The University of Southern Maine is hosting a daylong conference about the impact of ocean acidification on the state’s coastal waters.

The National Oceanic and Atmospheric Administration describes ocean acidification as a change to the chemistry of the ocean over an extended period of time primarily as a result of the absorption of carbon dioxide from the atmosphere. Some environmentalists refer to it as the “evil twin” of global warming.

Wednesday’s conference is scheduled to run from 8 a.m. to 5 p.m. at Hannaford Hall in the Abromson Center.

Speakers will include Libby Jewett, director of NOAA’s Ocean Acidification Program. There also will be a discussion of the impact of ocean acidification on commercially important marine species such as shellfish.

Organizers say at least 100 researchers, legislators and residents plan to attend.