ABSTRACT
Representatives of the Antarctic food web (krill, cephalopod, fish, penguin, seal) of the area around Elephant Island and from the Weddell Sea were analysed for the most recalcitrant organochlorine compounds. Due to sorption of the compounds to sinking particles and accumulation in sediments, two benthic fish species (Gobionotothen gibberifrons, Chaenocephalus aceratus) feeding on benthos invertebrates and fish reflected significantly increasing concentrations within a decade (1987-1996), while a benthopelagic species (Champsocephalus gunnari) feeding on krill did not. In the pelagic food chain, lipid normalised concentrations of all compounds increased from Antarctic krill to fish proving that biomagnification of highly lipophilic pollutants (log octanol-water partition coefficient>5) occurs in water-breathing animals. As top predators Weddell and southern elephant seals (Leptonychotes weddellii, Mirounga leonina) biomagnified the persistent organic pollutants relative to krill 30-160 fold with the exception of hexachlorobenzene, the levels of which were lower than in fish indicating its intense specific elimination.
Subject(s)
Food Chain , Hydrocarbons/pharmacokinetics , Insecticides/pharmacokinetics , Water Pollutants, Chemical/pharmacokinetics , Amphipoda , Animals , Antarctic Regions , Birds , Environmental Monitoring , Fishes , Hydrocarbons/analysis , Insecticides/analysis , Mollusca , Seals, Earless , Tissue Distribution , Water Pollutants, Chemical/analysisABSTRACT
Adult lice (Antarctophthirus ogmorhini) from the Weddell seal Leptonychotes weddellii were investigated by means of light and scanning electron microscopy. We established that this species is characterized by several morphological peculiarities which enable it to survive the low temperatures of the Antarctic sea and the body depression which occurs during the deep (450 m) and long diving periods of the seals. The main peculiarities are: (1) the cuticle of the ventral and lateral surfaces is much thinner than that of the dorsal surface, (2) the body has numerous stiff spines which are covered by a thick layer of the seal's sebum that closely surrounds the body of the louse, (3) the whole body is covered by a close layer of leaf-like scales which are apparently able to trap air bubbles and thus to provide a small zone of air close to the surface of the cuticle.