In microbial consortia bacteria often settle on other organisms that provide nutrients and organic material for their growth. This is true for the plankton where microalgae perform photosynthesis and exude metabolites that feed associated bacteria. The investigation of such processes is difficult since algae provide bacteria with a spatially structured environment with a gradient of released organic material that is hard to mimic. Here we introduce the design and synthesis of a cryogel-based microstructured habitat for bacteria that provides dimethylsulfoniopropionate (DMSP) as a carbon and sulfur source for growth. DMSP, a widely distributed metabolite released by algae, is thereby made available for bacteria in a biomimetic manner. Based on a novel DMSP derived building block (DMSP-HEMA), we synthesized cryogels providing structured surfaces for settlement and delivering the organic material fueling bacterial growth. By monitoring bacterial settlement and performance we show that the cryogels represent microbial arenas mimicking the ecological situation in the plankton.