Chlorophyll determined by extraction of samples taken approximately weekly from seawater intake starting at Palmer Station by station personnel including during winter-over period, 1995 - ongoing.

Chlorophyll a (Chl a) is the principal photosynthetic pigment of phytoplankton, and is used as a proxy measurent for estimating phytoplankton biomass in water samples. Chl a concentrations reflect the distribution of active phytoplankton spatially and with depth in the water column and their changes over time. Chl a is determined on every water sample collected at Palmer LTER Sttions B and E (October through March) and also weekly and year-round at the laboratory seawater intale (SWI), from a depth of 6 meters. Concentrations are typically very low (< 1 ug Chl a per liter) in winter (April-October), and higher (1-30 ug/L) following the initiation of the annual spring-summer phytopkankton bloom in November - January.