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A study was conducted on river biofilms that were composed of polycarbonate strips complemented by combined nutrients with or without hexadecane. It was observed that there was cyclic response of the anaerobic heterotrophic biofilm community and the effective interaction between nutrients and the contaminant hexadecane.

The study was conducted to assess the impact of nutrients, dissolved oxygen (DO) concentration and nickel on the formation of river biofilm, its structure, its role and the composition of the community. However, the outcome indicated that the groups were a part of the bacteria developing either from the freshwater and marine environments or from the agricultural soils or from the waste matter of the industries.

In this study, we investigated the bacterial communities in the shrimp and sea cucumber culture environment, including shrimp ponds (SP), sea cucumber ponds (SCP), mixed-culture ponds (MCP) and the effluent channel (EC) in Qingdao, China. Bacteria cultivation showed that the counts of heterotrophic, nitrate-reducing and sulfate-reducing bacteria in the sediment of SP were higher than that in the sediment of SCP and MCP, varying between 8.7 × 10 and 1.86 × 10, 2.1 × 10 and 1.1 × 10, and 9.3 × 10 and 1.1 × 10 CFU g, respectively. In contrast, the counts of ammonium-oxidizing and nitrifying bacteria in the sediment of SP was lower than that in the sediment of SCP and MCP. Denaturing gradient gel electrophoresis (DGGE) of 16S rDNA gene and dendrogram analyses showed that bacterial diversity in the mixed-culture environment was higher than that in the monocultures. The similarity of bacterial community between EC and SCP or MCP was higher than that between EC and SP. These results indicated that sea cucumber culture played a significant role in influencing the environmental bacterial communities that were composed mainly of Flavobacteriaceae (64.3%), Bacteriodetes (21%) and delta proteobacteria (14.7%), including the genera of Croceimarina, Lutibacter, Psychroserpens and so on. The results explained the benefit of sea cucumber culture in shrimp ponds at the level of microbial ecology. [ABSTRACT FROM AUTHOR]

The population density and activity of a microbial community associated with the sediment and rhizosphere of an intertidal freshwater wetland dominated by Scirpus pungens was monitored before and following the application of weathered Mesa light crude oil and fertilizers. The influence of nutrient enrichment (fertilizers) and plant growth on oil degradation rates was determined from the resulting data. The study plots (four blocks of replicates) were subjected to five treatments: oil only (natural attenuation); oil plus ammonium nitrate and phosphate, with regular cropping of the plants; oil plus ammonium nitrate and phosphate; oil plus sodium nitrate and phosphate; no oil, ammonium nitrate and phosphate. The plots were regularly monitored in the field for gas production (carbon dioxide and nitrous oxide), and samples were collected for laboratory analysis of denitrification activity, aliphatic and aromatic hydrocarbon degradation activity, and total heteroptrophic bacteria. The viable bacterial population density increased during the first 4 weeks in oiled and unoiled experimental plots that were fertilized. In contrast, population densities in untreated areas remained relatively unchanged throughout the monitoring period. The microbial population demonstrated a rapid and sustained increase in naphthalene mineralization activity in plots that were both fertilized and oiled. Hexadecane mineralization activity increased in response to fertilizer application, with ammonium nitrate causing a larger increase than sodium nitrate. A very significant difference observed in the mineralization of hexadecane was that the surface sediments were much more active than the subsurface sediments. This difference became even more pronounced in the second year of monitoring, even though the treatment regime had been discontinued. This compartmentalization of mineralization activity was not observed for naphthalene. Following fertilizer application, field and laboratory... [ABSTRACT FROM AUTHOR]

The article discusses a prospective epidemiological study on the acute health effects related to exposure to cyanobacteria in three lakes located in Quebec, Canada. Topics include the use of a Limulus amoebocyte lysate test to determine the presence and concentration of endotoxins in water samples from the lakes, the association of gastrointestinal symptoms with endotoxin exposure, and the association of high concentrations of endotoxins in cyanobacterial blooms with Gram-negative bacteria.