000094554 001__ 94554 000094554 005__ 20210902121750.0 000094554 0247_ $$2doi$$a10.1016/j.epsl.2020.116400 000094554 0248_ $$2sideral$$a118617 000094554 037__ $$aART-2020-118617 000094554 041__ $$aeng 000094554 100__ $$aBlattmann, Thomas M. 000094554 245__ $$aFerromagnetic resonance of magnetite biominerals traces redox changes 000094554 260__ $$c2020 000094554 5060_ $$aAccess copy available to the general public$$fUnrestricted 000094554 5203_ $$aRedox variations govern a multitude of key geochemical and microbiological processes within lacustrine and marine systems, yet the interpretation of these geological archives can be limited because redox-sensitive microorganisms leave behind sparse fossil evidence. Here, we assess a biologically controlled magnetic proxy through investigation of a well-constrained sedimentary record covering a perturbation of redox-conditions driven by a complete trophic cycle in Lake Constance. Ferromagnetic resonance spectroscopy of sediments reveals strong uniaxial anisotropy, indicative of single-domain magnetite particles in intact or fragmentary chain arrangements, which are an unambiguous trait of magnetotactic bacteria (MTB) and their magnetofossil remains. We show that biogenic magnetite formed intra-cellularly in MTB faithfully records changing redox-conditions at or close to the sediment water-interface. Biogenic magnetite within sedimentary records points to the proliferation of MTB parallel to a decline in water column dissolved oxygen and the formation of sulfidic surface sediments in Lake Constance associated with an episode of eutrophication (1955–1991). We conclude that magnetofossils may serve as a sensitive geological proxy to reconstruct dynamic redox-changes along the sediment-water interface and bottom waters. 000094554 536__ $$9info:eu-repo/grantAgreement/ES/DGA/E35-17R$$9info:eu-repo/grantAgreement/ES/MINECO/CTQ2015-64486-R 000094554 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/ 000094554 590__ $$a5.255$$b2020 000094554 591__ $$aGEOCHEMISTRY & GEOPHYSICS$$b7 / 87 = 0.08$$c2020$$dQ1$$eT1 000094554 592__ $$a2.829$$b2020 000094554 593__ $$aEarth and Planetary Sciences (miscellaneous)$$c2020$$dQ1 000094554 593__ $$aSpace and Planetary Science$$c2020$$dQ1 000094554 593__ $$aGeophysics$$c2020$$dQ1 000094554 593__ $$aGeochemistry and Petrology$$c2020$$dQ1 000094554 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000094554 700__ $$aLesniak, Barbara 000094554 700__ $$0(orcid)0000-0002-1827-1250$$aGarcía-Rubio, Inés$$uUniversidad de Zaragoza 000094554 700__ $$aCharilaou, Michalis 000094554 700__ $$aWessels, Martin 000094554 700__ $$aEglinton, Timothy I. 000094554 700__ $$aGehring, Andreas U. 000094554 7102_ $$12003$$2395$$aUniversidad de Zaragoza$$bDpto. Física Materia Condensa.$$cÁrea Física Materia Condensada 000094554 773__ $$g545 (2020), 116400 1-7$$pEarth planet. sci. lett.$$tEarth and Planetary Science Letters$$x0012-821X 000094554 8564_ $$s1359951$$uhttps://zaguan.unizar.es/record/94554/files/texto_completo.pdf$$yVersión publicada 000094554 8564_ $$s49297$$uhttps://zaguan.unizar.es/record/94554/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000094554 909CO $$ooai:zaguan.unizar.es:94554$$particulos$$pdriver 000094554 951__ $$a2021-09-02-09:48:13 000094554 980__ $$aARTICLE