Phytoplankton microbiome

A phytoplankton microbiome is the community of microorganisms—mainly bacteria, but also including fungi and viruses—that live in association with phytoplankton. These microbiomes play a critical role in marine ecosystems by supporting phytoplankton health, facilitating nutrient cycling, sustaining food webs, and contributing to climate regulation.

Microbial partners help decompose organic matter and recycle key nutrients like nitrogen and carbon, sustaining primary production, and supporting ocean productivity and phytoplankton community structure. Diazotrophic cyanobacteria, for example, fix atmospheric nitrogen, boosting productivity in nutrient-poor waters. As primary producers, phytoplankton absorb CO₂ through photosynthesis, contributing to the biological carbon pump and long-term carbon sequestration.

Phytoplankton–microbiome interactions are central to the global biogeochemical cycles. Microbial diversity influences host physiology and ecosystem functions, while environmental factors such as temperature, nutrient levels, and ocean chemistry shape microbiome composition and function. Chemical signaling—through Quorum sensing and Infochemicals—regulate microbial behavior, impacting bloom dynamics, symbiosis, and defense mechanisms. Viruses also affect phytoplankton populations by driving nutrient turnover and mediating carbon flow.

Current research focuses on microbial diversity, environmental drivers, and chemical communication, all of which are crucial to understanding the phytoplankton microbiome's ecological functions. These microbial interactions shape marine ecosystem stability, food web dynamics, and global climate processes.