Situation Report, Cruise NBP96-4A;    October 22, 1996, 0800 GMT


     The AESOPS Process Study I began science operations in earnest
this week, and at this time have completed 26 CTD (hydrographic and
trace metal clean) casts, eight MOCNESS tows, eight trace metal casts,
two in situ deployments, eight in situ pumping casts, and six ring net
tows.  We began our work at Site Orca (76 deg. 30 min. S, 178 deg. W)
with a long (ca. 30 h) station with multiple operations, and have
transited across the southern Ross Sea towards the coast.  We occupied
stations every two degrees along 76 deg. 30 min. S and completed
multiple operations at each station.  The transect will end tomorrow at
Site Minke (76 deg. 30 min.  S, 168 deg. E), where another long station
will be conducted.

     The weather has been variable at our stations, with temperatures
ranging between -12 and -25 deg. C, and winds between 6 and 50 knots. 
Wind chill factors have reached -77, conditions which can be hazardous to
the health of workers.  These circumstances have also created difficult
operational conditions.  For example, we have had difficulties with all
water casts, in that either the bottles and spigots themselves or the
winches used to raise and lower the bottles have frozen to some
degree.  Water temperatures are at the freezing point of seawater, and
hence any heat loss initiates frazil ice formation.  Samples incubated
for rate processes have begun freezing immediately upon removal from
incubators.

     Despite these conditions, we have begun to characterize the carbon
dynamics of the region.  Ice cover remains substantial, although in some
areas the ice is only ca. 0.4 m thick.  Noon-time irradiances are high
(>1,000 uE/m2/sec), but surface layer light levels are only 30% of those
values.  The water column is unstratified, and at at least one station 
the mixed layer extended from the surface to the bottom.  Nutrient
concentrations are high and do not reflect any biological removal. 
Chlorophyll levels were low (ca. 0.1 ug/l), and rates of production were
correspondingly low.  The phytoplankton appear to be dominated by
flagellated forms of Phaeocystis.  Zooplankton and bacterial biomass also
was low.  These conditions apparently represent those commonly found at
the start of the annual phytoplankton bloom in the Ross Sea.

     After the completion of station work at Site Minke, we will return
to Site Orca for our second occupation of that location, and then will
transit south towards the Ross Ice Shelf, where we expect to encounter
waters with reduced ice cover and increased biological activity.  We will
also assess these waters for trace metal and thorium concentrations. 
Occupation of these waters will provide a comparison with the late winter
conditions found along 76 deg. 30 min. S and a chance to sample an early
spring, ice-free environment.  The science party looks forward to this
opportunity.  

Submitted:     Walker Smith, Chief Scientist