Which term refers to very small free-floating photosynthetic organisms that often dominate open-ocean surface waters?

Which term refers to very small free-floating photosynthetic organisms that often dominate open-ocean surface waters?

• A. Phytoplankton
• B. Picoplankton
• C. Plankton
• D. Plankton Bloom

Answer: (B)

Open-ocean surface waters are often dominated by extremely small photosynthetic plankton called picoplankton. These tiny organisms, about 0.2 to 2 micrometers in size, include important cyanobacteria like Prochlorococcus and Synechococcus. Their small size gives a high surface-area-to-volume ratio, which helps them take up nutrients efficiently in nutrient-poor (oligotrophic) oceans and contributes a large share of primary production. Phytoplankton is the broader term for all floating photosynthetic organisms, from picoplankton up to larger forms, while plankton refers to any drifting organisms (not necessarily photosynthetic). A plankton bloom is a rapid increase in plankton abundance, not a type of organism.

Open-ocean surface waters are often dominated by extremely small photosynthetic plankton called picoplankton. These tiny organisms, about 0.2 to 2 micrometers in size, include important cyanobacteria like Prochlorococcus and Synechococcus. Their small size gives a high surface-area-to-volume ratio, which helps them take up nutrients efficiently in nutrient-poor (oligotrophic) oceans and contributes a large share of primary production. Phytoplankton is the broader term for all floating photosynthetic organisms, from picoplankton up to larger forms, while plankton refers to any drifting organisms (not necessarily photosynthetic). A plankton bloom is a rapid increase in plankton abundance, not a type of organism.