ZOOPLANKTON Diversity of the Heterotrophic Plankton Community
Feb 23, 2016
ZOOPLANKTON
Diversity of the Heterotrophic Plankton Community
Major Groups of Zooplankton
• Ciliates• Rhizopods• Rotifers• Cladocerans• Copepods
Ciliate Zooplankton
• Animal-like unicellular heterotrophs.• All have two different types of nuclei.• They move and feed by cilia.
Some common ciliates in the microzooplankton community
• Stentor
• Halteria
• Tintinnida
Rhizopod Zooplankton
• These are amoeboid unicellular heterotrophs• Most common taxa observed in the
microzooplankton are thecate like Difflugia.
Actinopod Zooplankton
• These are free-floating cells with radiating axopods. e.g. Actinosphaerium.
Turbellarian Zooplankton
• These are free-living flatworms that live in stagnant pools and eutrophic lakes. e.g. Stenostomum
Rotiferan Zooplankton
• Animal heterotrophs that feed by ciliary pads surrounding the mouth.
• All have a specialized “jaws” called trophi in the gullet.
• Many are covered by a lorica.
Typical Life Cycle of a Rotifer
Some Rotifers in the Zooplankton
• Keratella
• Polyarthra
• Filinia
More Rotifers
• Brachionus
• Asplanchna
• Conochilus
Annelid Zooplankton
• Oligochaete segmented worm. e.g. Aeolosoma
Arthropod Zooplankters
Most freshwater taxa are Crustaceans (arthropods with cephalothorax and abdomen)– Order Anostraca– Order Ostracoda– Order Cladocera– Order Copepoda
• Suborder Calanoida• Suborder Cyclopoida• Suborder Harpacticoida
Anostracan Zooplankton
• Fairy Shrimp
• Clam Shrimp
• Tadpole Shrimp
Ostracod Zooplankters
• Sometimes called seed shrimp. Rarely in the euplankton.
Cladoceran Zooplankton
Cladoceran Life Cycle
Filter-Feeding Cladocerans
• Holopedium
• Diaphanosoma
• Chydorus
More Filter-Feeding Cladocerans
• Daphnia
• Bosmina
• Moina
Predaceous Cladocerans
• Leptodora
• Polyphemus
Copepod Diversity
• Suborder Cyclopoida
• Suborder Calanoida
• Suborder Harpacticoida
Copepod Life Cycle
Calanoid Copepods
• Diaptomus
• Epischura
• Limnocalanus
Cyclopoid Copepods
• Cyclops
• Macrocyclops
• Megacyclops
Harpacticoid Copepods