What is picoplanktons role in primary productivity?

Picoplankton, typically defined as microorganisms ranging from 0.2 to 2 micrometers in size, play a crucial role in primary productivity, particularly in oligotrophic (nutrient-poor) marine environments. They contribute significantly to the ocean's carbon fixation through photosynthesis, forming the base of the marine food web. By converting inorganic carbon into organic matter, picoplankton support higher trophic levels and influence global biogeochemical cycles. Their abundance and metabolic efficiency make them vital players in sustaining marine ecosystems and regulating climate processes.