Baseline Levels of Selected Minerals and Fat-Soluble Vitamins in Weddell Seals (Leptonychotes weddellii) from Erebus Bay, McMurdo Sound, Antarctica

摘要

The mineral and vitamin concentrations in animal tissues are a reflection of the essential amounts of these substances necessary for enzymatic and metabolic pathways, coupled with any excess picked up from the environment in which the animal resides. To recognize this excess, the baseline or 'starting point' levels must first be established (Anderlini et al., 1972; Steinhagen-Schneider, 1986). In organisms inhabiting the Antarctic ecosystem, the measured concentrations may actually approximate baseline values if environmental or anthropogenic inputs are low. By virtue of its status as an upper trophic level predator, a long-lived organism, and the southern-most breeding mammal in the world, the Weddell seal (Leptonychotes weddellii) has been identified as a possible indicator of pollutants in the Antarctic environment (Wagemann and Muir, 1984; Yamamoto et al., 1987; Szefer et al., 1994). However, the existing data are limited by small sample sizes (Schneider et al., 1985 (9 individuals); Steinhagen-Schneider, 1986 (8); Yamamoto et al., 1987 (3); Szefer et al., 1993 (1 animal)). Additionally, the tendencies for some trace metals to bioaccumulate in seal tissues over time (Thompson, 1990) or to negatively correlate with age (Holden, 1978) imply that accurate estimates of animal age may be necessary prerequisites to interpreting trace metal loads, and the studies cited above did not include estimates of the ages of the individuals.