Bacterial paleontology is oriented towards recognition of bacterial remnants as microfossils in the sedimentary rock. Presence of bacteria in ancient rocks makes a fundamental contribution to the understanding of the most part of the history of the biosphere as an empirical date set and starting point for its reconstruction corrected for microtaphonomy conditions. In addition to use of organowalled and silicified microbial structures SEM adds fascinating new possibilities, which are however based on neontological dates. It is not realized how poor is the knowledge of neontological microbiologists obtained from direct microscopic observations and how disputable are conclusions made on this basis. Only mass development, as e.g. in microbial mats, is accepted by microbial ecologists as a fact for consideration. The large body of information obtained from molecular methods in situ identification of phylogenetic position is not in the facilities of bacterial paleontology. Morphology in most cases is insufficient for understanding the functioning of bacteria. In paleontological record function might be deduced from the composition of biogenic minerals. Bacterial mineralogy both in formation of minerals and destruction of lithogenic ones makes the critical link between Life and Earth sciences for interpretation of Precambrian events. Etching of minerals indicating microbially mediated weathering might be the major source of information particularly for subaerial environments, which are most poorly understood parts of processes in past. Another point is the link between microbial landscape and facial analysis based on paleontological and geological reconstructions. Relict microbial communities in volcanic and evaporative environments seems to be the key model sites for the reconstruction. Bacterial paleontology now is a well established and proliferating field of basic knowledge, which cannot develop without its own methodology formed with large input from actualistic models.

The ecobiological interpretation of the microfossils (M), considered in Acritarcha, from Neoproterozoic sediments of Southern margin of Siberian Platform has been carried out. The advantage of the studied strata is that they reflect the conditions of shelfs and more deep-sea sites. Morphological features of M determined the comparison to possible types of the recent bacteria whose metabolic properties mostly corresponded to the reconstructed biotopes. The characteristic features and a relationship with carbon-bearing matrix allowed us to speculate on attribution of the most part of M (Bavlinella Schep., etc.) to anaerobic, sulphate-reducing bacteriacoenosis and about their dwelling in varied settings. Orthorhombic shape of the forms Octoedrixium Rud are likely determined by the crystallization of the trapped sulfur and its later diffusion in the diagenesis from the cells of aerobic sulphur bacteria. The star-like forms Floris Stan. are similar in their habitat and morphology to the aerobic prosthecobacteria of recent water-bodies. The forms of two last-named groupings are found in shallow sediments. The organic-walled M, attributed to bacteria, preserve their volume and features in metamorphic conditions. To take into account this ability and to make natural systematic perspective of the group Acritarcha classification, its modified version is proposed.

Organic-walled microfossils from two Siberian representative microbiotes of the Neoproterozoic Miroedikha and Lakhanda Formations include mat-building cyanobacteria, accompanied by less common bacteria-like microfossils from the terrigenous rocks. Bacterial remains not so often are mentioned under the study of the organic-walled microfossils. Three morphotypes of microfossils bearing a close resemblance to bactera are discussed. These morphologically simple but complex in physiology organisms had the great importance for the Precambrian biota evolution. The occurrence of Prokaryotes among sufficiently differentiated microfossils of the Upper Riphean allows extrapolating back to the time, when evolutionary innovations had took place in the Precambrian.

A new fossil complex of organic micro-organisms from Upper Vendian deposits of Mezen syneclise is described. This complex consists of cyanobacterial mat fragments represented by taxa Leiotrichoides tipicus Hermannn, 1974 and Palaeolyngbya aff. catenata Hermann, 1974. On the surface of this communities were found remains of cord-like thalli Eoholynia mosquensis Gnilovskaya, 1975. They may be referred to the eucaryotic algae with parenchimatous type of tallus structure. The phytoleims of megascopic probably eucaryotic algae were also found jointly with organic biofilms. Their type of preservation was determinated by this burial with the organic biofilms produced by cyanobacterial communities.

The study of organic films from Zimnie Gory Beds, Ust'-Pinega Formation (Upper Vendian) permits to identify numerous colonial coccoid cyanobacteria of genus Ostiana Hermann (O. microcystis and O. aphanotece sp. nov.). Spheroid acritarchs of genus Leiospheridia Eis. (L. tenuissima and L. ternata) are occasionally found together with the colonial microfossils. Pyritized organic films with filamentous Leiotrichoides tipicus were found in some layers of Ust'-Pinega formation. Phytoleims with numerous colonial coccoid micrfossils assiged to the genus Ostiana Hermann, 1976, were found in the Upper Vendian terrigenous deposits (Zimnegorsk Beds, Ust'-Pinega Formation) in the Borehole 1000-1 (depth: 470 - 475 m). The fossils are represented with minute (from 1 to 10 - 12 micron in diameter rarely larger) spherical or ellipsoid forms with thin, smooth or rough envelope and slightly thickened margin. The colonies are claster-like, rounded or irregular in shape. The cells are usually tightly placed in colony to form the thickened outline or overlap each other. Sometimes the cluster-like colonies are connected by the rows of smaller cells forming threads (table I, fig. 1; tabl. II, fig. 2,4). The phytoleims with microfossils are mostly thin, transparent, but darker ones with uneven margin and distinct meshes of various shape and size resembling cellular structures can be found (tabl. I, fig. 2). Piritized organic films were found in some layers Ust'-Pinega Formation. Framboids of pyrite are deployed of over decomposed organic matter signaling the activities of sulphatereducing bacteria. Together with the colonial cyanobacteria occasional spheroid mocrofossils (acritarchs) were discovered and assigned to two species: Leiosphaeridia ternata (Timofeev, 1966) emend. Mikhailova et Jankauskas, 1989 and Leiosphaeridia tenuissima Eisenack, 1958. L. ternata has a dense dark, opaque envelope with specific radial crack on an exterior edge. The diameter is 20 to 30 mm (table II, fig. 1). Thin-walled acritarchs with smooth wall and rare flexibility folding are assigned to L. tenuissima Eisenach, 1958. The diameter of the envelopes varies from 15 - 20 to 150 - 200 mm (table II, fig. 6). Varions groups of numerous microfossils differing in size, shape of colonies and cells are assigned to genus Ostiana Hermann, 1976. Two species of colonial cyanobacters: Ostiana microcystis and Ostiana aphanothece sp. nov. are described from the material studied.

The biostratigraphical significance of individual taxa of Precambrian micro-organisms has been considered. The results of an analysis of the morphological variability of ancient colonial forms are comparable to present-day coccoidal cyanobacteria of the Gloeocapsa Kutz. genus. Conclusions have been made on the origin, nature, and direction of changes in the Gloeocapsa-shaped colony composition as well as on an opportunity to use them for biostratigraphical purposes.

To determine age and genesis of rock series fossiles of macro- and microbiote have a great importance. In altered rocks organogenic remnants could be preserved as relics of initial substrate or pseudomorphic replaced by hemogenic substance fossils. It is necessity in difference of replaced remnants and mineralogical aggregates.

Individual calcareous algae were known in Riphean. Their mass distribution is connected to the beginning of Cambrian. Despite of a long history of study, the nature of this group long time remained not clear. The new unique finds of algae from East Sayan region have shown, that primary carbonate thallus disappeared in the process of fossilization, and after it the calcareous cover formed by association of bacteria and cyanobacteria only.

Late Cretaceous phosphogenesis of the Voronezh Anteclise has occurred during Cenomanian and Early Campanian. SEM studies show the presence of phosphatized algal-bacterial assemblages both in Cenomanian and Campanian phosphorites. In some Cenomanian nodular phosphorite samples revealed empty tubes 1 - 5 microns in diameter, which are most likely trichomes of cyanobacterial filaments. Other samples contained accumulations of spheres 0,5-3 microns, similar to coccoidal bacteria. Complicated tubular forms with variable diameter 2 - 5 microns occur on surface of some quartz grains in nodules. They are probably pseudomorphs after algae. We found similar formations in the Campanian phosphate grains. Frequently, grain represents a cyanobacterial mat, which is sometimes concentrically coated by phosphatic films. The films of some grains retain the primary structure, their concentric layers are formed by pseudomorphs after different bacterial types and obviously they represent oncolite. In other cases, the primary structure is unobservable because of recrystallization process erases them. Occasionally, the central part retains the coccoidal structure and the recrystallization affects only films. Besides the core of such oncolite can be represented not only by phosphatic grain, but also by grains of other minerals, such as quartz, glauconite and heavy minerals, which serve as a substrate for cyanobacterial colonies. Bacteria also could settle on cavity surfaces and interiors frames of sponge fragments, teeth and bones.

Owing to the latest investigations in bacterial paleontology and geomicrobiology a number of minerals known to be formed with the participation of micro-organisms increases continuously. 12 - 15 years ago we know nearly 20 minerals: carbonates (calcite, aragonite, monohydrocalcite), phosphates (dalite, francolite, struvite, vivianite, and some other), sulfates (jarosite), ferric oxides (magnetite, ferrohydrite), sulfides (pyrite, hydrotroilite, sphalerite, wurtzite, and some others) (Lowernstan, Weiner, 1989). Now their number is several times greater. Quartz cristobalite, pyrolusite, silicates (including layer ones), and feldspars are of special interest (Geomicrobiology..., 1997; Tazaki et al., 1997; Geptner et al., 1997; Bacterial paleontology, 2002).

Mesozoic lake deposits of 12 localities mainly from carbon-rich facies were studied by SEM for fossilized remains of bacteria and cyanobacteria. Few Devonian, Carboniferous and Permian localities were studied too. Lithified voluminous bacteriomorph objects were found in most localities. Some of them were lithified very fast and incorporated in sediment thus can not be recent pollution. Filamentous remnants are rare, spheroids about 3 μm are most common.

The investigations of the fossil microbial remains from black carbonate shales of the Sinsk formation (Lower Cambrian) of the Siberian platform were provided. The main types of fossil bacterial remains found in the rocks under investigation are described.

The laboratory supervision above culture filament cyanobacterias, which form of construction stromatolites, have shown, that at various types of influences in originally homogeneous community (film) from filament cyanobacterias there are allocated structures specific to each kind of influence. It was interpreted as the phenomena having similarities to such processes at more developed organisms, as differentiation and ontogenesis. Proceeding from this, cyanobacterias films was attached the status organism with all complex whole of display of functions, including with function of formation of a skeleton. These data were applied to understanding of nature stromatolites, constructions, when all observable morphological variety of constructions can be explained by the morphological answers of community of filaments to change of the factors of environment.

New data on the composition and genesis of volkonskoite based on mineralogical investigation of the mineral and enclosing rocks are presented. SEM investigations of volkonskoites display undoubted role of organic matter (living and dead) in the formation of volkonskoite, i.e. in the chromium concentration and fixation in the smectite structure.

Study of the inner structure, mineral, chemical and isotope composition of siderite and phosphate-siderite concretions from the upper Jurassic deposits of the Viatka-Kama basin has been made. A possible mechanism of their formation is discussed. A number of mineralogical and isotopic features indicate that the siderites and phosphates were formed at the diagenetic stage by the agency of both inorganic and microbial processes.

Hundreds of specimens of phosphorites, bauxites and manganese ores of different genetic types from all continents, from Quarternary to Proterozoic by age were studied with SEM analysis. Mineralized remains of prokaryotes and to less degree of eukaryotes made up the majority of such unchanged ores. The process of replication of biological fabric with different ore matters is general and determining for the origin of these ores, though for bauxites is characteristic somewhat pure chemical deposition during initial transformation stage of host rocks. Highly productively during initial stages of the ore genesis favors for phosphate and manganese ores, beside some other factors. The microbiota actively take part in decomposition of rocks during bauxite genesis side by side with forming of ore biomorphoses.

It was established that the same type of organic matter was accumulated in ancient salts independently of their ages and mineralogical compositions. The origin of hydrocarbons of salt bitumoids was aquagennic organic matter, which accumulated in restore conditions. Data of alkane, sterane and triterpane distributions in conjunction with other geochemical and geological information were used here.

The Earst-European platform Archean crystalline basement rocks opened by Vorotilov Deep Well (VDW) were studied within depths 2575 - 2805 m. VDW was drilled through Puchezh-Katunki impact structure and opened some rocks characterized by high magnetic saturation. Micro-dispersed structure of magnetite indicated on a possibility of its biogenic origin. Really some pure cultures of magnet-ordered compound producing bacilli were isolated. Thus, the identification of fatty acids and other lipid components of microbial cells inside rocks was made to establish the iron reduction role in common biochemical activity in deep subsurface. 34 microbial lipid markers were detected by gas chromatography -- mass-spectrometry and 22 species were identidied by private database. Bacteria of g. Bacillus reached 6.8% in subsurface communities. However, representatives of gg. Clostridium (37.1 - 33.2%) and Rhodococcus (27.6 - 33.7%) were absolute dominants within studied depth interval. Geochemical conditions in situ as well as physiological features of these micro-organisms allow to constitute a following trophic chain: subsurface fluid hyudrocarbons → it oxidizing rhodococci → free aminoacids and biomass proteins (products of rhodococci metabolism) → it fermenting clostridia. This syntrophic association may be a new basement for subsurface ecosystem and can support the magnet-ordered compounds production.

Looking for a habitable planet one should keep in mind that the Earth has a unique combination of physical properties needed for the evolution of the life based on amino acids and a RNA/DNA and its transition, first into multicellular and then vertebrate organisms. Other planets played an important role in the process. There are even revivals of the "anthropic principal," stating that the onset of terrestrial life is obligated to Jupiter. The question of life beyond the Earth has exercised human imagination since the ancient Greeks. The discovery of Earth type extrasolar planets may be awaited in a nearest future. What could be the impact of their discovery on human philosophy? With no exaggeration one may consider it as a milestone for the whole science. The main factors of the planet, that is critical for the existence of life, form a peculiar labyrinth with many impasses. A planet feasible for the advent of life and its evolution towards multicellular organisms should be searched for only in planetary systems of stars of spectral types, from late F to early subtypes of K and should possess the features listed in this paper.

The microbiological investigations of icy formations on the Earth, including Central Antarctic glacier, are closely related to the problem of origin of life on the Earth and other planets, as well as to the problem of transferring of some primitive life forms through the space. The study of the Central Antarctic ice core (50 - 3540 m depth) provided us with the information on abundance and morphological diversity of procaryotic and eucaryotic microorganisms brought on glacier surface by atmospheric currents in different geological epochs. Some microorganisms remained viable owing to the anabiotic state. The incubation of the thawed water of ice core samples showed that the intensity of bacterial propagation depended on several factors including initial cell concentration, organic matter content in the sample and incubation temperature. The quantity of microorganisms increased more noticeably at 20, 25 and 28°C than at 15°C. These results suggest the occurrence of mesophilic microorganisms in the samples from the horizons studied. It is obvious that these microorganisms are resistant to such external environments. In addition the results obtained may indirectly evidence for climatic conditions in ancient epochs.

The complex studies of bacterioplankton in the Barents Sea during the period from 1983 to 1993 and analysis of the samples gathered at the stations in the south-eastern part of the Pacific Ocean including electron microscopy of bacteria of different sizes allow to conclude that: (1) the number, biomass of bacteria calculated with the bacterial size taken into consideration are indicative of the waters of different origin as well as some bacteria genera (Synechococcus, Caulobacter) and the activity of nitrogen fixation. (2) The volume of bacterial cells grows with advancement to the pole. (3) Filtration showed the presence of considerable number of small-sized bacteria, nanobs, passing through 0.2μm pores. In the culture of marine Treponema hyponeustonicum microcells without cell wall emerge. The presence of small-size organisms in the sea water is conditioned by the properties of the marine environment: salinity, the nature of the organic matter, and presence or absence of streams.

In this paper, the microscopic textures of clay minerals resemble of recent biomorphous layer silicate precipitates are described and the possible environment for their formation discussed. Fossilized biomorphous-like microstructures in clay precipitates in the Miocene and Pliocene basalt piles were identified by comparison with published data on bacterial forms, both living and fossilized. The sizes, shapes, and fabric of the mineral precipitates are the key factors in a successful analysis of biomorphous-like microstructures. The studied morphological types of biomorphous-like microstructures were: rod-like, spheres, filaments, hemispheres and films. The nature of formerly existing hydrothermal systems in the lava piles, has been reconstructed by studies of the present mineral paragenesis and by the analogy with modern hydrothermal mineral precipitation.

Non-spore-forming bacteria of the genera Micrococcus and Arthrobacter, including the isolates from permafrost sediments, were found to be able to form cystlike cells under special conditions. Cystlike cells maintained the viability during long-term storage (for up to several years), had undetectable respiratory activity and the elevated resistance to heating and other unfavorable conditions, possessed the specific fine structure and morphology, and were formed in the life cycles of the microorganism. These properties allow cystlike cells to be attributed to a new type of resting microbial forms. Furthermore, the distinctive feature of resting cystlike cells was their low P/S ratios and high Ca/K ratios in comparison to vegetative cells as shown by X-ray microanalysis. The experimentally obtained bacterial cystlike cells with thickened and laminated cell walls and altered texture of the cytoplasm were similar to the cells abundant in native microbial populations isolated from permafrost sediments and ancient soils of the Kolyma lowland (Siberia, Russia). Due to the inherent elevated resistance to adverse conditions and maintenance of viability for prolonged periods, resting cystlike cells are likely to ensure long-term survival of non-spore-forming bacteria in cold environments.

The method of X-ray microanalysis was used for the detection of microbial cells among cell-like particles immediately in the samples of 170 thousand year old ancient Antarctic permafrost sediments. The X-ray spectra and the quantitative parameters of P, S, Ca and K contents in cell-like particles, as well as ratios Ca/K and P/S, were compared with the corresponding data obtained for microbial cells of various physiological states: vegetative cells -- resting forms -- non-viable micromummies. The absence of P and S peaks in X-ray spectra in the most of cell-like particles allowed us to regard them as non-living objects. Among other investigated cell-like particles we were able to find the resting forms of microorganisms with the increased intracellular level of Ca, high Ca/K ratio and low P/S ratio. So, X-ray microanalysis is a promising tool for a primary detection of microbial cells in situ and determination of their physiological state.

Biogenic mineral formation in the culture of marine psychrophilic ferrioxidizing bacteria of Siderococcus genus is studied in this work. During this process, hematite was formed through ferrihydride. The method of microdiffraction of mineral's electrons on ultrafine cuts showed hematite sedimentation on the surface of the cells deprived of cell walls. Fine homogeneity of this mineral is vindicated. The laboratory model of evolutionary ancient marine bacteria Siderococcus was used to show the formation of hypergene oxides: protoferrihydride -- ferrihydride -- hematite. Microdiffractional analysis of biogenic material, which was taken from technogene zone, gave additional characteristic of the ecosystem through the detection of hematite mineral modification, which was formed by ingress of seawater Pb ions into the structure of the mineral.

This paper is devoted to possibility of the study of organic molecules synthesis under modeling space conditions and by new experimental methods used in plasma and shock wave physic.

Most bodies of our Solar System are "Frozen Worlds" where the prevailing surface temperature remains at or below freezing. On Earth there are vast permanently frozen regions of permafrost, polar ice sheets, and glaciers and the deep oceans and deep-sea marine sediments have remained at 2 - 4°C for eons. Psychrophilic and psychrotrophic microbiota that inhabit these regimes provide analogs for microbial life that might inhabit ice sheets and permafrost of Mars, comets, or the ice/water interfaces or sediments deep beneath the icy crusts of Europa, Callisto, or Ganymede. Cryopreserved micro-organisms can remain viable (in a deep anabiotic state) for millions of years frozen in permafrost and ice. Psychrophilic and psychrotrophic (cold-loving) microbes can carry out metabolic processes in water films and brine, acidic, or alkaline chanels in permafrost or ice at temperatures far below 0°C. These microbes of the cryosphere help define the thermal and temporal limits of life on Earth and may provide clues to where and how to search for evidence of life elsewhere in the Cosmos. Astrobiologists at the NASA Marshall Space Flight Center have collected microbial extremophiles from the Pleistocene ice wedges and frozen thermokarst ponds from the Fox Permafrost Tunnel of Alaska. Microbes have also been isolated from samples of Magellanic Penguin guano from Patagonia; deep-sea marine muds near hydrothermal vents; snow and permafrost from Siberia, and deep ice cores, ice-bubble and cryoconite rocks of the Central Antarctic Ice Sheet. These samples have yielded microbial extremophiles representing a wide variety of anaerobic bacteria and archaea. These microbes have been isolated, cultured, characterized and analyzed by phylogenetic and genomic methods. Images were obtained by Phase Contrast, Environmental, Field Emission Scanning and Transmission Electron Microscopes to study the ultra-microstructure and elemental distribution in the composition of these micro-organisms. We consider the Astrobiological significance of the Fox Tunnel with its rich assemblage of frozen microbes as proxy for developing techniques that may help optimize the search for evidence of life in the permafrost of Mars. We provide images of a novel anaerobic, heterotrophic, psychrotrophic bacterium (str.FTR1) isolated in pure culture from the Fox Tunnel. We also describe novel psychrotrophs isolated from guano of the Magellanic penguin (Spheniscus magellanicus) from the southern tip of Patagonia. These strains PmagG1 and PPP2) represent new species and genera of anaerobic microbes that grow at very low temperatures. The lowest limit for growth without morphological changes of str.PmagG1 is −4°C.

Thin sections of the Upper Moscovian shallow-marine limestones of central European Russia exhibit various products of synsedimentary and earliest diagenetic degradation of carbonate allochems. Micritized grains and related features (microcrystalline overgrowths, oncoids, and endolithic borings) are very similar to modern micritized grains forming on the shallow protected seafloors of warm-water carbonate basins. Surface-sediment micritization in the late Moscovian epicontinental basin of central European Russia is expressed in microendolithic destruction, micrite-minimicrite precipitation in intraskeletal voids, and non-selective replacements of the original skeletal structures. Most conspicuous products of surface-sediment micritization are peloidized large foraminifers (fusulinoids and palaeotextulariids), micritic-minimicritic envelopes on brachiopod and echinoderm bioclasts, and internal micritization in echinoderm stereomal pores. The last feature is structurally controlled and where not related to other surface-sediment alterations, may be attributed to intrasedimentary degradation. Surface-sediment micritization was produced by a syntrophic microbial community that must have included phototrophic cyanobacteria and/or chlorophytes and heterotrophic bacteria and fungae responsible for the intragranular microcrystalline recrystallization and internal cementation. Microborings are diverse, include microbial and metazoan varieties. Microendolithic destruction and subsequent microcrystalline occlusion of borings was locally important in micritizing processes, although cinder-like peripheral replacements in massive bioclasts and persistence of test walls in deeply peloidized foraminifers suggest that recrystallization and internal cementation was equally or more important. Many skeletal packstones, wackestones, mudstones, and tempestites irrespectible of their inferred paleobathymetric position exhibit the signs of selective intrasedimentary degradation: peripheral mergence of massive bioclasts to micritic matrix, degraded paleotextulariid tests, and recrystallized matrix. Dense micritic-minimicritic allochems were most resistant to the degradation. These alterations are recognized as intrasedimentary micritization, the process also known in modern carbonate sediments. Possible relation to, or contemporaneity with, early intrasedimentary hardening, as well as scattered mud intraclasts with signs of grain degradation in storm basal lags, suggest that intrasedimentary micritization started very early within the muddy sediment. Environments of these alterations must have been dark, stagnant, enriched in sapropelic organic matter and decomposing it bacteria, oxygen-deficient or anoxic, reducing, with elevated pH. Intrasedimentary micritization is supposed to be largely bacterial, with possible role of heterotrophic microendoliths (primarily fungae). Early generations of dolomite formed deeper in the sediment than intrasedimentary degradation but before the sediment compaction. They tend to replace marly subtidal lithofacies. Presumably, the early dolomitization is explained by the bacterial dolomitization model.

The discovery of biominerals, chemical biomarkers and evidence of microfossils in the Mars meteorite (ALH84001) stimulated research into biomarkers, microbial extremophiles and provided impetus to the newly emerging fields of Astrobiology and Bacterial Paleontology. The debate following the ALH84001 results has highlighted the importance of developing methodologies for recognition of mineral and elemental bioindicators, chemical biomarkers and microfossils in terrestrial rocks and meteorites prior to sample return missions to comets, asteroids, and Mars. Comparative studies of living and fossil micro-organisms and biomarkers are vital to developing expertise needed to recognize indigenous biosignatures and recent contaminants. This paper reviews elemental and mineral bioindicators, chemical biomarkers and keropgen in terrestrial rocks and meteorites. Electron Microscopy images of hyperthermophilic nanobacteria, sulfur and sulfate reducing bacteria, and mineralized microfossils and kerogen found in-situ in carbonaceous meteorite rock matrix are presented.