The Upper Jurassic/Lower Cretaceous brackish carbonate sequences of the Weserbergland area (NW Germany) contain numerous calcareous algae and cyanobacteria closely associated with layers dominated by serpulids and ooids. Algae are an essential tool for the interpretation of brackish environments. Several new taxa of Chlorophyta (Pseudopenicillus weseri n.sp., Springerella bifurcata n.gen. n.sp., S. fuchtbaueri n.sp., Brachydactylus reisi n.sp.) and one new species of Cyanobacteria (Ponsella freyteti n.sp.) are described.