Home|Search|Identify|Taxonomic tree|Quiz|About this site|Feedback
Developed by ETI BioInformatics
Characteristics, distribution and ecology
Taxonomische classification
Synonyms and common names
Literature references
Images, audio and video
Links to other Web sites

Noctiluca scintillans (Macartney) Kofoid and Swezy, 1921

Species Overview:

Noctiluca scintillans is an unarmoured, marine planktonic dinoflagellate species. This large and distinctive bloom-forming species has been associated with fish and marine invertebrate mortality events.

Taxonomic Description:

Noctiluca scintillans is a distinctively shaped athecate species in which the cell is not divided into epitheca and hypotheca. Cells are very large, inflated (balloon-like) and subspherical (Figs. 1-4). The ventral groove is deep and wide, and houses a flagellum, a tooth and a tentacle (Figs. 1,2,4). Only one flagellum is present in this species and is equivalent to the transverse flagellum in other dinoflagellates (Fig. 1). The tooth is a specialized extension of the cell wall (Fig. 4). The prominent tentacle is striated and extends posteriorly (Fig. 4). Cells have a wide range in size: from 200-2000 µm in diameter (Zingmark, 1970, Dodge, 1973, Dodge, 1982, Lucas, 1982, Fukuyo et al., 1990, Hallegraeff, 1991, Taylor et al., 1995, Steidinger and Tangen, 1996).

Morphology and Structure:

Noctiluca scintillans is a nonphotosynthetic heterotrophic and phagotrophic dinoflagellate species; chloroplasts are absent and the cytoplasm is mostly colorless (Figs. 1,2). The presence of photosynthetic symbionts can cause the cytoplasm to appear pink or green in color (Sweeney, 1978). A number of food vacuoles are present within the cytoplasm. A large eukaryotic nucleus is located near the ventral groove with cytoplasmic strands extending from it to the edge of the cell (Fig. 2) (Zingmark, 1970, Dodge, 1982, Fukuyo et al., 1990, Hallegraeff, 1991, Steidinger and Tangen, 1996).

Reproduction:

Noctiluca scintillans reproduces asexually by binary fission (Fig. 3) and also sexually via formation of isogametes. This species has a diplontic life cycle: the vegetative cell is diploid while the gametes are haploid. The gametes are gymnodinioid with dinokaryotic nuclei (Zingmark, 1970).

Remarks:

This species is frequently referred to as Noctiluca miliaris, although Macartney's specific name has priority. Taylor, 1976 suggested the simplest solution to the problem of nomenclature is to accept the priority of the 'scintillans'' especially as this has been used by two major works (Kofoid and Swezy, 1921, Lebour, 1925).

Ecology:

Noctiluca scintillans is a strongly buoyant planktonic species common in neritic and coastal regions of the world. It is also bioluminescent in some parts of the world. This bloom-forming species is associated with fish and marine invertebrate mortality events. N. scintillans red tides frequently form in spring to summer in many parts of the world often resulting in a strong pinkish red or orange discoloration of the water (tomato-soup). Blooms have been reported from Australia (Hallegraeff, 1991), Japan, Hong Kong and China (Huang and Qi, 1997) where the water is discolored red. Recent blooms in New Zealand were reported pink with cell concentrations as high as 1.9 X 10^6 cells/L (Chang, 2000). In Indonesia, Malaysia and Thailand (tropical regions), however, the water color is green due to the presence of green prasinophyte endosymbionts (Sweeney, 1978, Dodge, 1982, Fukuyo et al., 1990, Hallegraeff, 1991, Taylor et al., 1995, Steidinger and Tangen, 1996).

This large cosmopolitan species is phagotrophic, feeding on phytoplankton (mainly diatoms and other dinoflagellates), protozoans, detritus and fish eggs (Fig. 2) (Dodge, 1982, Fukuyo et al., 1990, Hallegraeff, 1991, Taylor et al., 1995, Steidinger and Tangen, 1996).

Toxicity:

Toxic blooms of N. scintillans have been linked to massive fish and marine invertebrate kills. Although this species does not produce a toxin, it has been found to accumulate toxic levels of ammonia which is then excreted into the surrounding waters possibly acting as the killing agent in blooms (Okaichi and Nishio, 1976, Fukuyo et al., 1990). Extensive toxic blooms have been reported off the east and west coasts of India, where it has been implicated in the decline of fisheries (Aiyar, 1936, Bhimachar and George, 1950).

Habitat and Locality:

Noctiluca scintillans is a cosmopolitan species distributed world wide in cold and warm waters. Populations are commonly found in coastal areas and embayments of tropical and subtropical regions (Dodge, 1982, Fukuyo et al., 1990, Hallegraeff, 1991, Taylor et al., 1995, Steidinger and Tangen, 1996).

Noctiluca scintillans