Ocean acidification can interact with ontogeny to determine the trace element composition of bivalve shell

We sought to determine how p CO 2 will affect the incorporation of trace elements into bivalve shell. This was to validate that under high p CO 2 conditions reconstruction of animal movements is still viable; and to investigate potential trace element proxies for ocean carbonate chemistry. Here, we examined shell of the bivalve Perna canaliculus formed under current CO 2 ( p CO2 = 400 μatm) conditions and those predicted to exist in 2100 ( p CO2 = 1050 μatm). Seventeen trace element:calcium ratios were examined at two locations within shells. Elements that are typically most useful in determining connectivity patterns (e.g., Sr, Mn, Ba, Mg, B) were not affected by p CO 2 in shell produced early in individual's lives. This suggests that the effects of ocean acidification on dispersal signatures may be dampened. However, cobalt, nickel, and titanium levels were influenced by p CO 2 consistently across shells suggesting their role as potential indicators of CO 2 level.