Microorganisms marine sediments

Molecular hydrogen is an important intermediate in the degradation of organic matter by microorganisms in anoxic habitats such as freshwater and marine sediments, wet land soils, and the gastrointestinal tract of animals. In these particular conditions H2 is produced during fermentation of carbohydrates, lipids, nucleic acids, and proteins by anaerobic bacteria and,... 

Thirty-five microorganisms isolated from marine sediment and marine water samples taken from Hawaii and Houston, TX were capable of degrading p,p- DDT. jO,//-DDD was identified as the major metabolite. Minor transformation products included 2,2-bis(/t-chlorophenyl)-ethanol (DDOH), 2,2-bis(/t-chlorophenyl)ethane, and p,p-DDE (Path et al., 1972). 

Meyer-Reil, L.-A. 1986. Measurement of hydrolytic activity and incorporation of dissolved organic substrates by microorganisms in marine sediments. Marine Ecology Progress Series 31 143-149. 

Marine sediments are an important compartment for N cycHng. Shelf sediments in particular are sites of active denitrification (Codispoti et al., 2001), and estuarine, coastal, and coral reef sediments can be important sites of nitrogen fixation (Burns et al, 2002 Capone, 1983 Capone et al., 1992). Despite extensive study of biogeochemical processes in sediments, the study of the microbial loop in this compartment has had considerably less attention, possibly due to difficulty in studying sediment microorganisms. There are two primary differences between water column and sediment microbial processes. The first of these is the presence... 

MacGregor, B. J., Boschker, H. T. S., and Amann, R. (2006). Comparison of rRNA and polar-lipid-derived fatty acid biomarkers for assessment of C-13-substrate incorporation by microorganisms in marine sediments. Appl. Environ. Microbiol. 72, 5246—5253. 

Research since 1990 has greatly expanded our understanding of anaerobic metabolism. Novel microorganisms have been discovered, such as those performing anaerobic ammonium oxidation to N2 (anammox). These organisms were predicted to exist based on thermodynamic considerations, but have since been shown to contribute substantially to N2 production in some marine sediments. Organisms that were known to exist for sometime have been shown to perform... 

Laboratory studies have shown that the microorganisms present in natural marine sediments from British Columbia (Canada) and sediments contaminated with mine-tailings were capable of methylating arsenic under either aerobic or anaerobic conditions. Incubation of sediments with culture media produced volatile arsines (including AsHj, MeAsHj and MCjAs) as well as the methylarsenic(V) compounds Me As(0)(0H)j (n= 1,2,3) L... 

However, much of the methane produced in bottom sediments never reaches the atmosphere because it is oxidized to CO2 by microorganisms living in the surficial layers of the sediments and in the oxic, overlying waters. The oxidation of methane by sulfate reducers (or other organisms in the community) also has been examined and it is the principal removal mechanism of methane from shallow marine sediments (24, 25). Methane is also oxidized by certain chemoautotrophic bacteria in the presence of dissolved oxygen, although at much lower rates compared to those observed in sediments (27). 

The evidence of such a relationship can be obtained from the analysis of stromatolites. Stromatolites, i.e., laminated sedimentary structures, were formed by microorganisms, which trapped, bound and cemented marine sediments during the long geological development of our planet. 

Mannisto MK, Puhakka JA, Ferguson JF. 1997. Degradation of Aroclor 1221,1242 and anaerobically transformed Aroclor 1254 by aerobic marine sediment microorganisms. In Alleman BC, Leeson A, eds. In situ and on-site bioremediation Volume 2. Columbus, OH Battelle Press, 421-426. 

Anaerobic - Describes a situation or an area characterized by the lack of oxygen. The term can also be used in reference to organisms such as some bacteria that can survive and grow in the absence of gaseous or dissolved oxygen. For example, many marine sediments are anaerobic below a depth of a few centimetres from the surface. Oil deposited in such areas degrades slowly and is primarily associated with anaerobic types of microorganisms. 

Luminous bacteria are bioluminescent microorganisms whose luciferase genes (lux), proteins and intact cells are widely used in applied research and commercial products. Acknowledging the commercial value of luminescent cells also in entertainment and education, we have conducted research on luminous bacteria from marine samples and have isolated Photobacterium phosphoreum (strain RL-1) from coastal marine sediment. In order to maximize the luminescence activity of RL-1, we examined a series of extracts prepared from dried marine foodstuff. Because chitinous compounds and some amino acids are known to be abundant in dried squid and shrimp, we also tested the effects of those compounds on the luminescence activity. Among the supplemental compounds tested, chitosan, cysteine, and aspartic acid were found to enhance the luminescence activity of RL-1. The present results indicate that some amino acids and chitinous compounds are effective supplements for further enhancing bacterial light production in an enriched medium (SWC ). 

In oceanic sediments, macro- (> 1 mm) and microorganisms adapt to the existing environment. They play an important role in the mixing of surface sediment layers. Burrowing by organisms in marine sediments is so common that it is the preservation of depositional structures that requires explanation, not their destruction (Arrhenius, 1952, p. 86). 

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