TY - JOUR AU - Németh, Péter TI - Aszteroidabecsapódások során keletkező összetett gyémántszerkezetek JF - FIZIKAI SZEMLE J2 - FIZIKAI SZEMLE VL - 74 PY - 2024 IS - 2 SP - 50 EP - 55 PG - 6 SN - 0015-3257 UR - https://m2.mtmt.hu/api/publication/34561977 ID - 34561977 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Lange-Enyedi, Nóra AU - Németh, Péter AU - Kériné Borsodi, Andrea AU - Spötl, C AU - Makk, Judit TI - Calcium carbonate precipitating extremophilic bacteria in an Alpine ice cave JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 14 PY - 2024 IS - 1 SN - 2045-2322 DO - 10.1038/s41598-024-53131-y UR - https://m2.mtmt.hu/api/publication/34560277 ID - 34560277 N1 - Export Date: 10 May 2024 Correspondence Address: Németh, P.; Institute for Geological and Geochemical Research, Budaörsi út 45, Hungary; email: nemeth.peter@csfk.org AB - Extensive research has provided a wealth of data on prokaryotes in caves and their role in biogeochemical cycles. Ice caves in carbonate rocks, however, remain enigmatic environments with limited knowledge of their microbial taxonomic composition. In this study, bacterial and archaeal communities of the Obstans Ice Cave (Carnic Alps, Southern Austria) were analyzed by next-generation amplicon sequencing and by cultivation of bacterial strains at 10 °C and studying their metabolism. The most abundant bacterial taxa were uncultured Burkholderiaceae and Brevundimonas spp. in the drip water, Flavobacterium, Alkanindiges and Polaromonas spp. in the ice, Pseudonocardia, Blastocatella spp., uncultured Pyrinomonadaceae and Sphingomonadaceae in carbonate precipitates, and uncultured Gemmatimonadaceae and Longimicrobiaceae in clastic cave sediments. These taxa are psychrotolerant/psychrophilic and chemoorganotrophic bacteria. On a medium with Mg2+/Ca2+ = 1 at 21 °C and 10 °C, 65% and 35% of the cultivated strains precipitated carbonates, respectively. The first ~ 200 µm-size crystals appeared 2 and 6 weeks after the start of the cultivation experiments at 21 °C and 10 °C, respectively. The crystal structure of these microbially induced carbonate precipitates and their Mg-content are strongly influenced by the Mg2+/Ca2+ ratio of the culture medium. These results suggest that the high diversity of prokaryotic communities detected in cryogenic subsurface environments actively contributes to carbonate precipitation, despite living at the physical limit of the presence of liquid water. LA - English DB - MTMT ER - TY - JOUR AU - Bujtor, László AU - Demény, Attila AU - Németh, Péter AU - Bajnóczi, Bernadett TI - Laevaptychi as reliable paleotemperature archives: high-resolution stable isotope compositions of Kimmeridgian (Jurassic) lamellar structured aspidoceratid lower mandibles from Zengővárkony (Mecsek Mountains, Hungary) JF - INTERNATIONAL JOURNAL OF EARTH SCIENCES J2 - INT J EARTH SCI VL - 113 PY - 2024 SP - 353 EP - 367 PG - 15 SN - 1437-3254 DO - 10.1007/s00531-023-02376-5 UR - https://m2.mtmt.hu/api/publication/34538363 ID - 34538363 N1 - Institute of Geography and Environmental Sciences, Eszterházy Károly Catholic University, 6-8 Leányka Street, Eger, 3300, Hungary HUN-REN CSFK, MTA Centre of Excellence, Konkoly Thege Miklós út 15-17., Budapest, 1121, Hungary Institute for Geological and Geochemical Research, HUN-REN Research Centre for Astronomy and Earth Sciences, Budaörsi út 45, Budapest, 1112, Hungary Export Date: 18 February 2024 CODEN: IJESF Correspondence Address: Bujtor, L.; Institute of Geography and Environmental Sciences, 6-8 Leányka Street, Hungary; email: bujtor.laszlo@uni-eszterhazy.hu Correspondence Address: Demény, A.; Institute for Geological and Geochemical Research, Budaörsi út 45, Hungary; email: demeny.attila@csfk.org AB - Fieldwork provided well-preserved Laevaptychus sp. ex gr. hoplisus – obliquus specimens from the lower Kimmeridgian of Zengővárkony (Mecsek Mountains, south Hungary). This study presents the stable isotope analysis of these aptychi and control samples from brachiopods ( Nucleata and Pygope ) derived from the Zengővárkony section bed 3. Rarely observed structures in the upper lamellar layers of the studied laevaptychi revealed 24–32 concentric lamellae that represent primary textural features and indicate excellent preservation. After careful screening for diagenetic effects, stable oxygen isotope compositions yielded seawater temperatures between 20 and 26 °C in good agreement with earlier studies on Jurassic formations, with improved precision. Our research presents for the first time that well-preserved laevaptychi may be a reliable data source for paleoclimate and paleotemperature reconstructions. LA - English DB - MTMT ER - TY - JOUR AU - Lange-Enyedi, Nóra AU - Kériné Borsodi, Andrea AU - Németh, Péter AU - Czuppon, György AU - Kovács, Ivett AU - Leél-Őssy, Szabolcs AU - Dobosy, Péter AU - Felföldi, Tamás AU - Demény, Attila AU - Makk, Judit TI - Habitat-related variability in the morphological and taxonomic diversity of microbial communities in two Hungarian epigenic karst caves JF - FEMS MICROBIOLOGY ECOLOGY J2 - FEMS MICROBIOL ECOL VL - 99 PY - 2023 IS - 12 PG - 17 SN - 0168-6496 DO - 10.1093/femsec/fiad161 UR - https://m2.mtmt.hu/api/publication/34431117 ID - 34431117 N1 - Institute for Geological and Geochemical Research, HUN-REN Research Centre for Astronomy and Earth Sciences, Budaörsi út 45, Budapest, H-1112, Hungary Department of Microbiology, Institute of Biology, Faculty of Science, Eötvös Loránd University, Pázmány P. sétány 1/C, Budapest, H-1117, Hungary Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research, Karolina út 29, Budapest, H-1113, Hungary Research Institute of Biomolecular and Chemical Engineering, Nanolab, University of Pannonia, Egyetem út 10, Veszprém, H-8200, Hungary Department of Physical and Applied Geology, Faculty of Science, Eötvös Loránd University, Pázmány P. sétány 1/C, Budapest, H-1117, Hungary Export Date: 8 February 2024 CODEN: FMECE Correspondence Address: Makk, J.; Department of Microbiology, Pázmány P. sétány 1/C, Hungary; email: makk.judit@ttk.elte.hu AB - The physical and chemical characteristics of the bedrock, along with the geological and hydrological conditions of karst caves may influence the taxonomic and functional diversity of prokaryotes. Most studies so far have focused on microbial communities of caves including only a few samples and have ignored the chemical heterogeneity of different habitat types such as sampling sites, dripping water, carbonate precipitates, cave walls, cave sediment and surface soils connected to the caves. The aim of the present study was to compare the morphology, the composition and physiology of the microbiota in caves with similar environmental parameters (temperature, host rock, elemental and mineral composition of speleothems) but located in different epigenic karst systems. Csodabogyós Cave and Baradla Cave (Hungary) were selected for the analysis of bacterial and archaeal communities using electron microscopy, amplicon sequencing, X-ray diffraction and mass spectroscopic techniques. The microbial communities belonged to the phyla Pseudomonadota, Acidobacteriota, Nitrospirota and Nitrososphaerota, and they showed site-specific variation in composition and diversity. The results indicate that morphological and physiological adaptations provide survival for microorganisms according to the environment. In epigenic karst caves, prokaryotes are prone to increase their adsorption surface, cooperate in biofilms, and implement chemolithoautotrophic growth with different electron-donors and acceptors available in the microhabitats. LA - English DB - MTMT ER - TY - CONF AU - Bujtor, László AU - Demény, Attila AU - Németh, Péter AU - Bajnóczi, Bernadett TI - Lamellar structured Jurassic Laevaptychi (Kimmeridgian, Mecsek Mountains, Hungary) as reliable paleotemperature archives T2 - 22nd Czech - Slovak - Polish Palaeontological Conference, Abstracts PY - 2023 SP - 27 EP - 28 PG - 2 UR - https://m2.mtmt.hu/api/publication/34203944 ID - 34203944 LA - English DB - MTMT ER - TY - CONF AU - Karlik, Máté AU - Lázár, Anett AU - Németh, Péter AU - Demény, Attila ED - Raucsikné Varga, Andrea Beáta TI - IKAIT–ACC–KALCIT ÁTALAKULÁS FOLYAMATÁNAK NYOMONKÖVETÉSE ANALITIKAI MÓDSZEREKKEL T2 - 13. Kőzettani és Geokémiai Vándorgyűlés PB - Szegedi Tudományegyetem TTIK, Ásványtani, Geokémiai és Kőzettani Tanszék CY - Szekszárd SN - 9789633069615 PY - 2023 SP - 9 UR - https://m2.mtmt.hu/api/publication/34161510 ID - 34161510 N1 - Poszter LA - Hungarian DB - MTMT ER - TY - CONF AU - Németh, Péter ED - Raucsikné Varga, Andrea Beáta TI - ASZTEROIDA-BECSAPÓDÁSHOZ KÖTHETŐ BIZARR SZERKEZETŰ GYÉMÁNTOK T2 - 13. Kőzettani és Geokémiai Vándorgyűlés PB - Szegedi Tudományegyetem TTIK, Ásványtani, Geokémiai és Kőzettani Tanszék CY - Szekszárd SN - 9789633069615 PY - 2023 SP - 39 EP - 40 PG - 2 UR - https://m2.mtmt.hu/api/publication/34158291 ID - 34158291 N1 - Előadás LA - Hungarian DB - MTMT ER - TY - CONF AU - Lázár, Anett AU - Karlik, Máté AU - Demény, Attila AU - Németh, Péter ED - Raucsikné Varga, Andrea Beáta TI - IKAIT (KALCIUM-KARBONÁT-HEXAHIDRÁT) – ACC (AMORF KALCIUM-KARBONÁT) – KALCIT ÁTALAKULÁS FOLYAMATA ÉS JELENTŐSÉGE A PALEOKLÍMA KUTATÁSBAN T2 - 13. Kőzettani és Geokémiai Vándorgyűlés PB - Szegedi Tudományegyetem TTIK, Ásványtani, Geokémiai és Kőzettani Tanszék CY - Szekszárd SN - 9789633069615 PY - 2023 SP - 37 EP - 38 PG - 2 UR - https://m2.mtmt.hu/api/publication/34158272 ID - 34158272 N1 - Előadás LA - Hungarian DB - MTMT ER - TY - JOUR AU - Németh, Péter AU - Garvie, LAJ. AU - Salzmann, CG. TI - Canyon Diablo lonsdaleite is a nanocomposite containing c/h stacking disordered diamond and diaphite JF - PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A - MATHEMATICAL PHYSICAL & ENGINEERING SCIENCES J2 - PHILOS TRANS - R SOC A VL - 381 PY - 2023 IS - 2259 PG - 20 SN - 1364-503X DO - 10.1098/rsta.2022.0344 UR - https://m2.mtmt.hu/api/publication/34140510 ID - 34140510 AB - In 1967, a diamond polymorph was reported from hard, diamond-like grains of the Canyon Diablo iron meteorite and named lonsdaleite. This mineral was defined and identified by powder X-ray diffraction (XRD) features that were indexed with a hexagonal unit cell. Since 1967, several natural and synthetic diamond-like materials with XRD data matching lonsdaleite have been reported and the name lonsdaleite was used interchangeably with hexagonal diamond. Its hexagonal structure was speculated to lead to physical properties superior to cubic diamond, and as such has stimulated attempts to synthesize lonsdaleite. Despite numerous reports, several recent studies have provided alternative explanations for the XRD, transmission electron microscopy and Raman data used to identify lonsdaleite. Here, we show that lonsdaleite from the Canyon Diablo diamond-like grains are a nanocomposite material dominated by subnanometre-scale cubic/hexagonal stacking disordered diamond and diaphite domains. These nanostructured elements are intimately intergrown, giving rise to structural features erroneously associated with h diamond. Our data suggest that the diffuse scattering in XRD and the hexagonal features in transmission electron microscopy images reported from various natural and laboratory-prepared samples that were previously used for lonsdaleite identification, in fact arise from cubic/hexagonal stacking disordered diamond and diaphite domains. LA - English DB - MTMT ER - TY - CONF AU - Lázár, Anett AU - Karlik, Máté AU - Molnár, Zsombor AU - Demény, Attila AU - Németh, Péter TI - Ikaite (CaCO3*6H2O) -> ACC (amorphous calcium carbonate) -> calcite transformation and its paleoclimatological implication T2 - EGU General Assembly 2023: Abstracts PB - European Geosciences Union (EGU) C1 - München PY - 2023 DO - 10.5194/egusphere-egu23-1133 UR - https://m2.mtmt.hu/api/publication/33828942 ID - 33828942 LA - English DB - MTMT ER -