What does bioaccumulation refer to?

Bioaccumulation refers to the process by which certain substances, such as heavy metals or persistent organic pollutants, accumulate in the tissues of living organisms faster than they can be eliminated. Over time, these chemicals are taken up from the environment through various means, such as ingestion or absorption, leading to increasingly higher concentrations in the organisms' bodies. This accumulation can occur at different trophic levels, impacting not only individual organisms but entire ecosystems.

In contrast, the other options do not accurately describe bioaccumulation. The increase of animal populations pertains to ecology and population dynamics, while the transition of energy through a food web describes energy flow, not chemical accumulation. Lastly, migration patterns relate to organism movement rather than the concentration of chemicals within their bodies.