Microfacies and diagenesis of an upper oxfordian carbonate buildup in Mydlniki (Cracow Area,Southern Poland)

Summary A carbonate buildup near the top of the Upper Jurassic limestone sequence in the Cracow area with a rigid framework built ofTubiphytes and thrombolites, and some fragments of encrusted siliceous sponges and serpules is described. The limestones form a dome-like elevation at the eastern wall of a 15 m high quarry flanked on both sides by stratified limestones with cherts. Six microfacies have been distinguished within the buildup: (1)Tubiphytes/thrombolite boundstone and (2) bioclasticTubiphytes/thrombolite wackestone dominate in the central and bottom part of the buildup. They gradually replace the cyanobacterial crusts and siliceous sponges (3. sponge-algal boundstone), which are sporadically the rock-forming elements in the basal part of the buildup as well as the top. Serpules randomly distributed within the buildup also form small cm-sized structures with a rigid framework (4. serpula-peloid boundstone). (5) tuberoid-peloid wackestone/floatstone and (6) ooid intraclastic grainstone exhibit no significant distributional pattern. Bioclastic-peloidal packstone comprising material derived from the destruction of the buildup occurs in the highest part of the outcrop, overlying the buildup. The sediments of the buildup were subject to rapid lithification, evidence by borings and neptunian microdykes filled with internal sediments, as well as by fracturedTubiphytes. Numerous petrographic features indicate probable episodic emergence of the buildup during its growth; these include asymmetric dissolution textures, asymmetric cements, vadose crystal silt and calcite pseudomorphs after gypsum. Upper Oxfordian carbonate buildups in the Cracow area display various stages of evolution. The carbonate buildup in Mydlniki most closely resembles classical Upper Jurassic reefs.     

Microbial crusts of the late jurassic: Composition,palaeoecological significance and importance in reef construction

Summary Upper Jurassic reefs contain variable amounts of calcareous microbial crusts. In examples from Portugal, Spain and southern Germany they occur within coral biostromes and bioherms, mixed coral-siliceous sponge reefs, siliceous sponge meadows and mudmounds, and build up thrombolities with or without additional reef metazoans. The crusts are of paramount importance for the establishment and development of positive buildups. Commonly, reef growth starts with crusts which develop from a narrow base and rapidly expand laterally by rising above the sea floor. Reef associations with little or no microbial crust normally did not develop distinct relief. The basic microbial crust type is characterised by a dense to peloidal, mostly clotted, hence thrombolitic fabric which developed due to calcification triggered by microbes. Morphological evidence for this organic nature are positive relief, bridge-structures, and the shape and arrangement of peloids. The basic thrombolitic crust type is a eurytopic feature, equally occurring in settings of different bathymetry, waterenergy, salinity and oxygen/nutrient concentrations. However, the crusts also comprise additional micro-encrusters of variable abundance and diversity. The concurrent occurrence of these encrusters and diversity trends allows discrimination between crusts of different environments, particularly of different water depths. Microbial crusts from non-reefal marine oncoids show both similarities and differences with reefal crusts. For some of the mostly enigmatic micro-encrusters new clues to their nature could be detected. For instance, bubble-like structures, formerly interpreted as sporangia inLithocodium could be identified as the foraminiferBullopora aff.laevis, possibly living as a parasite or symbiont in theLithocodium algal tissue.Lithocodium andBacinella are regarded as different organisms.‘Tubiphytes’ morronensis clearly represents a symbiotic intergrowth between a nubeculinellid foraminifer and a microbe of unknown nature. The main prerequisite for the occurrence of microbial crusts is a cessation of background sedimentation which commonly can be tied to rises in sea level. This results in the development of crust-rich reefs. Fluctuations in oxygen and nutrient levels are indicated by dysaerobic bivalves and richness in authigenic glauconite, and led to the microbes outcompeting reefal metazoans, and to the development of thrombolites. Such thrombolites occur at very different depths which is interpreted to be related to a rise of dysaerobic waters due to climatic buffering and lowering of oceanic circulation during sea level rises. Microbial crusts in modern reefs are largely restricted to shaded, cryptic settings which contrasts with the wide distribution of crusts in Upper Jurassic reefs. Microbial crusts were increasingly replaced by coralline red algae since the Late Mesozoic, but despite their restricted modern habitat seem to still play an important, commonly overlooked role in the stabilisation of reef framework.     

Sarmatian (Late Middle Miocene) gastropod assemblages of the Central Paratethys

Summary A rather diverse gastropod fauna from Sarmatian deposits of the Austrian/Hungarian Eisenstadt-Sopron Basin was studied. The fauna derives from two layers of clay and silt within a siliciclastic section at St. Margarethen in Burgenland (Austria). These layers are interpreted as littoral mudflats which formed during the Sarmatian (Late Middle Miocene) along the western coast of the Central Paratethys. Strong shifts in the composition of the gastropod fauna, dominated by Potamididae (Cenogastropoda: Cerithioidea), within each layer indicate successions of limnic-fluvial to oligohaline, brackish-littoral, and marine-littoral environments. These shifts in facies are reflected by an alternational of thePotamides hartbergensis assemblage,Granulolabium bicinctum assemblage, and thePotamides disjunctus assemblage. The speciesJujubinus turriculus (Eichwald, 1850),Gibbula buchi (Dubois, 1831), andCylichnina elongata (Eichwald, 1830) are reported for the first time from the Sarmatian of the Paratethys.Mitrella agenta nov. sp. (Neogastropoda: Columbellidae) is introduced as a new species. These species might represent relics of the diverse Badenian fauna but could also prove a minor ingression of marine species from an adjacent bioprovince in the Late SarmatianMactra “Zone”.     

Production of l (+) lactic acid by Lactobacillus delbrueckii immobilized in functionalized alginate matrices

The role of functionalized alginate gels as immobilized matrices in production of l (+) lactic acid by Lactobacillus delbrueckii was studied. L. delbrueckii cells immobilized in functionalized alginate beads showed enhanced bead stability and selectivity towards production of optically pure l (+) lactic acid in higher yields (1.74Yp/s) compared to natural alginate. Palmitoylated alginate beads revealed 99% enantiomeric selectivity (ee) in production of l (+) lactic acid. Metabolite analysis during fermentation indicated low by-product (acetic acid, propionic acid and ethanol) formation on repeated batch fermentation with functionalized immobilized microbial cells. The scanning electron microscopic studies showed dense entrapped microbial cell biomass in modified immobilized beads compared to native alginate. Thus the methodology has great importance in large-scale production of optically pure lactic acid.     

贺兰山东麓荒漠藻结皮微生物群落结构及其演替研究

以宁夏贺兰山东麓荒漠藻结皮为研究对象,对处于不同发育阶段的藻结皮中微生物群落结构及其演替进行了研究。结皮样品高通量测序结果分别得到521个16S rDNA序列操作分类单元(OTU)和64个18S rDNA序列OTU,表明藻结皮中原核微生物多样性远高于真核微生物;贺兰山东麓藻结皮中原核微生物分布于26个纲,Cyanobacteria在各个发育阶段中都是优势微生物类群,Actinobacteria、Chloroplast、Alphaproteobacteria和Bacilli在藻结皮发育的各个阶段相对丰度也较高;从属水平上分析,Bacillus、Leptolyngbya、Microcoleus、Microvirga、Chroococcidiopsis、Rubellimicrobium、Phormidium、Mastigocladopsis、Skermanella、Nostoc、Scytonema共11个属在各个发育阶段的藻结皮中都存在,只是出现了丰度的差异。Bacillus在藻结皮形成期、发育初期和发育中期相对丰度较大,成熟期丰度显著下降,而成熟期Microvirga丰度较前3个时期显著增...     

A modern-type Kimmeridgian reef (Ota Limestone,Portugal): Implications for Jurassic reef models

Upper Jurassic reefs rich in microbial crusts generally appear in deeper (sponge—‘algal’ crust reefs) or in very shallow but protected settings (coral or coral-coralline sponge meadows with ‘algal’ crusts). Upper Jurassic high-energy reefs (coral reefs and coral-stromatoporoid reefs) normally lack major participation of microbial crusts but rather represent huge bioclastic piles with only minor framestone patches preserved. An exception to this rule is represented by the high-energy, coral-‘algal’ Ota Reef from the Kimmeridgian of the Lusitanian Basin (Portugal). The narrow Ota Reef tract rims a small intra-basinal carbonate platform exhibiting perfect facies zonation (from W to E: Reef tract, back reef sands, peritidal belt, low-energy shallow lagoon). The reef is dominated by massive corals (Thamnasteria, Microsolena, Stylina). Complete preservation of coral framework is rare: like other Upper Jurassic high-energy reefs, the Ota Reef is very rich in debris; however, this debris is largely stabilized by algal and microbial crusts, what contrasts the other examples and gives the Ota Reef the appearance of a typical modern high-energy coral-melobesioid algal reef. Further similarities to modern reefs are the likely existence of a spur-and-groove system, the perfect sheltering of inner platform areas and the occurrence of small islands, as indicated by local blackenings and early vadose and karstic features.     

Das Trockenelement in der jungtertiären Flora Mitteleuropas

Zusammenfassung Im Jungtertiär Ungarns sind einzelne Floren wie im Alttertiär durch das massenhafte Vorkommen mikro- und stenophyller Holzarten ausgezeichnet. Sie verdanken ihre Entstehung, wie im Alttertiär, einem im nordatlantischen Raum Eurasiens gelegenen Entwicklungszentrum und einem Halbtrockenklima. Dieses Klima entsprach dem heutigen Klima in höherem Mass als das Klima desselben Raumes im Alttertiär. Ein Teil der jungtertiären Trockenarten sind aus dem Alttertiär zurückgebliebene Elemente. Sie überlebten die feuchteren Zeiten an günstigsten Stellen. Unter ihnen sind die meisten mit rezenten Arten abgelegener Gebiete, so des öfteren der südlichen Hemisphäre, verwandt. Nur wenige (z.B. Arbutus unedo L.) sind heute mediterran. Die im Jungtertiär entstandenen Trockenarten sind mehrheitlich mit mediterranen Arten verwandt. Die Hartlaubgehölze mediterraner Verwandtschaft kamen im Karpatenbecken in grösster Zahl im ersten Abschnitt des unteren Sarmats vor und beherrschten zu dieser Zeit die Trockenwälder.Die Umweltverhältnisse des oberen Tortons waren jenen von Makaronesien ähnlich. Im unteren Sarmat entwickelte sich ein Klima von echt mediterranem Charakter. Etwas später milderte sich indessen die sommerliche Aridität und die Niederschläge nahmen zu. Die Trockenwälder wurden durch mesophile Waldungen verdrängt. Die Entwicklung der Strauchschicht verspätete sich aber gegenüber der Kronschicht und mediterrane Straucharten erschienen in grösster Anzahl unter einer Kronschicht, die zur Hauptsache aus mesophilen Arten bestand. Eine überaus reiche Entwicklung von xerophilen Quercus-Arten charakterisiert den stark geschichteten xero-mesophilen Mischwald von Balaton-Déllö.

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Summary By analizing the Late Tertiary floras of Hungary the writer found that from Middle Miocene time the number of the leaves of xerophytic character increases. According to his opinion these xerophytic types were — like those of the Early Tertiary — formed in a plant evolution center situated in the North Atlantic region in the latitude of the Spanish and Moroccan meseta or a little more northward. This dry element called xero-atlantic element appears as third besides the temperate Turgayan and the warmer evergreen Poltawa-element.In Hungary the climate changed in the Tortonean to a subtropical one with a hot and dry summer and a mild and moist winter approaching the recent climate of the Mediterranean region. This climate was favourable to the hard-leaved arborescent vegetation.In the German text a list of the dry elements hitherto observed is given with their leaf character, their living equivalent and its geographical distribution. Then the origin of these species is discussed especially whether they are descendants of the Poltawan or Turgayan flora. At the beginning of the dry period of the Late Tertiary, during the Late Tortonean and Early Sarmatian, some dry elements of the Austral type (Proteacea, Myrsinaceae, Callistemophyllum) are yet found. Then the forms of Mediterranean type become dominant. A special attention is paid to the dry oakes. The majority of the hard-leaved oaks is Mediterranean but some of them (e.g. Quercus pseudoilex Kov.) have their equivalence in the Gulf region of North America. The typical hard-leaved oaks of the Pacific region are in no connection with the species of Mediterranean relationship and according to Axelrod (1958) they had their center of evolution in the Sierra Madre region. Besides the hard-leaved forms there are deciduous and semideciduous oaks and one of the laurel type. The latter has his equivalence in southern Atlantic North America.The climate from the Tortonean to the Early Pliocene is fairly well known. During the Tortonian it was similar to the recent climate of the Canary Islands with a rainless summer and a mild winter. The aridity of the summer was nevertheless moderated by the equalized temperature and the high air moisture. At the beginning of the Sarmatian the climate changed to a more extreme one, the summer became hot and dry. In the younger Sarmatian the precipitations increased and the summer aridity decreased.The changes in the vegetation followed the changes of climate. The greatest evolution of the arid and semiarid plant forms took place during the early Sarmatian. But no treeless formations, steppes, or desert vegetation can be supposed. The Tortonean forests were dominated by the Lauraceae. In consequence to the increasing aridity the Lauraceae disappeared from the tree level but remained as shrubs. In the Early Sarmatian especially in the flora of Erdöbénye, the hard-leaved forest was the dominant plant formation consisting of hard-leaved, half-evergreen oaks and other deciduous trees with xeromorphic foliage (Acer decipiens A.Br. etc). The majority of the dry elements were of Mediterranean type. The evolution in the undergrowth of the forest was a little late and the hard-leaved shrubs reached their highest evolution at a time in the Sarmatian when the hard-leaved forest changed gradually into a mesophilous one.

     

Development and eustatic control of an Upper Jurassic reef complex (Saint Germain-de-Joux,Eastern France)

Summary This study consists of a sedimentological and diagenetical analysis of reef facies from the Upper Kimmeridgian (sensu gallico). The investigated deposits are situated in eastern France, about fifty kilometres west of the city of Geneva (Switzerland). The reef complex is a fine example of vertical development and facies differentiation. It is subdivided into two distinct sequences by a perforated hardground horizon and sand shoals. The onset of the first reef sequence is characterized by a pioneer growth stage followed by up to 20 m of reef-core and-flank facies. Corals forming the reef-core are typically the ramose variety ofCalamophylliopsis flabellum. The second reef sequence has a reef-core with an average thickness of about 5 m. Corals, however, display much more varied morphologies, and in some areas massive rudist (Heterodiceras) build-ups occur. Development of the second reef sequence was seriously weakened by a storm which produced a 2 m thick accumulation of coral rubble. A shallowing-upwards trend gradually leads to the formation of beach deposits, followed by a newly detected black-pebble horizon. Diagenesis is an important aspect of the reef complex. Especially noteworthy is the dolomitization of certain horizons. At the base of the reef formation, the passage of the phreatic mixing zone provoked invasive dolomitization in large irregular patches (probably deposits richer in Mg-calcite). Some of the beds above the black-pebble horizon, in particular a deposit of accumulated microbial mats, are also dolomitized. In this case, dolomitization is stratiform and is interpreted as having precipitated under conditions of evaporative pumping. The sedimentary record clearly shows the imprint of eustasy. The reef complex was initiated during a transgressive cycle and the hardground found between the two reef sequences is interpreted as a maximum flooding surface (mfs). At the top of the sequence, the horizon overlain by the black-pebble conglomerate is believed to represent the new sequence boundary SB140. Other significant features identified from the St. Germain-de-Joux deposits include the discovery of a new foraminifera,Troglotella incrustans, which is only marginally covered here but is the topic of another paper (Wernli & Fookes, 1992); the subdivision of the first coralligenous level defined byPelletier (1953) into two reef sequences; and a proposition to redefine the ‘Calcaires de la Semine’ (Bernier, 1984). The investigations carried out in the past on the Kimmeridgian deposits in the area of St. Germain-de-Joux were mostly based on stratigraphy and palaeontology. These reefs are among the finest known in the Jura Mountains, but no thorough study had been made on their sedimentological aspects. The aim of this study is to fill this void and also to clarify the more confusing aspects of local stratigraphy (paper based onFookes, 1991).     

Dynamics of Dimethyl Sulfide in a Marine Microbial Mat

Abstract The microbial mat was chosen as a model ecosystem to study dynamics of dimethyl sulfide (DMS) in marine sediments in order to gain insight into key processes and factors which determine emission rates. A practical advantage, compared to open ocean ecosystems, is that microbial mats contain high biomasses of different functional groups of bacteria involved in DMS dynamics, and that DMS concentrations are generally high enough to allow direct measurement of emission rates. Field data showed that, during the seasonal development of microbial mats, concentrations of chlorophyll a corresponded to dimethylsulfoniopropionate (DMSP). DMSP is an important precursor of DMS. It was demonstrated, with laboratory cultures, that various species of benthic diatoms produce substantial amounts of DMSP. The abundances of aerobic and anaerobic DMS- or DMSO-utilizing bacteria were estimated using the most-probable-number technique. Laboratory experiments with relatively undisturbed sediment cores showed that microbial mats act as a sink for DMS under oxic/light (day) conditions, and as a source of DMS under anoxic/dark (night) conditions. Axenic culture studies with Chromatium vinosum M2 and Thiocapsa pfennigii M8 (isolated from a microbial mat) showed that, under anoxic/light conditions, DMS was quantitatively converted to dimethylsulfoxide (DMSO). T. roseopersicina M11 converted DMSP to DMS and acrylate, apparently without use of either substrate. Received: 5 May 1997; Accepted: 21 August 1997     

Fagopyritol B1, O-α-D-galactopyranosyl-(1→2)-D-chiro-inositol, a galactosyl cyclitol in maturing buckwheat seeds associated with desiccation tolerance

O-α-D-Galactopyranosyl-(1→2)-D-chiro-inositol, herein named fagopyritol B1, was identified as a major soluble carbohydrate (40% of total) in buckwheat (Fagopyrum esculentum Moench, Polygonaceae) embryos. Analysis of hydrolysis products of purified compounds and of the crude extract led to the conclusion that buckwheat embryos have five α-galactosyl D-chiro-inositols: fagopyritol A1 and fagopyritol B1 (mono-galactosyl D-chiro-inositol isomers), fagopyritol A2 and fagopyritol B2 (di-galactosyl D-chiro-inositol isomers), and fagopyritol B3 (tri-galactosyl D-chiro-inositol). Other soluble carbohydrates analyzed by high-resolution gas chromatography included sucrose (42% of total), D-chiro-inositol, myo-inositol, galactinol, raffinose and stachyose (1% of total), but no reducing sugars. All fagopyritols were readily hydrolyzed by α-galactosidase (EC 3.2.1.22) from green coffee bean, demonstrating α-galactosyl linkage. Retention time of fagopyritol B1 was identical to the retention time of O-α-D-galactopyranosyl-(1→2)-D-chiro-inositol from soybean (Glycine max (L.) Merrill, Leguminosae), suggesting that the α-ga-lactosyl linkage is to the 2-position of D-chiro-inositol. Accumulation of fagopyritol B1 was associated with acquisition of desiccation tolerance during seed development and maturation in planta, and loss of fagopyritol B1 correlated with loss of desiccation tolerance during germination. Embryos of seeds grown at 18 °C, a condition that favors enhanced seed vigor and storability, had a sucrose-to-fagopyritol B1 ratio of 0.8 compared to a ratio of 2.46 for seeds grown at 25 °C. We propose that fagopyritol B1 facilitates desiccation tolerance and storability of buckwheat seeds. Received: 21 May 1997 / Accepted: 5 June 1997     

Anisian (middle triassic) buildups of the Northern Dolomites (Italy): The recovery of reef communities after the permian/triassic crisis

Summary After the end-Permian crisis and a global ‘reef gap’ in the early Triassic, reefs appeared again during the early Middle Triassic. Records of Anisian reefs are rare in the Tethys as well as in non-Tethyan regions. Most Anisian reefs are known from the western part of the Tethys but there are only very few studies focused on biota, facies types and the paleogeographical situation of these reefs. From the eastern part of the Tethys, Anisian reefs, reefal buildups or potential reef-building organisms have been reported from different regions of southern China. Most of the Anisian reefs known from western and central Europe as well as from southern China seem to be of middle and late Pelsonian age. The study area is situated in the northern Dolomites (South Tyrol, Italy) southeast of Bruneck (Brunico). It comprises the area between Olang (Valdaora) and Prags (Braies). The study is based on detailed investigations of the regional geology, stratigraphy and lithofacies (R. Zühlke, T. Bechst?dt) as well as on a comprehensive inventory of Anisian reef organisms (B. Senowbari-Daryan, E. Flügel). These data are used in the discussion of the controls on the recovery of reefs during the early Middle Triassic. Most late Anisian reef carbonates studied are represented by allochthonous talus reef blocks of cubicmeter size. Small biostromal autochthonous mounds are extremely rare (Piz da Peres). The reef mounds as well as most of the reef blocks occur within the middle to late Pelsonian Recoaro Formation. They were formed on the middle reaches of carbonate ramps in subtidal depths, slightly above the storm wave base with only moderate water energy. Most lithotypes observed in the reef blocks correspond to sponge and/or algal bafflestones. Low-growing sessile organisms (Olangocoelia (sponge, alga?), sphinctozoan sponges, bryozoans, soleno-poracean algae, corals) and encrusting epibionts (sponges, porostromate algae, cyanophycean crusts, foraminifera, worms, microproblematica) created low cm-sized biogenic structures (bioconstructions) which baffled and bound sediment. Organic framework was only of minor importance; it is restricted to theOlangocoelia lithotype. Framework porosity was small in these reef mounds. Submarine carbonate cements, therefore, are only of minor importance s compared with Permian or Ladinian reefs. The relatively high number of lithotypes encountered in the reef blocks indicates a high biofacies diversity. Regarding the relative frequency, the diverse biota consist in descending order ofOlangocoelia, sponges (sphinctozoans, inozoans, siliceous sponges), bryozoans, porostromate algae and worm tubes. The sphinctozoans are characterized by small, mostly incrusting forms. The numerical diversity (species richness) is low compared with late Permian or Ladinian and late Triassic sphinctozoan faunas occurring within reefs. Following the sponges, monospecific bryozoans (Reptonoditrypa cautica Sch?fer & Fois) are the most common organisms in the reef limestones. Porostromate algae were restricted to areas within the bioconstructions not inhabited by sponges. The low-diverse corals had no importance in the construction of an organic framework. Surprisingly, microbial crusts are rare or even lacking in the investigated Anisian bioconstructions. This is in contrast to late Permian and Ladinian as well as Carnian reefs which are characterized by the abundance of specific organic crusts. The same comes true for‘Tubiphytes’ which is a common constituent in Permian, Ladinian and Carnian reef carbonates but is very rare in the Anisian of the Olang Dolomites. Instead of‘Tubiphytes’ different kinds of worm tubes (spirorbid tubes, Mg-calcitic tubes and agglutinated tubes) were of importance as epifaunal elements. Macrobial encrustations consisting of characteristic successions of sponges, bryozoans, algae, worm tubes and microproblematica seem to be of greater quantitative importance than in Ladinian reefs. Destruction of organic skeletons (predominantly of bryozoans) by macroborers (cirripedia?) is a common feature. The Anisian reef organisms are distinctly different from late Permian and from most Ladinian reef-builders. No Permian Lazarus taxa have been found. New taxa: Sphinctozoan sponges—Celyphia? minima n.sp.,Thaumastocoelia dolomitica n. sp.,Deningeria tenuireticulata n. sp.,Deningeria crassireticulata n. sp.,Anisothalamia minima n.g. n.sp., Inozoan sponges-Meandrostia triassica n.sp. Microproblematica-Anisocellula fecunda n.g. n.sp., Porostromate alga-Brandneria dolomitica n.g. n.sp. Most of our data are in agreement with the model described byFois & Gaetani (1984) for the recovery of reef-building communities during the Ansian but the biotic diversity seems to be considerably higher than previously assumed. Anisian deposition and the formation of the reef mounds within the Pelsonian Recoaro Formation of the Dolomites were controlled by the combined effects of synsedimentary tectonics and eustatic changes in sea-level. During several time intervals, especially the early Anisian (northern and western Dolomites: tectonic uplift), the early Pelsonian (eastern Dolomites: drowning) and the late Illyrian (wide parts of the Dolomites: uplift and drowning), the sedimentation was predominantly controlled by regionally different tectonic subsidence rates. The amount of terrigenous clastic input associated with synsedimentary tectonics (tectonic uplift of hinterlands) had a major influence on carbonate deposition and reef development. The re-appearance of reef environments in the Olang Dolomites was controlled by a combination of regional and global factors (paleogeographic situation: development of carbonate ramps; decreasing subsidence of horst blocks; reduced terrigenous input; moderate rise in sea-level).     

Microbial Community Structure in Three Deep-Sea Carbonate Crusts

Carbonate crusts in marine environments can act as sinks for carbon dioxide. Therefore, understanding carbonate crust formation could be important for understanding global warming. In the present study, the microbial communities of three carbonate crust samples from deep-sea mud volcanoes in the eastern Mediterranean were characterized by sequencing 16S ribosomal RNA (rRNA) genes amplified from DNA directly retrieved from the samples. In combination with the mineralogical composition of the crusts and lipid analyses, sequence data were used to assess the possible role of prokaryotes in crust formation. Collectively, the obtained data showed the presence of highly diverse communities, which were distinct in each of the carbonate crusts studied. Bacterial 16S rRNA gene sequences were found in all crusts and the majority was classified as α-, γ-, and δ- Proteobacteria. Interestingly, sequences of Proteobacteria related to Halomonas and Halovibrio sp., which can play an active role in carbonate mineral formation, were present in all crusts. Archaeal 16S rRNA gene sequences were retrieved from two of the crusts studied. Several of those were closely related to archaeal sequences of organisms that have previously been linked to the anaerobic oxidation of methane (AOM). However, the majority of archaeal sequences were not related to sequences of organisms known to be involved in AOM. In combination with the strongly negative δ ¹³C values of archaeal lipids, these results open the possibility that organisms with a role in AOM may be more diverse within the Archaea than previously suggested. Different communities found in the crusts could carry out similar processes that might play a role in carbonate crust formation.     

Microbial contribution to deposition of upper carboniferous and lower Permian seamount-top carbonates,Akiyoshi, Japan

Summary Microbial organisms significantly contributed to the accumulation of shallow-marine carbonates in an open-ocean realm of the Panthalassan Ocean during Late Carboniferous-Early Permian time. The Jigokudai plateau in the northern part of the Akiyoshidai Plateau is the study area, where the limestone of the Upper Carboniferous Kasimovian Stage to the Lower Permian Artinskian Stage is well exposed. The fusulinid biostratigraphy as well as top-bottom geopetal fabrics revealed that the rocks of the study area are overturned. The thickness of this succession is approximated to 150 m. The succession is lithologically divided into the Lower Jigokudai and Upper Jigokudai formations. The lime-stones of these formations were deposited in a lagoonal setting. The Lower Jigokudai formation (95 m thick: Kasimovian to Asselian) is characterized by sand shoal facies represented by crinoid-Tubiphytes-fusulinid peloidal pack/grainstones and oolitic grainstones. Phylloid algal grain/packstones and microbial boundstones subordinately crop out. The Upper Jigokudai Formation (55 m thick: Sakmarian to Artinskian) is characterized by shoal and tidal flat facies represented by mollusk-fusulinid peloidal grain/rudstones, and peloidal grain/rudstones and peloidal lime-mudstones, respectively. Laterally discontinuous microbial bound-stones occur intercalated in mollusk-fusulinid peloidal grain/rudstones. This formation contains pendant and meniscus cements, and flat-pebble breccia indicative of an intertidal deposition and subaerial exposure. Various types of boundstone and organosedimentary structures constructed mainly by filamentous cyanobacteria,Tubiphytes obscurus tubular microproblematicum A, and other microproblematica were recognized. Significant facies types are (1) filamentous cyanobacteria-microproblematicum A bind/framestones, (2)Tubiphytes obscurus bindstones, (3) stromatolitic bindstones, (4) microbial laminites, (5) microbially linked structures, (6) oncoids, (7) microproblematica B-C framestones. The calcimicrobes, combined with synsedimentary cementation, formed small-scale and low-relief mounds of these facies, and greatly contributed to the deposition of the Kasimovian to Artinskian Panthalassan buildup.     

Genomic variations of <Emphasis Type="Italic">Oenococcus oeni</Emphasis> strains and the potential to impact on malolactic fermentation and aroma compounds in wine

Malolactic fermentation (MLF) is the bacterially driven decarboxylation of l-malic acid to l-lactic acid and carbon dioxide, and brings about deacidification, flavour modification and microbial stability of wine. The main objective of MLF is to decrease wine sourness by a small increase in wine pH via the metabolism of l-malic acid. Oenococcus oeni is the main lactic acid bacterium to conduct MLF in virtually all red wine and an increasing number of white and sparkling wine bases. Over the last decade, it is becoming increasingly recognized that O. oeni exhibits a diverse array of secondary metabolic activities during MLF which can modify the sensory properties of wine. These secondary activities include the metabolism of organic acids, carbohydrates, polysaccharides and amino acids, and numerous enzymes such as glycosidases, esterases and proteases, which generate volatile compounds well above their odour detection threshold. Phenotypic variation between O. oeni strains is central for producing different wine styles. Recent studies using array-based comparative genome hybridization and genome sequencing of three O. oeni strains have revealed the large genomic diversity within this species. This review will explore the links between O. oeni metabolism, genomic diversity and wine sensory attributes.     

Effects of biological soil crusts on seed germination of four endangered herbs in a xeric Florida shrubland during drought

Soil crusts of rosemary scrubs in south-central Florida were examined for effects on seed germination of four herbs that are killed by fire and must recruit from seed: Eryngium cuneifolium (Apiaceae), Hypericum cumulicola (Hypericaceae), Polygonella basiramia (Polygonaceae), and Paronychia chartacea ssp. chartacea (Caryophyllaceae). Biological soil crusts in these sites are dominated by algae, cyanobacteria, fungi, and bacteria. Because crusts can change soil stability, water, and nutrients, they can affect seed germination. A series of greenhouse and field experiments were designed to first examine the effects of crusts in isolation and then to determine their role in the context of other environmental factors – time since fire and distance to the dominant shrub in this system, Ceratiola ericoides. In the greenhouse experiment, germination in autoclaved crusts was dramatically reduced relative to germination in living crusts for all but P. basiramia. In four field experiments where crusts were left intact, disturbed (mechanically or by flaming), or completely removed, the effects of crusts were variable and species-specific, but were significant enough to impact aboveground population sizes. More germination was consistently observed in recently burned sites away from C. ericoides shrubs. Overall rates of germination were generally very low during this study, possibly as a result of seasonal droughts that could have reduced germination, increased seed dormancy, and/or decreased seed viability. The importance of water for germination was confirmed in an experiment with two watering regimes and three crust treatments designed to create a gradient of soil water availability. Germination was significantly greater in the high water treatment and unaffected by soil crust moisture. Dry years are not uncommon in scrub and the results of this study help us to understand how scrub herbs fare during drought and what role biological soil crusts play in germination.     

d-Lysine production from l-lysine by successive chemical racemization and microbial asymmetric degradation

In order to develop a practical process for d-lysine production from l-lysine, successive chemical racemization and microbial asymmetric degradation were investigated. The racemization of l-lysine proceeded quantitatively at elevated temperatures. A sample␣of 1000 strains of bacteria, fungi, yeast and actinomyces were screened for the ability to degrade l-lysine asymmetrically. Microorganisms belonging to the Achromobacter, Agrobacterium, Candida, Comamonas, Flavobacterium, Proteus, Providencia, Pseudomonas and Yarrowia genera exhibited a high l-lysine-degrading activity. Comamonas testosteroni IAM 1048 was determined to be the best strain and used as a biocatalyst for eliminating the l isomer. The degradation rate of l-lysine with C. testosteroni IAM 1048 was influenced by pH, temperature and agitation speed. Under the optimal conditions, the l isomer in a 100-g/l mixture of racemic lysine was completely degraded within 72 h, with 47 g d-lysine/l left in the reaction mixture. Crystalline d-lysine, with a chemical purity greater than 99% and optical purity of 99.9% enantiomeric excess, was obtained at a yield of 38% from the reaction mixture by simple purification. An engineering analysis of l-lysine racemization and microbial degradation was carried out to establish the basis of process design for d-lysine production. Received: 24 September 1996 / Received last revision: 8 November 1996 / Accepted: 23 November 1996     

Microbial sensor for aspartame

Summary A microbial amperometric sensor using immobilized Bacillus subtilis cells was developed for the determination of the dipeptide sweetener aspartame (l-aspartyl-l-phenylalaninemethylester). From 0.07 to 0.6 mmol/l aspartame, a linear dependence of the initial current change (i.e., change in respiration rate) was obtained. The sensitivity for aspartame was one order of magnitude higher than for its amino acid constituents. The microbial sensor was stable for 8 weeks.     

Biological Soil Crusts of Sand Dunes in Cape Cod National Seashore,Massachusetts, USA

Biological soil crusts cover hundreds of hectares of sand dunes at the northern tip of Cape Cod National Seashore (Massachusetts, USA). Although the presence of crusts in this habitat has long been recognized, neither the organisms nor their ecological roles have been described. In this study, we report on the microbial community composition of crusts from this region and describe several of their physical and chemical attributes that bear on their environmental role. Microscopic and molecular analyses revealed that eukaryotic green algae belonging to the genera Klebsormidium or Geminella formed the bulk of the material sampled. Phylogenetic reconstruction of partial 16S rDNA sequences obtained from denaturing gradient gel electrophoresis (DGGE) fingerprints also revealed the presence of bacterial populations related to the subclass of the Proteobacteria, the newly described phylum Geothrix/Holophaga/Acidobacterium, the Cytophaga/Flavobacterium/Bacteroides group, and spirochetes. The presence of these crusts had significant effects on the hydric properties and nutrient status of the natural substrate. Although biological soil crusts are known to occur in dune environments around the world, this study enhances our knowledge of their geographic distribution and suggests a potential ecological role for crust communities in this landscape.This revised version was published online in November 2004 with corrections to Volume 48.     

Biogeochemistry of a gypsum-encrusted microbial ecosystem

Gypsum crusts containing multicolored stratified microbial populations grow in the evaporation ponds of a commercial saltern in Eilat, Israel. These crusts contain two prominent cyanobacterial layers, a bright purple layer of anoxygenic phototrophs, and a lower black layer with active sulphate reduction. We explored the diel dynamics of oxygen and sulphide within the crust using specially constructed microelectrodes, and further explored the crust biogeochemistry by measuring rates of sulphate reduction, stable sulphur isotope composition, and oxygen exchange rates across the crust–brine interface. We explored crusts from ponds with two different salinities, and found that the crust in the highest salinity was the less active. Overall, these crusts exhibited much lower rates of oxygen production than typical organic‐rich microbial mats. However, this was mainly due to much lower cell densities within the crusts. Surprisingly, on a per cell‐volume basis, rates of photosynthesis were similar to organic‐rich microbial mats. Due to relatively low rates of oxygen production and deep photic zones extending from 1.5 to 3 cm depth, a large percentage of the oxygen produced during the day accumulated into the crusts. Indeed, only between 16% to 34% of the O₂ produced in the crust escaped, and the remainder was internally recycled, used mainly in O₂ respiration. We view these crusts as potential homologs to ancient salt‐encrusted microbial ecosystems, and we compared them to the 3.45 billion‐year‐old quartz barite deposits from North Pole, Australia, which originally precipitated gypsum.     

Turnover characteristics in continuous l-lysine fermentation

The turnover characteristics of a microbial bioreactor were comparatively investigated as a closed (batch) and a continuous stirred tank reactor (CSTR) open system, using a 2-l fermentor. Corynebacterium glutamicum (ATCC 21544) was chosen as the microorganism since it has the ability to produce l-lysine. Parameters measured were l-lysine production rates, glucose consumption rates and biomass production rates as a function of dilution rate, bioreactor volume and biomass concentration. The modes of microbial cell behaviour under steady-state and transition-state conditions were examined. Investigations on scaling properties of the CSTR system were also aimed at comparing scaling or allometry of metabolic rates in organisms that are also open energy dissipative systems.This investigation was first presented at the 10th Dechema-Jahrestagung der Biotechnologen, 1–3 June 1992, Karlsruhe, Germany