Plankton dynamics and mesoscale turbulence

In aquatic ecosystems, primary production (the transformation of inorganic materials and light into living matter by photosynthesis) is operated mainly by small, unicellular algae that float freely in the upper layers of oceans and lakes and are collectively called phytoplankton, see for an illustration the phytoplankters depicted in figure 1. Since phytoplankton need light, they are confined to the water layer where solar radiation can penetrate. This region is called the “euphotic layer” and it has a maximum depth of about one hundred meters. In the ocean, this roughly corresponds to the depth of the mixed layer; thus, the environment where phytoplankton live is a highly energetic fluid region characterized by intense turbulent mixing.