TITLE:   Krill energetics: seasonal and environmental aspects of the
         physiology of Euphausia superba
AUTHOR:  Langdon Quetin, Robin M Ross, A Clarke

Palmer LTER Contribution (none)

ABSTRACT: The BIOMASS Programme (1976-91) has promoted the most intensive
study of the ecology of the antarctic kirll, Euphausia superba Dana,
since the pioneering work of the Discovery Investigations from 1926
onwards for 14 years.  The Discovery investigators learned much about
the distribution of krill during its life cycle and in relation to the
physical characteristics of its environment.  For example, krill were
found patchily distributed in the Southern Ocean, confinded almost
exclusively to regions south of the Antarctic Convergence, and
seasonally associated with pack-ice.  Based on catches of embryos and
early larvae deep in the water column and later larval stages at the
surface the developmental ascent of the larval stages of krill was
described.  Nonfeeding larval stages were found to spend considerable
time in Circumpolar Deep Water.  Adult krill were found to be
herbivores and to exist primarily in patches or swarms near the
surface.  Spawning was associated principally with shelf or slope
waters with hatching occurring in the open sea over deeper water.  The
above are just a few examples of the abundant and valuable information
gained during the Discovery Investigations.  The BIOMASS era has
greatly added to and expanded upon the arlier observations of the
Discovery investigators.  A significant advance during the BIOMASS
period has been the development of physiological and biochemical
studies of krill.  These studies not only have an intrinsic value in
attempting to understand the energetics of a pelagic organism living
at low temperatures in high latitudes; they also provide necessary
data for integration of krill dynamics within large-scale models of
the pelagic system of the Southern Ocean
  In this chapter we review current knowledge of the energetics of
Euphausia superba, emphasizing those topics where knowledge has
developed since the previous review by Clarke and Morris (1983).  We
base our discussion around the energy budget, and progress from
topics of uncertainty and debate to topics with more general
agreement.  We conclude with a discussion of the more ecological
aspects of the interface between the energetics and the environment
of krill.  Our review is thus complementary to the recent major
review of krill biology by Miller & Hampton (1989).