• Facets (new session)
• Description
• Metadata
• Settings
  • owl:sameAs
  • Inference Rule: asEquivalentb3sb3sifpfacetshttp://www.w3.org/2002/07/owl#ldpoplwebskos-transvirtrdf-labelvirtrdf-urlNone
    

'Mass concentration' means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. The phrase 'expressed_as' is used in the construction A_expressed_as_B, where B is a chemical constituent of A. It means that the quantity indicated by the standard name is calculated solely with respect to the B containedin A, neglecting all other chemical constituents of A. Chlorophyll is the green pigment found in most plants, algae and cyanobacteria. The presence of chlorophyll is essential for photosynthesis to take place. There are five different forms of chlorophyll that occur naturally. All contain a chlorin ring (chemical formula C20H16N4) which gives the green pigment and a side chain whose structure varies. The naturally occurring forms of chlorophyll contain between 35 and 55 carbon atoms. Diatoms are single-celled phytoplankton with an external skeleton made of silica. Phytoplankton are autotrophic prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis.