Sediments microbiological activity

Vertical distributions of dissolved Ba and total (dissolved+particulate) Pu, Am and Th in Framvaren Fjord all show increased concentrations with depth (Falkner etal., 1993 Roos etal., 1993). Ba cycling was dominated by its uptake into particulate matter associated with productivity in surface waters, followed by its regeneration at depth or in the sediments. Microbiological activity near the redox interface likely promotes the breakdown of settling particulate matter and the release of barite just above the 02/H2S interface (Falkner etal., 1993). Complex formation with dissolved organic carbon (DOC) is believed to be the main cause for the observed behavior of Pu, Am and Th (Roos etal., 1993). The distributions of these elements were not examined within the regions near the 02/H2S interface and the associated microbial layer. 

The fact that the average ratio of Miner. C/Miner. N (2.83) is considerably smaller than the ratio of Org. C/Org. N of plankton (5.7) indicates clearly that the organic nitrogen in plankton is more easily mineralized than the organic carbon by microbiological activities and also that the mineralization processes are active in the lake water. This fact may account for the relationship between the ratios of Org. C/Org. N of plankton, of detritus and of surface bottom sediments, which has been shown previously. 

This also suggests that the composition of organic matter in sediments gradually changes into a form richer in carbon as a result of microbiological activity. 

Battersby N. S. and Brown C. M. (1982) Microbial activity in organically enriched marine sediments. In Sediment Microbiology (eds. D. B. Nedwell and C. M. Brown). Academic Press, New York, pp. 147—170. 

Han J., Calvin M. (1969) Hydrocarbon distribution of algae and bacteria, and microbiological activity in sediments. Proc. Natl Acad. Sci. USA 64, 436—43. 

Marxsen, J., and D. M. Fiebig. 1993. Use of perfused cores for evaluating extracellular enzyme activity in streambed sediments. FEMS Microbiology Ecology 13 1-12. 

Tuominen, L., T. Kairesalo, and H. Hartikainen. 1994. Comparison of methods for inhibiting bacterial activity in sediment. Applied and Environmental Microbiology 60 3454—3457. 

Fabiano, M., and R. Danovaro. 1998. Enzymatic activity, bacterial distribution, and organic matter composition in sediments of the Ross Sea (Antarctica). Applied and Environmental Microbiology 64 3838-3845. 

King, G. M. 1986. Characterization of b-glucosidase activity in intertidal marine sediments. Applied Environmental Microbiology 51 373-380. 

Meyer-Reil, L.-A. 1987. Seasonal and spatial distribution of extracellular enzymatic activities and microbial incorporation of dissolved organic substrates in marine sediments. Applied Environmental Microbiology 53 1748-1755. 

Jensen, K., Revsbech, N. P., and Nielson, L. (1993). Microscale distribution of nitrification activity in sediment determined with a shielded microsensor for nitrate. Applied and Environmental Microbiology... 

Tal, Y., Watts, J. E. M., and Schreier, H. J. (2005). Anaerobic ammonia-oxidizing bacteria and related activity in Baltimore inner Harbor sediment. Applied and Environmental Microbiology 71, 1816—1821. Teske, A., Aim, E., Regan, J. M., Toze, S., Pattmann, B. E., and Stahl, D. A. (1994). Evolutionary relationships among ammonia- and nitrite-oxidizing bacteria. Journal of Bacteriology 176, 6623-6630. 

In the absence of mechanisms to accelerate phytic acid hydrolysis, the complexant will clearly persist in the environment for a long time. However, enzyme catalyzed phytate hydrolysis is known to be much faster than the thermal reaction (27). Thus biological activity may accelerate the hydrolysis reaction in soils. A recent report indicates that phytic acid is rapidly hydrolyzed by both aerobic and anaerobic microbiological processes in environmental samples (22). Complete phytate hydrolysis was observed in less than 40 days in anaerobic sediments, while half the available phosphate was released in 60 days under aerobic conditions (22). 

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