IPA: /ˌfaɪtəʊˈplæŋktənɪk/
KK: /faɪtoʊplæŋkˈtɒnɪk/
Relating to tiny plants that float in water and are a key part of the aquatic food chain.
The phytoplanktonic organisms are essential for the health of marine ecosystems.
Phytoplanktonic → It is formed from "phyto-" (from Greek "phyton", meaning plant) and "plankton" (from Greek "planktos", meaning wandering or drifting). The word "phytoplanktonic" refers to the drifting plant-like organisms found in aquatic environments.
Think of 'plant' ('phyto-') that 'drifts' ('plankton') in the water — that's what phytoplanktonic describes.