exhibit a predominantly uniaxial anisotropy. In the lake sediments, where diagenetic processes disintegrate the chains and diminish their uniaxiality, magnetite chains or chain fragments and dissociated bulk magnetite particles differ in their anisotropy properties. The two groups of assembly can be distinguished by empirical spectral separation of the FMR signal. This straightforward use of the characteristics of magnetic anisotropy provides a way to detect magnetofossils experimentally, thus allowing a better insight into microbial ecology during Earth's history.
Research Highlights
► Anisotropy reveals magnetofossils as remains of magnetotactic bacteria.
► FMR spectroscopy enables detection of anisotropy.
► Empirical spectral separation detects magnetofossils.
► Magnetofossils are crucial bacterial evidence in geological systems.
Journal: Earth and Planetary Science Letters - Volume 309, Issues 1–2, 1 September 2011, Pages 113–117