+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Microbial nucleation of Mg-rich dolomite in exopolymeric substances under anoxic modern seawater salinity New insight into an old enigma

, : Microbial nucleation of Mg-rich dolomite in exopolymeric substances under anoxic modern seawater salinity New insight into an old enigma. Geology 40(7): 587-590

Sulfate-reducing bacteria are known to mediate dolomite formation under hypersaline conditions, but details of the crystal nucleation process are still poorly constrained. Our laboratory study demonstrates for the first time that Desulfobulbus mediterraneus, a marine sulfate-reducing bacterium, mediates primary precipitation of Mg-rich dolomite under anoxic conditions in media replicating modern seawater chemistry at low temperature (21 °C). Precipitation of crystals was associated with extracellular polymeric substances in a monospecific biofilm, providing templates for nucleation by altering the molar Mg/Ca ratio. After initial nucleation of single nanospherulites (~5 nm), growth was mediated by aggregation, resulting in spherulites of ~2–3 μm in diameter. Nucleation led to differences in Mg/Ca ratios and 44/4Ca values among the organic material (i.e., biofilm including cells and extracellular polymeric substances; .87 ± .1 [2 SD] and .48 ± .11 [2 SE], respectively), the crystals (1.2 ± .11 [2 SD] and <–.8 ± .24 [2 SE], respectively), and the liquid bulk medium after mineral precipitation (4.53 ± .4 [2 SD] and 1.1 ± .24 [2 SE], respectively). These data indicate a two-step fractionation process involved in the sequestration of Ca from the solution into the crystal lattice of the mineral precipitated. Our results demonstrate the capability of extracellular polymeric substances to overcome kinetic inhibition, fostering the formation of kinetically less favorable Mg-rich dolomite, and they also question the applicability of the Ca isotopic system as a proxy for paleogeochemistry of seawater.


DOI: 10.1130/g32923.1

Other references

Goodman, M., 1971: Molecular evolution at the population level in higher Primates. Unknown

Miller, W.J.; Gonzalez-Sarmiento, R.; Kersey, J.H., 1988: Immunoglobulin and T-cell receptor gene rearrangement in blast crisis of chronic myelocytic leukemia. Chronic myelocytic leukemia (CML) displays a wide repertoire in its terminal phase, with blast cells showing characteristics of myeloid, B-lymphoid, or T-lymphoid cells in some patients. Blast crisis (BC) cells from 14 patients were studied for im...

Dorizzi, R.M.; Perobelli, L.; Dimitri, G.; Menna, C.; Bonaldo, A.; Scandola, S.; Rizzotti, P., 2004: High consistency of the results provided by HLC-723G7 and RA8140 systems in glycated hemoglobin measurement. Clinical Chemistry 50(6, Suppl S, Part 2): A30-A31, June

Braeye, T.; Verhaegen, J.; Mignon, A.; Flipse, W.; Pierard, D.; Huygen, K.; Schirvel, C.; Hens, N., 2016: Correction: Capture-Recapture Estimators in Epidemiology with Applications to Pertussis and Pneumococcal Invasive Disease Surveillance. NlmCategory="UNASSIGNED">[This corrects the article DOI: 10.1371/journal.pone.0159832.].

Ichihara, K.'ichi; Shibahara, A.; Yamamoto, K.; Nakayama, T., 1996: An improved method for rapid analysis of the fatty acids of glycerolipids. An improved rapid procedure to determine the fatty acid composition of glycerolipids is described. The procedure includes KOH-catalyzed transesterification and high-speed gas chromatography. Glycerolipids (20-40 mg) were mixed with 2 mL of hexane...

Strauer, B-Eckehard., 2009: Milestones in cardiology. Proceedings of the birthday symposium for the 65th birthday of Professor Doctor Bodo-Eckehard Strauer. January 26, 2008. Düsseldorf, Germany. Deutsche Medizinische Wochenschrift 133 Suppl 8: S251-S294

Wilmer, Harry A., 1944: The static intrapelvic pressure of the hydronephrotic kidney. The static intrapelvic pressure of the hydronephrotic kidney varies from 7.5 mm. to 27.5 mm. Hg. at various intervals from 3-63 days. Because of the technical accuracy of the Null Point Manometer employed in this study the readings reported here a...

Kuberski, Z., 1968: Treatment of status epilepticus with urea. Wiadomosci Lekarskie 21(16): 1493-1495

Golay, M.; Mariaux, J., 1995: Situation of Diphyllobothrium latum L, 1758 in four lakes of the Swiss plateau. Bulletin de la Societe Neuchateloise des Sciences Naturelles 118(0): 79-86

Arnold, E.M.; Stewart, J.C.; McNeece, C.A., 2001: Enhancing services for offenders: the impact on treatment completion. Because of high drop out rates, it is important to determine if enhancing standard substance treatment services will impact treatment completion rates among those in need of specialized services who are involved in the criminal justice system. The...