Rotifer
Videos
The rotifers, commonly called wheel animals or wheel animalcules, make up a phylum of microscopic and near-microscopic pseudocoelomate animals.
Image: Mikrofoto.de Raedertier 14
Image: Pulchritia dorsicornuta Zoo Keys 342 001 g 001
Anatomy of a bdelloid rotifer
Scanning electron micrographs showing morphological variation of bdelloid rotifers and their jaws.
Plankton
Videos
Plankton are the diverse collection of organisms that drift in water but are unable to actively propel themselves against currents. The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales.
Marine microplankton and mesoplankton Part of the contents of one dip of a hand net. The image contains diverse planktonic organisms, ranging from photosynthetic cyanobacteria and diatoms to many different types of zooplankton, including both holoplankton (permanent residents of the plankton) and meroplankton (temporary residents of the plankton, e.g., fish eggs, crab larvae, worm larvae).
Plankton (organisms that drift with water currents) can be contrasted with nekton (organisms that swim against water currents), neuston (organisms that live at the ocean surface) and benthos (organisms that live at the ocean floor).
Some marine diatoms — a key phytoplankton group
The amphipod Hyperia macrocephala – part of the zooplankton