The cyanobacterium Anabaena flos-aquae and many other phytoplankton species have a complex life cycle that includes a resting stage (akinete). We present a new agent-based (also known as individual-based) model of Anabaena that includes the formation and behavior of akinetes. The model is part of a coupled Eulerian--Lagrangian model and can reproduce the main features of the observed seasonal and interannual population dynamics in Bugach Reservoir (Siberia), including an unexpectedly large bloom in a year with low nutrient concentrations. Model analysis shows that the internal loading of phosphorus (P) due to germination from the sediment bed is ,10% of the total input. However, most of the long-term nutrient uptake for Anabaena occurs in the sediment bed, which suggests that the sediment bed is not just a convenient overwintering location but may also be the primary source of nutrients. An in silico tracing experiment showed that most water column cells (,90%) originated from cells located in the sediment bed during the preceding winter. An in silico gene knockout experiment (akinete formation is prohibited) showed that the formation of resting stages is of critical importance to the survival of the population on an annual basis. A nutrient-reduction management scenario indicates that Anabaena densities increase because they are less sensitive to water column nutrient levels (because of the sediment bed source) than other species. Hellweger, F. L., Kravchuk, E. S., Novotny, V., Gladyshev, M. I. 2008. Agent-based modeling of the complex lifecycle of a cyanobacterium (Anabaena) in a shallow reservoir. Limnol. Oceanogr., 53(4):1227-1241. Auteur: FerdiHellweger Tags: Cyanobacteria Ajoutée: mardi 12 août 2025 20:03:22

These are Cyanobacteria, a species of Oscillatoria, seen at 1,000x magnification. Each of the little disks in the long filament is a single cell, tracing its ancestory back 3.5-billion years. They spent the first 3-billion years creating our oxygen atmosphere, and Cyanobacteria are still the most important creatures responsible for regenerating and cleaning our oxygen atmosphere. This is a new version of the videomicrograph, with music. Cyanobacteria from Heron's Head Salt Marsh in San Francisco; 1,000x HMC Videomicrography & music by Wayne Lanier. Auteur: WLanier Tags: Cyanobacteria Oscillatoria Ajoutée: lundi 23 avril 1990 02:19:01

Motile Cyanobacteria and the community-defining Cylindrothecia move through the Weep stream. Magnification 200x. Also note the Ciliate that has gobbled some of the Cylindrothecia diatomds. It's a rough world under the microscope. Auteur: WLanier Tags: DBWeep ecology science Ajoutée: mardi 17 octobre 1961 16:58:12

A Dinoflagellate dances over a Cyanobacteria. Videomicrograph with a Nikon Coolpix 885 at 3x zoom, through Olympus microscope 1,000x oil immersion, Hoffman Modulation Contrast optics. Many small microorganisms cluster around Cyanobacterial filaments. Some, like ciliates come for the oxygen. I am not sure what attracted this Dinoflagellate. Auteur: WLanier Tags: Cyanobacteria Dinoflagellate ecology science Ajoutée: mercredi 20 janvier 1965 01:40:07

The James M. DuPont Meteorite Collection - The American Museum of Natural History. The Murray sample was received from the Institute of Meteoritics, The University of New Mexico, Albuquerque, New Mexico, where it had been labeled as I. O. M. No. CRi-102. The Bruderheim meteorite was obtained from the Depart- ment of Geology, University of Alberta, Edmonton, Alberta, Canada; it had been part of specimen B-79. The chemical analyses of the 3 carbonaceous chondrites are Usted in table 2. The analysis of 1 of the noncarbonaceous chondrites (Holbrook) is included in the table for comparison. The samples were examined for visible impurities with a microscope or by visual examination, or both. Trace Element Analysis The origin of carbonaceous chondrites has been discussed repeatedly since Berzelius' research in Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: mardi 31 décembre 1901 05:24:23

The James M. DuPont Meteorite Collection -indicatenextraterrestrial and a originofthe Orgueil amino cid.In2001, hrenfreund a E et al. 25 suggested that the unique amino acid composition of Orgueil indicates a comet was the possible parent body. 2.5. Biomarkers in the Murchison and Orgueil Meteorites The Murchison and Orgueil meteorites contains a host of complex orgamc compounds, biogeochemicals and fossil biomolecules that are considered indications of biological activity (i.e. biomarkers) when encountered in terrestrial rocks. These include weak bioindicators, that merely suggest biological activity may have occurred (e.g., racemic amino acids, carboxylic acids, aromatic, aliphatic and heterocyclic hydrocarbons, PAH's, amphiphilic components, sugars, Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: mardi 04 février 1902 07:07:05

The James M. DuPont Meteorite Collection -man's mind almost as far back as man himself. The divergence of views on the matter is about as broad as it could be. Only a century and a half ago the great English astronomer, Sir William Herschel, first President of the Royal Astronomical Society and discoverer of the planet Uranus said in one of his Presidential ad- dresses that he was convinced that life existed within the Sun. Unfortunately he did not elaborate upon what kind of life he had in mind. The present Secre- tary of the same Royal Astronomical Society, Michael Ovenden, in his recent book, Life in ihe Universe, as his view states that life is probably possible any- where in the universe except within a Sun! It would be hard to imagine Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: vendredi 20 décembre 1901 22:55:12

In another little video there was a Dinoflagellate dancing over the Cyanobacterial filament. Along came the Ciliate. Dino-gone. Video with a Nikon Coolpix 885 at 3x zoom, through an Olympus microscope 1,000x oil with Hoffman Modulation Contrast optics. Clearly some Ciliates hang around Cyanobacteria for lunch. Auteur: WLanier Tags: Cyanobacteria ecology science Ajoutée: mercredi 20 janvier 1965 01:51:51

The James M. DuPont Meteorite Collection - the neighborhood of 0, and cultures receiving no initial Vallentyne: Environmental Biophysics & Microbial Ubiquity 345 supply of H2S()4 can contain concentrations up to 2.08 n H2SO4 at the end of growth (Starkey, 1925). Several molds are capable of growth at a pH of 1.7 (Johnson, 1923). The most acid tolerant fungi known are Acontiuni velatum and fungus D (an un- identified member of the Dermatiaceae), originally isolated from strong acid B H J K L Figure 1. Eh-pH characteristics of diverse microorganisms. A, green algae and diatoms; B, DunalieUa; C, Enteromorpha; D, blue-green algae; E, photosynthetic ])urple bacteria; F, photosynthetic green bacteria; G, sulfate reducing bacteria; //, thiobacteria; /, iron bac- teria; J, denitrifying Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: vendredi 20 décembre 1901 23:20:12

The James M. DuPont Meteorite Collection - limonite-Fe203" Theremaining nH20). 13.9% found was tobecomprised elemental of Sulfur, andinsolublerganic atter"kerogen"). studies showed o m ( Other 22'23 thatOrgueil alsocontains several minormineral species including:ammonium salts,anhydrite-CaSO4; calcite-CaCo3; serpentine-(Mg6Si4Ol0(OH)8+FezSiO trevorite-NiFe204; pyrrhotite-(Fe,Ni)0.9S; olivine-(Mg2SiO4+Fe2SiO4); and pyroxene-(Mg Ca silicates). Fe 22"23 Claytonfound 24 theOrgueil carbonates tohave - +60%0 hich 813C w clearly established tobeof extraterrestrial them origin. he values f-7 to-9 %0 T 513C o forthe_-alanine intheOrgueil meteorite falloutside also therange fterrestrial o values (typically20to-30%0) Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: mardi 04 février 1902 07:05:39

The James M. DuPont Meteorite Collection - the stratosphere, can explain the observed surface layer. Two other aluminum oxide spheres, U2071B3 and D8, also showed traces of F and Cl on their respective surfaces. During the first optical examination of the dust collector two particles were found in direct contact with aerosols [7]. While U2071D1 (unidentified origin) showed the halogens F, Cl, and Br on the surface, only traces of F were detected on U2071I9 (suspected to be terrestrial contamination). Our TOF-SIMS analyses revealed another artificial contaminant: Beryllium was found on several particles, resulting from the SEM-EDS analysis that was performed on Be-substrates. The results suggest that contamination of IDPs collected in the stratosphere can be a severe problem for the Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: vendredi 24 janvier 1902 18:45:47

The James M. DuPont Meteorite Collection -Japan. UWS: University of Washington, Dept. Geological Sciences, Box 351310, UAng: Université d'Angers, Faculté des Sciences, 2 bd Lavoisier, F-49045 Seattle, WA 98195, USA. Angers Cedex, France. Verish: Robert Verish, Meteorite Recovery Foundation, P.O. Box 237, UAz: Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ Sunland, CA 91040, USA. 85721, USA. Vernad: Vernadsky Institute of Geochemistry and Analytical Chemistry, UChi: University of Chicago, Chicago, IL 60637, USA. Russian Academy of Sciences, Kosygin Str. 19, Moscow 117975, Russia. UCLA: Institute of Geophysics and Planetary Physics, University of Yemen: Geological Survey of Yemen, c/o Dr. M. A. Mattash, Geological California, Los Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: mardi 04 février 1902 13:48:26

The James M. DuPont Meteorite Collection - Gazz. chim. ital. 42: 67. 142. Johnson, T. B. & B. H. Nicolet. 1914. J. Am. Chem. Soc. 36: 345. 143. HoRBACZEWSKi, R. 1882. Monatsh. 3: 796. 144. Bredereck, H., H. Ulmer & H. Waldman. 1956. Ber. 89: 12. 145. Bredereck, H., F. Effenberger & G. Rainer. 1961. Angew. Chem. 73: 63. 146. Oro, J. & M. A. Q. Siddiqui. Unpublished experiments. 147. Davidson, D. & O. Baudisch. 1926. J. Am. Chem. Soc. 48: 2379. 148. Fox, S. W. & K. Harada. 1961. Science. 133: 1923. 149. Bredereck, H., R. Gomper & H. Herlinger. 1958. Ber. 91: 2832. 150. Kuiper, G. p. 1957. The Threshold of Space. : 78. M. Zelikoff, Ed. Pergamon Press. London. 151. Dashkevich, L. B. 1960. Doklady Akad. Nauk. S.S.S.R. 132: 1319. 152. Oro, J. Unpublished experiments. 153. Katchalski, E. 1951. Advances in Protein Chem. Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: lundi 30 décembre 1901 15:42:05

The James M. DuPont Meteorite Collection - extensively in the literature on photochemistry and need not be discussed in this paper. AMINOACID AND PROTEIN STRUCTURE R R R ? NH ? CH? CO? NH ? CH ? CO? NH ? CH- CO ? V. H I / Y H I N ? -C C- II H II H / c4_ -N- C II Figure 2. In a number of experiments high energy particle radiation as well as x- and 7-rays were utilized. Dose and Rajewsky obtained amino acids and amines from gaseous mixtures of NH3 , N2 , H2O, CH4 , and CO2 with X-rays.' The action of 2 Mev electrons on CH4 , H2O, and NH3 yielded also amino acids.''* Calvin irradiated CH4 , NH3 , H2O, and PH3 in the gas phase with electrons.' Radiochemical analysis showed the presence of small quantities of nucleic acid bases, substances which are of vast importance in genetic material (figure Auteur: H4ck3rm1k3 Tags: Carbonaceous Cyanobacteria Fossils Life Meteorite Ajoutée: lundi 30 décembre 1901 22:25:52