Noctiluca scintillans

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Noctiluca scintillans
Scientific classification
Domain: Eukaryota Phylum: Dinoflagellata Genus: Noctiluca Species: N.scintillans

Description and Significance

Noctiluca scintillans, also known as sea sparkles, are single-celled dinoflagellates that exhibit bioluminescence. They are free-living marine plankton, which range between 200-2000 micrometers in diameter. They are mostly found in estuaries and other coastal regions and can be found in both warm and cold waters. N. Scintillans are heterotrophic and non-photosynthetic, meaning they receive their carbon from organic compounds and receive their energy through the ingestion of organic substances. They don’t have any chloroplasts so, their cytoplasm is relatively clear. Noctiluca scintillans are non-motile, even though they possess a flagellum, and only move vertically by changing their buoyancy using gas vacuoles. N. Scintillans can reproduce asexually, by binary fission, and sexually, using isogametes through a diplontic lifecycle.

Cell Structure and Metabolism

Noctiluca scintillans has a round, balloon-like, body shape and is unarmored, meaning it does not have a protective shell. Since they do not photosynthesize, they don’t have chloroplasts and thus are fairly clear. The red and green color usually associated with this species, in the red and green tides, are due to the pigments of the photosynthetic symbionts within the vacuoles of N. scintillans and not the species itself. N. scintillans have a ventral groove that run through their bodies which contains the flagellum, a tooth and a tentacle. They also have a mouth-like structure called the cytostome which they use to capture and consume prey.

Noctiluca scintillans is a phagotrophic species with many food vacuoles found throughout their cytoplasm. They engulf smaller marine species such as diatoms, protozoans, fish eggs, and certain bacteria and then digest them in these food vacuoles. N. scintillans also contain gas vacuoles, which are filled with ammonia gas, that allow them to control their buoyancy.

Ecology and Pathology

Noctiluca scintillans are found mostly in coastal areas, in both temperate and tropical waters. Their population density has been found to be dependent on food availability, which is why they tend to stay in shallow, coastal areas, where phytoplankton thrive.