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

Abstract

We sought to determine how pCO2 will affect the incorporation of trace elements into bivalve shell. This was to validate that under high pCO2 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 CO2 (pCO2 = 400 μatm) conditions and those predicted to exist in 2100 (pCO2 = 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 pCO2 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 pCO2 consistently across shells suggesting their role as potential indicators of CO2 level.