Dinoflagellates are single celled organisms that reflect the ecological conditions in modern oceans and lakes. Their earliest undisputed fossil record suggests that dinoflagellates originated from the Middle Triassic ...Dinoflagellates are single celled organisms that reflect the ecological conditions in modern oceans and lakes. Their earliest undisputed fossil record suggests that dinoflagellates originated from the Middle Triassic (c. 240 Ma ago). However, the presence of molecular biomarkers (dinosterane, 4α-methyl-24-ethylcholestane and tria-romatic dinosteroids) in rock extracts and coccoid dinoflagellate fossils from the upper Sinian to Cambrian of the Tarim basin confirms the hypothesis that dinoflagellates have an ancient origin, and predate the oldest undisputed dinoflagellate fossils at least by 300 Ma, as early as the late Sinian-Cambrian.展开更多
This research developed estimates of plant crown transpiration and water-use-efficiency using reflectance and derivative indices extracted from remotely sensed chlorophyll fluorescence measurements under natural condi...This research developed estimates of plant crown transpiration and water-use-efficiency using reflectance and derivative indices extracted from remotely sensed chlorophyll fluorescence measurements under natural conditions. Diurnal changes of leaf-level gas exchange (carbon assimilation rate (A), stomatal conductance (gs), transpiration rate (E)), chlorophyll fluorescence and canopy-scale remote sensing were measured on top crown of valley oak (Quercus lobata) in the foothills of central California, USA. The results indicated Q. lobata experienced saturating irradiance (PAR), which induced photoinhibition indicated by a decrease in the quantum efficiency of photosystem II (r2 = 0.648 with Fv ′/Fm′ and r2 = 0.73 with FPSII) and open reaction centers (qP;r2 = 0.699). The excess absorbed quantum energy was dissipated as heat through the Xanthophyll cycle and other processes (photorespiration and the water-water cycle) rather than energy emission as steady state chlorophyll fluorescence (Fs). An increase in leaf temperature caused by the activity of Xanthophyll cycle was correlated to a decrease in Fs (r2 = 0.381) and an increase in evaporative cooling through E (r2 = 0.800) and water use efficiency (WUE;r2 = 0.872).展开更多
The Mottled Zone(MZ) or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains debatable.Mottled Zone Complex/Complexes(MZ...The Mottled Zone(MZ) or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains debatable.Mottled Zone Complex/Complexes(MZC/MZCs) consist of brecciated carbonate and low-temperature calcium-hydro-silicate rocks,which include unusual high- and ultra-high-temperature low-pressure(HT-LP) meta-morphic mineral assemblages.The MZ has been regarded as a product of combustion of bituminous chalks of the Ghareb Fm.of Cretaceous(Maastrichtian) age.In this paper we present detailed geographic, geomorphologic,structural and geological data from the MZCs of the South Levant,which show that the MZCs cannot be stratigraphically correlated with the Ghareb Fm.,because MZC late Oligocene-late Pleistocene deposits occur within or unconformable i.e.,with stratigraphic hiatus,overlap both the late Cretaceous and,in places,Neogene stratigraphic units.We propose an alternative model for the formation of MZCs by tectonically induced mud volcanism during late Oligocene-late Pleistocene time. This model explains(i) the presence of dikes and tube-like bodies,which consist of brecciated exotic clastic material derived from stratigraphically and hypsometrically lower horizons;(ii) mineral assemblages of sanidinite facies metamorphism;(iii) multi-stage character of HT-LP pyrometamorphism;and (iv) multi-stage low-temperature hydrothermal alteration.High temperatures(up to 1500℃) mineral assemblages resulted from combustion of hydrocarbon gases of mud volcanoes.Mud volcanism was spatially and structurally related to neotectonic folds and deformation zones formed in response to opening of the Red Sea rift and propagation of the Levantine Transform Fault.Our model may significantly change the prospects for oil-and-gas deposits in the region.展开更多
Highly oriented pyrolytic graphites are irradiated with 40.5-Me V and 67.7-Me V ^112Sn-ions in a wide range of fluences: 1×10^11 ions/cm^2–1×10^14ions/cm^2. Raman spectra in the region between 1200 cm^-1 a...Highly oriented pyrolytic graphites are irradiated with 40.5-Me V and 67.7-Me V ^112Sn-ions in a wide range of fluences: 1×10^11 ions/cm^2–1×10^14ions/cm^2. Raman spectra in the region between 1200 cm^-1 and 3500cm^-1 show that the disorder induced by Sn-ions increases with ion fluence increasing. However, for the same fluence, the amount of disorder is greater for 40.5-Me V Sn-ions than that observed for 67.7-Me V Sn-ions, even though the latter has a slightly higher value for electronic energy loss. This is explained by the ion velocity effect. Importantly, ~ 3-cm^-1frequency shift toward lower wavenumber for the D band and ~ 6-cm^-1 shift toward lower wavenumber for the 2D band are observed at a fluence of 1×10^14 ions/cm^2, which is consistent with the scenario of radiation-induced strain. The strain formation is interpreted in the context of inelastic thermal spike model, and the change of the 2D band shape at high ion fluence is explained by the accumulation of stacking faults of the graphene layers activated by radiation-induced strain around ion tracks. Moreover,the hexagonal structure around the ion tracks is observed by scanning tunneling microscopy, which confirms that the strains near the ion tracks locally cause electronic decoupling of neighboring graphene layers.展开更多
Natural geological, chronic and acute release of volcanic gases can have a dramatic impact on vegetative ecosystems and potential impact on regional agriculture and human health. This research incorporates a series of...Natural geological, chronic and acute release of volcanic gases can have a dramatic impact on vegetative ecosystems and potential impact on regional agriculture and human health. This research incorporates a series of observations using leaf level gas exchange, chlorophyll fluorescence and remotely sensed reflectance measurements of vegetation experiencing chronic exposure to volcanic gas emissions;to develop techniques for monitoring the relative health of vegetation along the edge of an acute vegetative kill zone of a natural disaster and potential preeruption vegetation physiology. Experiments were conducted along an elevation gradient that corresponds to the SO2 gradient on vegetation along the south flank of Volcán Turrialba, Costa Rica. This study site is a natural environment with high volcanic degassing activity with significant SO2 emissions (n/d-0.281 ppm). Corresponding to an SO2 gradient, a substantial increase in CO2 concentration of (430-517 ppm) was identified. We further show the physiological interactions of SO2 and CO2 have on vegetation along the kill zone of this natural disaster can be assessed by examining the SO2/CO2 ratios. The physiological indices tested and relationships among measurements emphasized in this research will add to the assessment of the impact atmospheric volcanic gas emissions have on the physiology of surrounding vegetation as well as advance the capability of remotely sensed environmental stress in natural settings.展开更多
Non-Darcian flow has been well documented for fractured media, while the potential non-Darcian flow and its driven factors in field-scale discrete fracture networks (DFNs) remain obscure. This study conducts Monte Car...Non-Darcian flow has been well documented for fractured media, while the potential non-Darcian flow and its driven factors in field-scale discrete fracture networks (DFNs) remain obscure. This study conducts Monte Carlo simulations of water flow through DFNs to identify non-Darcian flow and non-Fickian pressure propagation in field-scale DFNs, by adjusting fracture density, matrix hydraulic conductivity, and the general hydraulic gradient. Numerical simulations and analyses show that interactions of the fracture architecture with the hydraulic gradient affect non-Darcian flow in DFNs, by generating and adjusting complex pathways for water. The fracture density affects significantly the propagation of hydraulic head/pressure in the DFN, likely due to fracture connectivity and flow channeling. The non-Darcian flow pattern may not be directly correlated to the non-Fickian pressure propagation process in the regional-scale DFNs, because they refer to different states of water flow and their controlling factors may not be the same. Findings of this study improve our understanding of the nature of flow in DFNs.展开更多
Relatively high abundance of C<sub>31</sub> steranes has been identified from cretaceous source rocks and crude oils in the Songliao Basin, China. C<sub>31</sub> steranes which occur as ten iso...Relatively high abundance of C<sub>31</sub> steranes has been identified from cretaceous source rocks and crude oils in the Songliao Basin, China. C<sub>31</sub> steranes which occur as ten isomers were tentatively identified as 4, 22, 23, 24-tetrametyhlcholestane based on their retention time and mass spectrum.They bear a lower thermal stability and occur as important components in the immature oils of Chaochang region because they have three-methyl groups in their side chain. The relatively high abundance of C<sub>31</sub> steranes in the samples can indicate the source input of some special algae in the brackish and saline environment. Therefore they can be used as very useful biomarkers for organic facies analysis and oil correlation. Their biological source perhaps related to the dinoflagellate such as G. foliaceum and P. foliaceum. The gorgostanol are considered as possible precursors for the putative C<sub>31</sub>4methyl sterane which formed in the stage of diagenesis.展开更多
The genus Operculina,a large symbiont-bearing benthic foraminifer,is characterized by high morphological variability showing thick involute to intermediate semi-involute to flat evolute tests.Different morphotypes are...The genus Operculina,a large symbiont-bearing benthic foraminifer,is characterized by high morphological variability showing thick involute to intermediate semi-involute to flat evolute tests.Different morphotypes are either considered as ecophenotypes or distinct species.In order to test the hypothesis of ecophenotypes versus different species,a single cell high throughput sequencing approach was applied to assess the interspecific diversity of Operculina.This results in two groups of ribotypes,one corresponding to Operculina ammonoides/Operculina discoidalis,the other containing Operculina complanata/Operculina elegans.These groups can also be separated morphologically.Therefore,O.complanata and O.elegans represent a single species and the latter can be regarded as a junior synonym of O.complanata.Operculina ammonoides and O.discoidalis also form a single species,which makes the latter a junior synonym of O.ammonoides.Because generic differences in Operculina species are manifested in morphology and molecular genetics,the genus Neoassilina with the designated species Neoassilina ammonoides is installed.Additional analysis of ribosomal SSU rDNA data of eight recent nummulitid genera confirms the obtained high troughput sequencing results and further shows that Palaeonummulites venosus builds a clade with O.complanata that branches at the base of other Nummulitidae containing Planostegina,Planoperculina,Cycloclypeus,Heterostegina,Operculinella and Neoassilina.展开更多
As a promising candidate material for hydrogen storage, ammonia borane(NH3BH3) has attracted significant interest in recent years due to its remarkably high hydrogen content. Subjecting this material to high pressure ...As a promising candidate material for hydrogen storage, ammonia borane(NH3BH3) has attracted significant interest in recent years due to its remarkably high hydrogen content. Subjecting this material to high pressure not only enables the formation of novel phases and compounds with exotic properties, but also improves our basic understanding of material's behavior at different levels of atomic and molecular interactions. This review focuses on the perspective of high-pressure chemical hydrogen storage related to NH3BH3-based materials. Four main aspects are discussed: the structures and bonding of NH3BH3 over a wide pressure–temperature space, thermolysis of NH3BH3 at high pressure, the formation of a novel high-pressure H-rich compound as a result of storage of additional molecular H2 in NH3BH3, and the potential rehydrogenation of the thermally decomposed NH3BH3 under the extreme of pressure.展开更多
Zircon SHRIMP dating from Qaidamshan granite shows that the granite age is 446 Ma, similar to that of eclogite in the UHP belt. We think that both granite and eclogite may be formed at different stages during tectonic...Zircon SHRIMP dating from Qaidamshan granite shows that the granite age is 446 Ma, similar to that of eclogite in the UHP belt. We think that both granite and eclogite may be formed at different stages during tectonic evolution of this area. Together with other studies we suggested that the collision of ocean and continent plates may occur at the early Caledonian in this area, forming the eclogite, and the collision of continent and continent plates at the late Caledonian, forming the Qaidanishan granite with the zircon SHRIMP age of 446 Ma.展开更多
Anaerobic oxidation of methane(AOM) plays a crucial role in controlling global methane emission. This is a microbial process that relies on the reduction of external electron acceptors such as sulfate, nitrate/nitrite...Anaerobic oxidation of methane(AOM) plays a crucial role in controlling global methane emission. This is a microbial process that relies on the reduction of external electron acceptors such as sulfate, nitrate/nitrite, and transient metal ions. In marine settings, the dominant electron acceptor for AOM is sulfate, while other known electron acceptors are transient metal ions such as iron and manganese oxides. Despite the AOM process coupled with sulfate reduction being relatively well characterized,researches on metal-dependent AOM process are few, and no microorganism has to date been identified as being responsible for this reaction in natural marine environments. In this review, geochemical evidences of metal-dependent AOM from sediment cores in various marine environments are summarized. Studies have showed that iron and manganese are reduced in accordance with methane oxidation in seeps or diffusive profiles below the methanogenesis zone. The potential biochemical basis and mechanisms for metal-dependent AOM processes are here presented and discussed. Future research will shed light on the microbes involved in this process and also on the molecular basis of the electron transfer between these microbes and metals in natural marine environments.展开更多
文摘Dinoflagellates are single celled organisms that reflect the ecological conditions in modern oceans and lakes. Their earliest undisputed fossil record suggests that dinoflagellates originated from the Middle Triassic (c. 240 Ma ago). However, the presence of molecular biomarkers (dinosterane, 4α-methyl-24-ethylcholestane and tria-romatic dinosteroids) in rock extracts and coccoid dinoflagellate fossils from the upper Sinian to Cambrian of the Tarim basin confirms the hypothesis that dinoflagellates have an ancient origin, and predate the oldest undisputed dinoflagellate fossils at least by 300 Ma, as early as the late Sinian-Cambrian.
文摘This research developed estimates of plant crown transpiration and water-use-efficiency using reflectance and derivative indices extracted from remotely sensed chlorophyll fluorescence measurements under natural conditions. Diurnal changes of leaf-level gas exchange (carbon assimilation rate (A), stomatal conductance (gs), transpiration rate (E)), chlorophyll fluorescence and canopy-scale remote sensing were measured on top crown of valley oak (Quercus lobata) in the foothills of central California, USA. The results indicated Q. lobata experienced saturating irradiance (PAR), which induced photoinhibition indicated by a decrease in the quantum efficiency of photosystem II (r2 = 0.648 with Fv ′/Fm′ and r2 = 0.73 with FPSII) and open reaction centers (qP;r2 = 0.699). The excess absorbed quantum energy was dissipated as heat through the Xanthophyll cycle and other processes (photorespiration and the water-water cycle) rather than energy emission as steady state chlorophyll fluorescence (Fs). An increase in leaf temperature caused by the activity of Xanthophyll cycle was correlated to a decrease in Fs (r2 = 0.381) and an increase in evaporative cooling through E (r2 = 0.800) and water use efficiency (WUE;r2 = 0.872).
基金Dr.Ella Sokol is acknowledged for joint collaboration while studying metamorphic mineralogy of MSCz.Contribution to IGCP Project #592 sponsored by UNESCOIUGSIn memory of Prof.R.Shagam (Beer-Sheva University),recently passed away,who encouraged our model and supported our researchfulfilled in the frame of Science project of Institute of Geology and Mineralogy,Siberian Branch,Russian Academy of Sciences
文摘The Mottled Zone(MZ) or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains debatable.Mottled Zone Complex/Complexes(MZC/MZCs) consist of brecciated carbonate and low-temperature calcium-hydro-silicate rocks,which include unusual high- and ultra-high-temperature low-pressure(HT-LP) meta-morphic mineral assemblages.The MZ has been regarded as a product of combustion of bituminous chalks of the Ghareb Fm.of Cretaceous(Maastrichtian) age.In this paper we present detailed geographic, geomorphologic,structural and geological data from the MZCs of the South Levant,which show that the MZCs cannot be stratigraphically correlated with the Ghareb Fm.,because MZC late Oligocene-late Pleistocene deposits occur within or unconformable i.e.,with stratigraphic hiatus,overlap both the late Cretaceous and,in places,Neogene stratigraphic units.We propose an alternative model for the formation of MZCs by tectonically induced mud volcanism during late Oligocene-late Pleistocene time. This model explains(i) the presence of dikes and tube-like bodies,which consist of brecciated exotic clastic material derived from stratigraphically and hypsometrically lower horizons;(ii) mineral assemblages of sanidinite facies metamorphism;(iii) multi-stage character of HT-LP pyrometamorphism;and (iv) multi-stage low-temperature hydrothermal alteration.High temperatures(up to 1500℃) mineral assemblages resulted from combustion of hydrocarbon gases of mud volcanoes.Mud volcanism was spatially and structurally related to neotectonic folds and deformation zones formed in response to opening of the Red Sea rift and propagation of the Levantine Transform Fault.Our model may significantly change the prospects for oil-and-gas deposits in the region.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11179003,10975164,10805062,and 11005134)
文摘Highly oriented pyrolytic graphites are irradiated with 40.5-Me V and 67.7-Me V ^112Sn-ions in a wide range of fluences: 1×10^11 ions/cm^2–1×10^14ions/cm^2. Raman spectra in the region between 1200 cm^-1 and 3500cm^-1 show that the disorder induced by Sn-ions increases with ion fluence increasing. However, for the same fluence, the amount of disorder is greater for 40.5-Me V Sn-ions than that observed for 67.7-Me V Sn-ions, even though the latter has a slightly higher value for electronic energy loss. This is explained by the ion velocity effect. Importantly, ~ 3-cm^-1frequency shift toward lower wavenumber for the D band and ~ 6-cm^-1 shift toward lower wavenumber for the 2D band are observed at a fluence of 1×10^14 ions/cm^2, which is consistent with the scenario of radiation-induced strain. The strain formation is interpreted in the context of inelastic thermal spike model, and the change of the 2D band shape at high ion fluence is explained by the accumulation of stacking faults of the graphene layers activated by radiation-induced strain around ion tracks. Moreover,the hexagonal structure around the ion tracks is observed by scanning tunneling microscopy, which confirms that the strains near the ion tracks locally cause electronic decoupling of neighboring graphene layers.
文摘Natural geological, chronic and acute release of volcanic gases can have a dramatic impact on vegetative ecosystems and potential impact on regional agriculture and human health. This research incorporates a series of observations using leaf level gas exchange, chlorophyll fluorescence and remotely sensed reflectance measurements of vegetation experiencing chronic exposure to volcanic gas emissions;to develop techniques for monitoring the relative health of vegetation along the edge of an acute vegetative kill zone of a natural disaster and potential preeruption vegetation physiology. Experiments were conducted along an elevation gradient that corresponds to the SO2 gradient on vegetation along the south flank of Volcán Turrialba, Costa Rica. This study site is a natural environment with high volcanic degassing activity with significant SO2 emissions (n/d-0.281 ppm). Corresponding to an SO2 gradient, a substantial increase in CO2 concentration of (430-517 ppm) was identified. We further show the physiological interactions of SO2 and CO2 have on vegetation along the kill zone of this natural disaster can be assessed by examining the SO2/CO2 ratios. The physiological indices tested and relationships among measurements emphasized in this research will add to the assessment of the impact atmospheric volcanic gas emissions have on the physiology of surrounding vegetation as well as advance the capability of remotely sensed environmental stress in natural settings.
文摘Non-Darcian flow has been well documented for fractured media, while the potential non-Darcian flow and its driven factors in field-scale discrete fracture networks (DFNs) remain obscure. This study conducts Monte Carlo simulations of water flow through DFNs to identify non-Darcian flow and non-Fickian pressure propagation in field-scale DFNs, by adjusting fracture density, matrix hydraulic conductivity, and the general hydraulic gradient. Numerical simulations and analyses show that interactions of the fracture architecture with the hydraulic gradient affect non-Darcian flow in DFNs, by generating and adjusting complex pathways for water. The fracture density affects significantly the propagation of hydraulic head/pressure in the DFN, likely due to fracture connectivity and flow channeling. The non-Darcian flow pattern may not be directly correlated to the non-Fickian pressure propagation process in the regional-scale DFNs, because they refer to different states of water flow and their controlling factors may not be the same. Findings of this study improve our understanding of the nature of flow in DFNs.
文摘Relatively high abundance of C<sub>31</sub> steranes has been identified from cretaceous source rocks and crude oils in the Songliao Basin, China. C<sub>31</sub> steranes which occur as ten isomers were tentatively identified as 4, 22, 23, 24-tetrametyhlcholestane based on their retention time and mass spectrum.They bear a lower thermal stability and occur as important components in the immature oils of Chaochang region because they have three-methyl groups in their side chain. The relatively high abundance of C<sub>31</sub> steranes in the samples can indicate the source input of some special algae in the brackish and saline environment. Therefore they can be used as very useful biomarkers for organic facies analysis and oil correlation. Their biological source perhaps related to the dinoflagellate such as G. foliaceum and P. foliaceum. The gorgostanol are considered as possible precursors for the putative C<sub>31</sub>4methyl sterane which formed in the stage of diagenesis.
基金supported by Israel Science Foundation(No.1267/21)to Sigal Abramovichthe Swiss National Science Foundation(No.31003A_179125)to Jan PawlowskiOpen Access funding provided by University of Geneva。
文摘The genus Operculina,a large symbiont-bearing benthic foraminifer,is characterized by high morphological variability showing thick involute to intermediate semi-involute to flat evolute tests.Different morphotypes are either considered as ecophenotypes or distinct species.In order to test the hypothesis of ecophenotypes versus different species,a single cell high throughput sequencing approach was applied to assess the interspecific diversity of Operculina.This results in two groups of ribotypes,one corresponding to Operculina ammonoides/Operculina discoidalis,the other containing Operculina complanata/Operculina elegans.These groups can also be separated morphologically.Therefore,O.complanata and O.elegans represent a single species and the latter can be regarded as a junior synonym of O.complanata.Operculina ammonoides and O.discoidalis also form a single species,which makes the latter a junior synonym of O.ammonoides.Because generic differences in Operculina species are manifested in morphology and molecular genetics,the genus Neoassilina with the designated species Neoassilina ammonoides is installed.Additional analysis of ribosomal SSU rDNA data of eight recent nummulitid genera confirms the obtained high troughput sequencing results and further shows that Palaeonummulites venosus builds a clade with O.complanata that branches at the base of other Nummulitidae containing Planostegina,Planoperculina,Cycloclypeus,Heterostegina,Operculinella and Neoassilina.
基金supported by United States Department of Energy through the Stanford Institute for Materials and Energy Science(DE-AC02-76SF00515)
文摘As a promising candidate material for hydrogen storage, ammonia borane(NH3BH3) has attracted significant interest in recent years due to its remarkably high hydrogen content. Subjecting this material to high pressure not only enables the formation of novel phases and compounds with exotic properties, but also improves our basic understanding of material's behavior at different levels of atomic and molecular interactions. This review focuses on the perspective of high-pressure chemical hydrogen storage related to NH3BH3-based materials. Four main aspects are discussed: the structures and bonding of NH3BH3 over a wide pressure–temperature space, thermolysis of NH3BH3 at high pressure, the formation of a novel high-pressure H-rich compound as a result of storage of additional molecular H2 in NH3BH3, and the potential rehydrogenation of the thermally decomposed NH3BH3 under the extreme of pressure.
文摘Zircon SHRIMP dating from Qaidamshan granite shows that the granite age is 446 Ma, similar to that of eclogite in the UHP belt. We think that both granite and eclogite may be formed at different stages during tectonic evolution of this area. Together with other studies we suggested that the collision of ocean and continent plates may occur at the early Caledonian in this area, forming the eclogite, and the collision of continent and continent plates at the late Caledonian, forming the Qaidanishan granite with the zircon SHRIMP age of 446 Ma.
基金supported by the National Natural Science Foundation of China (91751205, 41525011)the National Key R&D project of China (2018YFC0310800)+1 种基金China Postdoctoral Science Foundation Grant (2018T110390)the joint Israel Science Foundation-National Natural Science Foundation of China (ISF-NSFC) (31661143022 (FW), 2561/16 (OS))
文摘Anaerobic oxidation of methane(AOM) plays a crucial role in controlling global methane emission. This is a microbial process that relies on the reduction of external electron acceptors such as sulfate, nitrate/nitrite, and transient metal ions. In marine settings, the dominant electron acceptor for AOM is sulfate, while other known electron acceptors are transient metal ions such as iron and manganese oxides. Despite the AOM process coupled with sulfate reduction being relatively well characterized,researches on metal-dependent AOM process are few, and no microorganism has to date been identified as being responsible for this reaction in natural marine environments. In this review, geochemical evidences of metal-dependent AOM from sediment cores in various marine environments are summarized. Studies have showed that iron and manganese are reduced in accordance with methane oxidation in seeps or diffusive profiles below the methanogenesis zone. The potential biochemical basis and mechanisms for metal-dependent AOM processes are here presented and discussed. Future research will shed light on the microbes involved in this process and also on the molecular basis of the electron transfer between these microbes and metals in natural marine environments.