It is generally assumed that during denitrification bacteria oxidize organic substances completely to carbon dioxide concomitant with the reduction of nitrate or nitrite to nitrogen and nitrous oxide. This assumption is based upon the early experiments of Gayon and Dupetit (1886) which demonstrated that the ratio of carbon dioxide to nitrogen in denitrifying cultures corresponded to the theoret...

Carbon- and nitrogen-to-volume (C/V and N/V) ratios were determined for freshwater bacterial assemblages grown in lake water filtrate or in water enriched with nutrients (aqueous extract of lake seston, glucose, arginine, phosphate, or ammonium). Biovolume was measured by epifluorescence microphotography, and carbon and nitrogen biomasses were measured with a CHN analyzer. Despite large variati...

This work aims to prepare and study amorphous carbon nitride (CNx) films. Films were deposited by reactive magnetron radiofrequency (RF) sputtering from graphite target in argon and nitrogen mixture discharge at room temperature. The ratio of the gas flow rate was varied from 0.1 to 1. Deposited films were found to be amorphous. Highest Nitrogen concentration achieved was 42 atomic percent whic...

The biological variables consist of a single population each of phytoplankton and grazers, which are denominated in phosphorus units (mmol m23) in the constant (Redfield) ratio model (CRM) and are given the symbols Pp and Pz. In the variable ratio model (VRM), there are separate state variables for phytoplankton carbon (Cp), nitrogen (Np), phosphorus (Pp), and chlorophyll (M). Grazer biomass is...

Total organic carbon has a major influence on both the chemical and biological processesthat take place in sediments. Algal bloom is one of the organic carbon levels in aquatic ecosystems. In 2009 algal bloom occurred in the Hormozgan province and prolonged for months, which finally setteled down in 2010. In this study the variations of total organic carbon (TOC), organic matter (TOM) and tot...

We examined the flows of nitrogen in two batch incubations of plankton assemblages under controlled conditions, using mesopelagic seawater from different depths. Observations included concentrations of nutrients, organic matter (particulate and dissolved) and plankton (biomass by species). Because nitrogen flows were not observed directly (as is generally the case), we examined them using a mul...

The aim of this study was to assess the decomposition efficiency of earthworms, local (L.mauritii) as well as exotic (Eisenia foetida) in vermicomposting of garden litter in SRM University campus. The vermicompost produced through vermicomposting of garden litter mixed with cow dung in the ratio of 3:1 by using local and exotic earthworms (Eisenia foetida) was rich in ammoniacal nitrogen, nitra...

The amount of inorganic carbon is one of the main limiting environmental factors for photosynthetic organisms such as cyanobacteria. Using Synechococcus elongatus PCC 7942, we characterized metabolic and transcriptomic changes in cells that had been shifted from high to low CO(2) levels. Metabolic phenotyping indicated an activation of glycolysis, the oxidative pentose phosphate cycle, and glyc...

Drought stress triggers mature leaf senescence, which supports plant survival and remobilization of nutrients; yet leaf senescence also critically decreases post-drought crop yield. Drought generally results in carbon/nitrogen imbalance, which is reflected in the increased carbon:nitrogen (C:N) ratio in mature leaves, and which has been shown to be involved in inducing leaf senescence under nor...