Free living viruses are ubiquitous in marine waters and concentrations are usually several times higher than the bacterial abundance. These viruses are capable of lysing host bacteria and therefore, play an important role in the microbial loop in oligotrophic waters. However, few studies have been conducted to compare the role of viruses in regulating bacterial abundance and heterotrophic activ...

We used the oxygen method (dark and light bottles) to study photic-layer-integrated microbial metabolism along a latitudinal transect in the Atlantic Ocean (50° S to 50° N) during May and October 1997. The temperate region was more productive than the other oceanic environments, showing a net autotrophic balance (gross primary production/total respiration, GPP/R = 1.41 ± 0.34; mean ± SE). The G...

Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total ...

The nutrient and trophic status were used to assess the impact of human activities on lagoon by determining the trophic status of the lagoons and then using nutrient parameters and transparency in a form of model to predict the trophic status index (TSI) of the lagoon waters. The trophic index of Benya, Nakwa, Amisa and Nyanya ranges between 35.0– 39.0 and falls within Carlson’s TSI range scale...

BACKGROUND The recycling of the organic matter is a crucial function in any environment, especially in oligotrophic environments such as Acid Mine Drainages (AMDs). Polymer-degrading bacteria might play an important role in such ecosystem, at least by releasing by-products useful for the rest of the community. In this study, physiological, molecular and biochemical experiments were performed to...

Nutrient enrichment of peatlands may alter patterns of heterotrophic microbial activity (HMA) and organic matter cycling. The utilization of C-substrates by heterotrophic microbial communities in response to changes in environmental conditions may serve as sensitive indicators of changes in the trophic state of wetlands. The objective of this study was to measure the response of heterotrophic m...

Ammonia-oxidizing bacteria (AOB) have well characterized genes that encode and express nitrite reductases (NIR) and nitric oxide reductases (NOR). However, the connection between presence or absence of these and other genes for nitrogen transformations with the physiological production of nitric oxide (NO) and nitrous oxide (N2O) has not been tested across AOB isolated from various trophic stat...