In this study, we used HPLC based measurement of the relative
abundance of different phytoplankton groups (Mackey et al., 1996)
associated with microscopic observations (Utermöhl, 1958) to confirm
the calculated results, especially the dominated group and species.
Seawater samples for phytoplankton pigment analysis (4–10 L, based
on biomass) were filtered through 47 mm GF/F glass fiber filters
(under a vacuum pressure less than 75 mm Hg and in dim light).
Pigment samples stored in liquid nitrogen during the cruise, and
transferred to a deep freezer (−80 °C) in the laboratory.