The effects of the nitrogen sources sodium nitrate (NaNO3) and urea (CH4N2O) on growth, lipid production, and fatty acid composition of Nannochloropsis oceanica IMET1 were investigated. Nitrogen source affected cell density, dry cell weight, and lipid production. Cells grown in the nitrate medium increased dry cell weight and lipid weight in comparison with cells grown in the urea medium. The c...

The input of new nitrogen into the euphotic zone constrains the export of organic carbon to the deep ocean and thereby the biologically mediated long-term CO2 exchange between the ocean and atmosphere. In low-latitude open-ocean regions, turbulence-driven nitrate diffusion from the ocean's interior and biological fixation of atmospheric N2 are the main sources of new nitrogen for phytoplankton ...

Cooperative Extension Service • Kansas State University • Manhattan Nitrate toxicity Nitrate is a natural product formed from the oxidation of organic compounds. Most of the soil nitrogen absorbed by plant roots is in nitrate form. Normally, nitrate in a plant is rapidly converted to amino acids by the enzyme nitrate reductase. This reduction requires energy from sunlight, adequate water, nutri...

A numerical model of nitrogen uptake and growth was developed for the temperate seagrass Zostera marina L. Goals were to evaluate the relative effects of light and nitrogen availability on nitrogen uptake and partitioning between leaf and root tissue. and to estimate nitrogen concentrations in the sedmen t and water column required to saturate growth. Steady-state predichons are quite robust wi...

When cells of Chlorella are grown in a medium containing a limiting quantity of nitrate or ammonia as nitrogen source, photosynthesis and cell division continue after all the available nitrogen in the medium has been abstracted by the growing plants. The cells become nitrogen-deficient. When kept in darkness with added nitrate these nitrogen-deficient cells synthesize a considerable quantity of...

In sugar beet seedling period and sugar accumulation period, the quantity of NR-mRNA raised with the rate of nitrate nitrogen and ammonium nitrogen raised, and the activity of NR raised also, that was the quantity of NR-mRNA of NO3/NH4 —4:0 was the highest. In phyllome formation period and root growth period, the quantity of NR-mRNA of NO3/NH4—3:1 was the highest, and its activity was the highe...

Maintaining the levels of nitrogen in agricultural fields to ensure crop yield performance is challenging due to the complex dynamics of nitrogen transformation in soil. Nitrogen is mainly taken up by plant roots in the form of nitrate, but it is considered as an environmental pollutant that threatens human and animal health. Therefore, it is necessary to use adsorbent compounds to retain nitra...

A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for wa...

Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This sp...