IOWA CITY, Iowa (AP) -

Regent Bruce Rastetter told University of Iowa President Sally Mason that ethanol lobbyists wanted to educate an "uninformed" professor who warned that water-intensive ethanol production was depleting the water supply.

The Jan. 30 email is another example in which critics say Rastetter, an ethanol backer and top donor to Gov. Terry Branstad, is meddling in research.

Rastetter's email targeted Jerald Schnoor, co-founder of Iowa's Center for Global and Regional Environmental Research.

Schnoor recently warned that ethanol production was using large amounts of water and "unsustainably pumping down" aquifers.

Monte Shaw, executive director of the Iowa Renewable Fuels Association, sent an email calling Schnoor "an embarrassment." Rastetter forwarded Shaw's email to Mason, saying -- quote -- "the industry would appreciate being able to provide factual information so this professor isn't uninformed."