AME 21:49-57 (2000)  -  doi:10.3354/ame021049

Utilisation of seaweed carbon by three surface-associated heterotrophic protists, Stereomyxa ramosa, Nitzschia alba and Labyrinthula sp.

Evelyn Armstrong1,3,*, Andrew Rogerson2, John W. Leftley3

1University Marine Biological Station Millport, Isle of Cumbrae KA28 0EG, Scotland, UK
2Oceanographic Center, Nova Southeastern University, 8000 N. Ocean Drive, Dania Beach, Florida 33004, USA
3Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, PO Box 3, Oban, Argyll PA34 4AD, Scotland, UK
*Present address: Department of Biological Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, Scotland, UK. E-mail:

ABSTRACT: In view of the abundance of protists associated with seaweeds and the diversity of nutritional strategies displayed by protists in general, the ability of 3 closely associated protists to utilise seaweed carbon was investigated. Stereomyxa ramosa, Nitzschia alba and Labyrinthula sp. were cultured with seaweed polysaccharides as well as seaweed itself. N. alba and Labyrinthula sp. were found to utilise seaweed polysaccharides in axenic culture. All 3 protists were capable of penetrating intact but 'damaged' (autoclaved) seaweed particularly when bacteria were present. The possibility that these and other heterotrophic protists are directly removing macroalgal carbon in the field is discussed.


KEY WORDS: Protist · Heterotroph · Seaweed · Carbon · Utilisation


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