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I am
a physiologist with research interests in the role and importance
of marine lipids, and how the biochemical characteristics of these
molecules fit into functional and evolutionary contexts in various
groups of marine organisms. Most marine vertebrates (including marine
mammals, large teleosts, and seabirds) have developed unique, highly
specialized adipose depots with specific functions. My laboratory
will use a combination of methods, including anatomical, histological,
and biochemical techniques, to examine three facets of the physiology
of marine animals: metabolism/health, specialized adaptations, and
phylogenetic lineage.
Of particular interest
are endogenously synthesized lipids, which can be essential components
of specialized adipose tissues and are often unique to certain groups
of animals. One example of these can be found in the lipid-rich
cranial adipose depots found in the heads of toothed whales, which
are associated with the transmission and reception of sound during
echolocation and hearing. One of my current projects involves comparing
the topographical variation in the lipid composition of the acoustic
fats of beaked whales, porpoises, and dolphins, to examine the question
of whether the processes of sound transmission and reception are
fundamentally different in these species. I am also interested in
the importance of waxes in the adipose tissues of marine animals
that spend significant time at depth: sperm whales, beaked whales,
myctophid fishes, and copepods. We do not yet understand the effects
that pressure and temperature have on lipid metabolism, nor do we
fully understand the basic synthetic pathways of wax esters in most
groups of animals. Why animals like beaked whales and myctophids
have developed such an unusual lipid synthesis pathway is a question
I plan to investigate using a comparative approach. In addition,
I also study basic patterns of lipid deposition and mobilization
in marine vertebrates. These animals all face the challenges of
energy storage, movement, reproduction and hydrodynamics. The ways
in which different types of lipids are partitioned within the body
in order to meet these challenges can provide valuable insight into
life history strategies, energetics, and specialized adaptations.
Koopman, H.N., Iverson, S.
J., and Read, A. J. 2003. High concentrations of isovaleric acid
in the fats of odontocetes: Stability in the melon vs. variation
and patterns of accumulation in blubber. Journal of Comparative
Physiology B 173: 247-261.
Koopman, H. N., Pabst,
D. A., McLellan, W. A., Dillaman, R. M., and Read, A. J. 2002. Changes
in blubber distribution and morphology associated with starvation
in the harbour porpoise (Phocoena phocoena): Evidence for
regional differences in blubber structure and function. Physiological
and Biochemical Zoology 75: 498-512.
McLellan, W. A., Koopman, H. N., Rommel,
S. A., Read, A. J., Potter, C. W., Nicolas, J. R., Westgate, A.
J., and Pabst, D. A. 2002. Ontogenetic allometry and body composition
of harbour porpoises (Phocoena phocoena L.) from the western
north Atlantic. Journal of Zoology, London 257:457-472.
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