A new requirement to reduce sulfur emissions into the air from ships could be met by using low-sulfur fuel, or by scrubbers, and the cheap scrubbers dump the sulfur in the water.

Dumping substantial quantities of sulfur residue in the small area of a port could cause local harm, but if the dumping occurs in the open sea, will it have any significant effect on the sea? The answer is not obvious to me -- what do scientists say?