Question

why is it important for phytoplankton to stay in the photic zone

Answer 1

Phytoplankton must be in the photic zone to photosynthesize. They rely on many different adaptations to move into or remain there. Non-motile phytoplankton rely on physical factors (water viscosity, convection cells, and wind- induced rotations), morphological features (branching frustules, colony formation, and bladder- like or needles-like cell shape), and physiological adaptations (production of mucilage and accumulation of lighter ions with a reduction of heavier ions or compounds) to reduce sinking rates (Dawes 1998). Cyanobacteria contain gas vacuoles that act like flotation and motile species can swim toward light.