Question

List two things phytoplankton need to survive. Name at least two special adaptations phytoplankton have to stay in the photic zone.

Answer 1

Sunlight and Water (from which they derive nutrients) are the two basic things that phytoplankton need to survive.

To stay in the photic zone, they need to be light-weight. Some adaptations for this are: Projections - which increase their surface area leading to decreased rate of descent (seen on forams and radiolarians.)

Diatoms are made of silica which is a lightweight material.

Some have flagella, for e.g. dinoflagellates use two flagella to move about the water column and move towards areas of higher UVA/UVB concentrations.