Hasle (1965, 1972) divided this diatom into two species : N.pungens f. pungens and N. pungens f. multiserie. Zhang (1994) confirmed that the species in South China Sea was N. pungen f. pungens according to its morphological characteristics.
Morphological Characteristics :
Spindle-shaped cells with pointed ends and two chromatophores. They form long chains by overlapping of their ends. Central pseudonodulus is absent.
Size of Specimen :
80-140 mm (L), 4-6 mm (W)
Distribution :
Neritic species which can survive in a wide range of temperature. The diatom has been seen in Europe, California Straits, Japan and other subtropical and tropical environments. Commonly be found in the South China Sea and Hainan Island, China. Sometimes, cause discoloration of seawater in the coast of Guangdong, Guangsei and Jiangsu provinces.
Major Limiting Factors :
DIN and DIP; silicates; Fe ions and EDTA as chelator.
Toxicity :
Harmful to marine organisms in South China Sea due to eutrophication and oxygen depletion. However, reports showed that the species was associated with ASP in Prince Edward Island, Canada.