Big surprise: A new study predicts that increased demand for ethanol will increase the pollution of the Chesapeake Bay.

A surge in the demand for ethanol -- touted as a greener alternative to gasoline -- could have a serious environmental downside for the Chesapeake Bay, because more farmers growing corn could mean more pollution washing off farm fields, a new study warned yesterday.

The study, whose sponsors included the U.S. government and an environmental group, predicted that farmers in the bay watershed will plant 500,000 or more new acres of corn in the next five years. Because fields of corn generally produce more polluted runoff than those of other crops, that's a problem.