TITLE:    Southern Ocean: fraction of total water column biomass 
          and primary productivity within the upper optical 
	  attenuation length
AUTHOR:   MA Moline and BB Prezelin
DATE:     10-14 February 1997 
PLACE:    ASLO, Aquatic Sciences Meeting, Santa Fe, New Mexico
          Talk
ABSTRACT:  

The depth distribution of chlorophyll-a (chl-a) and primary
productivity were determined every 2-4 days at two coastal stations
near Palmer Station, Antarctica for three consecutive spring/summer
periods between 1991 and 1994.  Comparison of results indicated depth
distribution patterns were highly variable on several time scales and
not repeated from one year to the next.  The fraction of total water
column biomass and primary productivity located within the upper
optical attenuation length (K-1par) varied up to 9-fold (6% to 53%)
within and between years.  A significant decrease in the fraction
occurred during a large diatom bloom (> 450 mg Chl-a m-2) in 1991-1992
when < 7% of the water column biomass was in K-1par and > 70% of the
water column chl-a was below the 1% Qpar light level.  The fraction of
total water column biomass and productivity within the depth of K-1par
were highest during mid summer periods when cryptophyte populations
dominated the surface waters.  The implications of the variability in
this region for interpretation of remotely sensed phytoplankton
biomass and primary production will be discussed.