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Story: Plankton

Common plankton groups in New Zealand

Group Habitat Size (mm) Features
Phytoplankton Single-celled photosynthesisers
Diatoms Marine and freshwater 0.002–0.02 Golden-brown, silica shell
Dinoflagellates Marine and freshwater 0.005–0.07 Red-brown, cellulose plates, two flagella, cause red tides, some toxic
Desmids Freshwater 0.005–0.07 Green
Coccolithophores Marine 0.005–0.015 Small, calcite shell, two flagella, cause white blooms
Zooplankton Single- and many-celled consumers
Foraminifera Marine 0.03–2 Single-celled, chambered calcite shell
Radiolaria Marine 0.05–3 Single-celled, silica shell
Copepods Marine and freshwater 0.2–1 Crustaceans, diverse group, herbivores and carnivores
Arrow worms Marine 0.2–40 Narrow transparent body, carnivores
Jellyfish Marine and freshwater 0.2–1,000 Two cell layers, carnivores
Bacteria Single-celled, some photosynthetic, most consumers
Cyanobacteria Marine and freshwater 0.0007–0.001 Blue-green, can fix nitrogen
Bacteria Marine and freshwater 0.0002–0.001 Abundant, act as decomposers

The table lists the three subgroups of plankton: phytoplankton, zooplankton and bacteria. It describes their habitat, their typical size, and some distinctive features.

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Te Ara – The Encyclopedia of New Zealand

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How to cite this page

Maggy Wassilieff, Plankton – Plant plankton, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/table/5131/common-plankton-groups-in-new-zealand (accessed 4 June 2026).

Story by Maggy Wassilieff, published 2 March 2009.