Comparative investigations on the metabolomic responses to cadmium in clams Ruditapes philippinarum from the Bohai Sea and South China Sea.

Cadmium (Cd) is a typical heavy metal contaminant along China coasts. Clams Ruditapes philippinarum are widely distributed in multiple climatic zones. However, few research has been conducted on the different responses to Cd in clams from different climatic zones. In this study, the temperate zone Bohai Sea (BS) and tropical zone South China Sea (SCS) clams exhibited distinct background metabolome profiles, characterized by different strategies of osmotic regulation, energy metabolism, and anaerobiosis tendencies, suggesting different tolerance and enrichment capacities to Cd. After Cd treatments, the BS clams demonstrated quicker and higher accumulations of Cd than the SCS clams. Despite differences in their background metabolomes, both BS and SCS clams displayed similar metabolomic responses to Cd, such as anaerobiosis inhibition and increased energy demands. Overall, these findings suggested that the inconsistency of biological responses induced by geographic conditions should be considered in ecotoxicological studies. CAPSULE ABSTRACT: This study elucidated the biological differences in clams Ruditapes philippinarum from the Bohai Sea and South China Sea, and the metabolomic responses in these two clam populations after Cd (200 μg/L) treatments.