Аннотация:1. The distribution of fatty acids in different groups of bacteria, ciliated protozoans and microalgae is reviewed emphasizing specific fatty acids like odd‐branched fatty acids and ( n ‐3) polyunsaturated fatty acids. 2. Odd‐branched fatty acids and ( n ‐6) fatty acids appear to be good indicators of zooplankton grazing on bacteria and ciliates when they are detected in microcrustacean triacylglycerols. We give several examples where these fatty acids may be used as markers. The value of ( n ‐3) fatty acids in describing zooplankton grazing on phytoplankton seems to be low.
