Showing papers on "Magnetotactic bacteria published in 1986"
TL;DR: In this article, the authors have studied surface sediments from the Santa Barbara Basin and reported the occurrence of living magnetotactic bacteria and the deposition of biogenic ultra-fine-grained, single-domain magnetite.
Abstract: Remanent magnetism in marine sediments has been used extensively over the past twenty years to calibrate the geological time-scale, study geomagnetic reversals and secular variation, and measure the rates of seafloor spreading. Although these sediments may contain different magnetic minerals, magnetite is the most commonly observed and magnetically stable phase, and its size, shape and post-depositional fate affect the magnetic remanence of the sediments. Biogenic magnetites are single-domain, with a high natural magnetic remanence (NRM), and have been suggested as a significant source of magnetic remanence in marine sediments. We have studied surface sediments from the Santa Barbara Basin and report the occurrence of living magnetotactic bacteria and the deposition of biogenic ultra-fine-grained, single-domain magnetite. Using a novel extraction technique, transmission electron microscopy and SQUID magnetometry, we show that these bacteria and the magnetite they produce are the major source of stable remanent magnetism in these sediments.
218 citations
TL;DR: Photomicrography has demonstrated that magnetotactic bacteria have a highly ordered, helical flight path when exposed to the magnetic field of a bar magnet.
Abstract: Magnetotactic bacteria, in particular 2 morphological forms of magnetococci, are of common occurrence at the sediment/water interface of ponds, lakes and estuaries in the U.K. Photomicrography has demonstrated that the organisms have a highly ordered, helical flight path when exposed to the magnetic field of a bar magnet. In the earth's magnetic field, the helical characteristic of the flight path was evident, but the organisms failed to move in a straight path.
22 citations
TL;DR: The first direct measurements of magnetic properties of magnetotactic bacteria from natural samples are presented and an anisotropy is obtained that is typical of magnetized ferro- or ferri-magnetic materials.
18 citations
TL;DR: Procedures for demonstrating magnetotactic bacteria in aquatic sediments are described and investigations suggested.
Abstract: Procedures for demonstrating magnetotactic bacteria in aquatic sediments are described and investigations suggested.