Palmer LTER Long-Term Plan

Table  1.  Goals  of  seasonal  sampling:   Investigate  hy-
pothesized  temporal  linkages among physical factors (solar
radiation, atmospheric  forcing,  oceanic  circulation,  sea
ice)  and biological processes at all trophic levels and the
linkages among trophic levels.  These linkages include  both
long-term  and  short-term  ecological processes.  These are
the hypotheses from the proposal that  are  being  addressed
with the core data sets.

Hypothesis
H1:  Total annual production is dominated by the  high  pri-
mary  production rates associated with the spring bloom; the
development and community composition  of  these  blooms  is
timed  and paced by ice-driven water column stability and/or
meteorological conditions.

Data Sets Required
-  weather (storms, precipitation, temperature etc.)
-  sea ice dynamics (regional and local)
-  surface layer hydrography and optical characteristics
-  accumulation of phytoplankton biomass
-  phytoplankton composition over season
-  rates of primary production (simulated in situ)
-  macronutrient concentrations

Hypothesis
H2:  During an above average ice year  the  accumulation  of
phytoplankton  biomass and export of organic matter are pri-
marily regulated by zooplankton processes, whereas during  a
below average ice year, phytoplankton processes dominate.

Data Sets Required
-  all as for H1
-  acoustic biomass and demographic characteristics of
zooplankton grazers
-  response of grazers to phytoplankton community (derived
from experiments)
-  characteristics of material in sediment trap near station

Hypothesis
H3:  Increased primary production (food) in a  greater  than
normal  sea  ice  year will lead to higher condition factor,
optimal growth rates and higher recruitment success  in  An-
tarctic  krill.  Condition factor of young krill immediately
after winter is an index of winter conditions, whereas  dur-
ing spring reflects spring nutrition.

Data Sets Required
-  sea ice dynamics (regional and local)
-  accumulation of phytoplankton biomass
-  phytoplankton composition in 'blooms'
-  acoustic biomass and demographic characteristics of
Antarctic krill
-  condition factor and growth rates of young of the year
krill, both in the field and under controlled conditions in
the laboratory

Hypothesis
H4:  The magnitude and direction of change in Adelie  penguin
populations reflects the coincident availability of suitable
nesting and foraging habitats, and their effects  on  repro-
duction, survival and recruitment.

Data Sets Required
-  weather (storms, precipitation, temperature etc)
-  acoustic biomass and characteristics of aggregations
of Antarctic krill throughout the spring and summer
-  breeding biology and foraging ecology of Adelie penguins