ALBERT

Notes: Water from a newly installed well (4A) at the Canadian Forces Base, Shilo in Manitoba, Canada was reported to be producing a hydrocarbon smell and sporadic turbidity which was shown to be caused by the generation of a significant population of the bacterium Pseudomonas aureofaciens. In this investigation, the pseudomonad was isolated, identified and found to be able to degrade mineral oil (as a source of organic carbon) aerobically but was not capable of nitrate respiration or of anaerobic growth. The generation of high populations (and turbidity) of Pseudomonas aureofaciens in the well water was linked to the presence of dissolved oxygen in the water along with sufficient hydrocarbons to support growth. The maximum population recorded was 8 × 105 C.F.U./ml. The origin of the hydrocarbons in the ground water was postulated to have been long-term solvent spills from a nearby paint shop.

Notes: The persistence of [14C]dicamba (3,6-dichloro-2-methoxy-benzoic acid) at the 2 ppm level was studied in three prairie soils at field capacity moistures and temperatures ranging from –5±1° to 35±1°C. Following extraction of the soils with aqueous calcium chloride solution a radiochemical analytical procedure was used to monitor the breakdown.In all soils no loss of dicamba was observed at –5± 1°C, but breakdown was apparent at temperatures above 5±1°C. On a heavy clay and a silty clay an almost steady relationship between temperature and percentage degradation occurred between 5± 1° to 35± 1°C. Rate of breakdown was more rapid on the organic silty clay than on heavy clay or sandy loam. Over 80% of the [14C]dicamba was dissipated from the silty clay in 8 days at temperatures above 15±1°C, while 14 days, and temperatures in excess of 20± 1°C, were required for loss of similar amounts of the herbicide from the heavy clay and the sandy loam.Degradation biologique de l'herbicide dicamba dans les sols humides a diverses temperaturesLa persistance du [C14] dicamba (acide 3,6-dichloro-2-méthoxybenzoique) à la concentration de 2 ppm a étáétudiée dans trois sols de prairies à l'humidité de la capacité au champ et à des températures allant de – 5± 1°C à 35± 1° C. Aprés extraction des sols par une solution aqueuse de chlorum de calcium, un procédé analytique radiochimique a été utilisé pour suivre la dégradation.Dans tous les sols, aucune perte de dicamba n'a été observée à 5±1° C, mais la dégradation s'est produite aux températures supérieures à 5±1°C. Dans une argile lourde et dans un limon argileux, une relation presque constante est apparue, entre 5±1° et 35± 1° C, entre la température été le pourcentage de dégradation. Le taux de dégradation a été plus rapide dans un limon argileux organique dans une argile lourde ou dans les sol argilo-silicieux. Plus de 80% du [C14] dicamba a disparu dans le limon argileux, en huit jours, à des températures supérieures à 15±1° C, alors que quatorze jours et des températures supérieures à 20± 1° C ont été nécessaires pour des pertes similaires d'herbicide dans l'argile lourde et le sol argilo-silicieux.Der mikrobielle Abbau des Herbizlds Dicamba in feuchten Boden, bei unterschieldlicher TemperaturEs wurde die Persistenz von 14C-Dicamba (3,6-Dichlor-2-methoxy-benzoesaure) bei einer Konzentration von 2 ppm in drei Prärieboden bei Feldkapazitat und einem Tempera-turbereich von – 5± 1°C bis 35+1°C untersucht. Nach der Extraktion der Boden mit einer wSsserigen Lösung von Cal-ciumchlorid wurde der Abbau radiochemisch verfolgt.Bei – 5±1°C war in alien Böden keine Abnahme des Dicambagehalts festzustellen. Bei Temperaturen über 5°C war jedoch ein Abbau des Herbizids zu verzeichnen. Bei einem schweren Ton- und einem Schluff-Tonboden war bei 5± 1°C bis 35± 1°Ceine nahezu gleichmassige Beziehung zwischen Temperatur und prozentualem Abbau festzustellen. Die Abbaurate war im Schluff-Tonboden, der einen gewissen Gehalt an organischer Substanz aufwies, grosser als im schweren Tonboden oder in sandigen Lehmboden. Vom Schluff-Tonboden verschwanden mehr als 80% des 14C-Dicamba innerhalb von acht Tagen bei Temperaturen von über 15°C. Für den schweren Ton- und den sandigen Lehmboden waren hingegen 14 Tage und Temperaturen von über 20°C notig.

Notes: [Auszug] Roberts2 had isolated some single-spore cultures from strains of the f at-producing yeast genus Lipomyces and an investigation was carried out on ten of these strains: B to H were isolated from a parent culture of L. lipofer, and I to L from a culture of L. starkeyi. Lactose was used as the carbon ...

Notes: [Auszug] To examine whether the rhizosphere could have any influence on algoe, the following experiment was devised. Germinated seedlings were grown under sterile conditions on the surface of mineral agar, seeded with a crude culture of algae, and incubated for ten days under a very low level of ...

Notes: [Auszug] During confirmation of this work, P. zopfii (Strain 263/5) from the National Collection of Algae and Protozoa, Botany School, Cambridge, was grown in liquid culture consisting of a carbon energy source at a dilution of 0.1 per cent in a basal medium suggested by Whickerham2. Glucose, ethanol, and ...

Notes: [Auszug] During an investigation of a new method of soil bio-assay using algae I found4 that Hormidium floccidum, when impregnated into nutrient-deficient soils, would give, by way of its growth, indication of the distance and of the rate at which nutrient ions may diffuse in the soil. Fig. 1. Enhanced ...

Notes: Summary During the bioassay of soils for the content of available phosphorus by Tchan's method some factor interferred significantly with the expected result. Further evidence was found by relating the yield of the assay alga to the original yield of potatoes (in tons/acre) for the soils. Here, the relationship was linear but inverse in that the yield of alga fell as the potato yield increased. Various causes for this phenomenon are discussed.

Notes: Summary Four herbicides (2,4-D, trifluralin, MCPA and TCA) were applied at two concentration levels to isolated cores of a grassland loam soil. After herbicide contact times of 1, 5, and 20 days, samples were taken and the algal population estimated both quantitatively and qualitatively using two selective mineral salts media. Thirty one genera of algae were identified as occurring in the soil. Of these, Chlamydomonas, Chlorococcum, Hormidium, Palmella, and Ulothrix proved to be so sensitive to the four herbicides that they were rarely isolated from the cores after treatment. Other algal genera were found to be less sensitive, and the theoretical percentile sensitivity of fifteen genera was calculated. Chlorella, Lyngbya, Nostoc, and Hantzschia were found to be the most resistant algae, having percentile sensitivity to all four herbicides of less than 50%. Some algal genera varied in their sensitivity to each of the herbicides. Scytonema was sensitive to all of the herbicides except 2,4-D, while Tolypothrix showed a greater tolerance to MCPA. In the top cm of the soil, the reduction in cell numbers experienced by many algal genera after herbicide treatment was offset by an increase in the population of Chlorella. Stichococcus, Oscillatoria, and Spongiochloris all exhibited the ability to recover rapidly after a reduction in cell numbers resulting from the application of one of the herbicides. An overall reduction in cell numbers was noted for the algae growing preferentially on a nitrogen-free medium (i.e. potential nitrogen-fixers). re]19760511