Reimer, Andreas

[["dc.bibliographiccitation.firstpage","159"],["dc.bibliographiccitation.issue","1-4"],["dc.bibliographiccitation.journal","Sedimentary Geology"],["dc.bibliographiccitation.lastpage","176"],["dc.bibliographiccitation.volume","126"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Thiel, Volker"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Michaelis, Walter"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2019-11-06T10:58:31Z"],["dc.date.available","2019-11-06T10:58:31Z"],["dc.date.issued","1999"],["dc.description.abstract","Calcium carbonate precipitation and microbialite formation at highly supersaturated mixing zones of thermal spring waters and alkaline lake water have been investigated at Pyramid Lake, Nevada. Without precipitation, pure mixing should lead to a nearly 100-fold supersaturation at 40°C. Physicochemical precipitation is modified or even inhibited by the properties of biofilms, dependent on the extent of biofilm development and the current precipitation rate. Mucus substances (extracellular polymeric substances, EPS, e.g., of cyanobacteria) serve as effective Ca2+-buffers, thus preventing seed crystal nucleation even in a highly supersaturated macroenvironment. Carbonate is then preferentially precipitated in mucus-free areas such as empty diatom tests or voids. After the buffer capacity of the EPS is surpassed, precipitation is observed at the margins of mucus areas. Hydrocarbon biomarkers extracted from (1) a calcifying Phormidium-biofilm, (2) the stromatolitic carbonate below, and (3) a fossil 'tufa' of the Pleistocene pinnacles, indicate that the cyanobacterial primary producers have been subject to significant temporal changes in their species distribution. Accordingly, the species composition of cyanobacterial biofilms does not appear to be relevant for the formation of microbial carbonates in Pyramid Lake. The results demonstrate the crucial influence of mucus substances on carbonate precipitation in highly supersaturated natural environments."],["dc.identifier.doi","10.1016/S0037-0738(99)00038-X"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/62576"],["dc.language.iso","en"],["dc.relation.issn","0037-0738"],["dc.title","Biofilm exopolymers control microbialite formation at thermal springs discharging into the alkaline Pyramid Lake, Nevada, USA"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","304"],["dc.bibliographiccitation.issue","3-4"],["dc.bibliographiccitation.journal","Geomicrobiology Journal"],["dc.bibliographiccitation.lastpage","315"],["dc.bibliographiccitation.volume","32"],["dc.contributor.author","Spitzer, S."],["dc.contributor.author","Brinkmann, Nicole"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Ionescu, Danny"],["dc.contributor.author","Friedl, Thomas"],["dc.contributor.author","de Beer, Dirk"],["dc.contributor.author","Arp, Gernot"],["dc.date.accessioned","2018-11-07T09:59:35Z"],["dc.date.available","2018-11-07T09:59:35Z"],["dc.date.issued","2015"],["dc.description.abstract","Two different cyanobacterial biofilms from German karstwater creeks were investigated with respect to their photosynthetic effect on Ca2+ removal and potential CaCO3 precipitation in artificial creek waters of different CO2 partial pressures at a given, constant calcite supersaturation. CO2 partial pressures were adjusted to 350 ppmV, 2200 ppmV and 8700 ppmV respectively, covering the range of Phanerozoic atmospheric CO2 partial pressures inferred from palaeosoils, stomatal indices and model calculations. Microsensor measurements of calcium, pH and oxygen revealed differences in the potential to precipitate CaCO3 between the two model organisms Tychonema-relative strain SAG 2388 and Synechococcus sp. strain SAG 2387. Whereas a strong removal of Ca2+ from the solution was measured at Tychonema-relative biofilm, the Synechococcus sp. biofilm exercised a much lower Ca2+ removal during photosynthesis. Photosynthesis was enhanced in both organisms with increasing CO2 and HCO3-, as indicated by enhanced O-2 production, but only for the motile filamentous taxon Tychonema-relative a concomitantly increasing calcium removal was measured. However, model calculations indicate that this short-term Ca2+ binding in the Tychonema-relative is due to complexation to exopolymers or oscillin, with no immediate CaCO3 precipitation. In contrast, Ca2+ and pH measurements at Synechococcus sp. biofilm could be consistent with immediate CaCO3 precipitation at the cells. In both biofilms, pH gradients increase with increasing pCO(2) from 350 to 2200 ppmV due to enhanced photosynthesis, but decrease at a pCO(2) of 8700 ppmV despite of further enhanced photosynthesis. This observation, regardless whether CO2 or HCO3- is used by the cyanobacteria, is in accordance with hydrochemical modeling demonstrating an increased DIC buffering at high pCO(2) conditions. These results indicate that the potential of cyanobacteria to form spatially defined calcification pattern via pH gradients at their cell envelopes ('calcified cyanobacteria') increases at elevated pCO(2), while at high pCO(2) conditions Ca2+ binding and lowered pH microgradients lead to spatially diffuse calcification without defined cell envelope precipitates."],["dc.identifier.doi","10.1080/01490451.2014.885617"],["dc.identifier.isi","000352349600010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37626"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1521-0529"],["dc.relation.issn","0149-0451"],["dc.title","Effect of Variable pCO(2) on Ca2+ Removal and Potential Calcification of Cyanobacterial Biofilms -An Experimental Microsensor Study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4883"],["dc.bibliographiccitation.issue","20"],["dc.bibliographiccitation.journal","Biogeosciences"],["dc.bibliographiccitation.lastpage","4902"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Arif, Sania"],["dc.contributor.author","Nacke, Heiko"],["dc.contributor.author","Schliekmann, Elias"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Hoppert, Michael"],["dc.date.accessioned","2022-11-01T10:17:31Z"],["dc.date.available","2022-11-01T10:17:31Z"],["dc.date.issued","2022"],["dc.description.abstract","Abstract. The Kilianstollen Marsberg (Rhenish Massif, Germany) has\r\nbeen extensively mined for copper ores, dating from early medieval period\r\nuntil 1945. The exposed organic-rich alum shale rocks influenced by the\r\ndiverse mine drainages at an ambient temperature of 10 ∘C could\r\nnaturally enrich biogeochemically distinct heavy metal resistant microbiota.\r\nThis amplicon-sequence-based study evaluates the microbially colonized\r\nsubterranean rocks of the abandoned copper mine Kilianstollen to\r\ncharacterize the colonization patterns and biogeochemical pathways of\r\nindividual microbial groups. Under the selective pressure of the heavy metal\r\ncontaminated environment at illuminated sites, Chloroflexi (Ktedonobacteria) and Cyanobacteria (Oxyphotobacteria) build up\r\nwhitish–greenish biofilms. In contrast, Proteobacteria, Firmicutes and Actinobacteria dominate rocks around the\r\nuncontaminated spring water streams. The additional metagenomic analysis\r\nrevealed that the heavy metal resistant microbiome was evidently involved in\r\nredox cycling of transition metals (Cu, Zn, Co, Ni, Mn, Fe, Cd, Hg). No\r\ndeposition of metals or minerals, though, was observed by transmission\r\nelectron microscopy in Ktedonobacteria biofilms which may be indicative for the presence of\r\ndifferent detoxification pathways. The underlying heavy metal resistance\r\nmechanisms, as revealed by analysis of metagenome-assembled genomes, were\r\nmainly attributed to transition metal efflux pumps, redox enzymes,\r\nvolatilization of Hg, methylated intermediates of As3+, and reactive\r\noxygen species detoxification pathways."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2022"],["dc.identifier.doi","10.5194/bg-19-4883-2022"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/116831"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-605"],["dc.relation.eissn","1726-4189"],["dc.rights","CC BY 4.0"],["dc.title","Composition and niche-specific characteristics of microbial consortia colonizing Marsberg copper mine in the Rhenish Massif"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","unpublished"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","579"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Geology"],["dc.bibliographiccitation.lastpage","580"],["dc.bibliographiccitation.volume","30"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T10:27:58Z"],["dc.date.available","2018-11-07T10:27:58Z"],["dc.date.issued","2002"],["dc.identifier.doi","10.1130/0091-7613(2002)030<0579:COCFGA>2.0.CO;2"],["dc.identifier.isi","000176152100024"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43327"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0091-7613"],["dc.title","Calcification of cyanobacterial filaments: Girvanella and the origin of lower Paleozoic lime mud: Comment and reply - Comment"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2085"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Biogeosciences"],["dc.bibliographiccitation.lastpage","2106"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Fussmann, Dario"],["dc.contributor.author","von Hoyningen-Huene, Avril Jean Elisabeth"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Schneider, Dominik"],["dc.contributor.author","Babková, Hana"],["dc.contributor.author","Peticzka, Robert"],["dc.contributor.author","Maier, Andreas"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Daniel, Rolf"],["dc.contributor.author","Meister, Patrick"],["dc.date.accessioned","2020-04-28T12:42:41Z"],["dc.date.available","2020-04-28T12:42:41Z"],["dc.date.issued","2020"],["dc.description.abstract","Despite advances regarding the microbial and organic-molecular impact on nucleation, the formation of dolomite in sedimentary environments is still incompletely understood. Since 1960, apparent dolomite formation has been reported from mud sediments of the shallow, oligohaline and alkaline Lake Neusiedl, Austria. To trace potential dolomite formation or diagenetic alteration processes in its deposits, lake water samples and sediment cores were analyzed with respect to sediment composition, hydrochemistry and bacterial community composition. Sediments comprise 20 cm of homogenous mud with 60 wt % carbonate, which overlies dark-laminated consolidated mud containing 50 wt % carbonate and plant debris. Hydrochemical measurements reveal a shift from oxic lake water with pH 9.0 to anoxic sediment pore water with pH 7.5. A decrease in SO42- with a concomitant increase in ΣH2S and NH4+ from 0 to 15 cm core depth indicates anaerobic heterotrophic decomposition, including sulfate reduction. The bacterial community composition reflects the zonation indicated by the pore water chemistry, with a distinct increase in fermentative taxa below 15 cm core depth. The water column is highly supersaturated with respect to (disordered) dolomite and calcite, whereas saturation indices of both minerals rapidly approach zero in the sediment. Notably, the relative proportions of different authigenic carbonate phases and their stoichiometric compositions remain constant with increasing core depth. Hence, evidence for Ca–Mg carbonate formation or ripening to dolomite is lacking within the sediment of Lake Neusiedl. As a consequence, precipitation of high-magnesium calcite (HMC) and protodolomite does not occur in association with anoxic sediment and sulfate-reducing conditions. Instead, analytical data for Lake Neusiedl suggest that authigenic HMC and protodolomite precipitate from the supersaturated, well-mixed aerobic water column. This observation supports an alternative concept to dolomite formation in anoxic sediments, comprising Ca–Mg carbonate precipitation in the water column under aerobic and alkaline conditions."],["dc.identifier.doi","10.5194/bg-17-2085-2020"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/17461"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/64457"],["dc.language.iso","en"],["dc.relation.issn","1726-4189"],["dc.title","Authigenic formation of Ca-Mg carbonates in the shallow alkaline Lake Neusiedl, Austria"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1701"],["dc.bibliographiccitation.issue","5522"],["dc.bibliographiccitation.journal","Science"],["dc.bibliographiccitation.lastpage","1704"],["dc.bibliographiccitation.volume","292"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T09:02:39Z"],["dc.date.available","2018-11-07T09:02:39Z"],["dc.date.issued","2001"],["dc.description.abstract","Photosynthetic carbon assimilation is commonly invoked as the cause of calcium carbonate precipitation in cyanobacterial biofilms that results in the formation of calcareous stromatolites. However, biofilm calcification patterns in recent lakes and simulation of photosynthetically induced rise in calcium carbonate supersaturation demonstrate that this mechanism applies only in settings Low in dissolved inorganic carbon and high in calcium. Taking into account paleo-partial pressure curves for carbon dioxide, we show that Phanerozoic oceans sustaining calcified cyanobacteria must have had considerably higher calcium concentrations than oceans of today. In turn, the enigmatic lack of calcified cyanobacteria in stromatolite-bearing Precambrian sequences can now be explained as a result of high dissolved inorganic carbon concentrations."],["dc.identifier.doi","10.1126/science.1057204"],["dc.identifier.isi","000169031800040"],["dc.identifier.pmid","11387471"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24737"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1095-9203"],["dc.relation.issn","0036-8075"],["dc.title","Photosynthesis-induced biofilm calcification and calcium concentrations in phanerozoic oceans"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","83"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Geomicrobiology Journal"],["dc.bibliographiccitation.lastpage","94"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Shiraishi, Fumito"],["dc.contributor.author","Bissett, Andrew"],["dc.contributor.author","de Beer, Dirk"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Arp, Gernot"],["dc.date.accessioned","2018-11-07T11:19:58Z"],["dc.date.available","2018-11-07T11:19:58Z"],["dc.date.issued","2008"],["dc.description.abstract","The impact of microbial activity on biofilm calcification in aquatic environments is still a matter of debate, especially in settings where ambient water has high CaCO3 mineral supersaturation. In this study, biofilms of two CO(2-)degassing karst-water creeks in Germany, which attain high calcite supersaturation during their course downstream, were investigated with regard to water chemistry of the biofilm microenvironment. The biofilms mainly consisted of filamentous cyanobacteria (Phormidium morphotype) and heterotrophic bacteria (including sulfate-reducing bacteria), which affect the microenvironment and produce acidic exopolymers. In situ and ex situ microelectrode measurements showed that a strong pH increase, coupled with Ca2+ consumption, occurred in light conditions at the biofilm surface, while the opposite occurred in the dark. Calcite supersaturation at the biofilm surface, calculated from ex situ Ca2+ and CO32- microelectrode measurements, showed that photosynthesis resulted in high omega values during illumination, while respiration slightly lowered supersaturation values in the dark, compared to values in the water column. Dissociation calculation demonstrated that the potential amount of Ca2+ binding by exopolymers would be insufficient to explain the Ca2+ loss observed, although Ca2+ complexation to exopolymers might be crucial for calcite nucleation. No spontaneous precipitation occurred on biofilm-free limestone substrates under the same condition, regardless of high supersaturation. These facts indicate that photosynthesis is a crucial mechanism to overcome the kinetic barrier for CaCO3 precipitation, even in highly supersaturated settings."],["dc.identifier.doi","10.1080/01490450801934888"],["dc.identifier.isi","000254214400002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55419"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1521-0529"],["dc.relation.issn","0149-0451"],["dc.title","Photosynthesis, respiration and exopolymer calcium-binding in biofilm calcification (Westerhfer and deinschwanger creek, germany)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1159"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Limnology and Oceanography"],["dc.bibliographiccitation.lastpage","1168"],["dc.bibliographiccitation.volume","53"],["dc.contributor.author","Bissett, Andrew"],["dc.contributor.author","de Beer, Dirk"],["dc.contributor.author","Schoon, Raphaela"],["dc.contributor.author","Shiraishi, Fumito"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Arp, Gernot"],["dc.date.accessioned","2018-11-07T11:15:41Z"],["dc.date.available","2018-11-07T11:15:41Z"],["dc.date.issued","2008"],["dc.description.abstract","Epilithic and endolithic biofilms were found to control the formation of stromatolites in karst-water creeks. We used microsensors to determine the influence of biological processes on chemical conditions within the microenvironment of crystal nucleation sites: the stromatolite surface. Phototrophic members of the biofilms consisted of mainly cyanobacteria and diatoms. Oxygen, pH, calcium, and carbonate concentration microprofiles at the stromatolite surface and boundary layer showed a strong diurnal rhythm of calcium carbonate precipitation. During illumination, photosynthesis caused oxygen production, a marked increase in pH and CO32- concentrations, and a decrease in Ca2+ concentration at the stromatolite surface due to calcium carbonate precipitation. The opposite occurred in the dark, indicating decalcification. Calcite was approximately 16 times oversaturated in the bulk water, photosynthesis induced an increase of the supersaturation to > 27 at the stromatolite surface under illumination, and respiration induced a decrease of the supersaturation to < 10 in the dark. Photosynthetically stimulated calcium carbonate precipitation was confirmed by radioactive isotope ( Ca-45(2+)) uptake studies. Over a 24 h light : dark cycle, biofilms showed net calcification. Biotic activity within the stromatolite has a large effect on conditions at its surface and, therefore, contributes considerably to the stromatolite precipitation process."],["dc.identifier.doi","10.4319/lo.2008.53.3.1159"],["dc.identifier.isi","000256498900024"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54423"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1939-5590"],["dc.relation.issn","0024-3590"],["dc.title","Microbial mediation of stromatolite formation in karst-water creeks"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","105"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Sedimentary Research"],["dc.bibliographiccitation.lastpage","127"],["dc.bibliographiccitation.volume","73"],["dc.contributor.author","Arp, Gernot"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T10:42:37Z"],["dc.date.available","2018-11-07T10:42:37Z"],["dc.date.issued","2003"],["dc.description.abstract","The crater lake of the small volcanic island Satonda, Indonesia, is unique for its red-algal microbial reefs thriving in marine-derived water of increased alkalinity. The lake is a potential analogue for ancient oceans sustaining microbialites under open-marine conditions. Current reef surfaces are dominated by living red algae covered by non-calcified biofilms with scattered cyanobacteria and diatoms. Minor CaCO3 precipitates are restricted to the seasonally flooded reef tops, which develop biofilms up to 500 mum thick dominated by the cyanobacteria Pleurocapsa, Calothrix, Phormidium, and Hyella. Microcrystalline aragonite patches form within the biofilm mucilage, and fibrous aragonite cements grow in exopolymer-poor spaces such as the inside of dead, lysed green algal cells, and reef framework voids. Cementation of lysed hadromerid sponge resting bodies results in the formation of \"Wetheredella-like\" structures. Hydrochemistry data and model calculations indicate that CO2 degassing after seasonal mixis can shift the carbonate equilibrium to cause CaCO3 precipitation. Increased concentrations of dissolved inorganic carbon limit the ability of autotrophic biofilm microorganisms to shift the carbonate equilibrium. Therefore, photosynthesis-induced cyanobacterial calcification does not occur. Instead, passive, diffusion-controlled EPS-mediated permineralization of biofilm mucus at contact with the considerably supersaturated open lake water takes place. In contrast to extreme soda lakes, the release of Ca2+ from aerobic degradation of extracellular polymeric substances does not support CaCO3 precipitation in Satonda because the simultaneously released CO2 is insufficiently buffered. Subfossil reef parts comprise green algal tufts encrusted by micro-stromatolites with layers of fibrous aragonite and an amorphous, unidentified Mg-Si phase. The microstromatolites probably formed when Lake Satonda evolved from seawater to Ca2+-depleted raised-alkalinity conditions because of sulfate reduction in bottom sediments and pronounced seasonality with deep mixing events and strong CO2 degassing. The latter effect caused rapid growth of fibrous aragonite, while Mg-Si layers replaced the initially Mg-calcite-impregnated biofilms. This could be explained by dissolution of siliceous diatoms and sponge spicules at high pH, followed by Mg-calcite dissolution and Mg-silica precipitation at low pH due to heterotrophic activity within the entombed biofilms."],["dc.identifier.doi","10.1306/071002730105"],["dc.identifier.isi","000180490900011"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?goescholar/2202"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/46842"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1938-3681"],["dc.relation.issn","1527-1404"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Microbialite formation in seawater of increased alkalinity, Satonda crater lake, Indonesia"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","6306"],["dc.bibliographiccitation.issue","20"],["dc.bibliographiccitation.journal","Applied and Environmental Microbiology"],["dc.bibliographiccitation.lastpage","6312"],["dc.bibliographiccitation.volume","74"],["dc.contributor.author","Bissett, Andrew"],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","de Beer, Dirk"],["dc.contributor.author","Shiraishi, Fumito"],["dc.contributor.author","Arp, Gernot"],["dc.date.accessioned","2018-11-07T11:10:16Z"],["dc.date.available","2018-11-07T11:10:16Z"],["dc.date.issued","2008"],["dc.description.abstract","Ex situ microelectrode experiments, using cyanobacterial biofilms from karst water creeks, were conducted under various pH, temperature, and constant-alkalinity conditions to investigate the effects of changing environmental parameters on cyanobacterial photosynthesis-induced calcification. Microenvironmental chemical conditions around calcifying sites were controlled by metabolic activity over a wide range of photosynthesis and respiration rates, with little influence from overlying water conditions. Regardless of overlying water pH levels (from 7.8 to 8.9), pH at the biofilm surface was approximately 9.4 in the light and 7.8 in the dark. The same trend was observed at various temperatures (4 C and 17 C). Biological processes control the calcium carbonate saturation state (Omega) in these and similar systems and are able to maintain Omega at approximately constant levels over relatively wide environmental fluctuations. Temperature did, however, have an effect on calcification rate. Calcium flux in this system is limited by its diffusion coefficient, resulting in a higher calcium flux (calcification and dissolution) at higher temperatures, despite the constant, biologically mediated pH. The ability of biological systems to mitigate the effects of environmental perturbation is an important factor that must be considered when attempting to predict the effects of increased atmospheric partial CO2 pressure on processes such as calcification and in interpreting microfossils in the fossil record."],["dc.description.sponsorship","German Research Foundation [DFGFOR 571]"],["dc.identifier.doi","10.1128/AEM.00877-08"],["dc.identifier.isi","000259985300017"],["dc.identifier.pmid","18689512"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/53177"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0099-2240"],["dc.title","Metabolic microenvironmental control by photosynthetic biofilms under changing macroenvironmental temperature and pH conditions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]