Gibson has taken the new role of G3 editor, which oversees all four G3 products - Media, Education, Society and the science and online Life supplement.
A Guardian spokeswoman said the decision was taken partly for commercial reasons: "There was a need for someone to look entirely over the four products and think about making sure they remain the best in the market, particularly concerning classified advertisers."
In her new role, Gibson also retains an overseeing role of the Media Guardian, taking the title of editor-in-chief for that section. The paper will also launch a search for an editor to handle the day-to-day running of the supplement and to report to Gibson.
The spokeswoman stressed that while Gibson will work alongside staff at the online media.guardian.co.uk, she will not have an overseeing role.
Meanwhile, it has also been announced this week that Harriet Sherwood, foreign editor for the last ten years and Ed Pilkington, home editor for the last five years, are to swap roles. The changeover will take place at the beginning of June.
In a statement, Guardian editor Alan Rusbridger said the move was taken to give "each of them a new canvas to work on".
At a less senior level, the paper has also announced some changes to its foreign postings. Germany correspondent John Hooper is to become Italy correspondent for both The Guardian and the Economist. Also, the paper's Tokyo stringer Jonathan Watts is to become China correspondent.
These latest changes come a month after the paper recruited Evening Standard journalist Hugh Muir as a senior reporter.
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