Plankton refer to diverse populations of microscopic or slow-moving organisms that drift in water masses, including oceans, lakes, and rivers. This ecological grouping is broadly divided into phytoplankton, which are photosynthetic primary producers, and zooplankton, which are primarily consumers that graze on other organisms. As the foundation of almost all aquatic food webs, plankton communities are biologically vital, forming the base of marine and freshwater ecosystems. They play a critical role in global biogeochemical cycles, particularly the oceanic carbon cycle, through processes like photosynthesis, which absorbs atmospheric carbon dioxide, and subsequent sinking that sequesters carbon into the deep ocean.