Study Links Port Traffic to Shifting Port-Water Bacteria

A global study of port waters has found that shipping activity, port size and wastewater discharges play a significant role in shaping bacterial communities, highlighting environmental pressures facing some of the world’s busiest maritime gateways.

Researchers analysed more than 1,000 water samples from 23 ports in eight countries across five continents, examining over 16.5 million DNA sequences. Port capacity emerged as the strongest factor associated with changes in bacterial communities and a higher abundance of potential pathogens, while wastewater discharge was linked to reduced bacterial diversity.

The researchers identified 295 potential pathogenic bacterial variants, about 6% of sequences analysed, and said the findings strengthen the case for tighter ballast water management, improved wastewater treatment and routine microbial monitoring as ports expand and vessel traffic grows.