Recent worksuggests that diatoms predominate during May in the Barents Sea while coccolithophores bloom in August. The above MODIS scene, collected on July 10, 2014, may show those arctic waters in transition between greener diatom-dominated and milkier coccolithophore-dominated waters.
Ocean colors in the above image represent remote-sensing reflectance in the red, green, and blue portions of the spectrum. Green and blue reflectances have been scaled the same way, but the red reflectance has been scaled brighter to accentuate differences in this relatively dark portion of the spectrum. (Note that positive identification of phytoplankton species is not possible from these data alone; sea-surface sampling would be required for that.)
Click on the above image for a broader view, or get a full-resolution version (8 megabytes).