Abstract :
[en] In sea turtles, parental investment is limited to the nutrients and energy invested in eggs that will support
embryonic development. Leatherback females have the largest clutches with the biggest eggs of the
sea turtles and the highest reproductive output in reptiles. The migration between foraging sites and
nesting beaches also represents high energy expenditure. The toxicokinetic of pollutants in the tissues
is thus expected to vary during those periods but there is a lack of information in reptiles. Concentrations
of essential (Copper, Zinc, Selenium) and non-essentials elements (Cadmium, Lead, Mercury) were
determined in blood (n = 78) and eggs (n = 76) of 46 free-ranging leatherback females collected in French
Guiana. Maternal transfer to eggs and relationships between blood and eggs concentrations during the
nesting seasonwere investigated. All trace elementswere detectable in both tissues. Levels of toxic metals
were lower than essential elements likely due to the high pelagic nature of leatherbacks that seems to
limit exposure to toxic elements. Significant relationships between blood and egg concentrations were
observed for Se and Cd. Se could have an important role in embryonic development of leatherback turtles
and Cd transfer could be linked to similar carrier proteins as Se. Finally, as multiple clutcheswere sampled
from each female, trends in trace elements were investigated along the nesting season. No change was
observed in eggs but changeswere recorded in blood concentrations of Cu. Cu level decreased while blood
Pb levels increased through the nesting season. The high demand on the body during the breeding season
seems to affect blood Cu concentrations. Calcium requirement for egg production with concomitant Pb
mobilization could explain the increase in blood Pb concentrations along the nesting season.
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