What's on the move

Red tide

Noctiluca scintillans

(Image credit: Anita Slotwinski)

Individually these critters are tiny and not usually visible to the naked eye. There are documented cases in Tasmania in which dense 'red tides' of Noctiluca, a type of phytoplankton, has bloomed in response to a combination of increased nutrient loads and warming waters. Red tides are made up of many individual buoyant, balloon shaped cells with a short flagellum and tentacle. The cells are colourless, except for the presence of red and yellow pigments. They are also bioluminescent (produce light).

The changes to noctiluca and other plankton species are very important and the role of plankton in the environment is not to be underestimated.

Length: Up to 0.2 cm in diameter


Mostly coastal in temperate, subtropical and tropical waters, especially near river mouths following heavy rainfalls; 0-30 m depth

Log it

Log if spotted in Tasmanian waters

Related links/info

Species names on the Redmap site are based on the Codes for Australian Aquatic Biota or CAAB (http://www.cmar.csiro.au/caab/). This is updated regularly and lists the approved common name, family, species name and more.

Redmap species descriptions were based, with permission on 'The guide to the marine zooplankton of south eastern Australia'.

For more on the effects of climate change on marine species see our resources pages, the impacts of Climate Change On Marine Species, phenology and physiology.

Number of sightings 3

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