Phytoplankton growth in the oceans ultimately depends on
seasonal and interannual climatological cycles that determine
the availability of nutrients and light. In addition, loss factors
such a grazing, viral lyses, and sinking influence phytoplankton
standing stock. In the open ocean, vertical density stratifi-
cation is an important process in shaping the resource availability
for phytoplankton growth. Stabilization of the water
column allows phytoplankton to exploit higher irradiance intensities
near the surface. However, stratification also inhibits
exchange with nutrient-rich deep water, potentially leading
to nutrient limitation of phytoplankton near the surface