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On the origin of microbial magnetoreception

National Science Review 2020年第2期7卷 472-479页

作者： Wei Lin Joseph L.Kirschvink greig a.paterson Dennis A.Bazylinski Yongxin Pan Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences France-China Joint Laboratory for Evolution and Development of Magnetotactic Multicellular Organisms Chinese Academy of Sciences Division of Geological & Planetary Sciences California Institute of Technology Earth-Life Science Institute Tokyo Institute of Technology Department of Earth Ocean and Ecological Sciences University of Liverpool School of Life Sciences University of Nevada at Las Vegas College of Earth and Planetary Sciences University of Chinese Academy of Sciences

A broad range of organisms, from prokaryotes to higher animals, have the ability to sense and utilize Earth’s geomagnetic field—a behavior known as magnetoreception. Although our knowledge of the physiological mechanisms of magnetoreception has increased substantially over recent decades, the origin of this behavior remains a fundamental question in evolutionary biology. Despite this, there is growing evidence that magnetic iron mineral biosynthesis by prokaryotes may represent the earliest form of biogenic magnetic sensors on Earth. Here, we integrate new data from microbiology, geology and nanotechnology, and propose that initial biomineralization of intracellular iron nanoparticles in early life evolved as a mechanism for mitigating the toxicity of reactive oxygen species(ROS), as ultraviolet radiation and free-iron-generated ROS would have been a major environmental challenge for life on early Earth. This iron-based system could have later been co-opted as a magnetic sensor for magnetoreception in microorganisms, suggesting an origin of microbial magnetoreception as the result of the evolutionary process of exaptation.

关键词： magnetoreception biomineralization magnetotactic bacteria exaptation

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A simple test for the presence of multidomain behavior during paleointensity experiments

A simple test for the presence of multidomain behavior durin...

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中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： greig a.paterson paleomagnetism and Geochronology Laboratory Key Laboratory of Earth’s Deep InteriorInstitute of Geology and GeophysicsChinese Academy of Sciences

Detecting and excluding non-ideal behavior during paleointensity experiments is critical to asserting the reliability of *** knowledge of detecting non-ideal behavior, in particular the influence of multidomain(MD) grains,has expanded considerably over the past decade and experimental procedures now commonly incorporate checks to detect the effects of MD ***,many older studies were carried out before these checks were devised and provide no quantifiable means of testing for the presence of MD *** estimated one third of all entries in the most recent paleointensity database do not include some form of check for MD *** reliability of these results is therefore questionable and can only hinder efforts to understand the evolution of the geomagnetic field and the geodynamo.I propose a simple phenomenological check that can be applied to previous studies,provided that the raw data are available,that will allow the exclusion of MD behavior and provide a means of identifying reliable *** check is a quantification of the curvature,k,of data points on an Arai plot,a feature commonly associated with MD *** of paleointensity data from samples with known grain size indicates that this new parameter is significantly correlated with grain size and with the accuracy of the paleointensity estimates made from both limbs of the curved *** of 181 samples from five historical data sets indicates that k is significantly correlated with experimentally obtained MD and alteration check parameters,and the accuracy of the paleointensity estimate. A threshold selection value of k≤0.164 can be defined using the samples with known grain *** this cut-off value,combined with a threshold on the quality of the circle fit and a commonly used alteration check,to the historical data yields an accurate result with low *** compared with previously published selection criteria that incorporate experimental checks for non-ide

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The effects of anisotropic and non-linear thermoremanent magnetizations on Thellier-type paleointensity data

The effects of anisotropic and non-linear thermoremanent mag...

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中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： greig a.paterson Paleomagnetism and Geochronology Laboratory Key Laboratory of Earth’s Deep InteriorInstitute of Geology and GeophysicsChinese Academy of Sciences

Numerous non-ideal factors can influence paleointensity data,but the detection of these factors remains problematic and new approaches to understanding how paleointensity data behave are *** this study,a recently developed stochastic model of single domain(SD) paleointensity behaviour is expanded to investigate the effects that anisotropic and non-linear thermoremanent magnetizations(TRMs) have on the paleointensity results and the parameters used to select *** model results indicate that before applying any form of correction these non-ideal factors can produce results that are self-consistent,but highly *** methods that are currently used to correct for anisotropic and non-linear TRMs are effective and greatly increase the likelihood of obtaining accurate *** corrections,however,do not restore the results to those of ideal SD samples measured with the same laboratory-to-ancient field ratio,but the data are restored to those of ideal SD samples with the equivalent laboratory-to -ancient magnetization ratios(M/M).The simulations indicate that non-linear and anisotropic TRM have no or only a weak influence on the parameters commonly used to select paleointensity data,which means that these non-ideal factors are effectively undetectable. These new models suggest that the paleointensity behaviour of thermally/chemically stable SD samples,whether they are ideally behaved,anisotropy or non-linear TRM corrected,is near universal and depends only on(M/M) and the choice of paleointensity protocol (***-type versus Thellier).Given the high self-consistency and highly inaccurate results that anisotropic and non-linear TRM can yield,it is essential to test for such effects and all Thellier-type paleointensity studies must include tests for anisotropic and non-linear TRM to assert the reliability of the data obtained.

关键词： Archaeomagnetism Palaeointensity

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The fidelity of paleomagnetic records carried by magnetosome chains

The fidelity of paleomagnetic records carried by magnetosome...

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中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： greig a.paterson Yinzhao Wang Yongxin Pan Paleomagnetism & Geochronology Laboratory Key Laboratory of Earth’s Deep InteriorInstitute of Geology and GeophysicsChinese Academy of Sciences

Magnetotactic bacteria(MTB),which use aligned chains of magnetosomes(magnetic crystals) as a navigation tool,are found in a wide range of modern day marine,river and lacustrine environments and their fossilized remains are being increasing recognized in geological *** an increasing realization that biogenically derived magnetic particles may play a key role in sedimentary magnetizations,little is known about the influence that they may have on the fidelity of paleomagnetic *** cultured Magnetospirillum magneticum strain AMB-1,we have conducted simple 2D(i.e.,zero-inclination) deposition experiments to assess the efficiency with which magnetosome chains align along magnetic field lines and the implications that this has for paleomagnetic *** results indicate that the natural remanent magnetization(NRM) acquired by deposited MTB is near linear with applied field(0-120 pT),but that NRM acquisition does not perfectly follow the assumed linear trend and over a six-fold increase in applied field only a factor～5.5 increase in NRM intensity is observed(i.e.,～9%lower than the assumed trend).Both anhysteretic remanent magnetization(ARM) and saturation isothermal remanent magnetization (SIRM) normalized relative paleointensities(RPls) can successfully recover field strength variations under identical *** the MTB concentration of the initial solution is varied(up to a factor 8), NRM carried by MTB responds in the expected fashion(i.e.,a doubling of bacteria produces a doubling of NRM intensity).Both ARM and SIRM,however,do not respond to as expected:A doubling of concentration corresponds to an increase of～1.76 in SIRM intensity and an increase of only～1.63 in ARM *** are influenced by magnetostatic interactions that arise from the close packing of bacterial cells or subchain interactions within a single bacterial ***-order reversal curve(FORC) diagrams, however,are too insensitive to indicate the presence of paleom

关键词： magnetotactic bacteria sedimentary magnetism relative paleointensity magnetofossils magnetic interactions

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A new mechanism for the magnetic enhancement of hematite during heating:the role of clay minerals

A new mechanism for the magnetic enhancement of hematite dur...

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中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： CHUNXIA ZHANG greig a.paterson QINGSONG LIU State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences State Key Laboratory of Lithospheric Evolution

The magnetic properties of loess,lake,and ocean sediments are often used as indicators for paleoclimatic/paleoenvironmental *** analysis is a conventional approach for identifying magnetic phases and thermal alteration of *** concentration parameters are often enhanced after thermal treatment. In this study,the role of clay minerals in magnetic enhancement at elevated temperatures is systematically *** results indicate that the clay minerals(saponite, Ca-montmorillonite,kaolinite,and chlorite) are dominated by paramagnetic behaviour and that the magnetic properties remain relatively stable after heating to 700℃in argon. In contrast,mixtures of hematite and chlorite,have a high degree of magnetic enhancement after heating in argon,which indicates that clay minerals play important role in magnetic *** results improve our understanding of the processes involved in complicated mineral transformations,which is important for retrieving paleoclimatic/paleoenvironemntal signals from magnetic proxies.

关键词： clay minerals saponite montmorillonite kaolinite chlorite magnetic enhancement hematite thermomagnetic analysis

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Towards the robust selection of Thellier-type paleointensity data:The influence of experimental noise

Towards the robust selection of Thellier-type paleointensity...

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中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： greig a.paterson Andrew J.Biggin Yuhji Yamamoto Yongxin Pan Paleomagnetism and Geochronology Laboratory Key Laboratory of Earth's Deep InteriorInstitute of Geology and GeophysicsChinese Academy of Sciences Geomagnetism Laboratory Geology and GeophysicsSchool of Environmental SciencesUniversity of Liverpool Center for Advanced Marine Core Research Kochi University

[1]The process of data selection in paleointensity studies is an essential step to ensure data *** is, however,no consensus as to the best approach to consistently select data with most studies using arbitrarily defined thresholds for *** present a new numerical model that simulates the variability of paleointensity data from hypothetical ideal samples acquiring a thermoremanent magnetization(TRM) by incorporating experimental noise,which has been constrained using over 75,000 data *** Monte Carlo analyses,we investigate the behavior of simulated data and characterize the distributions of parameters typically used to select paleointensity *** use the 95th percentiles of the distributions to define thresholds for the maximum likely parameter values that can result from experimental *** represent values below which we cannot distinguish non-ideal behavior from *** find that a number of parameters are highly sensitive to noise and laboratory field strength(e.g.,partial TRM,pTRM,check CDRAT and pTRM tail checkδt);this sensitivity may diminish their ability to identify non-ideal *** fractional(f) dependence of some parameters and the proportion of inaccurate results provide justification for f≥0.35 when selecting data from both Thellier-Thellier and Coe protocol *** manifestation of noise in the original Thellier method,however,is different to that of methods that use zero-field heating *** suggests that the data selection procedure for the Thellier method should be different,but it also suggests that, contrary to previous analyses,the accuracy and scatter of results from this method are more sensitive to noise than methods that use zero-field heating *** general approach taken here is shown to be a powerful means of understanding the behavior of selection parameters and has the potential to be extended to models incorporating non-ideal behavior resulting from alteration and multidomain

关键词： error analysis experimental noise non-ideal behavior paleointensity

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Thellier-type paleointensity data from multidomain specimens

Thellier-type paleointensity data from multidomain specimens

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中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： greig a.paterson Andrew J.Biggin Emma Hodgson Mimi J.Hill Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences

Identifying and excluding inaccurate paleointensity estimates that can arise from the effects of multidomain(MD) particles remains a key challenge for paleointensity studies. Here we approach this problem by incorporating realistic experimental noise into a phenomenological MD model, systematically exploring the parameter space of paleointensity experiments(the choice of protocol, laboratory field strengths and directions), applying optimization algorithms to the model predictions, and testing these against experimental datasets. The results allow us to conclude that:(1) In some cases, applying the lab field in a direction [60 from the NRM direction and with a magnitude～2 times larger than the ancient field may help to produce more linear and accurate Arai plots by allowing partial thermoremanent magnetization(p TRM) tails to compensate from excess natural remanent magnetization(NRM) loss, the mechanism behind typical MD Arai plot curvature.(2) The recently proposed FRAC criterion is consistently better at isolating accurate results than the traditionally used f parameter and should ideally have minimum values of 0.65, 0.45, 0.65, and 0.55 for the Thellier, Coe, Aitken, and IZZI protocols, respectively.(3) Newly developed sets of selection criteria(MC-CRIT) should maximize the likelihood of accepting accurate estimates from a suite of specimens influenced by MD behavior. The models, methods, and data presented here provide the means to objectively define data selection and demonstrate the effectiveness of a given set of criteria. Such approaches are vital, if we wish to remove the arbitrariness that hinders the identification of reliable paleointensity data.

关键词： Paleointensity Archeointensity Multidomain Non-ideal behavior

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The effects of secondary mineral formation on Coe-type paleointensity determinations:Theory and simulation

The effects of secondary mineral formation on Coe-type paleo...

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中国科学院地质与地球物理研究所2014年度（第14届）学术年会

作者： Xiangyu Zhao Qingsong Liu greig a.paterson Huafeng Qin Shuhui Cai Yongjae Yu Rixiang Zhu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of Earth's Deep Interior Institute of Geology and GeophysicsChinese Academy of Sciences Department of Geology and Earth Environmental Sciences Chungnam National University

Thellier-type experiments are the most widely applied approaches for determining the absolute paleointensities of Earth’s magnetic field. One major problem, however, is that specimens are prone to thermal alteration due to the intensive thermal treatment during experiments. Linear Arai plots with acceptable partial thermal remanent magnetization(p TRM) checks have been considered as evidence for the absence of or negligible effects of thermal alteration and as reliable indicators of high-quality paleointensity estimates. However, by simulating the Coe variant of the Thellier method on assemblages of single domain(SD) magnetite particles, it is demonstrated that new magnetic minerals, which form during thermal treatments, can result in linear, concave-up, or concave-down Arai plots depending on the magnetic properties of both the primary and secondary magnetic phases. Among this range of behavior, pseudoideal Arai plots,which are linear with acceptable p TRM check statistics, would lead to paleointensity underestimates. It is further demonstrated that p TRM checks are proportional to the degree of underestimate with a magnetic granulometry dependency for SD particles. Due to the complexity of this dependency, p TRM check statistics are only comparable when specimens have similar magnetic properties. This suggests that a universal threshold for p TRM check statistics is not likely to be effective. Since the criteria of linearity and low p TRM check statistics are insufficient to guarantee the fidelity of the estimates auxiliary rock magnetic methods such as temperature-dependent hysteresis parameters and anhysteretic remanent magnetization are highly recommended to identify the presence of alteration.

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On improving the selection of Thellier-type paleointensity data

On improving the selection of Thellier-type paleointensity d...

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中国科学院地质与地球物理研究所2014年度（第14届）学术年会

作者： greig a.paterson Lisa Tauxe Andrew J.Biggin Ron Shaar Lori C.Jonestrask Key Laboratory of Earth’s Deep Interior Institute of Geology and GeophysicsChinese Academy of Sciences Geosciences Research Division Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA

The selection of paleointensity data is a challenging,but essential step for establishing data *** is,however,no consensus as to how best to quantify paleointensity data and which data selection processes are most *** address these issues,we begin to lay the foundations for a more unified and theoretically justified approach to the selection of paleointensity *** present a new compilation of standard definitions for paleointensity statistics to help remove ambiguities in their *** also compile the largest-to-date data set of raw paleointensity data from historical locations and laboratory control experiments with which to test the effectiveness of commonly used sets of selection *** most currently used criteria are capable of increasing the proportion of accurate results accepted,criteria that are better at excluding inaccurate results tend to perform poorly at including accurate results and vice *** the extreme case,one widely used set of criteria,which is used by default in the ThellierTool software(v4.22),excludes so many accurate results that it is often statistically indistinguishable from randomly selecting *** demonstrate that,when modified according to recent single domain paleointensity predictions,criteria sets that are no better than a random selector can produce statistically significant increases in the acceptance of accurate results and represent effective selection *** use of such theoretically derived modifications places the selection of paleointensity data on a more justifiable theoretical foundation and we encourage the use of the modified criteria over their original forms.

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Tectonic and sedimentary evolution of the late Miocene–Pleistocene Dali Basin in the southeast margin of the Tibetan Plateau: Evidences from anisotropy of magnetic susceptibility and rock magnetic data

Tectonic and sedimentary evolution of the late Miocene–Plei...

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中国科学院地质与地球物理研究所2014年度（第14届）学术年会

作者： Shihu Li Chenglong Deng greig a.paterson Haitao Yao Sheng Huang Chengying Liu Huaiyu He Yongxin Pan Rixiang Zhu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of the Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences Institute of Geomechanics Chinese Academy of Geological Sciences

The Cenozoic Dali Basin, located at the northeast of Diancang Shan and south of the first bend of Yangtze River, is tectonically controlled by the Dali fault system in the southeast margin of the Tibetan Plateau. The basin is filled with late Miocene to Pleistocene fluviolacustrine sediments, which provide invaluable information about the tectonic deformation and drainage network reorganization in this area. In this study, we discuss the anisotropy of magnetic susceptibility(AMS) of the Dasongping section in the Dali Basin, which spans an interval from 7.6 to1.8 Ma. Although rock magnetic experiments indicate that magnetite and hematite are the main remanence carriers, hysteresis loops, low values of bulk susceptibility and low temperature susceptibility suggest that paramagnetic minerals are major contributors to lowfield AMS. The rock magnetic parameters indicate that the Dali Basin experienced four stages of in filling and the sediment sources may have changed at 4.2 Ma. The clustering of the minimum principle axes(K min) nearly perpendicular to the bedding plane and the pronounced N–S magnetic lineation parallel to the bedding plane indicate that the AMS of the Dali Basin is a superimposed fabric consisting of a sedimentary-compaction and a mild initial deformation overprint. The well-de fined N–S magnetic lineation is likely due to the NNW and NNE oblique shear caused by the Heqing and Red River faults.

关键词： Anisotropy of magnetic susceptibility Dali Basin Southeast margin of the Tibetan Plateau Dali fault system

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