摘要:

The amounts of organic compounds such as amino acids (proteinaceous substances), fatty acids, and sterols in lacustrine sediments were found to decrease greatly from the mud‐water interface to depths of 20 cm and less at greater core depths. The amounts of methane produced by microbial activity in subsamples incubated for 40 days at 27°C were also found to decrease with core depth, apparently limited by the exhaustion of organic substrates subject to methane fermentation. Decomposition rates of certain organic compounds added to sediment samples were determined by incubation experiments at different temperatures for 40 to 450 days. Experimental results with mixed cultures of microorganisms in lacustrine sediments indicated the following: (a) The marked decomposition of organic compounds such as amino acids, fatty acids, and sterols in the lacustrine sediments resulted mainly in the formation of methane, (b) Unsaturated compounds were more readily decomposed with the ultimate formation of methane than saturated compounds, (c) The susceptibility of saturated fatty acids to methane formation decreased in proportion to their molecular weights.

ISSN:0149-0451    

DOI:10.1080/01490457909377738

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Data on temperature, water chemistry, and abundance of bacteria in Ace Lake, Antarctica are presented. In particular, the sulfur chemistry and microbiological fractionation of sulfur isotopes are discussed in relation to the possible development of the lake and the climatic history of the lake catchment. The lake is covered by ice for 9 months each year and has a maximum depth of 23 m. A layer of water at a 10‐m depth contains colloidal sulfur and is situated between a well‐oxygenated mixolimnion and an anoxic monimolimnion. In the monimolimnion, H2S concentrations rapidly increase with depth and SO42‐decreases to below the limit of detection near the bottom. High δ34S values (up to +67‰) were encountered in sulfate from the lake and mean δ34S values of sulfate plus sulfide were similar at all depths measured.

ISSN:0149-0451    

DOI:10.1080/01490457909377739

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Tharae rate of methane released from the sediment‐water interface and from the surface of the water of Lake Wingra, Madison, Wisconsin, was measured during the summer months for 2 years. The amount of methane escaping the lake is estimated to be an important factor in the carbon budget of the lake. Most rapid methanogenesis was in shallow water (less than 1 m deep) and in the uppermost 5 cm of sediment. The numbers of methanogenic bacteria were estimated by a most probable number technique to vary from approximately 102to 3 × 104methanogens per gram of dry weight sediment during winter and summer, respectively.

ISSN:0149-0451    

DOI:10.1080/01490457909377740

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Measurable changes occurred in the electrical impedance of growing cultures ofDesuljovibrio aestuariias compared with sterile media. The ratio of these changes (electrical impedance ratio,RI) was measured continuously using a Bactometer 32, a magnetic tape recorder, and a computer for data retrieval. The rate of sulfate reduction correlated with the rate of change inRIinD. aestuariicultures and sediment slurries from San Francisco Bay. Both sulfide and iron were required for maximalRIresponse. Molybdate (5–20 mM) totally inhibited both sulfate reduction and changes inRIinD. aestuariicultures. Molybdate (20 mM) completely inhibited sulfate reduction in sediment slurries as measured by the impedance ratio technique or35SO42‐reduction. Sulfate reduction in sediment slurries was stimulated by lactate but not by formate, acetate, or pyruvate. The rates of sulfate reduction in San Francisco Bay sediment, estimated in vitro by the impedance ratio technique, ranges from 0.85 to 1.78 mmol/liter/lbday and compared favorably with estimates made by33SO42‐reduction.

ISSN:0149-0451    

DOI:10.1080/01490457909377741

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Laboratory simulations have helped resolve several problems concerning the role of bacteria in producing acidic drainage from active and abandoned coal mines. It is well established that the bacteriumThiobacillus ferrooxidansoxidizes pyrite in synthetic liquid media and in flooded or agitated experimental simulations of coal mine environments. However, many geologists remain skeptical regarding the role ofT. ferrooxidansin producing acidity below a near‐surface belt of soil water. We have demonstrated thatT. ferrooxidansis capable of colonizing and acidifying a near‐neutralpH environment of crushed coal or overburden, without prior establishment of apH‐dependent succession of bacteria. We have suggested thatT. ferrooxidansmay accomplish this by direct oxidation of pyrite. We have also shown thatT. ferrooxidanscatalyzes pyrite oxidation in the intermediate belt of the zone of aeration, although only for a limited period of time after rainfall infiltration.T. ferrooxidanswas not found to be significant in the simulated zone of groundwater saturation.

ISSN:0149-0451    

DOI:10.1080/01490457909377742

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Sulfate reduction rates in Sapelo IslandSpartinamarsh soils were assessed by a radiometric method. There was a significant linear correlation (r= 0.93) between the H235S produced and incubation period, and the regression line passed close to the origin. Sulfide reduction rates for the topmost 35 cm of soil in the short and tallSpartinazones were 62.3 and 201 mmol sulfide/m2/lb day, respectively. To reduce sulfate at these daily rates, the sulfate‐reducing bacteria would require a maximum of 67 and 36% of the organic carbon produced by the summer crops of short and tallSpartina,respectively. In both zones, highest rates occurred in the 0‐ to 5‐cm layer. In the shortSpartinazone, 80% of the sulfate reduction in the topmost 35 cm occurred in the 0‐ to 5‐cm layer, whereas a value of 29% was found for the same situation in the tallSpartinazone. In the topmost 10 cm of the shortSpartinazone, some sulfate appeared to be immobilized as organic sulfate.

ISSN:0149-0451    

DOI:10.1080/01490457909377743

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Advances in Microbial Ecology (Vol. 1)M. Alexander (Editor). Plenum Press, New York, 1977. 268 pp., $24.50.

ISSN:0149-0451    

DOI:10.1080/01490457909377744

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0149-0451    

DOI:10.1080/01490457909377737

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor